The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.
An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.
A small nodular mass of specialized muscle fibers located in the interatrial septum near the opening of the coronary sinus. It gives rise to the atrioventricular bundle of the conduction system of the heart.
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.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
Transmission of sound waves through vibration of bones in the SKULL to the inner ear (COCHLEA). By using bone conduction stimulation and by bypassing any OUTER EAR or MIDDLE EAR abnormalities, hearing thresholds of the cochlea can be determined. Bone conduction hearing differs from normal hearing which is based on air conduction stimulation via the EAR CANAL and the TYMPANIC MEMBRANE.
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.
A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand.
Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.
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.
The period of time following the triggering of an ACTION POTENTIAL when the CELL MEMBRANE has changed to an unexcitable state and is gradually restored to the resting (excitable) state. During the absolute refractory period no other stimulus can trigger a response. This is followed by the relative refractory period during which the cell gradually becomes more excitable and the stronger impulse that is required to illicit a response gradually lessens to that required during the resting state.
A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm.
The chambers of the heart, to which the BLOOD returns from the circulation.
The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium.
Methods to induce and measure electrical activities at specific sites in the heart to diagnose and treat problems with the heart's electrical system.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
Impaired impulse conduction from HEART ATRIA to HEART VENTRICLES. AV block can mean delayed or completely blocked impulse conduction.
The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot.
A type of fluent aphasia characterized by an impaired ability to repeat one and two word phrases, despite retained comprehension. This condition is associated with dominant hemisphere lesions involving the arcuate fasciculus (a white matter projection between Broca's and Wernicke's areas) and adjacent structures. Like patients with Wernicke aphasia (APHASIA, WERNICKE), patients with conduction aphasia are fluent but commit paraphasic errors during attempts at written and oral forms of communication. (From Adams et al., Principles of Neurology, 6th ed, p482; Brain & Bannister, Clinical Neurology, 7th ed, p142; Kandel et al., Principles of Neural Science, 3d ed, p848)
Rapid, irregular atrial contractions caused by a block of electrical impulse conduction in the right atrium and a reentrant wave front traveling up the inter-atrial septum and down the right atrial free wall or vice versa. Unlike ATRIAL FIBRILLATION which is caused by abnormal impulse generation, typical atrial flutter is caused by abnormal impulse conduction. As in atrial fibrillation, patients with atrial flutter cannot effectively pump blood into the lower chambers of the heart (HEART VENTRICLES).
Diagnosis of disease states by recording the spontaneous electrical activity of tissues or organs or by the response to stimulation of electrically excitable tissue.
Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.
A branch of the tibial nerve which supplies sensory innervation to parts of the lower leg and foot.
Modified cardiac muscle fibers composing the terminal portion of the heart conduction system.
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).
Removal of tissue with electrical current delivered via electrodes positioned at the distal end of a catheter. Energy sources are commonly direct current (DC-shock) or alternating current at radiofrequencies (usually 750 kHz). The technique is used most often to ablate the AV junction and/or accessory pathways in order to interrupt AV conduction and produce AV block in the treatment of various tachyarrhythmias.
Diseases of the peripheral nerves external to the brain and spinal cord, which includes diseases of the nerve roots, ganglia, plexi, autonomic nerves, sensory nerves, and motor nerves.
A form of ventricular pre-excitation characterized by a short PR interval and a long QRS interval with a delta wave. In this syndrome, atrial impulses are abnormally conducted to the HEART VENTRICLES via an ACCESSORY CONDUCTING PATHWAY that is located between the wall of the right or left atria and the ventricles, also known as a BUNDLE OF KENT. The inherited form can be caused by mutation of PRKAG2 gene encoding a gamma-2 regulatory subunit of AMP-activated protein kinase.
Use of electric potential or currents to elicit biological responses.
A nerve which originates in the lumbar and sacral spinal cord (L4 to S3) and supplies motor and sensory innervation to the lower extremity. The sciatic nerve, which is the main continuation of the sacral plexus, is the largest nerve in the body. It has two major branches, the TIBIAL NERVE and the PERONEAL NERVE.
