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).
Tachycardia, Sinoatrial Nodal Reentry
Heart Conduction System
Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels
Cyclic Nucleotide-Gated Cation Channels
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).
Sick Sinus Syndrome
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.
Calcium Channels, L-Type
Long-lasting voltage-gated CALCIUM CHANNELS found in both excitable and nonexcitable tissue. They are responsible for normal myocardial and vascular smooth muscle contractility. Five subunits (alpha-1, alpha-2, beta, gamma, and delta) make up the L-type channel. The alpha-1 subunit is the binding site for calcium-based antagonists. Dihydropyridine-based calcium antagonists are used as markers for these binding sites.
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.
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).
Calcium Channels, T-Type
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.
Cardiac Pacing, Artificial
Lymph Node Excision
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.
Delayed Rectifier Potassium Channels
Sentinel Lymph Node Biopsy
A methylpyrrole-carboxylate from RYANIA that disrupts the RYANODINE RECEPTOR CALCIUM RELEASE CHANNEL to modify CALCIUM release from SARCOPLASMIC RETICULUM resulting in alteration of MUSCLE CONTRACTION. It was previously used in INSECTICIDES. It is used experimentally in conjunction with THAPSIGARGIN and other inhibitors of CALCIUM ATPASE uptake of calcium into SARCOPLASMIC RETICULUM.
Autonomic Nervous System
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.
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.
Natriuretic Peptide, C-Type
A PEPTIDE of 22 amino acids, derived mainly from cells of VASCULAR ENDOTHELIUM. It is also found in the BRAIN, major endocrine glands, and other tissues. It shares structural homology with ATRIAL NATRIURETIC FACTOR. It has vasorelaxant activity thus is important in the regulation of vascular tone and blood flow. Several high molecular weight forms containing the 22 amino acids have been identified.
Parasympathetic Nervous System
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.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
Signal transduction mechanisms whereby calcium mobilization (from outside the cell or from intracellular storage pools) to the cytoplasm is triggered by external stimuli. Calcium signals are often seen to propagate as waves, oscillations, spikes, sparks, or puffs. The calcium acts as an intracellular messenger by activating calcium-responsive proteins.
Ion Channel Gating
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.
Electrophysiologic Techniques, Cardiac
Ryanodine Receptor Calcium Release Channel
A tetrameric calcium release channel in the SARCOPLASMIC RETICULUM membrane of SMOOTH MUSCLE CELLS, acting oppositely to SARCOPLASMIC RETICULUM CALCIUM-TRANSPORTING ATPASES. It is important in skeletal and cardiac excitation-contraction coupling and studied by using RYANODINE. Abnormalities are implicated in CARDIAC ARRHYTHMIAS and MUSCULAR DISEASES.
Dual allosteric modulation of pacemaker (f) channels by cAMP and voltage in rabbit SA node. (1/896)1. A Monod-Whyman-Changeux (MWC) allosteric reaction model was used in the attempt to describe the dual activation of 'pacemaker' f-channel gating subunits by voltage hyperpolarization and cyclic nucleotides. Whole-channel kinetics were described by assuming that channels are composed of two identical subunits gated independently according to the Hodgkin-Huxley (HH) equations. 2. The simple assumption that cAMP binding favours open channels was found to readily explain induction of depolarizing voltage shifts of open probability with a sigmoidal dependence on agonist concentration. 3. Voltage shifts of open probability were measured against cAMP concentration in macropatches of sino-atrial (SA) node cells; model fitting of dose-response relations yielded dissociation constants of 0.0732 and 0.4192 microM for cAMP binding to open and closed channels, respectively. The allosteric model correctly predicted the modification of the pacemaker current (If) time constant curve induced by 10 microM cAMP (13.7 mV depolarizing shift). 4. cAMP shifted deactivation more than activation rate constant curves, according to sigmoidal dose-response relations (maximal shifts of +22.3 and +13.4 mV at 10 microM cAMP, respectively); this feature was fully accounted for by allosteric interactions, and indicated that cAMP acts primarily by 'locking' f-channels in the open configuration. 5. These results provide an interpretation of the dual voltage- and cyclic nucleotide- dependence of f-channel activation. (+info)
