Cardiac arrhythmias that are characterized by excessively slow HEART RATE, usually below 50 beats per minute in human adults. They can be classified broadly into SINOATRIAL NODE dysfunction and ATRIOVENTRICULAR BLOCK.
The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
A transient absence of spontaneous respiration.
The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).
Abnormally low BLOOD PRESSURE that can result in inadequate blood flow to the brain and other vital organs. Common symptom is DIZZINESS but greater negative impacts on the body occur when there is prolonged depravation of oxygen and nutrients.
An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
The small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (VENA CAVA, SUPERIOR) and right atrium. Contraction impulses probably start in this node, spread over the atrium (HEART ATRIUM) and are then transmitted by the atrioventricular bundle (BUNDLE OF HIS) to the ventricle (HEART VENTRICLE).
PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.
Irregular HEART RATE caused by abnormal function of the SINOATRIAL NODE. It is characterized by a greater than 10% change between the maximum and the minimum sinus cycle length or 120 milliseconds.
Change of heartbeat induced by pressure on the eyeball, manipulation of extraocular muscles, or pressure upon the tissue remaining in the orbital apex after enucleation.
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
Impaired conduction of cardiac impulse that can occur anywhere along the conduction pathway, such as between the SINOATRIAL NODE and the right atrium (SA block) or between atria and ventricles (AV block). Heart blocks can be classified by the duration, frequency, or completeness of conduction block. Reversibility depends on the degree of structural or functional defects.
Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.
An activity in which the organism plunges into water. It includes scuba and bell diving. Diving as natural behavior of animals goes here, as well as diving in decompression experiments with humans or animals.
Biguanides are a class of oral hypoglycemic agents, including metformin, which primarily reduce blood glucose levels by decreasing hepatic gluconeogenesis and increasing insulin sensitivity, but not by stimulating insulin secretion, and they are commonly used in the treatment of type 2 diabetes.
A condition caused by dysfunctions related to the SINOATRIAL NODE including impulse generation (CARDIAC SINUS ARREST) and impulse conduction (SINOATRIAL EXIT BLOCK). It is characterized by persistent BRADYCARDIA, chronic ATRIAL FIBRILLATION, and failure to resume sinus rhythm following CARDIOVERSION. This syndrome can be congenital or acquired, particularly after surgical correction for heart defects.
A response by the BARORECEPTORS to increased BLOOD PRESSURE. Increased pressure stretches BLOOD VESSELS which activates the baroreceptors in the vessel walls. The net response of the CENTRAL NERVOUS SYSTEM is a reduction of central sympathetic outflow. This reduces blood pressure both by decreasing peripheral VASCULAR RESISTANCE and by lowering CARDIAC OUTPUT. Because the baroreceptors are tonically active, the baroreflex can compensate rapidly for both increases and decreases in blood pressure.
A transient loss of consciousness and postural tone caused by diminished blood flow to the brain (i.e., BRAIN ISCHEMIA). Presyncope refers to the sensation of lightheadedness and loss of strength that precedes a syncopal event or accompanies an incomplete syncope. (From Adams et al., Principles of Neurology, 6th ed, pp367-9)
A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external).
Abnormally rapid heartbeat, usually with a HEART RATE above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia.
A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures.
The interruption or removal of any part of the vagus (10th cranial) nerve. Vagotomy may be performed for research or for therapeutic purposes.
Analogs and derivatives of atropine.
The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).
The HEART and the BLOOD VESSELS by which BLOOD is pumped and circulated through the body.
Impaired impulse conduction from HEART ATRIA to HEART VENTRICLES. AV block can mean delayed or completely blocked impulse conduction.
Receptors in the vascular system, particularly the aorta and carotid sinus, which are sensitive to stretch of the vessel walls.
Loss of consciousness due to a reduction in blood pressure that is associated with an increase in vagal tone and peripheral vasodilation.
Cells specialized to detect chemical substances and relay that information centrally in the nervous system. Chemoreceptor cells may monitor external stimuli, as in TASTE and OLFACTION, or internal stimuli, such as the concentrations of OXYGEN and CARBON DIOXIDE in the blood.
The hollow, muscular organ that maintains the circulation of the blood.
The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.
Any disturbances of the normal rhythmic beating of the heart or MYOCARDIAL CONTRACTION. Cardiac arrhythmias can be classified by the abnormalities in HEART RATE, disorders of electrical impulse generation, or impulse conduction.
Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.
A condition characterized by abnormal posturing of the limbs that is associated with injury to the brainstem. This may occur as a clinical manifestation or induced experimentally in animals. The extensor reflexes are exaggerated leading to rigid extension of the limbs accompanied by hyperreflexia and opisthotonus. This condition is usually caused by lesions which occur in the region of the brainstem that lies between the red nuclei and the vestibular nuclei. In contrast, decorticate rigidity is characterized by flexion of the elbows and wrists with extension of the legs and feet. The causative lesion for this condition is located above the red nuclei and usually consists of diffuse cerebral damage. (From Adams et al., Principles of Neurology, 6th ed, p358)
An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION.
Agents that inhibit the actions of the parasympathetic nervous system. The major group of drugs used therapeutically for this purpose is the MUSCARINIC ANTAGONISTS.
The dilated portion of the common carotid artery at its bifurcation into external and internal carotids. It contains baroreceptors which, when stimulated, cause slowing of the heart, vasodilatation, and a fall in blood pressure.
The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system.
The placing of a body or a part thereof into a liquid.
The ENTERIC NERVOUS SYSTEM; PARASYMPATHETIC NERVOUS SYSTEM; and SYMPATHETIC NERVOUS SYSTEM taken together. Generally speaking, the autonomic nervous system regulates the internal environment during both peaceful activity and physical or emotional stress. Autonomic activity is controlled and integrated by the CENTRAL NERVOUS SYSTEM, especially the HYPOTHALAMUS and the SOLITARY NUCLEUS, which receive information relayed from VISCERAL AFFERENTS.
Poisoning caused by ingestion of SEAFOOD containing microgram levels of CIGUATOXINS. The poisoning is characterized by gastrointestinal, neurological and cardiovascular disturbances.
Physiological integration of multiple SYNAPTIC POTENTIAL signals to reach the threshold and initiate postsynaptic ACTION POTENTIALS. In spatial summation stimulations from additional synaptic junctions are recruited to generate s response. In temporal summation succeeding stimuli signals are summed up to reach the threshold. The postsynaptic potentials can be either excitatory or inhibitory (EPSP or IPSP).
GRAY MATTER located in the dorsomedial part of the MEDULLA OBLONGATA associated with the solitary tract. The solitary nucleus receives inputs from most organ systems including the terminations of the facial, glossopharyngeal, and vagus nerves. It is a major coordinator of AUTONOMIC NERVOUS SYSTEM regulation of cardiovascular, respiratory, gustatory, gastrointestinal, and chemoreceptive aspects of HOMEOSTASIS. The solitary nucleus is also notable for the large number of NEUROTRANSMITTERS which are found therein.
Agents used for the treatment or prevention of cardiac arrhythmias. They may affect the polarization-repolarization phase of the action potential, its excitability or refractoriness, or impulse conduction or membrane responsiveness within cardiac fibers. Anti-arrhythmia agents are often classed into four main groups according to their mechanism of action: sodium channel blockade, beta-adrenergic blockade, repolarization prolongation, or calcium channel blockade.
The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.
A malignant form of polymorphic ventricular tachycardia that is characterized by HEART RATE between 200 and 250 beats per minute, and QRS complexes with changing amplitude and twisting of the points. The term also describes the syndrome of tachycardia with prolonged ventricular repolarization, long QT intervals exceeding 500 milliseconds or BRADYCARDIA. Torsades de pointes may be self-limited or may progress to VENTRICULAR FIBRILLATION.
The heart rate of the FETUS. The normal range at term is between 120 and 160 beats per minute.
The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.
Cessation of heart beat or MYOCARDIAL CONTRACTION. If it is treated within a few minutes, heart arrest can be reversed in most cases to normal cardiac rhythm and effective circulation.
Drugs that inhibit the actions of the sympathetic nervous system by any mechanism. The most common of these are the ADRENERGIC ANTAGONISTS and drugs that deplete norepinephrine or reduce the release of transmitters from adrenergic postganglionic terminals (see ADRENERGIC AGENTS). Drugs that act in the central nervous system to reduce sympathetic activity (e.g., centrally acting alpha-2 adrenergic agonists, see ADRENERGIC ALPHA-AGONISTS) are included here.
Small clusters of chemoreceptive and supporting cells located near the ARCH OF THE AORTA; the PULMONARY ARTERIES; and the CORONARY ARTERIES. The aortic bodies sense PH; CARBON DIOXIDE; and OXYGEN concentrations in the BLOOD and participate in the control of RESPIRATION. The aortic bodies should not be confused with the PARA-AORTIC BODIES in the abdomen (which are sometimes also called aortic bodies).
The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.
Complications that affect patients during surgery. They may or may not be associated with the disease for which the surgery is done, or within the same surgical procedure.
Polycyclic ethers produced by Gambierdiscus (DINOFLAGELLATES) from gambiertoxins, which are ingested by fish which in turn may be ingested by humans who are susceptible to the CIGUATERA POISONING.
A standard and widely accepted diagnostic test used to identify patients who have a vasodepressive and/or cardioinhibitory response as a cause of syncope. (From Braunwald, Heart Disease, 7th ed)
Sense of awareness of self and of the environment.
A cardioselective beta-1 adrenergic blocker possessing properties and potency similar to PROPRANOLOL, but without a negative inotropic effect.
PROCEDURES that use NEUROENDOSCOPES for disease diagnosis and treatment. Neuroendoscopy, generally an integration of the neuroendoscope with a computer-assisted NEURONAVIGATION system, provides guidance in NEUROSURGICAL PROCEDURES.
Processes and properties of the CARDIOVASCULAR SYSTEM as a whole or of any of its parts.
Procedure in which an anesthetic is injected directly into the spinal cord.
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety.
A muscarinic antagonist used as an antispasmodic, in some disorders of the gastrointestinal tract, and to reduce salivation with some anesthetics.
An alpha-1 adrenergic antagonist that is commonly used as an antihypertensive agent.
Drugs that bind to but do not activate MUSCARINIC RECEPTORS, thereby blocking the actions of endogenous ACETYLCHOLINE or exogenous agonists. Muscarinic antagonists have widespread effects including actions on the iris and ciliary muscle of the eye, the heart and blood vessels, secretions of the respiratory tract, GI system, and salivary glands, GI motility, urinary bladder tone, and the central nervous system.
'Infant, Premature, Diseases' refers to health conditions or abnormalities that specifically affect babies born before 37 weeks of gestation, often resulting from their immature organ systems and increased vulnerability due to preterm birth.
A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.

Effect of the cannabinoid receptor agonist WIN55212-2 on sympathetic cardiovascular regulation. (1/860)

1. The aim of the present study was to analyse the cardiovascular actions of the synthetic CB1/CB2 cannabinoid receptor agonist WIN55212-2, and specifically to determine its sites of action on sympathetic cardiovascular regulation. 2. Pithed rabbits in which the sympathetic outflow was continuously stimulated electrically or which received a pressor infusion of noradrenaline were used to study peripheral prejunctional and direct vascular effects, respectively. For studying effects on brain stem cardiovascular regulatory centres, drugs were administered into the cisterna cerebellomedullaris in conscious rabbits. Overall cardiovascular effects of the cannabinoid were studied in conscious rabbits with intravenous drug administration. 3. In pithed rabbits in which the sympathetic outflow was continuously electrically stimulated, intravenous injection of WIN55212-2 (5, 50 and 500 microg kg(-1)) markedly reduced blood pressure, the spillover of noradrenaline into plasma and the plasma noradrenaline concentration, and these effects were antagonized by the CB1 cannabinoid receptor-selective antagonist SR141716A. The hypotensive and the sympathoinhibitory effect of WIN55212-2 was shared by CP55940, another mixed CB1/CB2 cannabinoid receptor agonist, but not by WIN55212-3, the enantiomer of WIN55212-2, which lacks affinity for cannabinoid binding sites. WIN55212-2 had no effect on vascular tone established by infusion of noradrenaline in pithed rabbits. 4. Intracisternal application of WIN55212-2 (0.1, 1 and 10 microg kg(-1)) in conscious rabbits increased blood pressure and the plasma noradrenaline concentration and elicited bradycardia; this latter effect was antagonized by atropine. 5. In conscious animals, intravenous injection of WIN55212-2 (5 and 50 microg kg(-1)) caused bradycardia, slight hypotension, no change in the plasma noradrenaline concentration, and an increase in renal sympathetic nerve firing. The highest dose of WIN55212-2 (500 microg kg(-1)) elicited hypotension and tachycardia, and sympathetic nerve activity and the plasma noradrenaline concentration declined. 6. The results obtained in pithed rabbits indicate that activation of CB1 cannabinoid receptors leads to marked peripheral prejunctional inhibition of noradrenaline release from postganglionic sympathetic axons. Intracisternal application of WIN55212-2 uncovered two effects on brain stem cardiovascular centres: sympathoexcitation and activation of cardiac vagal fibres. The highest dose of systemically administered WIN55212-2 produced central sympathoinhibition; the primary site of this action is not known.  (+info)

Hypoxia inhibits baroreflex vagal bradycardia via a central action in anaesthetized rats. (2/860)

It is known that arterial baroreflexes are suppressed in stressful conditions. The present study was designed to determine whether and how hypoxia affects arterial baroreflexes, especially the heart rate component, baroreflex vagal bradycardia. In chloralose-urethane-anaesthetized rats, baroreflex vagal bradycardia was evoked by electrical stimulation of the aortic depressor nerve, and the effect of 15 s inhalation of hypoxic gas (4% O2) was studied. Inhalation of hypoxic gas was found to inhibit baroreflex vagal bradycardia. The inhibition persisted after bilateral transection of the carotid sinus nerve. Cervical vagus nerves were cut bilaterally and their peripheral cut ends were stimulated to provoke vagal bradycardia of peripheral origin so as to determine whether hypoxia could inhibit vagal bradycardia by acting on a peripheral site. In contrast to baroreflex vagal bradycardia, the vagus-induced bradycardia was not affected by hypoxic gas inhalation. It is concluded that baroreflex vagal bradycardia is inhibited by hypoxia and the inhibition is largely mediated by its direct central action.  (+info)

Pseudo second degree atrioventricular block with bradycardia. Successful treatment with quinidine. (3/860)