Neurons which activate MUSCLE CELLS.
The hemodynamic and electrophysiological action of the HEART ATRIA.
Peripheral, autonomic, and cranial nerve disorders that are associated with DIABETES MELLITUS. These conditions usually result from diabetic microvascular injury involving small blood vessels that supply nerves (VASA NERVORUM). Relatively common conditions which may be associated with diabetic neuropathy include third nerve palsy (see OCULOMOTOR NERVE DISEASES); MONONEUROPATHY; mononeuropathy multiplex; diabetic amyotrophy; a painful POLYNEUROPATHY; autonomic neuropathy; and thoracoabdominal neuropathy. (From Adams et al., Principles of Neurology, 6th ed, p1325)
A voltage-gated sodium channel subtype that mediates the sodium ion PERMEABILITY of CARDIOMYOCYTES. Defects in the SCN5A gene, which codes for the alpha subunit of this sodium channel, are associated with a variety of CARDIAC DISEASES that result from loss of sodium channel function.
Regularly spaced gaps in the myelin sheaths of peripheral axons. Ranvier's nodes allow saltatory conduction, that is, jumping of impulses from node to node, which is faster and more energetically favorable than continuous conduction.
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)
A 43-kDa peptide which is a member of the connexin family of gap junction proteins. Connexin 43 is a product of a gene in the alpha class of connexin genes (the alpha-1 gene). It was first isolated from mammalian heart, but is widespread in the body including the brain.
Abnormally rapid heartbeats caused by reentry of atrial impulse into the dual (fast and slow) pathways of ATRIOVENTRICULAR NODE. The common type involves a blocked atrial impulse in the slow pathway which reenters the fast pathway in a retrograde direction and simultaneously conducts to the atria and the ventricles leading to rapid HEART RATE of 150-250 beats per minute.
The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot.
Abnormal cardiac rhythm that is characterized by rapid, uncoordinated firing of electrical impulses in the upper chambers of the heart (HEART ATRIA). In such case, blood cannot be effectively pumped into the lower chambers of the heart (HEART VENTRICLES). It is caused by abnormal impulse generation.
Entrapment of the MEDIAN NERVE in the carpal tunnel, which is formed by the flexor retinaculum and the CARPAL BONES. This syndrome may be associated with repetitive occupational trauma (CUMULATIVE TRAUMA DISORDERS); wrist injuries; AMYLOID NEUROPATHIES; rheumatoid arthritis (see ARTHRITIS, RHEUMATOID); ACROMEGALY; PREGNANCY; and other conditions. Symptoms include burning pain and paresthesias involving the ventral surface of the hand and fingers which may radiate proximally. Impairment of sensation in the distribution of the median nerve and thenar muscle atrophy may occur. (Joynt, Clinical Neurology, 1995, Ch51, p45)
Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.
Recording of regional electrophysiological information by analysis of surface potentials to give a complete picture of the effects of the currents from the heart on the body surface. It has been applied to the diagnosis of old inferior myocardial infarction, localization of the bypass pathway in Wolff-Parkinson-White syndrome, recognition of ventricular hypertrophy, estimation of the size of a myocardial infarct, and the effects of different interventions designed to reduce infarct size. The limiting factor at present is the complexity of the recording and analysis, which requires 100 or more electrodes, sophisticated instrumentation, and dedicated personnel. (Braunwald, Heart Disease, 4th ed)
A form of heart block in which the electrical stimulation of HEART VENTRICLES is interrupted at either one of the branches of BUNDLE OF HIS thus preventing the simultaneous depolarization of the two ventricles.
The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.
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.
Recording of the changes in electric potential of muscle by means of surface or needle electrodes.
Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.
A group of homologous proteins which form the intermembrane channels of GAP JUNCTIONS. The connexins are the products of an identified gene family which has both highly conserved and highly divergent regions. The variety contributes to the wide range of functional properties of gap junctions.