Regional differences in effects of E-4031 within the sinoatrial node. (2/896)Effects of block of the rapid delayed rectifier K+ current (IK,r) by E-4031 on the electrical activity of small ball-like tissue preparations from different regions of the rabbit sinoatrial node were measured. The effects of partial block of IK,r by 0.1 microM E-4031 varied in different regions of the node. In tissue from the center of the node spontaneous activity was generally abolished, whereas in tissue from the periphery spontaneous activity persisted, although the action potential was prolonged, the maximum diastolic potential was decreased, and the spontaneous activity slowed. After partial block of IK,r, the electrical activity of peripheral tissue was more like that of central tissue under normal conditions. One possible explanation of these findings is that the density of IK,r is greater in the periphery of the node; this would explain the greater resistance of peripheral tissue to IK,r block and help explain why, under normal conditions, the maximum diastolic potential is more negative, the action potential is shorter, and pacemaking is faster in the periphery. (+info)
Contribution of L-type Ca2+ current to electrical activity in sinoatrial nodal myocytes of rabbits. (3/896)The role of L-type calcium current (ICa,L) in impulse generation was studied in single sinoatrial nodal myocytes of the rabbit, with the use of the amphotericin-perforated patch-clamp technique. Nifedipine, at a concentration of 5 microM, was used to block ICa,L. At this concentration, nifedipine selectively blocked ICa,L for 81% without affecting the T-type calcium current (ICa,T), the fast sodium current, the delayed rectifier current (IK), and the hyperpolarization-activated inward current. Furthermore, we did not observe the sustained inward current. The selective action of nifedipine on ICa,L enabled us to determine the activation threshold of ICa,L, which was around -60 mV. As nifedipine (5 microM) abolished spontaneous activity, we used a combined voltage- and current-clamp protocol to study the effects of ICa,L blockade on repolarization and diastolic depolarization. This protocol mimics the action potential such that the repolarization and subsequent diastolic depolarization are studied in current-clamp conditions. Nifedipine significantly decreased action potential duration at 50% repolarization and reduced diastolic depolarization rate over the entire diastole. Evidence was found that recovery from inactivation of ICa,L occurs during repolarization, which makes ICa,L available already early in diastole. We conclude that ICa,L contributes significantly to the net inward current during diastole and can modulate the entire diastolic depolarization. (+info)
Electrophysiological effects of mexiletine in man. (4/896)The electrophysiological effects of intravenous mexiletine in a dose of 200 to 250 mg given over 5 minutes, followed by continuous infusion of 60 to 90 mg per hour, were studied in 5 patients with normal conduction and in 20 patients with a variety of disturbances of impulse formation and conduction, by means of His bundle electrography, atrial pacing, and the extrastimulus method. In all but 2 patients the plasma level was above the lower therapeutic limit. Mexiletine had no consistent effects on sinus frequency and atrial refractoriness. The sinoatrial recovery time changed inconsistently in both directions; however, of the 5 patients in whom an increase was evident, 3 had sinus node dysfunction. In most patients mexiletine increased the AV nodal conduction time at paced atrial rates and shifted the Wenckebach point to a lower atrial rate. The effective refractory period of the AV node was not consistently influenced, while the functional refractory period increased in 12 out of 14 patients. The HV intervals increased by a mean of 11 ms in 8 patients and were unchanged in 17. Both the relative and effective refractory period of the His-Purkinje system increased after mexiletine. Non-cardiac side effects occurred in 7 out of 25 patients, and cardiac side effects, including one serious, in 2. The results indicate that mexiletine shares some electrophysiological properties with procainamide and quinidine, when given to patients with conduction defects, and that the drug should not be used in patients with pre-existing impairment of impulse formation or conduction. It has additional effects on AV nodal conduction which may be of value in the treatment of re-entrant tachycardias involving the AV node. (+info)
The nerve supply and conducting system of the human heart at the end of the embryonic period proper. (5/896)The nerve supply and conducting system were studied in a stage 23 human embryo of exceptional histological quality. The nerves on the right side arose from cervical sympathetic and from cervical and thoracic vagal filaments. Out of their interconnexions vagoxympathetic nerves emerged, which (1) sent a branch in front of the trachea to the aorticopulmonary ganglion, thereby supplying arterial and venous structures, and (2) formed the right sinal nerve, which supplied the sinu-atrial node, and gave filaments to the interatrial septum which could be traced to the atrioventricular node and pulmonary veins. The nerves on the left side arose similarly from cervical sympathetic and from cervical and thoracic vagal filaments. These formed several descending, ganglionated, vagosympathetic filaments that descended to the right of the arch of the aorta and entered the aorticopulmonary ganglion. Filaments leaving the ganglion supplied the pulmonary trunk, ascending aorta, interatrial septum, pulmonary veins, and, as the left sinal nerve, the fold of the left vena cava. The thoracic vagal filaments descended to the left of the arch of the aorta and supplied chiefly the arterial end of the heart. No thoracic