Pseudo second degree atrioventricular block resulting from blocked His premature beats was successfully treated with quinidine. The diagnosis was proved by His bundle electrogam which showed both blocked and conducted His premature beats. The blocked His prematures produced second degree atrioventricular block by making the atrioventricular junction refractory. Quinidine abolished both conducted and blocked His extrasystoles. There has been no recurrence of arrhythmia during a one-year follow-up.  (+info)

Incidence of bradycardia during recovery from spinal anaesthesia: influence of patient position. (4/860)

We administered 0.5% plain bupivacaine 4 ml intrathecally (L2-3 or L3-4) in three groups of 20 patients, according to the position in which they were nursed in the post-anaesthesia care unit (PACU): supine horizontal, 30 degrees Trendelenburg or hammock position (trunk and legs 30 degrees elevated). Patients were observed until anaesthesia descended to less than S1. The incidence of severe bradycardia (heart rate < 50 beat min-1) in the PACU was significantly higher in patients in the Trendelenburg position (60%) than in the horizontal (20%, P < 0.01) or hammock (10%, P < 0.005) position. After 90 min, following admission to the PACU, only patients in the hammock position did not have severe bradycardia. In this late phase, the incidence of severe bradycardia in the Trendelenburg group was 35% (P < 0.005) and 10% in patients in the supine horizontal position. In four patients, severe bradycardia first occurred later than 90 min after admission to the PACU. The latest occurrence of severe bradycardia was recorded 320 min after admission to the PACU. We conclude that for recovery from spinal anaesthesia, the Trendelenburg position should not be used and the hammock position is preferred.  (+info)

Relation between mode of pacing and long-term survival in the very elderly. (5/860)

OBJECTIVES: This study analyzes the relationship between pacing mode and long-term survival in a large group of very elderly patients (> or = 80 years old). BACKGROUND: The relationship between pacing mode and long-term survival is not clear. Because the number of very elderly who are candidates for pacing is increasing, issues related to pacemaker (PM) use in the elderly have important clinical and economic implications. METHODS: We retrospectively reviewed 432 patients (mean age, 84.5+/-3.9 years) who received their initial PM (ventricular in 310 and dual chamber in 122) between 1980 and 1992. Follow-up was complete (3.5+/-2.6 years). Observed survival was estimated by the Kaplan-Meier method. Age- and gender-matched cohorts from the Minnesota population were used for expected survival. Log-rank test and Cox regression hazard model were used for univariate and multivariate analyses. RESULTS: Patients with ventricular PMs appeared to have poor overall survival compared with those with dual-chamber PMs. Observed survival after PM implantation in high grade atrioventricular block (AVB) patients was significantly worse than expected survival of the age- and gender-matched population (p < 0.0001), whereas observed survival of patients with sinus node dysfunction was not significantly different from expected survival of the matched population (p = 0.413). By univariate analysis, ventricular pacing in patients with AVB appeared to be associated with poor survival compared with dual-chamber pacing (hazard ratio [HR] 2.08; 95% confidence interval [CI] 1.33 to 3.33). After multivariate analysis, this difference was no longer significant (HR 1.41; 95% CI 0.88 to 2.27). Independent predictors of all-cause mortality were number of comorbid illnesses, New York Heart Association functional class, left ventricular depression and older age at implant. Pacing mode was not an independent predictor of overall survival. Older age at implantation, diabetes mellitus, dementia, history of paroxysmal atrial fibrillation and earlier year of implantation were independent predictors of ventricular pacemaker selection. CONCLUSIONS: After PM implantation, long-term survival among very elderly patients was not affected by pacing mode after correction of baseline differences. Selection bias was present in pacing mode in the very elderly, with ventricular pacing selected for sicker and older patients, perhaps partly explaining the apparent "beneficial impact on survival" observed with dual-chamber pacing.  (+info)

Relative bradycardia is not a feature of enteric fever in children. (6/860)

We investigated pulse-temperature relationships in 66 children with enteric fever (group 1) and in 76 with other infections (group 2). Group 1 children were older than group 2 children (mean age +/- SD, 91 +/- 36 vs. 66 +/- 32 months, respectively; P < .001) and had mean oral temperatures +/- SD similar to those of group 2 children (38.3 +/- 1.0 vs. 38.3 +/- 0.9 degrees C, respectively; P > .2); however, group 1 children had lower mean baseline pulse rates +/- SD than did group 2 children (119 +/- 25 vs. 127 +/- 28 beats/min, respectively; P < .001). In a multiple linear regression model, pulse rate was independently associated with age (inversely; P < .001) and oral temperature (positively; P < .006) but not with diagnostic group or gender (P > .5). After adjustment of the mean initial pulse rate +/- SD to age of 72 months, there was no difference between group 1 and group 2 children (126 +/- 24 vs. 126 +/- 20 beats/min, respectively; P > .5). From 4 to 72 hours after commencement of treatment, the mean oral temperature in group 1 patients was approximately 0.3 degrees C higher than that in group 2 patients, and the age-adjusted pulse rate was 5 beats/min higher in group 1 children than in group 2 children. These data suggest that relative bradycardia is not characteristic of enteric fever in children.  (+info)

Estrogen enhancement of baroreflex sensitivity is centrally mediated. (7/860)

We have recently shown that estrogen enhances baroreceptor control of reflex bradycardia in conscious rats. The present study replicated this finding in pentobarbital sodium-anesthetized rats, and the study was extended to investigate whether this effect of estrogen is centrally or peripherally mediated. Hemodynamic responses to electrical stimulation of the central end of the aortic depressor or the vagal efferent nerve were evaluated in pentobarbital sodium-anesthetized sham-operated (SO), ovariectomized (OVX), and OVX estradiol-treated Sprague-Dawley rats. Phenylephrine (1-16 microgram/kg iv) elicited dose-dependent pressor and bradycardic responses. Regression analysis of the baroreflex curves, relating changes in mean arterial pressure and heart rate, revealed a significantly smaller baroreflex sensitivity in OVX compared with SO anesthetized rats (-0.54 +/- 0.05 and -0.91 +/- 0.12 beats. min-1. mmHg-1, respectively; P < 0.05). Treatment of OVX rats with 17beta-estradiol (E2, 50 microgram. kg-1. day-1 for 2 days subcutaneously) significantly enhanced baroreflex sensitivity to a level similar to that of SO rats (P < 0.05). The enhancing effect of E2 on the baroreflex-mediated bradycardia, observed in conscious and anesthetized rats, seems to be selective because the baroreflex-mediated tachycardic responses measured in a separate group of conscious rats were not altered by ovariectomy or E2 administration. Electrical stimulation of the aortic nerve elicited frequency-dependent depressor and bradycardic responses that were significantly smaller in OVX compared with SO values (P < 0.05). Treatment of OVX rats with E2 restored the hemodynamic responses to aortic stimulation to near SO levels. On the other hand, hemodynamic responses to vagal stimulation were not affected by OVX or treatment with E2. These findings suggest that enhancement of reflex bradycardia by estrogen is centrally mediated and involves interaction with central projections of the aortic nerve.  (+info)

Electrocardiographic abnormalities in a murine model injected with IgG from mothers of children with congenital heart block. (8/860)

BACKGROUND: It is a widely held view that congenital heart block (CHB) is caused by the transplacental transfer of maternal autoantibodies (anti-SSA/Ro and/or anti-SSB/La) into the fetal circulation. To test this hypothesis and to reproduce human CHB, an experimental mouse model (BALB/c) was developed by passive transfer of human autoantibodies into pregnant mice. METHODS AND RESULTS: Timed pregnant mice (n=54) were injected with a single intravenous bolus of purified IgG containing human anti-SSA/Ro and anti-SSB/La antibodies from mothers of children with CHB. To parallel the "window period" of susceptibility to CHB in humans, 3 groups of mice were used: 8, 11, and 16 days of gestation. Within each group, we tested 10, 25, 50, and 100 microg of IgG. At delivery, ECGs were recorded and analyzed for conduction abnormalities. Bradycardia and PR interval were significantly increased in 8-, 11-, and 16-day gestational groups when compared with controls (P<0.05). QRS duration was not significantly different between all groups. Antibody levels measured by ELISA in both mothers and their offspring confirmed the transplacental transfer of the human antibodies to the pups. CONCLUSIONS: The passive transfer model demonstrated bradycardia, first-degree but not complete atrioventricular block in pups. The greater percentage and degree of bradycardia and PR prolongation in the 11-day mouse group correlates with the "window period" of susceptibility observed in humans. The high incidence of bradycardia suggests possible sinoatrial node involvement. All together, these data provide relevant insights into the pathogenesis of CHB.  (+info)

Bradycardia is a medical term that refers to an abnormally slow heart rate, typically defined as a resting heart rate of less than 60 beats per minute in adults. While some people, particularly well-trained athletes, may have a naturally low resting heart rate, bradycardia can also be a sign of an underlying health problem.

There are several potential causes of bradycardia, including:

* Damage to the heart's electrical conduction system, such as from heart disease or aging
* Certain medications, including beta blockers, calcium channel blockers, and digoxin
* Hypothyroidism (underactive thyroid gland)
* Sleep apnea
* Infection of the heart (endocarditis or myocarditis)
* Infiltrative diseases such as amyloidosis or sarcoidosis

Symptoms of bradycardia can vary depending on the severity and underlying cause. Some people with bradycardia may not experience any symptoms, while others may feel weak, fatigued, dizzy, or short of breath. In severe cases, bradycardia can lead to fainting, confusion, or even cardiac arrest.

Treatment for bradycardia depends on the underlying cause. If a medication is causing the slow heart rate, adjusting the dosage or switching to a different medication may help. In other cases, a pacemaker may be necessary to regulate the heart's rhythm. It is important to seek medical attention if you experience symptoms of bradycardia, as it can be a sign of a serious underlying condition.

Heart rate is the number of heartbeats per unit of time, often expressed as beats per minute (bpm). It can vary significantly depending on factors such as age, physical fitness, emotions, and overall health status. A resting heart rate between 60-100 bpm is generally considered normal for adults, but athletes and individuals with high levels of physical fitness may have a resting heart rate below 60 bpm due to their enhanced cardiovascular efficiency. Monitoring heart rate can provide valuable insights into an individual's health status, exercise intensity, and response to various treatments or interventions.

Apnea is a medical condition defined as the cessation of breathing for 10 seconds or more. It can occur during sleep (sleep apnea) or while awake (wakeful apnea). There are different types of sleep apnea, including obstructive sleep apnea, central sleep apnea, and complex sleep apnea syndrome. Obstructive sleep apnea occurs when the airway becomes blocked during sleep, while central sleep apnea occurs when the brain fails to signal the muscles to breathe. Complex sleep apnea syndrome, also known as treatment-emergent central sleep apnea, is a combination of obstructive and central sleep apneas. Sleep apnea can lead to various complications, such as fatigue, difficulty concentrating, high blood pressure, heart disease, and stroke.

The vagus nerve, also known as the 10th cranial nerve (CN X), is the longest of the cranial nerves and extends from the brainstem to the abdomen. It has both sensory and motor functions and plays a crucial role in regulating various bodily functions such as heart rate, digestion, respiratory rate, speech, and sweating, among others.

The vagus nerve is responsible for carrying sensory information from the internal organs to the brain, and it also sends motor signals from the brain to the muscles of the throat and voice box, as well as to the heart, lungs, and digestive tract. The vagus nerve helps regulate the body's involuntary responses, such as controlling heart rate and blood pressure, promoting relaxation, and reducing inflammation.

Dysfunction in the vagus nerve can lead to various medical conditions, including gastroparesis, chronic pain, and autonomic nervous system disorders. Vagus nerve stimulation (VNS) is a therapeutic intervention that involves delivering electrical impulses to the vagus nerve to treat conditions such as epilepsy, depression, and migraine headaches.

Hypotension is a medical term that refers to abnormally low blood pressure, usually defined as a systolic blood pressure less than 90 millimeters of mercury (mm Hg) or a diastolic blood pressure less than 60 mm Hg. Blood pressure is the force exerted by the blood against the walls of the blood vessels as the heart pumps blood.

Hypotension can cause symptoms such as dizziness, lightheadedness, weakness, and fainting, especially when standing up suddenly. In severe cases, hypotension can lead to shock, which is a life-threatening condition characterized by multiple organ failure due to inadequate blood flow.

Hypotension can be caused by various factors, including certain medications, medical conditions such as heart disease, endocrine disorders, and dehydration. It is important to seek medical attention if you experience symptoms of hypotension, as it can indicate an underlying health issue that requires treatment.

A reflex is an automatic, involuntary and rapid response to a stimulus that occurs without conscious intention. In the context of physiology and neurology, it's a basic mechanism that involves the transmission of nerve impulses between neurons, resulting in a muscle contraction or glandular secretion.

Reflexes are important for maintaining homeostasis, protecting the body from harm, and coordinating movements. They can be tested clinically to assess the integrity of the nervous system, such as the knee-j jerk reflex, which tests the function of the L3-L4 spinal nerve roots and the sensitivity of the stretch reflex arc.

The sinoatrial (SA) node, also known as the sinus node, is the primary pacemaker of the heart. It is a small bundle of specialized cardiac conduction tissue located in the upper part of the right atrium, near the entrance of the superior vena cava. The SA node generates electrical impulses that initiate each heartbeat, causing the atria to contract and pump blood into the ventricles. This process is called sinus rhythm.

The SA node's electrical activity is regulated by the autonomic nervous system, which can adjust the heart rate in response to changes in the body's needs, such as during exercise or rest. The SA node's rate of firing determines the heart rate, with a normal resting heart rate ranging from 60 to 100 beats per minute.

If the SA node fails to function properly or its electrical impulses are blocked, other secondary pacemakers in the heart may take over, resulting in abnormal heart rhythms called arrhythmias.

Blood pressure is the force exerted by circulating blood on the walls of the blood vessels. It is measured in millimeters of mercury (mmHg) and is given as two figures:

1. Systolic pressure: This is the pressure when the heart pushes blood out into the arteries.
2. Diastolic pressure: This is the pressure when the heart rests between beats, allowing it to fill with blood.

Normal blood pressure for adults is typically around 120/80 mmHg, although this can vary slightly depending on age, sex, and other factors. High blood pressure (hypertension) is generally considered to be a reading of 130/80 mmHg or higher, while low blood pressure (hypotension) is usually defined as a reading below 90/60 mmHg. It's important to note that blood pressure can fluctuate throughout the day and may be affected by factors such as stress, physical activity, and medication use.