The hollow, muscular organ that maintains the circulation of the blood.
A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.
Diseases of multiple peripheral nerves simultaneously. Polyneuropathies usually are characterized by symmetrical, bilateral distal motor and sensory impairment with a graded increase in severity distally. The pathological processes affecting peripheral nerves include degeneration of the axon, myelin or both. The various forms of polyneuropathy are categorized by the type of nerve affected (e.g., sensory, motor, or autonomic), by the distribution of nerve injury (e.g., distal vs. proximal), by nerve component primarily affected (e.g., demyelinating vs. axonal), by etiology, or by pattern of inheritance.
The ability of a substrate to allow the passage of ELECTRONS.
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 generic expression for any tachycardia that originates above the BUNDLE OF HIS.
Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.
Connections between cells which allow passage of small molecules and electric current. Gap junctions were first described anatomically as regions of close apposition between cells with a narrow (1-2 nm) gap between cell membranes. The variety in the properties of gap junctions is reflected in the number of CONNEXINS, the family of proteins which form the junctions.
Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.
Elements of limited time intervals, contributing to particular results or situations.
The electric response evoked in the CEREBRAL CORTEX by stimulation along AFFERENT PATHWAYS from PERIPHERAL NERVES to CEREBRUM.
The lipid-rich sheath surrounding AXONS in both the CENTRAL NERVOUS SYSTEMS and PERIPHERAL NERVOUS SYSTEM. The myelin sheath is an electrical insulator and allows faster and more energetically efficient conduction of impulses. The sheath is formed by the cell membranes of glial cells (SCHWANN CELLS in the peripheral and OLIGODENDROGLIA in the central nervous system). Deterioration of the sheath in DEMYELINATING DISEASES is a serious clinical problem.
Abnormally rapid heartbeats with sudden onset and cessation.
A potent anti-arrhythmia agent, effective in a wide range of ventricular and atrial ARRHYTHMIAS and TACHYCARDIAS.
Paired bundles of NERVE FIBERS entering and leaving the SPINAL CORD at each segment. The dorsal and ventral nerve roots join to form the mixed segmental spinal nerves. The dorsal roots are generally afferent, formed by the central projections of the spinal (dorsal root) ganglia sensory cells, and the ventral roots are efferent, comprising the axons of spinal motor and PREGANGLIONIC AUTONOMIC FIBERS.
The hemodynamic and electrophysiological action of the HEART VENTRICLES.
A local anesthetic and cardiac depressant used as an antiarrhythmia agent. Its actions are more intense and its effects more prolonged than those of PROCAINE but its duration of action is shorter than that of BUPIVACAINE or PRILOCAINE.
A class Ia antiarrhythmic drug that is structurally-related to PROCAINE.
Diseases characterized by loss or dysfunction of myelin in the central or peripheral nervous system.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
The time from the onset of a stimulus until a response is observed.
Optical imaging techniques used for recording patterns of electrical activity in tissues by monitoring transmembrane potentials via FLUORESCENCE imaging with voltage-sensitive fluorescent dyes.
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.
Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.
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.
The innermost layer of the heart, comprised of endothelial cells.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
The study of the electrical activity and characteristics of the HEART; MYOCARDIUM; and CARDIOMYOCYTES.
A conical fibro-serous sac surrounding the HEART and the roots of the great vessels (AORTA; VENAE CAVAE; PULMONARY ARTERY). Pericardium consists of two sacs: the outer fibrous pericardium and the inner serous pericardium. The latter consists of an outer parietal layer facing the fibrous pericardium, and an inner visceral layer (epicardium) resting next to the heart, and a pericardial cavity between these two layers.
A group of cardiac arrhythmias in which the cardiac contractions are not initiated at the SINOATRIAL NODE. They include both atrial and ventricular premature beats, and are also known as extra or ectopic heartbeats. Their frequency is increased in heart diseases.
The electrical properties, characteristics of living organisms, and the processes of organisms or their parts that are involved in generating and responding to electrical charges.
An abnormally rapid ventricular rhythm usually in excess of 150 beats per minute. It is generated within the ventricle below the BUNDLE OF HIS, either as autonomic impulse formation or reentrant impulse conduction. Depending on the etiology, onset of ventricular tachycardia can be paroxysmal (sudden) or nonparoxysmal, its wide QRS complexes can be uniform or polymorphic, and the ventricular beating may be independent of the atrial beating (AV dissociation).
An autosomal dominant defect of cardiac conduction that is characterized by an abnormal ST-segment in leads V1-V3 on the ELECTROCARDIOGRAM resembling a right BUNDLE-BRANCH BLOCK; high risk of VENTRICULAR TACHYCARDIA; or VENTRICULAR FIBRILLATION; SYNCOPAL EPISODE; and possible sudden death. This syndrome is linked to mutations of gene encoding the cardiac SODIUM CHANNEL alpha subunit.
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
A class I anti-arrhythmic agent (one that interferes directly with the depolarization of the cardiac membrane and thus serves as a membrane-stabilizing agent) with a depressant action on the heart similar to that of guanidine. It also possesses some anticholinergic and local anesthetic properties.
The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
The valve consisting of three cusps situated between the right atrium and right ventricle of the heart.
A group of conditions in which HEART VENTRICLE activation by the atrial impulse is faster than the normal impulse conduction from the SINOATRIAL NODE. In these pre-excitation syndromes, atrial impulses often bypass the ATRIOVENTRICULAR NODE delay and travel via ACCESSORY CONDUCTING PATHWAYS connecting the atrium directly to the BUNDLE OF HIS.
The hemodynamic and electrophysiological action of the RIGHT ATRIUM.
The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)
Interruption of NEURAL CONDUCTION in peripheral nerves or nerve trunks by the injection of a local anesthetic agent (e.g., LIDOCAINE; PHENOL; BOTULINUM TOXINS) to manage or treat pain.
The veins that return the oxygenated blood from the lungs to the left atrium of the heart.
Diseases characterized by a selective degeneration of the motor neurons of the spinal cord, brainstem, or motor cortex. Clinical subtypes are distinguished by the major site of degeneration. In AMYOTROPHIC LATERAL SCLEROSIS there is involvement of upper, lower, and brainstem motor neurons. In progressive muscular atrophy and related syndromes (see MUSCULAR ATROPHY, SPINAL) the motor neurons in the spinal cord are primarily affected. With progressive bulbar palsy (BULBAR PALSY, PROGRESSIVE), the initial degeneration occurs in the brainstem. In primary lateral sclerosis, the cortical neurons are affected in isolation. (Adams et al., Principles of Neurology, 6th ed, p1089)
A potentially lethal cardiac arrhythmia that is characterized by uncoordinated extremely rapid firing of electrical impulses (400-600/min) in HEART VENTRICLES. Such asynchronous ventricular quivering or fibrillation prevents any effective cardiac output and results in unconsciousness (SYNCOPE). It is one of the major electrocardiographic patterns seen with CARDIAC ARREST.
Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.
A hereditary motor and sensory neuropathy transmitted most often as an autosomal dominant trait and characterized by progressive distal wasting and loss of reflexes in the muscles of the legs (and occasionally involving the arms). Onset is usually in the second to fourth decade of life. This condition has been divided into two subtypes, hereditary motor and sensory neuropathy (HMSN) types I and II. HMSN I is associated with abnormal nerve conduction velocities and nerve hypertrophy, features not seen in HMSN II. (Adams et al., Principles of Neurology, 6th ed, p1343)
A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand.
A class of nerve fibers as defined by their nerve sheath arrangement. The AXONS of the unmyelinated nerve fibers are small in diameter and usually several are surrounded by a single MYELIN SHEATH. They conduct low-velocity impulses, and represent the majority of peripheral sensory and autonomic fibers, but are also found in the BRAIN and SPINAL CORD.