Sinus arrhythmia is a type of heart rhythm disorder (arrhythmia) where the normal rhythm generated by the sinus node in the heart varies in rate or pattern. The sinus node is the natural pacemaker of the heart and usually sets a steady pace for heartbeats. However, in sinus arrhythmia, the heart rate may speed up or slow down abnormally during breathing in (inspiration) or breathing out (expiration).

When the heart rate increases during inspiration, it is called "inspiratory sinus arrhythmia," and when the heart rate decreases during expiration, it is called "expiratory sinus arrhythmia." Most people experience a mild form of inspiratory sinus arrhythmia, which is considered normal, especially in children and young adults.

However, if the variation in heart rate is significant or accompanied by symptoms such as palpitations, dizziness, shortness of breath, or chest discomfort, it may require medical evaluation and treatment. Sinus arrhythmia can be caused by various factors, including lung disease, heart disease, electrolyte imbalances, or the use of certain medications.

An oculocardiac reflex is a medical term that refers to a reflexive response that involves the eye and the heart. This reflex is elicited when there is pressure or traction applied to the eye or its surrounding structures, which can result in a decrease in heart rate.

The oculocardiac reflex is mediated by the ophthalmic division of the trigeminal nerve (cranial nerve V) and the vagus nerve (cranial nerve X). When the eye or its surrounding structures are stimulated, the impulses travel through the ophthalmic branch of the trigeminal nerve to the brainstem, where they synapse with neurons in the vagus nerve. The vagus nerve then carries these impulses to the sinoatrial node of the heart, which results in a decrease in heart rate.

The oculocardiac reflex is commonly seen during ophthalmic surgical procedures, particularly those that involve manipulation of the eye or its surrounding structures. It can also occur in response to other forms of stimulation, such as coughing, sneezing, or vomiting. In some cases, the oculocardiac reflex can lead to a significant decrease in heart rate, which may require medical intervention to prevent serious complications.

Atropine is an anticholinergic drug that blocks the action of the neurotransmitter acetylcholine in the central and peripheral nervous system. It is derived from the belladonna alkaloids, which are found in plants such as deadly nightshade (Atropa belladonna), Jimson weed (Datura stramonium), and Duboisia spp.

In clinical medicine, atropine is used to reduce secretions, increase heart rate, and dilate the pupils. It is often used before surgery to dry up secretions in the mouth, throat, and lungs, and to reduce salivation during the procedure. Atropine is also used to treat certain types of nerve agent and pesticide poisoning, as well as to manage bradycardia (slow heart rate) and hypotension (low blood pressure) caused by beta-blockers or calcium channel blockers.

Atropine can have several side effects, including dry mouth, blurred vision, dizziness, confusion, and difficulty urinating. In high doses, it can cause delirium, hallucinations, and seizures. Atropine should be used with caution in patients with glaucoma, prostatic hypertrophy, or other conditions that may be exacerbated by its anticholinergic effects.

Heart block is a cardiac condition characterized by the interruption of electrical impulse transmission from the atria (the upper chambers of the heart) to the ventricles (the lower chambers of the heart). This disruption can lead to abnormal heart rhythms, including bradycardia (a slower-than-normal heart rate), and in severe cases, can cause the heart to stop beating altogether. Heart block is typically caused by damage to the heart's electrical conduction system due to various factors such as aging, heart disease, or certain medications.

There are three types of heart block: first-degree, second-degree, and third-degree (also known as complete heart block). Each type has distinct electrocardiogram (ECG) findings and symptoms. Treatment for heart block depends on the severity of the condition and may include monitoring, medication, or implantation of a pacemaker to regulate the heart's electrical activity.

Electrocardiography (ECG or EKG) is a medical procedure that records the electrical activity of the heart. It provides a graphic representation of the electrical changes that occur during each heartbeat. The resulting tracing, called an electrocardiogram, can reveal information about the heart's rate and rhythm, as well as any damage to its cells or abnormalities in its conduction system.

During an ECG, small electrodes are placed on the skin of the chest, arms, and legs. These electrodes detect the electrical signals produced by the heart and transmit them to a machine that amplifies and records them. The procedure is non-invasive, painless, and quick, usually taking only a few minutes.

ECGs are commonly used to diagnose and monitor various heart conditions, including arrhythmias, coronary artery disease, heart attacks, and electrolyte imbalances. They can also be used to evaluate the effectiveness of certain medications or treatments.

The term "diving" is generally not used in the context of medical definitions. However, when referring to diving in relation to a medical or physiological context, it usually refers to the act of submerging the body underwater, typically for activities such as swimming, snorkeling, or scuba diving.

In a medical or physiological sense, diving can have specific effects on the human body due to changes in pressure, temperature, and exposure to water. Some of these effects include:

* Changes in lung volume and gas exchange due to increased ambient pressure at depth.
* Decompression sickness (DCS) or nitrogen narcosis, which can occur when dissolved gases form bubbles in the body during ascent from a dive.
* Hypothermia, which can occur if the water is cold and the diver is not adequately insulated.
* Barotrauma, which can occur due to pressure differences between the middle ear or sinuses and the surrounding environment.
* Other medical conditions such as seizures or heart problems can also be exacerbated by diving.

It's important for divers to undergo proper training and certification, follow safe diving practices, and monitor their health before and after dives to minimize the risks associated with diving.

Biguanides are a class of oral hypoglycemic agents used in the treatment of type 2 diabetes. The primary mechanism of action of biguanides is to decrease hepatic glucose production and increase insulin sensitivity, which leads to reduced fasting glucose levels and improved glycemic control.

The most commonly prescribed biguanide is metformin, which has been widely used for several decades due to its efficacy and low risk of hypoglycemia. Other biguanides include phenformin and buformin, but these are rarely used due to their association with a higher risk of lactic acidosis, a potentially life-threatening complication.

In addition to their glucose-lowering effects, biguanides have also been shown to have potential benefits on cardiovascular health and weight management, making them a valuable treatment option for many individuals with type 2 diabetes. However, they should be used with caution in patients with impaired renal function or other underlying medical conditions that may increase the risk of lactic acidosis.

Sick Sinus Syndrome (SSS) is a term used to describe a group of abnormal heart rhythm disturbances that originates in the sinoatrial node (the natural pacemaker of the heart). This syndrome is characterized by impaired functioning of the sinoatrial node, resulting in various abnormalities such as sinus bradycardia (abnormally slow heart rate), sinus arrest (complete cessation of sinus node activity), and/or sinoatrial exit block (failure of the electrical impulse to leave the sinus node and spread to the atria).

People with SSS may experience symptoms such as palpitations, dizziness, fatigue, shortness of breath, or syncope (fainting) due to inadequate blood supply to the brain caused by slow heart rate. The diagnosis of SSS is typically made based on the patient's symptoms and the results of an electrocardiogram (ECG), Holter monitoring, or event recorder that shows evidence of abnormal sinus node function. Treatment options for SSS may include lifestyle modifications, medications, or implantation of a pacemaker to regulate the heart rate.

The baroreflex is a physiological mechanism that helps regulate blood pressure and heart rate in response to changes in stretch of the arterial walls. It is mediated by baroreceptors, which are specialized sensory nerve endings located in the carotid sinus and aortic arch. These receptors detect changes in blood pressure and send signals to the brainstem via the glossopharyngeal (cranial nerve IX) and vagus nerves (cranial nerve X), respectively.

In response to an increase in arterial pressure, the baroreceptors are stimulated, leading to increased firing of afferent neurons that signal the brainstem. This results in a reflexive decrease in heart rate and cardiac output, as well as vasodilation of peripheral blood vessels, which collectively work to reduce blood pressure back towards its normal level. Conversely, if arterial pressure decreases, the baroreceptors are less stimulated, leading to an increase in heart rate and cardiac output, as well as vasoconstriction of peripheral blood vessels, which helps restore blood pressure.

Overall, the baroreflex is a crucial homeostatic mechanism that helps maintain stable blood pressure and ensure adequate perfusion of vital organs.

Syncope is a medical term defined as a transient, temporary loss of consciousness and postural tone due to reduced blood flow to the brain. It's often caused by a drop in blood pressure, which can be brought on by various factors such as dehydration, emotional stress, prolonged standing, or certain medical conditions like heart diseases, arrhythmias, or neurological disorders.

During a syncope episode, an individual may experience warning signs such as lightheadedness, dizziness, blurred vision, or nausea before losing consciousness. These episodes usually last only a few minutes and are followed by a rapid, full recovery. However, if left untreated or undiagnosed, recurrent syncope can lead to severe injuries from falls or even life-threatening conditions related to the underlying cause.

An artificial pacemaker is a medical device that uses electrical impulses to regulate the beating of the heart. It is typically used when the heart's natural pacemaker, the sinoatrial node, is not functioning properly and the heart rate is too slow or irregular. The pacemaker consists of a small generator that contains a battery and electronic circuits, which are connected to one or more electrodes that are placed in the heart.

The generator sends electrical signals through the electrodes to stimulate the heart muscle and cause it to contract, thereby maintaining a regular heart rhythm. Artificial pacemakers can be programmed to deliver electrical impulses at a specific rate or in response to the body's needs. They are typically implanted in the chest during a surgical procedure and can last for many years before needing to be replaced.

Artificial pacemakers are an effective treatment for various types of bradycardia, which is a heart rhythm disorder characterized by a slow heart rate. Pacemakers can significantly improve symptoms associated with bradycardia, such as fatigue, dizziness, shortness of breath, and fainting spells.

Tachycardia is a medical term that refers to an abnormally rapid heart rate, often defined as a heart rate greater than 100 beats per minute in adults. It can occur in either the atria (upper chambers) or ventricles (lower chambers) of the heart. Different types of tachycardia include supraventricular tachycardia (SVT), atrial fibrillation, atrial flutter, and ventricular tachycardia.

Tachycardia can cause various symptoms such as palpitations, shortness of breath, dizziness, lightheadedness, chest discomfort, or syncope (fainting). In some cases, tachycardia may not cause any symptoms and may only be detected during a routine physical examination or medical test.

The underlying causes of tachycardia can vary widely, including heart disease, electrolyte imbalances, medications, illicit drug use, alcohol abuse, smoking, stress, anxiety, and other medical conditions. In some cases, the cause may be unknown. Treatment for tachycardia depends on the underlying cause, type, severity, and duration of the arrhythmia.

Anesthesia is a medical term that refers to the loss of sensation or awareness, usually induced by the administration of various drugs. It is commonly used during surgical procedures to prevent pain and discomfort. There are several types of anesthesia, including:

1. General anesthesia: This type of anesthesia causes a complete loss of consciousness and is typically used for major surgeries.
2. Regional anesthesia: This type of anesthesia numbs a specific area of the body, such as an arm or leg, while the patient remains conscious.
3. Local anesthesia: This type of anesthesia numbs a small area of the body, such as a cut or wound, and is typically used for minor procedures.

Anesthesia can be administered through various routes, including injection, inhalation, or topical application. The choice of anesthesia depends on several factors, including the type and duration of the procedure, the patient's medical history, and their overall health. Anesthesiologists are medical professionals who specialize in administering anesthesia and monitoring patients during surgical procedures to ensure their safety and comfort.

A vagotomy is a surgical procedure that involves cutting or blocking the vagus nerve, which is a parasympathetic nerve that runs from the brainstem to the abdomen and helps regulate many bodily functions such as heart rate, gastrointestinal motility, and digestion. In particular, vagotomy is often performed as a treatment for peptic ulcers, as it can help reduce gastric acid secretion.

There are several types of vagotomy procedures, including:

1. Truncal vagotomy: This involves cutting the main trunks of the vagus nerve as they enter the abdomen. It is a more extensive procedure that reduces gastric acid secretion significantly but can also lead to side effects such as delayed gastric emptying and diarrhea.
2. Selective vagotomy: This involves cutting only the branches of the vagus nerve that supply the stomach, leaving the rest of the nerve intact. It is a less extensive procedure that reduces gastric acid secretion while minimizing side effects.
3. Highly selective vagotomy (HSV): Also known as parietal cell vagotomy, this involves cutting only the branches of the vagus nerve that supply the acid-secreting cells in the stomach. It is a highly targeted procedure that reduces gastric acid secretion while minimizing side effects such as delayed gastric emptying and diarrhea.

Vagotomy is typically performed using laparoscopic or open surgical techniques, depending on the patient's individual needs and the surgeon's preference. While vagotomy can be effective in treating peptic ulcers, it is not commonly performed today due to the development of less invasive treatments such as proton pump inhibitors (PPIs) that reduce gastric acid secretion without surgery.

Atropine derivatives are a class of drugs that are chemically related to atropine, an alkaloid found in the nightshade family of plants. These drugs have anticholinergic properties, which means they block the action of the neurotransmitter acetylcholine in the body.

Atropine derivatives can be used for a variety of medical purposes, including:

1. Treating motion sickness and vertigo
2. Dilating the pupils during eye examinations
3. Reducing saliva production during surgical procedures
4. Treating certain types of poisoning, such as organophosphate or nerve gas poisoning
5. Managing symptoms of some neurological disorders, such as Parkinson's disease and myasthenia gravis

Some examples of atropine derivatives include hyoscyamine, scopolamine, and ipratropium. These drugs can have side effects, including dry mouth, blurred vision, constipation, difficulty urinating, and rapid heartbeat. They should be used with caution and under the supervision of a healthcare provider.

Medical Definition of Respiration:

Respiration, in physiology, is the process by which an organism takes in oxygen and gives out carbon dioxide. It's also known as breathing. This process is essential for most forms of life because it provides the necessary oxygen for cellular respiration, where the cells convert biochemical energy from nutrients into adenosine triphosphate (ATP), and releases waste products, primarily carbon dioxide.

In humans and other mammals, respiration is a two-stage process:

1. Breathing (or external respiration): This involves the exchange of gases with the environment. Air enters the lungs through the mouth or nose, then passes through the pharynx, larynx, trachea, and bronchi, finally reaching the alveoli where the actual gas exchange occurs. Oxygen from the inhaled air diffuses into the blood, while carbon dioxide, a waste product of metabolism, diffuses from the blood into the alveoli to be exhaled.

2. Cellular respiration (or internal respiration): This is the process by which cells convert glucose and other nutrients into ATP, water, and carbon dioxide in the presence of oxygen. The carbon dioxide produced during this process then diffuses out of the cells and into the bloodstream to be exhaled during breathing.