Mechanical compression of nerves or nerve roots from internal or external causes. These may result in a conduction block to nerve impulses (due to MYELIN SHEATH dysfunction) or axonal loss. The nerve and nerve sheath injuries may be caused by ISCHEMIA; INFLAMMATION; or a direct mechanical effect.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
Recording the locations and measurements of electrical activity in the EPICARDIUM by placing electrodes on the surface of the heart to analyze the patterns of activation and to locate arrhythmogenic sites.
Subjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation.
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).
Computer-based representation of physical systems and phenomena such as chemical processes.
A colorless liquid with a fragrant odor. It is used as an intermediate, solvent and in cosmetics.
Cells specialized to transduce mechanical stimuli and relay that information centrally in the nervous system. Mechanoreceptor cells include the INNER EAR hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non-neural accessory structures.
Contractile tissue that produces movement in animals.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
This structure includes the thin muscular atrial septum between the two HEART ATRIA, and the thick muscular ventricular septum between the two HEART VENTRICLES.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
Specialized afferent neurons capable of transducing sensory stimuli into NERVE IMPULSES to be transmitted to the CENTRAL NERVOUS SYSTEM. Sometimes sensory receptors for external stimuli are called exteroceptors; for internal stimuli are called interoceptors and proprioceptors.
The process in which specialized SENSORY RECEPTOR CELLS transduce peripheral stimuli (physical or chemical) into NERVE IMPULSES which are then transmitted to the various sensory centers in the CENTRAL NERVOUS SYSTEM.
A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.
Disturbance in the atrial activation that is caused by transient failure of impulse conduction from the SINOATRIAL NODE to the HEART ATRIA. It is characterized by a delayed in heartbeat and pauses between P waves in an ELECTROCARDIOGRAM.
Diseases characterized by injury or dysfunction involving multiple peripheral nerves and nerve roots. The process may primarily affect myelin or nerve axons. Two of the more common demyelinating forms are acute inflammatory polyradiculopathy (GUILLAIN-BARRE SYNDROME) and POLYRADICULONEUROPATHY, CHRONIC INFLAMMATORY DEMYELINATING. Polyradiculoneuritis refers to inflammation of multiple peripheral nerves and spinal nerve roots.
The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.
The functions and activities of living organisms or their parts involved in generating and responding to electrical charges .
An aminoperhydroquinazoline poison found mainly in the liver and ovaries of fishes in the order TETRAODONTIFORMES, which are eaten. The toxin causes paresthesia and paralysis through interference with neuromuscular conduction.
Disease involving the ULNAR NERVE from its origin in the BRACHIAL PLEXUS to its termination in the hand. Clinical manifestations may include PARESIS or PARALYSIS of wrist flexion, finger flexion, thumb adduction, finger abduction, and finger adduction. Sensation over the medial palm, fifth finger, and ulnar aspect of the ring finger may also be impaired. Common sites of injury include the AXILLA, cubital tunnel at the ELBOW, and Guyon's canal at the wrist. (From Joynt, Clinical Neurology, 1995, Ch51 pp43-5)
The region of the upper limb between the metacarpus and the FOREARM.
Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)
Contractile activity of the MYOCARDIUM.
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.
An acute inflammatory autoimmune neuritis caused by T cell- mediated cellular immune response directed towards peripheral myelin. Demyelination occurs in peripheral nerves and nerve roots. The process is often preceded by a viral or bacterial infection, surgery, immunization, lymphoma, or exposure to toxins. Common clinical manifestations include progressive weakness, loss of sensation, and loss of deep tendon reflexes. Weakness of respiratory muscles and autonomic dysfunction may occur. (From Adams et al., Principles of Neurology, 6th ed, pp1312-1314)
Abnormally rapid heartbeats originating from one or more automatic foci (nonsinus pacemakers) in the HEART ATRIUM but away from the SINOATRIAL NODE. Unlike the reentry mechanism, automatic tachycardia speeds up and slows down gradually. The episode is characterized by a HEART RATE between 135 to less than 200 beats per minute and lasting 30 seconds or longer.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.