In summary, respiration is a vital physiological function that enables organisms to obtain the necessary oxygen for cellular metabolism while eliminating waste products like carbon dioxide.

The cardiovascular system, also known as the circulatory system, is a biological system responsible for pumping and transporting blood throughout the body in animals and humans. It consists of the heart, blood vessels (comprising arteries, veins, and capillaries), and blood. The main function of this system is to transport oxygen, nutrients, hormones, and cellular waste products throughout the body to maintain homeostasis and support organ function.

The heart acts as a muscular pump that contracts and relaxes to circulate blood. It has four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body, pumps it through the lungs for oxygenation, and then sends it back to the left side of the heart. The left side of the heart then pumps the oxygenated blood through the aorta and into the systemic circulation, reaching all parts of the body via a network of arteries and capillaries. Deoxygenated blood is collected by veins and returned to the right atrium, completing the cycle.

The cardiovascular system plays a crucial role in regulating temperature, pH balance, and fluid balance throughout the body. It also contributes to the immune response and wound healing processes. Dysfunctions or diseases of the cardiovascular system can lead to severe health complications, such as hypertension, coronary artery disease, heart failure, stroke, and peripheral artery disease.

Atrioventricular (AV) block is a disorder of the electrical conduction system of the heart that causes a delay or interruption in the transmission of electrical signals from the atria (the upper chambers of the heart) to the ventricles (the lower chambers of the heart). This results in an abnormal heart rhythm, also known as an arrhythmia.

There are three degrees of AV block:

1. First-degree AV block: In this type of AV block, there is a delay in the conduction of electrical signals from the atria to the ventricles, but all signals are eventually conducted. This condition may not cause any symptoms and is often discovered during a routine electrocardiogram (ECG).
2. Second-degree AV block: In this type of AV block, some electrical signals from the atria are not conducted to the ventricles. There are two types of second-degree AV block: Mobitz type I and Mobitz type II. Mobitz type I is characterized by a progressive prolongation of the PR interval (the time between the electrical activation of the atria and ventricles) until a QRS complex (which represents the electrical activation of the ventricles) is dropped. Mobitz type II is characterized by a constant PR interval with occasional non-conducted P waves.
3. Third-degree AV block: In this type of AV block, no electrical signals are conducted from the atria to the ventricles. The atria and ventricles beat independently of each other, resulting in a slow heart rate (bradycardia) and an irregular rhythm. This condition can be life-threatening if not treated promptly.

The causes of AV block include aging, heart disease, medications, and certain medical conditions such as hypothyroidism and Lyme disease. Treatment depends on the severity of the condition and may include medication, a pacemaker, or surgery.

Pressoreceptors are specialized sensory nerve endings found in the walls of blood vessels, particularly in the carotid sinus and aortic arch. They respond to changes in blood pressure by converting the mechanical stimulus into electrical signals that are transmitted to the brain. This information helps regulate cardiovascular function and maintain blood pressure homeostasis.

Vasovagal syncope is a type of fainting (syncope) that occurs when the body overreacts to certain triggers, such as the sight of blood or extreme emotional distress. This reaction causes the heart rate and blood pressure to drop, leading to reduced blood flow to the brain and loss of consciousness. Vasovagal syncope is usually not a cause for concern and does not typically indicate a serious underlying medical condition. However, it can be dangerous if it occurs during activities such as driving or operating heavy machinery. If you experience frequent episodes of vasovagal syncope, it is important to speak with a healthcare provider for evaluation and treatment options.

Chemoreceptor cells are specialized sensory neurons that detect and respond to chemical changes in the internal or external environment. They play a crucial role in maintaining homeostasis within the body by converting chemical signals into electrical impulses, which are then transmitted to the central nervous system for further processing and response.

There are two main types of chemoreceptor cells:

1. Oxygen Chemoreceptors: These cells are located in the carotid bodies near the bifurcation of the common carotid artery and in the aortic bodies close to the aortic arch. They monitor the levels of oxygen, carbon dioxide, and pH in the blood and respond to decreases in oxygen concentration or increases in carbon dioxide and hydrogen ions (indicating acidity) by increasing their firing rate. This signals the brain to increase respiratory rate and depth, thereby restoring normal oxygen levels.

2. Taste Cells: These chemoreceptor cells are found within the taste buds of the tongue and other areas of the oral cavity. They detect specific tastes (salty, sour, sweet, bitter, and umami) by interacting with molecules from food. When a tastant binds to receptors on the surface of a taste cell, it triggers a series of intracellular signaling events that ultimately lead to the generation of an action potential. This information is then relayed to the brain, where it is interpreted as taste sensation.

In summary, chemoreceptor cells are essential for maintaining physiological balance by detecting and responding to chemical stimuli in the body. They play a critical role in regulating vital functions such as respiration and digestion.

In medical terms, the heart is a muscular organ located in the thoracic cavity that functions as a pump to circulate blood throughout the body. It's responsible for delivering oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. The human heart is divided into four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it out to the rest of the body. The heart's rhythmic contractions and relaxations are regulated by a complex electrical conduction system.

The medulla oblongata is a part of the brainstem that is located in the posterior portion of the brainstem and continues with the spinal cord. It plays a vital role in controlling several critical bodily functions, such as breathing, heart rate, and blood pressure. The medulla oblongata also contains nerve pathways that transmit sensory information from the body to the brain and motor commands from the brain to the muscles. Additionally, it is responsible for reflexes such as vomiting, swallowing, coughing, and sneezing.

Cardiac arrhythmias are abnormal heart rhythms that result from disturbances in the electrical conduction system of the heart. The heart's normal rhythm is controlled by an electrical signal that originates in the sinoatrial (SA) node, located in the right atrium. This signal travels through the atrioventricular (AV) node and into the ventricles, causing them to contract and pump blood throughout the body.

An arrhythmia occurs when there is a disruption in this electrical pathway or when the heart's natural pacemaker produces an abnormal rhythm. This can cause the heart to beat too fast (tachycardia), too slow (bradycardia), or irregularly.

There are several types of cardiac arrhythmias, including:

1. Atrial fibrillation: A rapid and irregular heartbeat that starts in the atria (the upper chambers of the heart).
2. Atrial flutter: A rapid but regular heartbeat that starts in the atria.
3. Supraventricular tachycardia (SVT): A rapid heartbeat that starts above the ventricles, usually in the atria or AV node.
4. Ventricular tachycardia: A rapid and potentially life-threatening heart rhythm that originates in the ventricles.
5. Ventricular fibrillation: A chaotic and disorganized electrical activity in the ventricles, which can be fatal if not treated immediately.
6. Heart block: A delay or interruption in the conduction of electrical signals from the atria to the ventricles.

Cardiac arrhythmias can cause various symptoms, such as palpitations, dizziness, shortness of breath, chest pain, and fatigue. In some cases, they may not cause any symptoms and go unnoticed. However, if left untreated, certain types of arrhythmias can lead to serious complications, including stroke, heart failure, or even sudden cardiac death.

Treatment for cardiac arrhythmias depends on the type, severity, and underlying causes. Options may include lifestyle changes, medications, cardioversion (electrical shock therapy), catheter ablation, implantable devices such as pacemakers or defibrillators, and surgery. It is essential to consult a healthcare professional for proper evaluation and management of cardiac arrhythmias.

Artificial cardiac pacing is a medical procedure that involves the use of an artificial device to regulate and stimulate the contraction of the heart muscle. This is often necessary when the heart's natural pacemaker, the sinoatrial node, is not functioning properly and the heart is beating too slowly or irregularly.

The artificial pacemaker consists of a small generator that produces electrical impulses and leads that are positioned in the heart to transmit the impulses. The generator is typically implanted just under the skin in the chest, while the leads are inserted into the heart through a vein.

There are different types of artificial cardiac pacing systems, including single-chamber pacemakers, which stimulate either the right atrium or right ventricle, and dual-chamber pacemakers, which stimulate both chambers of the heart. Some pacemakers also have additional features that allow them to respond to changes in the body's needs, such as during exercise or sleep.

Artificial cardiac pacing is a safe and effective treatment for many people with abnormal heart rhythms, and it can significantly improve their quality of life and longevity.

A decerebrate state is a medical condition that results from severe damage to the brainstem, specifically to the midbrain and above. This type of injury can cause motor responses characterized by rigid extension of the arms and legs, with the arms rotated outward and the wrists and fingers extended. The legs are also extended and the toes pointed downward. These postures are often referred to as "decerebrate rigidity" or "posturing."

The decerebrate state is typically seen in patients who have experienced severe trauma, such as a car accident or gunshot wound, or who have suffered from a large stroke or other type of brain hemorrhage. It can also occur in some cases of severe hypoxia (lack of oxygen) to the brain, such as during cardiac arrest or drowning.

The decerebrate state is a serious medical emergency that requires immediate treatment. If left untreated, it can lead to further brain damage and even death. Treatment typically involves providing supportive care, such as mechanical ventilation to help with breathing, medications to control blood pressure and prevent seizures, and surgery to repair any underlying injuries or bleeding. In some cases, patients may require long-term rehabilitation to regain lost function and improve their quality of life.

Clonidine is an medication that belongs to a class of drugs called centrally acting alpha-agonist hypotensives. It works by stimulating certain receptors in the brain and lowering the heart rate, which results in decreased blood pressure. Clonidine is commonly used to treat hypertension (high blood pressure), but it can also be used for other purposes such as managing withdrawal symptoms from opioids or alcohol, treating attention deficit hyperactivity disorder (ADHD), and preventing migraines. It can be taken orally in the form of tablets or transdermally through a patch applied to the skin. As with any medication, clonidine should be used under the guidance and supervision of a healthcare provider.

Parasympatholytics are a type of medication that blocks the action of the parasympathetic nervous system. The parasympathetic nervous system is responsible for the body's rest and digest response, which includes slowing the heart rate, increasing intestinal and glandular activity, and promoting urination and defecation.

Parasympatholytics work by selectively binding to muscarinic receptors, which are found in various organs throughout the body, including the heart, lungs, and digestive system. By blocking these receptors, parasympatholytics can cause a range of effects, such as an increased heart rate, decreased glandular secretions, and reduced intestinal motility.

Some common examples of parasympatholytics include atropine, scopolamine, and ipratropium. These medications are often used to treat conditions such as bradycardia (slow heart rate), excessive salivation, and gastrointestinal cramping or diarrhea. However, because they can have significant side effects, parasympatholytics are typically used only when necessary and under the close supervision of a healthcare provider.

The carotid sinus is a small, dilated area located at the bifurcation (or fork) of the common carotid artery into the internal and external carotid arteries. It is a baroreceptor region, which means it contains specialized sensory nerve endings that can detect changes in blood pressure. When the blood pressure increases, the walls of the carotid sinus stretch, activating these nerve endings and sending signals to the brain. The brain then responds by reducing the heart rate and relaxing the blood vessels, which helps to lower the blood pressure back to normal.

The carotid sinus is an important part of the body's autonomic nervous system, which regulates various involuntary functions such as heart rate, blood pressure, and digestion. It plays a crucial role in maintaining cardiovascular homeostasis and preventing excessive increases in blood pressure that could potentially damage vital organs.

The Parasympathetic Nervous System (PNS) is the part of the autonomic nervous system that primarily controls vegetative functions during rest, relaxation, and digestion. It is responsible for the body's "rest and digest" activities including decreasing heart rate, lowering blood pressure, increasing digestive activity, and stimulating sexual arousal. The PNS utilizes acetylcholine as its primary neurotransmitter and acts in opposition to the Sympathetic Nervous System (SNS), which is responsible for the "fight or flight" response.

In medical terms, "immersion" is not a term with a specific clinical definition. However, in general terms, immersion refers to the act of placing something or someone into a liquid or environment completely. In some contexts, it may be used to describe a type of wound care where the wound is covered completely with a medicated dressing or solution. It can also be used to describe certain medical procedures or therapies that involve submerging a part of the body in a liquid, such as hydrotherapy.

The Autonomic Nervous System (ANS) is a part of the peripheral nervous system that operates largely below the level of consciousness and controls visceral functions. It is divided into two main subdivisions: the sympathetic and parasympathetic nervous systems, which generally have opposing effects and maintain homeostasis in the body.

The Sympathetic Nervous System (SNS) prepares the body for stressful or emergency situations, often referred to as the "fight or flight" response. It increases heart rate, blood pressure, respiratory rate, and metabolic rate, while also decreasing digestive activity. This response helps the body respond quickly to perceived threats.

The Parasympathetic Nervous System (PNS), on the other hand, promotes the "rest and digest" state, allowing the body to conserve energy and restore itself after the stress response has subsided. It decreases heart rate, blood pressure, and respiratory rate, while increasing digestive activity and promoting relaxation.

These two systems work together to maintain balance in the body by adjusting various functions based on internal and external demands. Disorders of the Autonomic Nervous System can lead to a variety of symptoms, such as orthostatic hypotension, gastroparesis, and cardiac arrhythmias, among others.

Ciguatera poisoning is a type of foodborne illness that is caused by consuming seafood (such as fish) that contains ciguatoxins. These toxins are produced by certain types of microalgae that can accumulate in larger marine animals and become concentrated in the flesh of fish.

Ciguatera poisoning is characterized by a variety of symptoms, including nausea, vomiting, diarrhea, abdominal pain, muscle weakness, and neurological symptoms such as tingling or numbness in the lips, tongue, and other parts of the body. In severe cases, it can also cause heart problems, seizures, and even coma.

The severity of ciguatera poisoning can vary widely depending on the amount and type of toxin consumed, as well as individual susceptibility. There is no specific antidote for ciguatera poisoning, and treatment typically involves supportive care such as fluid replacement, pain management, and monitoring for complications.

Prevention measures include avoiding consumption of fish known to carry a high risk of ciguatoxins, particularly larger predatory reef fish such as barracuda, grouper, moray eel, and red snapper. Cooking or freezing the fish does not destroy the toxin, so it is important to choose fish carefully when dining in areas where ciguatera poisoning is common.

Postsynaptic potential (PSP) summation is the process that occurs when multiple postsynaptic potentials are added together at a neuronal synapse, leading to a cumulative effect on the membrane potential of the postsynaptic cell. This phenomenon can be either excitatory or inhibitory and plays a crucial role in determining whether or not an action potential will be generated in the postsynaptic neuron.