A class of drugs that act by inhibition of sodium influx through cell membranes. Blockade of sodium channels slows the rate and amplitude of initial rapid depolarization, reduces cell excitability, and reduces conduction velocity.
A syndrome associated with inflammation of the BRACHIAL PLEXUS. Clinical features include severe pain in the shoulder region which may be accompanied by MUSCLE WEAKNESS and loss of sensation in the upper extremity. This condition may be associated with VIRUS DISEASES; IMMUNIZATION; SURGERY; heroin use (see HEROIN DEPENDENCE); and other conditions. The term brachial neuralgia generally refers to pain associated with brachial plexus injury. (From Adams et al., Principles of Neurology, 6th ed, pp1355-6)
The measurement of magnetic fields generated by electric currents from the heart. The measurement of these fields provides information which is complementary to that provided by ELECTROCARDIOGRAPHY.
A delayed rectifier subtype of shaker potassium channels that is selectively inhibited by a variety of SCORPION VENOMS.
Neuromuscular disorder characterized by PROGRESSIVE MUSCULAR ATROPHY; MYOTONIA, and various multisystem atrophies. Mild INTELLECTUAL DISABILITY may also occur. Abnormal TRINUCLEOTIDE REPEAT EXPANSION in the 3' UNTRANSLATED REGIONS of DMPK PROTEIN gene is associated with Myotonic Dystrophy 1. DNA REPEAT EXPANSION of zinc finger protein-9 gene intron is associated with Myotonic Dystrophy 2.
A general term encompassing lower MOTOR NEURON DISEASE; PERIPHERAL NERVOUS SYSTEM DISEASES; and certain MUSCULAR DISEASES. Manifestations include MUSCLE WEAKNESS; FASCICULATION; muscle ATROPHY; SPASM; MYOKYMIA; MUSCLE HYPERTONIA, myalgias, and MUSCLE HYPOTONIA.
A condition of fainting spells caused by heart block, often an atrioventricular block, that leads to BRADYCARDIA and drop in CARDIAC OUTPUT. When the cardiac output becomes too low, the patient faints (SYNCOPE). In some cases, the syncope attacks are transient and in others cases repetitive and persistent.
An abnormal response to a stimulus applied to the sensory components of the nervous system. This may take the form of increased, decreased, or absent reflexes.
The nervous system outside of the brain and spinal cord. The peripheral nervous system has autonomic and somatic divisions. The autonomic nervous system includes the enteric, parasympathetic, and sympathetic subdivisions. The somatic nervous system includes the cranial and spinal nerves and their ganglia and the peripheral sensory receptors.
Peripheral AFFERENT NEURONS which are sensitive to injuries or pain, usually caused by extreme thermal exposures, mechanical forces, or other noxious stimuli. Their cell bodies reside in the DORSAL ROOT GANGLIA. Their peripheral terminals (NERVE ENDINGS) innervate target tissues and transduce noxious stimuli via axons to the CENTRAL NERVOUS SYSTEM.
Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.
Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
A short vein that collects about two thirds of the venous blood from the MYOCARDIUM and drains into the RIGHT ATRIUM. Coronary sinus, normally located between the LEFT ATRIUM and LEFT VENTRICLE on the posterior surface of the heart, can serve as an anatomical reference for cardiac procedures.
A form of CARDIAC MUSCLE disease that is characterized by ventricular dilation, VENTRICULAR DYSFUNCTION, and HEART FAILURE. Risk factors include SMOKING; ALCOHOL DRINKING; HYPERTENSION; INFECTION; PREGNANCY; and mutations in the LMNA gene encoding LAMIN TYPE A, a NUCLEAR LAMINA protein.
Recording of the moment-to-moment electromotive forces of the heart on a plane of the body surface delineated as a vector function of time.
The heat flow across a surface per unit area per unit time, divided by the negative of the rate of change of temperature with distance in a direction perpendicular to the surface. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The electrical response evoked in a muscle or motor nerve by electrical or magnetic stimulation. Common methods of stimulation are by transcranial electrical and TRANSCRANIAL MAGNETIC STIMULATION. It is often used for monitoring during neurosurgery.
Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.
Assessment of sensory and motor responses and reflexes that is used to determine impairment of the nervous system.
Refers to animals in the period of time just after birth.
A group of diseases in which the dominant feature is the involvement of the CARDIAC MUSCLE itself. Cardiomyopathies are classified according to their predominant pathophysiological features (DILATED CARDIOMYOPATHY; HYPERTROPHIC CARDIOMYOPATHY; RESTRICTIVE CARDIOMYOPATHY) or their etiological/pathological factors (CARDIOMYOPATHY, ALCOHOLIC; ENDOCARDIAL FIBROELASTOSIS).
Act of eliciting a response from a person or organism through physical contact.
Abnormally rapid heartbeats caused by reentry circuit in or around the SINOATRIAL NODE. It is characterized by sudden onset and offset episodes of tachycardia with a HEART RATE of 100-150 beats per minute. The P wave is identical to the sinus P wave but with a longer PR interval.
Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.
A continuing periodic change in displacement with respect to a fixed reference. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.
Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.
The lower part of the SPINAL CORD consisting of the lumbar, sacral, and coccygeal nerve roots.
A general term indicating inflammation of a peripheral or cranial nerve. Clinical manifestation may include PAIN; PARESTHESIAS; PARESIS; or HYPESTHESIA.
A calcium channel blocker that is a class IV anti-arrhythmia agent.
A physical property showing different values in relation to the direction in or along which the measurement is made. The physical property may be with regard to thermal or electric conductivity or light refraction. In crystallography, it describes crystals whose index of refraction varies with the direction of the incident light. It is also called acolotropy and colotropy. The opposite of anisotropy is isotropy wherein the same values characterize the object when measured along axes in all directions.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
Ear-shaped appendage of either atrium of the heart. (Dorland, 28th ed)
A form of ventricular pre-excitation characterized by a normal PR interval and a long QRS interval with an initial slow deflection (delta wave). In this syndrome, the atrial impulse travel to the ventricle via the MAHAIM FIBERS which connect ATRIOVENTRICULAR NODE directly to the right ventricle wall (NODOVENTRICULAR ACCESSORY PATHWAY) or to the RIGHT BUNDLE BRANCH OF HIS (nodofascicular accessory pathway).
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.
Extra impulse-conducting tissue in the heart that creates abnormal impulse-conducting connections between HEART ATRIA and HEART VENTRICLES.
The minimum amount of stimulus energy necessary to elicit a sensory response.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
Pathological conditions involving the HEART including its structural and functional abnormalities.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.
Renewal or physiological repair of damaged nerve tissue.
A general term most often used to describe severe or complete loss of muscle strength due to motor system disease from the level of the cerebral cortex to the muscle fiber. This term may also occasionally refer to a loss of sensory function. (From Adams et al., Principles of Neurology, 6th ed, p45)
The TEMPERATURE at the outer surface of the body.
Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
A reflex in which the AFFERENT NEURONS synapse directly on the EFFERENT NEURONS, without any INTERCALATED NEURONS. (Lockard, Desk Reference for Neuroscience, 2nd ed.)
An antianginal and class III antiarrhythmic drug. It increases the duration of ventricular and atrial muscle action by inhibiting POTASSIUM CHANNELS and VOLTAGE-GATED SODIUM CHANNELS. There is a resulting decrease in heart rate and in vascular resistance.
A group of slowly progressive inherited disorders affecting motor and sensory peripheral nerves. Subtypes include HMSNs I-VII. HMSN I and II both refer to CHARCOT-MARIE-TOOTH DISEASE. HMSN III refers to hypertrophic neuropathy of infancy. HMSN IV refers to REFSUM DISEASE. HMSN V refers to a condition marked by a hereditary motor and sensory neuropathy associated with spastic paraplegia (see SPASTIC PARAPLEGIA, HEREDITARY). HMSN VI refers to HMSN associated with an inherited optic atrophy (OPTIC ATROPHIES, HEREDITARY), and HMSN VII refers to HMSN associated with retinitis pigmentosa. (From Adams et al., Principles of Neurology, 6th ed, p1343)
Fibers that arise from cells within the cerebral cortex, pass through the medullary pyramid, and descend in the spinal cord. Many authorities say the pyramidal tracts include both the corticospinal and corticobulbar tracts.