There are two types of PSP summation:

1. Temporal Summation: This occurs when multiple PSPs are evoked at the same synapse within a short period, resulting in their summation and influencing the overall effect on the postsynaptic cell's membrane potential. When these PSPs are of the same polarity (either excitatory or inhibitory), they can either facilitate or depress the generation of an action potential.
2. Spatial Summation: This type of summation occurs when multiple PSPs are evoked at different synapses on the same postsynaptic neuron, and their effects combine to alter the membrane potential. The combined effect depends on the location, number, and strength of the activated synapses.

In summary, postsynaptic potential summation is a fundamental mechanism in neural computation that enables the integration of information from multiple presynaptic neurons onto a single postsynaptic neuron, ultimately influencing its excitability and contributing to the complex processing of signals within the nervous system.

The solitary nucleus, also known as the nucleus solitarius, is a collection of neurons located in the medulla oblongata region of the brainstem. It plays a crucial role in the processing and integration of sensory information, particularly taste and visceral afferent fibers from internal organs. The solitary nucleus receives inputs from various cranial nerves, including the glossopharyngeal (cranial nerve IX) and vagus nerves (cranial nerve X), and is involved in reflex responses related to swallowing, vomiting, and cardiovascular regulation.

Anti-arrhythmia agents are a class of medications used to treat abnormal heart rhythms or arrhythmias. These drugs work by modifying the electrical activity of the heart to restore and maintain a normal heart rhythm. There are several types of anti-arrhythmia agents, including:

1. Sodium channel blockers: These drugs slow down the conduction of electrical signals in the heart, which helps to reduce rapid or irregular heartbeats. Examples include flecainide, propafenone, and quinidine.
2. Beta-blockers: These medications work by blocking the effects of adrenaline on the heart, which helps to slow down the heart rate and reduce the force of heart contractions. Examples include metoprolol, atenolol, and esmolol.
3. Calcium channel blockers: These drugs block the entry of calcium into heart muscle cells, which helps to slow down the heart rate and reduce the force of heart contractions. Examples include verapamil and diltiazem.
4. Potassium channel blockers: These medications work by prolonging the duration of the heart's electrical cycle, which helps to prevent abnormal rhythms. Examples include amiodarone and sotalol.
5. Digoxin: This drug increases the force of heart contractions and slows down the heart rate, which can help to restore a normal rhythm in certain types of arrhythmias.

It's important to note that anti-arrhythmia agents can have significant side effects and should only be prescribed by a healthcare professional who has experience in managing arrhythmias. Close monitoring is necessary to ensure the medication is working effectively and not causing any adverse effects.

Microinjection is a medical technique that involves the use of a fine, precise needle to inject small amounts of liquid or chemicals into microscopic structures, cells, or tissues. This procedure is often used in research settings to introduce specific substances into individual cells for study purposes, such as introducing DNA or RNA into cell nuclei to manipulate gene expression.

In clinical settings, microinjections may be used in various medical and cosmetic procedures, including:

1. Intracytoplasmic Sperm Injection (ICSI): A type of assisted reproductive technology where a single sperm is injected directly into an egg to increase the chances of fertilization during in vitro fertilization (IVF) treatments.
2. Botulinum Toxin Injections: Microinjections of botulinum toxin (Botox, Dysport, or Xeomin) are used for cosmetic purposes to reduce wrinkles and fine lines by temporarily paralyzing the muscles responsible for their formation. They can also be used medically to treat various neuromuscular disorders, such as migraines, muscle spasticity, and excessive sweating (hyperhidrosis).
3. Drug Delivery: Microinjections may be used to deliver drugs directly into specific tissues or organs, bypassing the systemic circulation and potentially reducing side effects. This technique can be particularly useful in treating localized pain, delivering growth factors for tissue regeneration, or administering chemotherapy agents directly into tumors.
4. Gene Therapy: Microinjections of genetic material (DNA or RNA) can be used to introduce therapeutic genes into cells to treat various genetic disorders or diseases, such as cystic fibrosis, hemophilia, or cancer.

Overall, microinjection is a highly specialized and precise technique that allows for the targeted delivery of substances into small structures, cells, or tissues, with potential applications in research, medical diagnostics, and therapeutic interventions.

Torsades de Pointes is a type of polymorphic ventricular tachycardia, characterized by a distinct pattern on the electrocardiogram (ECG) where the QRS complexes appear to twist around the isoelectric line. This condition is often associated with a prolonged QT interval, which can be congenital or acquired due to various factors such as medications, electrolyte imbalances, or heart diseases. Torsades de Pointes can degenerate into ventricular fibrillation, leading to sudden cardiac death if not promptly treated.

Fetal heart rate (FHR) is the number of times a fetus's heart beats in one minute. It is measured through the use of a fetoscope, Doppler ultrasound device, or cardiotocograph (CTG). A normal FHR ranges from 120 to 160 beats per minute (bpm), although it can vary throughout pregnancy and is usually faster than an adult's heart rate. Changes in the FHR pattern may indicate fetal distress, hypoxia, or other conditions that require medical attention. Regular monitoring of FHR during pregnancy, labor, and delivery helps healthcare providers assess fetal well-being and ensure a safe outcome for both the mother and the baby.

The sympathetic nervous system (SNS) is a part of the autonomic nervous system that operates largely below the level of consciousness, and it functions to produce appropriate physiological responses to perceived danger. It's often associated with the "fight or flight" response. The SNS uses nerve impulses to stimulate target organs, causing them to speed up (e.g., increased heart rate), prepare for action, or otherwise respond to stressful situations.

The sympathetic nervous system is activated due to stressful emotional or physical situations and it prepares the body for immediate actions. It dilates the pupils, increases heart rate and blood pressure, accelerates breathing, and slows down digestion. The primary neurotransmitter involved in this system is norepinephrine (also known as noradrenaline).

Cardiac arrest, also known as heart arrest, is a medical condition where the heart suddenly stops beating or functioning properly. This results in the cessation of blood flow to the rest of the body, including the brain, leading to loss of consciousness and pulse. Cardiac arrest is often caused by electrical disturbances in the heart that disrupt its normal rhythm, known as arrhythmias. If not treated immediately with cardiopulmonary resuscitation (CPR) and defibrillation, it can lead to death or permanent brain damage due to lack of oxygen supply. It's important to note that a heart attack is different from cardiac arrest; a heart attack occurs when blood flow to a part of the heart is blocked, often by a clot, causing damage to the heart muscle, but the heart continues to beat. However, a heart attack can sometimes trigger a cardiac arrest.

Sympatholytics are a class of drugs that block the action of the sympathetic nervous system, which is the part of the autonomic nervous system responsible for preparing the body for the "fight or flight" response. Sympatholytics achieve this effect by binding to and blocking alpha-adrenergic receptors or beta-adrenergic receptors located in various organs throughout the body, including the heart, blood vessels, lungs, gastrointestinal tract, and urinary system.

Examples of sympatholytic drugs include:

* Alpha blockers (e.g., prazosin, doxazosin)
* Beta blockers (e.g., propranolol, metoprolol)
* Centrally acting sympatholytics (e.g., clonidine, methyldopa)

Sympatholytics are used to treat a variety of medical conditions, including hypertension, angina, heart failure, arrhythmias, and certain neurological disorders. They may also be used to manage symptoms associated with anxiety or withdrawal from alcohol or other substances.

Aortic bodies, also known as aortic arch chemoreceptors or simply as carotid and aortic bodies, are small clusters of nerve cells located near the bifurcation of the common carotid artery (carotid body) and in the wall of the aortic arch (aortic body). They are part of the peripheral chemoreceptor system that responds to changes in chemical composition of the blood, particularly to decreases in oxygen levels, increases in carbon dioxide levels, and changes in pH. These receptors send signals to the brainstem, which in turn regulates breathing rate and depth to maintain adequate gas exchange and acid-base balance in the body.

Hemodynamics is the study of how blood flows through the cardiovascular system, including the heart and the vascular network. It examines various factors that affect blood flow, such as blood volume, viscosity, vessel length and diameter, and pressure differences between different parts of the circulatory system. Hemodynamics also considers the impact of various physiological and pathological conditions on these variables, and how they in turn influence the function of vital organs and systems in the body. It is a critical area of study in fields such as cardiology, anesthesiology, and critical care medicine.

Intraoperative complications refer to any unforeseen problems or events that occur during the course of a surgical procedure, once it has begun and before it is completed. These complications can range from minor issues, such as bleeding or an adverse reaction to anesthesia, to major complications that can significantly impact the patient's health and prognosis.

Examples of intraoperative complications include:

1. Bleeding (hemorrhage) - This can occur due to various reasons such as injury to blood vessels or organs during surgery.
2. Infection - Surgical site infections can develop if the surgical area becomes contaminated during the procedure.
3. Anesthesia-related complications - These include adverse reactions to anesthesia, difficulty maintaining the patient's airway, or cardiovascular instability.
4. Organ injury - Accidental damage to surrounding organs can occur during surgery, leading to potential long-term consequences.
5. Equipment failure - Malfunctioning surgical equipment can lead to complications and compromise the safety of the procedure.
6. Allergic reactions - Patients may have allergies to certain medications or materials used during surgery, causing an adverse reaction.
7. Prolonged operative time - Complications may arise if a surgical procedure takes longer than expected, leading to increased risk of infection and other issues.

Intraoperative complications require prompt identification and management by the surgical team to minimize their impact on the patient's health and recovery.

Ciguatoxins (CTXs) are a group of heat-stable, lipid-soluble toxins that can cause a type of foodborne illness known as ciguatera fish poisoning. These toxins are produced by microscopic marine dinoflagellates called Gambierdiscus toxicus and other related species, which grow on and around certain types of algae in warm, tropical waters.

When these dinoflagellates are consumed by herbivorous fish, the toxins accumulate in their tissues without causing harm to the fish. However, when larger carnivorous fish eat many smaller herbivorous fish, the concentration of CTXs can increase to potentially harmful levels.

Humans who consume contaminated fish may experience a range of symptoms including gastrointestinal disturbances (such as nausea, vomiting, diarrhea), neurological symptoms (such as tingling or numbness in the lips, tongue, and other parts of the body, reversal of hot and cold sensations, and muscle weakness), and cardiovascular symptoms (such as low blood pressure, irregular heartbeat).

These symptoms can be severe and may last for several weeks or even months. Currently, there is no specific antidote or treatment for ciguatera fish poisoning, and management typically involves supportive care to manage symptoms. Prevention measures include avoiding consumption of fish known to carry CTXs, such as barracuda, grouper, moray eel, and red snapper, among others.

A tilt-table test is a diagnostic procedure used to evaluate symptoms of syncope (fainting) or near-syncope. It measures your body's cardiovascular response to changes in position. During the test, you lie on a table that can be tilted to change the angle of your body from horizontal to upright. This simulates what happens when you stand up from a lying down position.

The test monitors heart rate, blood pressure, and oxygen levels while you're in different positions. If you experience symptoms like dizziness or fainting during the test, these can provide clues about the cause of your symptoms. The test is used to diagnose conditions like orthostatic hypotension (a sudden drop in blood pressure when standing), vasovagal syncope (fainting due to an overactive vagus nerve), and other heart rhythm disorders.

Consciousness is a complex and multifaceted concept that is difficult to define succinctly, but in a medical or neurological context, it generally refers to an individual's state of awareness and responsiveness to their surroundings. Consciousness involves a range of cognitive processes, including perception, thinking, memory, and attention, and it requires the integration of sensory information, language, and higher-order cognitive functions.

In medical terms, consciousness is often assessed using measures such as the Glasgow Coma Scale, which evaluates an individual's ability to open their eyes, speak, and move in response to stimuli. A coma is a state of deep unconsciousness where an individual is unable to respond to stimuli or communicate, while a vegetative state is a condition where an individual may have sleep-wake cycles and some automatic responses but lacks any meaningful awareness or cognitive function.

Disorders of consciousness can result from brain injury, trauma, infection, or other medical conditions that affect the functioning of the brainstem or cerebral cortex. The study of consciousness is a rapidly evolving field that involves researchers from various disciplines, including neuroscience, psychology, philosophy, and artificial intelligence.

Atenolol is a beta-blocker medication that is primarily used to treat hypertension (high blood pressure), angina (chest pain), and certain types of heart rhythm disorders. It works by blocking the action of certain hormones in the body, such as adrenaline, on the heart and blood vessels. This helps to reduce the heart's workload, lower its rate and force of contractions, and improve blood flow.

Beta-blockers like atenolol are also sometimes used to prevent migraines or to treat symptoms of anxiety, such as rapid heartbeat or tremors. Atenolol is available in immediate-release and extended-release forms, and it is typically taken orally once or twice a day. As with any medication, atenolol can have side effects, including dizziness, fatigue, and gastrointestinal symptoms, and it may interact with other medications or medical conditions. It is important to use atenolol only under the supervision of a healthcare provider.

Neuroendoscopy is a minimally invasive surgical technique that involves the use of an endoscope to access and treat various conditions within the brain and spinal column. An endoscope is a long, flexible tube with a light and camera at its tip, which allows surgeons to view and operate on internal structures through small incisions or natural openings in the body.

In neuroendoscopy, the surgeon uses the endoscope to navigate through the brain's ventricular system (fluid-filled spaces) or other narrow spaces within the skull or spine to diagnose and treat conditions such as hydrocephalus, brain tumors, arachnoid cysts, and intraventricular hemorrhage.

The benefits of neuroendoscopy include reduced trauma to surrounding tissues, shorter hospital stays, faster recovery times, and improved outcomes compared to traditional open surgical approaches. However, neuroendoscopic procedures require specialized training and expertise due to the complexity of the anatomy involved.

Cardiovascular physiological phenomena refer to the various functions and processes that occur within the cardiovascular system, which includes the heart and blood vessels. These phenomena are responsible for the transport of oxygen, nutrients, and other essential molecules to tissues throughout the body, as well as the removal of waste products and carbon dioxide.

Some examples of cardiovascular physiological phenomena include:

1. Heart rate and rhythm: The heart's ability to contract regularly and coordinate its contractions with the body's needs for oxygen and nutrients.
2. Blood pressure: The force exerted by blood on the walls of blood vessels, which is determined by the amount of blood pumped by the heart and the resistance of the blood vessels.
3. Cardiac output: The volume of blood that the heart pumps in one minute, calculated as the product of stroke volume (the amount of blood pumped per beat) and heart rate.
4. Blood flow: The movement of blood through the circulatory system, which is influenced by factors such as blood pressure, vessel diameter, and blood viscosity.
5. Vasoconstriction and vasodilation: The narrowing or widening of blood vessels in response to various stimuli, such as hormones, neurotransmitters, and changes in temperature or oxygen levels.
6. Autoregulation: The ability of blood vessels to maintain a constant blood flow to tissues despite changes in perfusion pressure.
7. Blood clotting: The process by which the body forms a clot to stop bleeding after an injury, which involves the activation of platelets and the coagulation cascade.
8. Endothelial function: The ability of the endothelium (the lining of blood vessels) to regulate vascular tone, inflammation, and thrombosis.
9. Myocardial contractility: The strength of heart muscle contractions, which is influenced by factors such as calcium levels, neurotransmitters, and hormones.
10. Electrophysiology: The study of the electrical properties of the heart, including the conduction system that allows for the coordinated contraction of heart muscle.

Spinal anesthesia is a type of regional anesthesia that involves injecting local anesthetic medication into the cerebrospinal fluid in the subarachnoid space, which is the space surrounding the spinal cord. This procedure is typically performed by introducing a needle into the lower back, between the vertebrae, to reach the subarachnoid space.

Once the local anesthetic is introduced into this space, it spreads to block nerve impulses from the corresponding levels of the spine, resulting in numbness and loss of sensation in specific areas of the body below the injection site. The extent and level of anesthesia depend on the amount and type of medication used, as well as the patient's individual response.

Spinal anesthesia is often used for surgeries involving the lower abdomen, pelvis, or lower extremities, such as cesarean sections, hernia repairs, hip replacements, and knee arthroscopies. It can also be utilized for procedures like epidural steroid injections to manage chronic pain conditions affecting the spine and lower limbs.

While spinal anesthesia provides effective pain relief during and after surgery, it may cause side effects such as low blood pressure, headache, or difficulty urinating. These potential complications should be discussed with the healthcare provider before deciding on this type of anesthesia.

I believe there might be a misunderstanding in your question. "Dogs" is not a medical term or condition. It is the common name for a domesticated carnivore of the family Canidae, specifically the genus Canis, which includes wolves, foxes, and other extant and extinct species of mammals. Dogs are often kept as pets and companions, and they have been bred in a wide variety of forms and sizes for different purposes, such as hunting, herding, guarding, assisting police and military forces, and providing companionship and emotional support.

If you meant to ask about a specific medical condition or term related to dogs, please provide more context so I can give you an accurate answer.

Adrenergic beta-antagonists, also known as beta blockers, are a class of medications that block the effects of adrenaline and noradrenaline (also known as epinephrine and norepinephrine) on beta-adrenergic receptors. These receptors are found in various tissues throughout the body, including the heart, lungs, and blood vessels.

Beta blockers work by binding to these receptors and preventing the activation of certain signaling pathways that lead to increased heart rate, force of heart contractions, and relaxation of blood vessels. As a result, beta blockers can lower blood pressure, reduce heart rate, and decrease the workload on the heart.

Beta blockers are used to treat a variety of medical conditions, including hypertension (high blood pressure), angina (chest pain), heart failure, irregular heart rhythms, migraines, and certain anxiety disorders. Some common examples of beta blockers include metoprolol, atenolol, propranolol, and bisoprolol.

It is important to note that while beta blockers can have many benefits, they can also cause side effects such as fatigue, dizziness, and shortness of breath. Additionally, sudden discontinuation of beta blocker therapy can lead to rebound hypertension or worsening chest pain. Therefore, it is important to follow the dosing instructions provided by a healthcare provider carefully when taking these medications.

Glycopyrrolate is an anticholinergic medication that works by blocking the action of acetylcholine, a chemical messenger in the body. It reduces the secretions of certain organs and is used to treat various conditions such as peptic ulcers, reducing saliva production during surgical procedures, preventing motion sickness, and managing some symptoms of Parkinson's disease.

In medical terms, glycopyrrolate is a competitive antagonist of muscarinic acetylcholine receptors. It has a particular affinity for the M1, M2, and M3 receptor subtypes. By blocking these receptors, it inhibits the parasympathetic nervous system's effects on various organs, leading to decreased glandular secretions (such as saliva, sweat, and gastric acid), slowed heart rate, and relaxation of smooth muscles in the digestive tract and bronchioles.

Glycopyrrolate is available in oral, intravenous, and topical forms and should be used under the supervision of a healthcare professional due to its potential side effects, including dry mouth, blurred vision, dizziness, drowsiness, and urinary retention.

Indoramin is not a medical condition, but rather a medication. It is a second-generation antihistamine and alpha-1 receptor blocker. It is primarily used in the treatment of high blood pressure (hypertension) and occasionally for the short-term treatment of symptoms associated with menopause.

Indoramin works by blocking the action of certain chemicals, such as histamine and norepinephrine, in the body. This leads to a relaxation of the muscle in the walls of blood vessels, which results in decreased blood pressure. It also helps to relieve symptoms associated with menopause, such as hot flashes, by blocking the action of histamine in the brain.

It is important to note that Indoramin should only be used under the supervision of a healthcare provider and may cause side effects, including dizziness, dry mouth, and drowsiness.

Muscarinic antagonists, also known as muscarinic receptor antagonists or parasympatholytics, are a class of drugs that block the action of acetylcholine at muscarinic receptors. Acetylcholine is a neurotransmitter that plays an important role in the parasympathetic nervous system, which helps to regulate various bodily functions such as heart rate, digestion, and respiration.

Muscarinic antagonists work by binding to muscarinic receptors, which are found in various organs throughout the body, including the eyes, lungs, heart, and gastrointestinal tract. By blocking the action of acetylcholine at these receptors, muscarinic antagonists can produce a range of effects depending on the specific receptor subtype that is affected.

For example, muscarinic antagonists may be used to treat conditions such as chronic obstructive pulmonary disease (COPD) and asthma by relaxing the smooth muscle in the airways and reducing bronchoconstriction. They may also be used to treat conditions such as urinary incontinence or overactive bladder by reducing bladder contractions.

Some common muscarinic antagonists include atropine, scopolamine, ipratropium, and tiotropium. It's important to note that these drugs can have significant side effects, including dry mouth, blurred vision, constipation, and confusion, especially when used in high doses or for prolonged periods of time.

A "premature infant" is a newborn delivered before 37 weeks of gestation. They are at greater risk for various health complications and medical conditions compared to full-term infants, due to their immature organ systems and lower birth weight. Some common diseases and health issues that premature infants may face include:

1. Respiratory Distress Syndrome (RDS): A lung disorder caused by the lack of surfactant, a substance that helps keep the lungs inflated. Premature infants, especially those born before 34 weeks, are at higher risk for RDS.
2. Intraventricular Hemorrhage (IVH): Bleeding in the brain's ventricles, which can lead to developmental delays or neurological issues. The risk of IVH is inversely proportional to gestational age, meaning that the earlier the infant is born, the higher the risk.
3. Necrotizing Enterocolitis (NEC): A gastrointestinal disease where the intestinal tissue becomes inflamed and can die. Premature infants are at greater risk for NEC due to their immature digestive systems.
4. Jaundice: A yellowing of the skin and eyes caused by an accumulation of bilirubin, a waste product from broken-down red blood cells. Premature infants may have higher rates of jaundice due to their liver's immaturity.
5. Infections: Premature infants are more susceptible to infections because of their underdeveloped immune systems. Common sources of infection include the mother's genital tract, bloodstream, or hospital environment.
6. Anemia: A condition characterized by a low red blood cell count or insufficient hemoglobin. Premature infants may develop anemia due to frequent blood sampling, rapid growth, or inadequate erythropoietin production.
7. Retinopathy of Prematurity (ROP): An eye disorder affecting premature infants, where abnormal blood vessel growth occurs in the retina. Severe ROP can lead to vision loss or blindness if not treated promptly.
8. Developmental Delays: Premature infants are at risk for developmental delays due to their immature nervous systems and environmental factors such as sensory deprivation or separation from parents.
9. Patent Ductus Arteriosus (PDA): A congenital heart defect where the ductus arteriosus, a blood vessel that connects two major arteries in the fetal heart, fails to close after birth. Premature infants are at higher risk for PDA due to their immature cardiovascular systems.
10. Hypothermia: Premature infants have difficulty maintaining body temperature and are at risk for hypothermia, which can lead to increased metabolic demands, poor feeding, and infection.

Propranolol is a medication that belongs to a class of drugs called beta blockers. Medically, it is defined as a non-selective beta blocker, which means it blocks the effects of both epinephrine (adrenaline) and norepinephrine (noradrenaline) on the heart and other organs. These effects include reducing heart rate, contractility, and conduction velocity, leading to decreased oxygen demand by the myocardium. Propranolol is used in the management of various conditions such as hypertension, angina pectoris, arrhythmias, essential tremor, anxiety disorders, and infants with congenital heart defects. It may also be used to prevent migraines and reduce the risk of future heart attacks. As with any medication, it should be taken under the supervision of a healthcare provider due to potential side effects and contraindications.