Inflammation of the PERICARDIUM from various origins, such as infection, neoplasm, autoimmune process, injuries, or drug-induced. Pericarditis usually leads to PERICARDIAL EFFUSION, or CONSTRICTIVE PERICARDITIS.
Disease involving the common PERONEAL NERVE or its branches, the deep and superficial peroneal nerves. Lesions of the deep peroneal nerve are associated with PARALYSIS of dorsiflexion of the ankle and toes and loss of sensation from the web space between the first and second toe. Lesions of the superficial peroneal nerve result in weakness or paralysis of the peroneal muscles (which evert the foot) and loss of sensation over the dorsal and lateral surface of the leg. Traumatic injury to the common peroneal nerve near the head of the FIBULA is a relatively common cause of this condition. (From Joynt, Clinical Neurology, 1995, Ch51, p31)
Diabetes mellitus induced experimentally by administration of various diabetogenic agents or by PANCREATECTOMY.
Abnormally high potassium concentration in the blood, most often due to defective renal excretion. It is characterized clinically by electrocardiographic abnormalities (elevated T waves and depressed P waves, and eventually by atrial asystole). In severe cases, weakness and flaccid paralysis may occur. (Dorland, 27th ed)
The twelve spinal nerves on each side of the thorax. They include eleven INTERCOSTAL NERVES and one subcostal nerve. Both sensory and motor, they supply the muscles and skin of the thoracic and abdominal walls.
The distal part of the arm beyond the wrist in humans and primates, that includes the palm, fingers, and thumb.
Any one of five terminal digits of the vertebrate FOOT.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
Unexpected rapid natural death due to cardiovascular collapse within one hour of initial symptoms. It is usually caused by the worsening of existing heart diseases. The sudden onset of symptoms, such as CHEST PAIN and CARDIAC ARRHYTHMIAS, particularly VENTRICULAR TACHYCARDIA, can lead to the loss of consciousness and cardiac arrest followed by biological death. (from Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 7th ed., 2005)
A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)
A polyhydric alcohol with about half the sweetness of sucrose. Sorbitol occurs naturally and is also produced synthetically from glucose. It was formerly used as a diuretic and may still be used as a laxative and in irrigating solutions for some surgical procedures. It is also used in many manufacturing processes, as a pharmaceutical aid, and in several research applications.
Treatment process involving the injection of fluid into an organ or tissue.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
Neuroglial cells of the peripheral nervous system which form the insulating myelin sheaths of peripheral axons.
The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and SALIVARY GLANDS, and convey afferent information for TASTE from the anterior two-thirds of the TONGUE and for TOUCH from the EXTERNAL EAR.
An adrenergic beta-antagonist that is used in the treatment of life-threatening arrhythmias.
Diseases of the central and peripheral nervous system. This includes disorders of the brain, spinal cord, cranial nerves, peripheral nerves, nerve roots, autonomic nervous system, neuromuscular junction, and muscle.
A widely used local anesthetic agent.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
The decrease in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.
The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Disease involving the median nerve, from its origin at the BRACHIAL PLEXUS to its termination in the hand. Clinical features include weakness of wrist and finger flexion, forearm pronation, thenar abduction, and loss of sensation over the lateral palm, first three fingers, and radial half of the ring finger. Common sites of injury include the elbow, where the nerve passes through the two heads of the pronator teres muscle (pronator syndrome) and in the carpal tunnel (CARPAL TUNNEL SYNDROME).
An antiarrhythmia agent that is particularly effective in ventricular arrhythmias. It also has weak beta-blocking activity.
Neural tracts connecting one part of the nervous system with another.