... is also part of the mammalian diving reflex. A diagnosis of bradycardia in adults is based on a heart rate less ... Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an ... The word "bradycardia" is from the Greek βραδύς bradys "slow", and καρδία kardia "heart". Atrial bradycardias are divided into ... Ventricular bradycardias occurs with sinus bradycardia, sinus arrest, and AV block. Treatment often consists of the ...
... is when people with temporal lobe epilepsy experience bradycardia with their seizures (epileptic discharges ... In comparison, ictal bradycardia causes epileptic discharges that disrupt the normal cardiac rhythm in a negative fashion. ... Slowing the heart beat down by more than 10 beats per minute below the average baseline.[citation needed] Ictal bradycardia is ... Although there is limited amount of information about ictal bradycardia, as it is a relatively new discovery and is considered ...
... is a bradycardia (decrease in heart rate) in response to the baroreceptor reflex, one of the body's ... In the presence of high mean arterial pressure, the baroreceptor reflex produces a reflex bradycardia as a method of decreasing ... Stimuli causing reflex bradycardia include: Oculocardiac reflex Sympathetic response to intracranial hypertension Systemically ... In reflex bradycardia, blood pressure is reduced by decreasing cardiac output (CO) via a decrease in heart rate (HR).[citation ...
Bradycardia is not necessarily problematic. People who practice sports may have sinus bradycardia, because their trained hearts ... "Sinus Bradycardia". Cedars-Sinai. Retrieved 2020-07-28. "Bradycardia - Signs and Symptoms , CardioSmart - American College of ... Sinus bradycardia is a sinus rhythm with a reduced rate of electrical discharge from the sinoatrial node, resulting in a ... Sinus bradycardia is a common condition found in both healthy individuals and those who are considered well-conditioned ...
... bradycardia; severe heart failure or coronary artery disease. Also: Raynaud's syndrome, intermittent claudication, epilepsy, ...
Chronic Bradycardia. Arch Intern Med (Chic). 1920;26(5):630-646. Observations on Negativity of the Final Ventricular T-Wave of ...
A heart rate below normal is called "bradycardia" (. 100 in adults). A complication of this is when the atria and ventricles ... "Bradycardia - an overview , ScienceDirect Topics". www.sciencedirect.com. Retrieved 28 October 2022. "Sample records for qrs ... arrhythmia Sinus bradycardia and sinus tachycardia Sinus pause and sinoatrial arrest Sinus node dysfunction and bradycardia- ... then it is sinus bradycardia. If it is not a sinus rhythm, then determining the rhythm is necessary before proceeding with ...
Control of bradycardia. Control of bronchodilatation. Methoctramine was shown to produce some cytotoxic effects, being the ... particularly against bradycardia. However, currently it is only addressed for research purposes, since the administration to ...
Bradycardia is a low heart rate, defined as below 60 bpm at rest. When a human sleeps, a heartbeat with rates around 40-50 bpm ... Bradycardia is defined as a resting heart rate below 60 bpm. However, heart rates from 50 to 60 bpm are common among healthy ... Bradycardia may be associated with medical conditions such as hypothyroidism. Trained athletes tend to have slow resting heart ... "Bradycardia - Symptoms and causes". Mayo Clinic. Retrieved 2021-08-08. Guinness World Records 2004 (Bantam ed.). New York: ...
"Bradycardia - Symptoms and causes". Mayo Clinic. Retrieved 2018-06-08. Maguire, Lillias H.; Thomas, Alyssa R.; Goldstein, Allan ... ROHHAD patients also often experience bradycardia, or low heart rate. This may require a cardiac pacemaker be placed in order ...
The strength of this reflex is greater in colder water and has three principal effects: Bradycardia, a slowing of the heart ... "Bradycardia - Symptoms and causes". Mayo Clinic. Retrieved 17 September 2022. Lundgren, Claus E. G.; Ferrigno, Massimo, eds. ( ... sinus bradycardia, or atrial fibrillation. Long-term neurological outcomes of drowning cannot be predicted accurately during ...
"Can Sinus Bradycardia Be Inherited?". NEJM Journal Watch. Massachusetts Medical Society. Campbell, Neil; Reece, Jane (2005). ...
"Relative bradycardia" may also be present, which is low to normal heart rate despite the presence of a fever. Laboratory tests ... ISBN 978-1-904455-26-4. Ostergaard L, Huniche B, Andersen PL (November 1996). "Relative bradycardia in infectious diseases". J ...
Atropine is administered for bradycardia. It acts on the vagus nerve so it's not effective in heart transplant patients as the ... Neurogenic shock is a distributive type of shock resulting in hypotension (low blood pressure), often with bradycardia (slowed ... respirations will be irregular and bradycardia will also be a feature. Neurogenic shock is diagnosed based on a person's ...
Follow bradycardia, prolonged QT closely. Roden DM (August 1998). "Mechanisms and management of proarrhythmia". Am. J. Cardiol ...
29 July 1893 Bradycardia in Health. 22 August 1903 Goats Milk for Infants. 29 September 1906 Pneumonia in Alcoholic Subjects. 6 ...
"Atropine and bradycardia after myocardial infarction". Kounis NG, Chopra RK. Ann Intern Med 1974; 81: 117-8. "Oxytetracycline- ...
Sinus bradycardia is also very common. In addition, depressed conduction is a predominant feature of digoxin toxicity. Other ...
By convention, a heart rate of less than 60 beats per minute in the adult patient is called bradycardia. Not all instances of ... It is only when bradycardia presents with signs and symptoms of shock that it requires emergency treatment with transcutaneous ... Some common causes of hemodynamically significant bradycardia include myocardial infarction, sinus node dysfunction and ... "The Evaluation and Management of Bradycardia". New England Journal of Medicine. 342 (10): 703-709. doi:10.1056/ ...
"Adult Bradycardia with a Pulse Algorithm". cpr.heart.org. 2021. Retrieved 2021-02-21. American Academy of Orthopaedic Surgeons ...
Complications include bradycardia, hypotension and hypothermia. Substances that may cause this toxidrome are opioids. The ... Complications include bradycardia, hypothermia and tachypnea. Substances that may cause this toxidrome include carbamates, ...
Fernandes CM, Daya MR (April 1995). "Sotalol-induced bradycardia reversed by glucagon". Canadian Family Physician. 41: 659-60, ... bradycardia (slow heart rate), a sensation of the heart beating too hard, fast, or irregularly, or chest pain. Higher doses of ...
Bradycardia is the response to facial contact with cold water: the human heart rate slows down ten to twenty-five percent. ... The diving bradycardia was first described by Edmund Goodwyn in 1786 and later by Paul Bert in 1870. Blood shift - Set index ... Mild bradycardia is caused by subjects holding their breath without submerging the face in water. When breathing with the face ... However, the greatest bradycardia effect is induced when the subject is holding their breath with their face wetted. Apnea with ...
Two major groups of arrhythmias are bradycardia and tachycardia. Bradycardia can be caused by heart blocks. Tachycardias ... Sick sinus syndrome, a sinus node dysfunction, causing alternating bradycardia and tachycardia. Often there is a long pause ( ... Various medications, such as beta blockers, may cause bradycardia induced syncope. A pulmonary embolism can cause obstructed ... This condition, called tachycardia-bradycardia syndrome, is usually caused by sinoatrial node dysfunction or block or ...
It is a cause of reflex bradycardia. Spontaneous intracranial hypotension may occur as a result of an occult leak of CSF into ... Cushing's triad involves an increased systolic blood pressure, a widened pulse pressure, bradycardia, and an abnormal ...
One person was hospitalized due to bradycardia. The National Institute for Occupational Safety and Health (NIOSH) began an ...
Hyperkalemia can develop and cause severe bradycardia. Only typical Addison's patients have the risk of Addisonian crisis due ... Electrocardiogram findings include sinus bradycardia, sinus arrest, sinoatrial heart block, and atrial tachycardia. The major ...
Patients with bradycardia are treated with atropine. Atropine is a muscarinic antagonist, which can obstruct the muscarinic ... Jones, Peter; Dauger, Stéphane; Peters, Mark J (2011-05-28). "Bradycardia during critical care intubation: mechanisms, ...
Symptoms include bradycardia, hypotension, miosis and sedation. There is a lack of information regarding toxicity caused by ... Toxicity of beta-1 blocker will contribute to symptoms including bradycardia, hypotension, due to its extensive blockage of ... The cardio-selective beta-1 blockers could cause adverse effects including bradycardia, reduced exercise ability, hypotension, ...
Bradycardia - Fewer heart beats per time unit. Both these effects lead to hypotension, which gives many symptoms including: ... Atropine has been used successfully in humans to treat bradycardias and arrhythmias caused by taxine. It is more effective if ... This produces bradycardia, hypotension, depressed myocardial contractility, conduction delay, arrhythmias, and other ...
Bradycardia is also part of the mammalian diving reflex. A diagnosis of bradycardia in adults is based on a heart rate less ... Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an ... The word "bradycardia" is from the Greek βραδύς bradys "slow", and καρδία kardia "heart". Atrial bradycardias are divided into ... Ventricular bradycardias occurs with sinus bradycardia, sinus arrest, and AV block. Treatment often consists of the ...
Bradycardia heart rhythms are characterized by a slowness of the heartbeat, usually at a rate under 60 beats per minute (normal ... Bradycardia heart rhythms are characterized by a slowness of the heartbeat, usually at a rate under 60 beats per minute (normal ...
Cite this: ECG Challenge: Bradycardia in an Active Woman - Medscape - Dec 27, 2016. ...
Sinus bradycardia can be defined as a sinus rhythm with a resting heart rate of 60 beats per minute or less. However, few ... Causes of sinus bradycardia include the following:. * One of the most common pathologic causes of symptomatic sinus bradycardia ... The pathophysiology of sinus bradycardia is dependent on the underlying cause. [1] Commonly, sinus bradycardia is an incidental ... encoded search term (Sinus Bradycardia) and Sinus Bradycardia What to Read Next on Medscape ...
Sinus bradycardia is a heart rhythm thats slower than expected, but otherwise normal. Severe cases that cause symptoms are ... Why is it called sinus bradycardia?. The term "sinus bradycardia" breaks down based on the two words. Bradycardia comes from ... An electrocardiogram example of sinus bradycardia.. What is sinus bradycardia?. Sinus bradycardia is a heart rhythm thats ... Sinus Bradycardia. Sinus bradycardia is a heart rhythm where your heart beats slower than expected (under 60 beats per minute ...
... Therapy A bradycardia is a condition of the heart, where the heart is beating in a (sometimes irregular) rhythm ... Bradycardia Therapy. A bradycardia is a condition of the heart, where the heart is beating in a (sometimes irregular) rhythm ... In these cases bradycardia therapy aims at restoring a regular sinus rhythm and sufficient heart rate through battery-powered ...
Learn more about the signs and symptoms of bradycardia. ... The American Heart Association defines bradycardia as the ... Treatment of bradycardia. Borderline or occasional bradycardia may not require treatment.. Severe or prolonged bradycardia can ... ECG strip showing bradycardia. Bradycardia is a heart rate thats too slow. Whats considered too slow can depend on your age ... Symptoms of bradycardia. A heart rate thats too slow can cause insufficient blood flow to the brain. Symptoms of bradycardia ...
If untreated, bradycardia can lead to complications, including congestive heart failure, stroke and, in some cases, sudden ...
Diving bradycardia should slow blood oxygen depletion and enhance dive time available for foraging at depth. However, blue ... Despite extreme bradycardia, we recorded a 2.5-fold increase above diving heart rate minima during the powered ascent phase of ... Extreme Bradycardia and Tachycardia in the Worlds Largest Animal. Proceedings of the National Academy of Sciences 116(50): ... Diving bradycardia should slow blood oxygen depletion and enhance dive time available for foraging at depth. However, blue ...
NOTOC__ {{Bradycardia}} Please help WikiDoc by adding content here. Its easy! Click [[Help:How_to_Edit_a_Page,here]] to learn ... Return to Bradycardia secondary prevention.. Retrieved from "https://www.wikidoc.org/index.php/Bradycardia_secondary_prevention ... Overview == There are no established measures for the secondary prevention of bradycardia. == Secondary Prevention == There are ... no established measures for the secondary prevention of bradycardia. ==References== {{Reflist,2}} [[Category:Needs content]] ...
Commercial: Amazon / FDA / bradycardia tachycardia #1376008. CBS Evening News for Friday, May 06, 2022 View other clips in this ...
Learn about heart condition Bradycardia, its symptoms, causes, diagnosis, treatment and prevention. ... How can bradycardia be prevented? Bradycardia is not typically preventable. However, it is possible to reduce the risk of heart ... What causes bradycardia? Bradycardia can be normal for people who are very physically fit - such as competitive athletes. It ... How is bradycardia treated? Treatment options will vary depending on the cause of the bradycardia. People that are physically ...
Christophe Beyls, M.D., from Amiens University Hospital in France, and colleagues examined the risk for bradycardia for COVID- ... treatment of COVID-19 is associated with an increased risk for bradycardia, according to a study published online July 9 in ... Nine patients experienced bradycardia, eight with sinus bradycardia and one with third-degree atrioventricular block. The ... the risk of bradycardia," the authors write. "Nevertheless, bradycardia could be a sign of severe cardiological or neurological ...
A 9 months old child with Asymptomatic Bradycardia. A 9 months old child with Asymptomatic Bradycardia. 10/08/2019 10/08/2019 ... Mall P, Shah I. A 9 months old child with Asymptomatic Bradycardia. Pediatr Oncall J. 2020;17. doi: 10.7199/ped.oncall.2020.13 ... Mall P, Shah I. A 9 months old child with Asymptomatic Bradycardia. Pediatr Oncall J. 2020;17. doi: 10.7199/ped.oncall.2020.13 ... A 9-month old boy, born of a non-consanguineous marriage was referred for bradycardia. The child was otherwise asymptomatic. On ...
... bradycardia, cyanosis (ABC), and the relation with the duration of bradycardia and/or SpO2 ≤80%. ... In ABCs where oxygen supply was increased, duration and severity of bradycardia (,80 bpm), SpO2 ≤80%, SpO2 ≥95% and their ... The risk for hyperoxaemia after apnoea, bradycardia and hypoxaemia in preterm infants ... The risk for hyperoxaemia after apnoea, bradycardia and hypoxaemia in preterm infants ...
Pressure applied to the carotid sinuses produces bradycardia.... taken from Advanced Diving: Technology and Techniques Is it ... Well, yes, if your suit is too tight, you could produce a bradycardia. However, since your force it, and your body isnt ... The overall is effect is a transient bradycardia. This increased thoracic pressure also immediately lowers the flow of blood ... It is better to get bradycardia by being relaxed than by forcing it.... K. Feenstra ...
Review: β blockers reduce mortality and therapy withdrawal in heart failure but increase dizziness and bradycardia ... Review: β blockers reduce mortality and therapy withdrawal in heart failure but increase dizziness and bradycardia ... all cause therapy withdrawal, all cause mortality, HF hospital admission, worsening HF, hypotension, dizziness, bradycardia, ... and all cause withdrawal of treatment but increased the risks of dizziness and bradycardia; groups did not differ for ...
Bradycardia after Myocardial Ischemia and Its Treatment with Atropine Paul Dauchot, M.D; Paul Dauchot, M.D ... Paul Dauchot, J. S. Gravenstein; Bradycardia after Myocardial Ischemia and Its Treatment with Atropine. Anesthesiology 1976; 44 ...
... is also part of the mammalian diving reflex.[10]. Diagnosis. A diagnosis of bradycardia in adults is based on a ... Bradycardia Bradycardia is a condition typically defined wherein an individual has a resting heart rate of under 60 beats per ... Patients with bradycardia have likely acquired it, as opposed to having it congenitally. Bradycardia is more common in older ... See also: Sinus bradycardia and Sick sinus syndrome. Atrial bradycardias are divided into three types. The first, respiratory ...
An adult is generally considered to have bradycardia if his or her heart rate is below 60 beats per minute. ... The term bradycardia is used if the heart rate is abnormally low. ... The term bradycardia is used if the heart rate is abnormally low. An adult is generally considered to have bradycardia if his ...
... bradycardia is a possible of., symptoms can develop a low heart rate that s called bradycardiabradycardia is a critical of ... You have bradycardia, your resting heart rate is normal for some people such. Reviewed against periods of bradycardia is a slow ... Bradycardia; Signs and Symptoms. Propofol and dexmedetomidine infusion in…. This case study describes sinus bradycardia … ... When heart rate habitually drops below 60 beats per minute, the condition is called bradycardia. Transient sinus bradycardia is ...
Always Ayurveda is a sister concern of Planet Ayurveda [USFDA Regd], GMP certified, ISO 9001-2015 Certified Manufacturing unit based in India. Dr. Vikram Chauhan (MD-Ayurveda) is CEO & Founder of Planet Ayurveda, who is having expertise in medicinal plants from all over the world. He believes in natures relieving power and working since 1999 to spread the knowledge of Ayurveda - the traditional healthcare system of India. ...
ALS - MCQ. Advanced Life Support Multiple Choice Questions. ...
Acetazolamide and Bradycardia. This page shows results related to Acetazolamide and Bradycardia from the FDA Adverse Event ...
Our main objective is to ensure high-quality Bradycardia Treatment at a price that is reasonable, affordable and transparent. ... Bradycardia is a serious condition that requires prompt and appropriate treatment. If you have Bradycardia, its important to ... What are the Bradycardia Treatment options? There are several treatment options available for people with Bradycardia. ... All You Need to Know About Bradycardia Treatment: Bradycardia is a condition where the heart beats too slowly, typically less ...
Steroids and bradycardia: How slow can you go? / Hsu, Daphne T. In: Journal of Pediatric Hematology/Oncology, Vol. 30, No. 2, ... Steroids and bradycardia: How slow can you go? Journal of Pediatric Hematology/Oncology. 2008 Feb 1;30(2):119-120. doi: 10.1097 ... Hsu, D. T. (2008). Steroids and bradycardia: How slow can you go? Journal of Pediatric Hematology/Oncology, 30(2), 119-120. ... Hsu, DT 2008, Steroids and bradycardia: How slow can you go?, Journal of Pediatric Hematology/Oncology, vol. 30, no. 2, pp. ...
Bradycardia. Bradycardia is an unusually slow heart rate. While there are several types of bradycardia, two types are more ... Sinus bradycardia: Sinus bradycardia is more common in premature babies.. *Heart block: Heart block happens when electrical ...
Learn everything about Bradycardia Part 1 Basics of the conduction system All you need to know about sinus node dysfunction ... What is a preautomatic pause? What is bradycardia-tachycardia syndrome? ... Second degree SA block type 2 is also known as Mobitz type 2, and usually presents as sinus bradycardia or sinus arrhythmia.. ... To detect bradycardia on the ECG, you must first be familiar with three basic principles.. ...
  • The syndrome includes signs and symptoms related to cerebral hypoperfusion in association with sinus bradycardia, sinus arrest, sinoatrial (SA) block, carotid hypersensitivity, or alternating episodes of bradycardia and tachycardia. (medscape.com)
  • What is bradycardia-tachycardia syndrome? (ecgbuddy.com)
  • Bradycardia refers to slower than normal heart rate (under 60 beats per minute), while tachycardia refers to faster than normal heat rate (over 100 beats per minute). (studentrdh.com)
  • Bradycardia- tachycardia syndrome are alternatives to sick sinus disorders, in which fast and slow heartbeats develop. (drvikram.com)
  • In this article, we are going to discuss bradycardia and tachycardia syndrome, its types, symptoms, causes, diagnosis and ayurvedic BTS care pack which is offered by Planet Ayurveda. (drvikram.com)
  • In addition there are a number of toxins that will occasionally lead to bradycardia and hypotension in very severe poisoning but which usually cause either tachycardia or no change to heart rate. (wikitox.org)
  • What are the symptoms of bradycardia? (edu.au)
  • In some cases, medications may be used to help manage symptoms of Bradycardia. (treatmentpossible.com)
  • Treating the underlying condition can help improve symptoms of Bradycardia. (treatmentpossible.com)
  • Making certain lifestyle changes can also help manage symptoms of Bradycardia and reduce the risk of complications. (treatmentpossible.com)
  • Patient 4 had three episodes of bradycardia, starting on day 10 of illness. (sundaysandcompany.com)
  • These portable devices continuously record the heart's electrical activity over a period of time, allowing for the detection of intermittent episodes of bradycardia that may not be captured during a short-term ECG. (bpincontrol.in)
  • The bradycardia could be diminished by atropine and its onset delayed by prior ventilation with oxygen. (sundaysandcompany.com)
  • Pediatric rapid sequence intubation incidence of reflex bradycardia and effects of pretreatment with atropine. (qxmd.com)
  • Atropine sulfate blocks the muscarinic effects of acetylcholine that cause bronchorrhoea, hypersalivation, bronchoconstriction and bradycardia, thereby reducing these effects. (who.int)
  • One of the most common pathologic causes of symptomatic sinus bradycardia is the sick sinus syndrome. (medscape.com)
  • It is imperative to maintain a broad differential with symptomatic bradycardia. (sundaysandcompany.com)
  • Severe or symptomatic bradycardia (heart rate less than 60 beats per minute). (sundaysandcompany.com)
  • A pacemaker is often the first line of treatment for people with symptomatic Bradycardia. (treatmentpossible.com)
  • Idioventricular rhythm, also known as atrioventricular bradycardia or ventricular escape rhythm, is a heart rate of less than 50 BPM. (wikipedia.org)
  • Ventricular bradycardias occurs with sinus bradycardia, sinus arrest, and AV block. (wikipedia.org)
  • Sinus bradycardia in athletes - physiological, with a high frequent wandering tone almost half of them simultaneously have sinus bradycardia and left ventricular hypertrophy, since with increasing volume and internal pressure, due to increased physical exertion, the heart rate decreases. (healthysinus.net)
  • In patients with heart failure (HF) with systolic dysfunction, β blockers reduce the risks of all cause mortality, HF hospital admission, worsening HF, and all cause withdrawal of treatment, but are associated with increased risks of dizziness and bradycardia. (bmj.com)
  • Bradycardia can cause dizziness, weakness, lack of energy or fainting spells. (sundaysandcompany.com)
  • There are a relatively small number of toxins that commonly lead to hypotension and bradycardia. (wikitox.org)
  • One hypothesis is that the inflammatory damage associated with COVID-19 increases intestinal absorption of RTV/LPV in elderly patients and [increases] the risk of bradycardia," the authors write. (physiciansweekly.com)
  • Factors that raise the risk of producing heart issues also increase the higher risk of bradycardia. (drvikram.com)
  • In this article, we will explore the term bradycardia - meaning and its significance in cardiovascular health. (bpincontrol.in)
  • The term bradycardia refers to a number of conditions in which the heart beats slower than usual. (bestherbalhealth.com)
  • The term "relative bradycardia" is used to refer to a heart rate slower than an individual's typical resting heart rate. (wikipedia.org)
  • All patients improved and relative bradycardia as a characteristic clinical feature were discharged. (cdc.gov)
  • Relative bradycardia is a characteristic physi- tions or medications) were excluded. (cdc.gov)
  • The term "relative bradycardia" is used to refer to a heart rate that, although not actually below 60 BPM, is still considered too slow for the individual's current medical condition. (iiab.me)
  • Severe or prolonged bradycardia can be treated in a few ways. (goredforwomen.org)
  • Nevertheless, bradycardia could be a sign of severe cardiological or neurological impairment since it is associated with lymphopenia that seems to reflect the severity of COVID-19 infection. (physiciansweekly.com)
  • An adult is generally considered to have bradycardia if his or her heart rate is below 60 beats per minute. (futura-sciences.us)
  • When heart rate habitually drops below 60 beats per minute, the condition is called bradycardia. (sundaysandcompany.com)
  • An AV-junctional rhythm, or atrioventricular nodal bradycardia, is usually caused by the absence of the electrical impulse from the sinus node. (wikipedia.org)
  • Nine patients experienced bradycardia, eight with sinus bradycardia and one with third-degree atrioventricular block. (physiciansweekly.com)
  • In some cases, Bradycardia can lead to more serious complications, such as fainting or even cardiac arrest. (treatmentpossible.com)
  • Sinus bradycardia may be seen in hypothermia , hypoglycemia , and sleep apnea . (medscape.com)
  • In some cases, Bradycardia may be caused by an underlying condition, such as hypothyroidism or sleep apnea. (treatmentpossible.com)
  • Sinus bradycardia is a sinus rhythm of less than 60 BPM. (wikipedia.org)
  • Bradycardia is a slower than normal heart rate - usually less than 60 beats per minute. (edu.au)
  • Bradycardia can cause a heart rate of less than 60 bpm. (sundaysandcompany.com)
  • This is variably defined as less than 60 or 50 beats per minute depending on the source … Electrocardiogram (ECG) findings included sinus bradycardia. (sundaysandcompany.com)
  • Bradycardia is a condition where the heart beats too slowly, typically less than 60 beats per minute. (treatmentpossible.com)
  • Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an electrocardiogram. (wikipedia.org)
  • Bradycardia heart rhythms are characterized by a slowness of the heartbeat, usually at a rate under 60 beats per minute (normal resting rate is 60 to 100 beats per minute). (medlineplus.gov)
  • Sinus bradycardia can be defined as a sinus rhythm with a resting heart rate of 60 beats per minute or less. (medscape.com)
  • Sinus bradycardia is a heart rhythm where your heart beats slower than expected (under 60 beats per minute for adults) but otherwise works normally. (clevelandclinic.org)
  • Sinus bradycardia is a heart rhythm that's slower than expected (fewer than 60 beats per minute in an adult) but is otherwise normal. (clevelandclinic.org)
  • In general, for adults, a resting heart rate of fewer than 60 beats per minute (BPM) qualifies as bradycardia. (goredforwomen.org)
  • As the intrinsic rhythm of the ventricles has a much lower frequency (about 40 beats/minute), compared to that of the atria (100 beats/minute) 1 , this condition manifests clinically as bradycardia. (pediatriconcall.com)
  • Bradycardia is a condition typically defined wherein an individual has a resting heart rate of under 60 beats per minute (BPM) in adults. (iiab.me)
  • Sometimes, the heart beats too slow, this abnormal heart rhythm issue is called Bradycardia syndrome. (drvikram.com)
  • If you are suffering with bradycardia, your heart beats lower than 60 times a minute. (drvikram.com)
  • In individuals with bradycardia , the heart beats at a rate that is below the standard resting heart rate, which is typically between 60 to 100 beats per minute in adults. (bpincontrol.in)
  • A heart rate below 60 beats a minute is considered bradycardia. (mayoclinic.org)
  • Athletes may have athletic heart syndrome, which includes bradycardia as part of the cardiovascular adaptations to training and participation. (wikipedia.org)
  • Studies have found that 50-85% of conditioned athletes have benign sinus bradycardia, as compared to 23% of the general population studied. (wikipedia.org)
  • [ 1 ] Commonly, sinus bradycardia is an incidental finding in otherwise healthy individuals, particularly in young adults, athletes or sleeping patients. (medscape.com)
  • Bradycardia can be normal for people who are very physically fit - such as competitive athletes. (edu.au)
  • Bradycardias can be a physiological state in athletes, but they can also be of significant concern. (libsyn.com)
  • Bradycardia can occur in athletes or in people who enter a state of deep relaxation. (bestherbalhealth.com)
  • For infants, bradycardia is defined as a heart rate less than 100 BPM (normal is around 120-160 BPM). (wikipedia.org)
  • In these cases bradycardia therapy aims at restoring a regular sinus rhythm and sufficient heart rate through battery-powered devices (referred to as pacemakers or implantable pulse generators [IPG]) using small electrical impulses delivered through leads directly to the heart in an effort to stimulate heart muscle cells externally, when intrinsic stimulation fails or is unreliable. (biotronik.com)
  • Bradycardia is a heart rate that's too slow. (goredforwomen.org)
  • Despite extreme bradycardia, we recorded a 2.5-fold increase above diving heart rate minima during the powered ascent phase of feeding lunges followed by a gradual decrease of heart rate during the prolonged glide as engulfed water is filtered. (cascadiaresearch.org)
  • In their study of 41 patients treated with lopinavir and ritonavir twice daily for 10 days, 22% developed a slow heart rate condition called bradycardia. (sundaysandcompany.com)
  • The primary symptom of bradycardia is a slow heart rate. (sundaysandcompany.com)
  • Bradycardia is a medical term for a slow heart rate. (sundaysandcompany.com)
  • Bradycardia is an unusually slow heart rate. (healthline.com)
  • So, the decrease in heart rate during hypothermia , as well as the sinus bradycardia that does not show itself in men and women of advanced age is a pathology, is the result of changes in the heart caused by aging. (healthysinus.net)
  • One such condition is bradycardia , which refers to a slow heart rate. (bpincontrol.in)
  • Bradycardia , derived from the Greek words "bradys" meaning slow and "kardia" meaning heart, is a medical term used to describe a condition characterized by a heart rate that is slower than the normal range. (bpincontrol.in)
  • Certain medications can help increase the heart rate and manage bradycardia. (bpincontrol.in)
  • If you have a slow heart rate and your heart isn't pumping enough blood, you may have a type of bradycardia. (mayoclinic.org)
  • Medications for other heart issues - Medications like digoxin, beta blockers and antiarrhythmics can also cause bradycardia. (drvikram.com)
  • With the right treatment and lifestyle changes, most people with Bradycardia can lead full and active lives without experiencing significant symptoms or complications. (treatmentpossible.com)
  • Without prompt treatment, bradycardia can lead to health complications. (bestherbalhealth.com)
  • When drugs are ineffective or there is significant bradycardia, pacemakers are frequently employed. (bpincontrol.in)
  • A total of 24 patients bradycardia. (cdc.gov)
  • Christophe Beyls, M.D., from Amiens University Hospital in France, and colleagues examined the risk for bradycardia for COVID-19 patients treated with LPV/RTV. (physiciansweekly.com)
  • Patients were classified according to presence of bradycardia and were compared. (physiciansweekly.com)
  • Patients with bradycardia were older, had higher RTV plasma concentration at 72 hours, and had a reduced lymphocyte count. (physiciansweekly.com)
  • Patients with imminent heart failure or unstable patients with bradycardia need immediate treatment. (healthysinus.net)
  • Treatment of bradycardia should be limited to patients in whom a clear correlation between symptoms and rhythm has been documented. (bestherbalhealth.com)
  • Patients with a history of fainting due to bradycardia may continue to have it recurrently. (bestherbalhealth.com)
  • Bradycardia can result from damage to either the sinus node or the AV node. (ecgbuddy.com)
  • When we talk about disorders of the sinus node, it is important to know the following terms that are all expressed by a pathological sinus node: sinus node syndrome, sick sinus syndrome, sinus node dysfunction, sinus node disease, sinu-atrial disease, and bradycardia-tachycardia syndrome. (ecgbuddy.com)
  • Nonetheless, persistent bradycardia may indicate an underlying health issue with the electrical system that controls the heart's rhythm, potentially affecting the heart's ability to pump blood efficiently throughout the body. (bpincontrol.in)
  • The overall is effect is a transient bradycardia. (deeperblue.com)
  • Transient sinus bradycardia is a possible manifestation of COVID-19 and is important for close CV surveillance. (sundaysandcompany.com)
  • Sinus bradycardia is less likely to occur in children (but still possible in rare cases) unless it happens because of a condition that a child has when they're born (congenital). (clevelandclinic.org)
  • Sinus bradycardia tends to happen in adults, especially those over age 65, as your heartbeat tends to naturally slow down as you age. (clevelandclinic.org)
  • Sinus bradycardia with symptoms happens in about 1 out of every 600 adults over age 65. (clevelandclinic.org)
  • Pressure applied to the carotid sinuses produces bradycardia. (deeperblue.com)
  • Clinicians … Activation of the orexin 1 receptor is a critical component of CO2-mediated anxiety and hypertension but not bradycardia. (sundaysandcompany.com)
  • The sinus bradycardia in pregnancy, which occurs in the first half due to the characteristic vomiting of the early toxicosis, also belongs to the physiological one, and at later dates - when the uterus begins to exert mechanical pressure on the lower vena cava. (healthysinus.net)
  • Below is the selection of side effect reports (a.k.a. adverse event reports) related to Metoprolol where reactions include bradycardia. (druglib.com)
  • Most people with sinus bradycardia don't have symptoms, making this a benign (harmless) condition. (clevelandclinic.org)
  • Bradycardia is not typically preventable. (edu.au)
  • The wide variety of etiologies responsible for bradycardia makes it, on its own, a typically nonspecific sign. (sundaysandcompany.com)
  • Borderline or occasional bradycardia may not require treatment. (goredforwomen.org)
  • FRIDAY, July 17, 2020 (HealthDay News) - Lopinavir/ritonavir (LPV/RTV) treatment of COVID-19 is associated with an increased risk for bradycardia, according to a study published online July 9 in Circulation: Arrhythmia and Electrophysiology . (physiciansweekly.com)
  • In this article, we'll discuss the most common Bradycardia Treatment options and what you should know about them. (treatmentpossible.com)
  • What are the Bradycardia Treatment options? (treatmentpossible.com)
  • There are several treatment options available for people with Bradycardia. (treatmentpossible.com)
  • Bradycardia is a serious condition that requires prompt and appropriate treatment. (treatmentpossible.com)
  • If you have Bradycardia, it's important to work closely with your doctor to develop a treatment plan that works best for you. (treatmentpossible.com)
  • Bradycardia (brad-e-KAHR-dee-uh) is a slow heartbeat. (mayoclinic.org)
  • Sinus bradycardia also happens normally to people who exercise regularly and are in very good physical condition. (clevelandclinic.org)
  • A bradycardia is a condition of the heart, where the heart is beating in a (sometimes irregular) rhythm that is too slow to maintain sufficient supply of oxygenated blood throughout the body. (biotronik.com)
  • NOTOC__ {{Bradycardia}} Please help WikiDoc by adding content here. (wikidoc.org)