sympathetic cardiac filaments were found. The sinu-atrial node began as a crescentic mass in front of the lower part of the superior vena cava. It gradually extended on each side of the superior vena cava and came to form its posterior wall at a more caudal level. The atrial myocardium that formed the septum spurium, venous valves, and interatrial septum could be traced from the sinu-atrial to the atrioventricular node. Myocardium also encircled the atrial aspects of the atrioventricular orifices, and could be traced caudally to the atrioventricular nde. The atrioventricular node was a conspicuous mass in the anterior and lower part of the interatrial septum, from which a clearly defined bundle left to enter the interventricular septum. Right and left limbs were observed, the former being a rounded bundle that passed immediately in front of the root of the aorta. (+info)
Defibrillation-guided radiofrequency ablation of atrial fibrillation secondary to an atrial focus. (6/896)OBJECTIVES: Our aim was to evaluate a potential focal source of atrial fibrillation (AF) by unmasking spontaneous early reinitiation of AF after transvenous atrial defibrillation (TADF), and to describe a method of using repeated TADF to map and ablate the focus. BACKGROUND: Atrial fibrillation may develop secondary to a rapidly discharging atrial focus that the atria cannot follow synchronously, with suppression of the focus once AF establishes. Focus mapping and radiofrequency (RF) ablation may be curative but is limited if the patient is in AF or if the focus is quiescent. Early reinitiation of AF has been observed following defibrillation, which might have a focal mechanism. METHODS: We performed TADF in patients with drug-refractory lone AF using electrodes in the right atrium (RA) and the coronary sinus. When reproducible early reinitiation of AF within 2 min after TADF was observed that exhibited a potential focal mechanism, both mapping and RF ablation were performed to suppress AF reinitiation. Clinical and ambulatory ECG monitoring was used to assess AF recurrence. RESULTS: A total of 44 lone AF patients (40 men, 4 women; 32 persistent, 12 paroxysmal AF) with a mean age of 58+/-13 years underwent TADF. Sixteen patients had early reinitiation of AF after TADF, nine (20%; 5 paroxysmal) exhibited a pattern of focal reinitiation. Earliest atrial activation was mapped to the right superior (n = 4) and the left superior (n = 3) pulmonary vein, just inside the orifice, in the seven patients who underwent further study. At the onset of AF reinitiation, the site of earliest activation was 86+/-38 ms ahead of the RA reference electrogram. The atrial activities from this site were fragmented and exhibited progressive cycle-length shortening with decremental conduction to the rest of the atrium until AF reinitiated. Radiofrequency ablation at the earliest activation site resulted in suppression of AF reinitiation despite pace-inducibility. Improved clinical outcome was observed over 8+/-4 months' follow-up. CONCLUSIONS: Transvenous atrial defibrillation can help to unmask, map, and ablate a potential atrial focus in patients with paroxysmal and persistent AF. A consistent atrial focus is the cause of early reinitiation of AF in 20% of patients with lone AF, and these patients may benefit from this technique. (+info)
Heterogeneity of 4-aminopyridine-sensitive current in rabbit sinoatrial node cells. (7/896)The electrophysiological properties of sinoatrial (SA) node pacemaker cells vary in different regions of the node. In this study, we have investigated variation of the 4-aminopyridine (4-AP)-sensitive current as a function of the size (as measured by the cell capacitance) of SA node cells to elucidate the ionic mechanisms. The 10 mM 4-AP-sensitive current recorded from rabbit SA node cells was composed of transient and sustained components (Itrans and Isus, respectively). The activation and inactivation properties [activation: membrane potential at which conductance is half-maximally activated (Vh) = 19.3 mV, slope factor (k) = 15.0 mV; inactivation: Vh = -31.5 mV, k = 7.2 mV] as well as the density of Itrans (9.0 pA/pF on average at +50 mV) were independent of cell capacitance. In contrast, the density of Isus (0.97 pA/pF on average at +50 mV) was greater in larger cells, giving rise to a significant correlation with cell capacitance. The greater density of Isus in larger cells (presumably from the periphery) can explain the shorter action potential in the periphery of the SA node compared with that in the center. Thus variation of the 4-AP-sensitive current may be involved in regional differences in repolarization within the SA node. (+info)
Contribution of baroreceptors and chemoreceptors to ventricular hypertrophy produced by sino-aortic denervation in rats. (8/896)1. To test whether sino-aortic denervation (SAD)-induced right ventricular hypertrophy (RVH) is a consequence of baroreceptor or chemoreceptor denervation, we compared the effects of aortic denervation (AD), carotid denervation (CD), SAD and a SAD procedure modified to spare the carotid chemoreceptors (mSAD), 6 weeks after denervation surgery in rats. A sham surgery group served as the control. 2. The blood pressure (BP) level was unaffected by AD, CD or SAD, but increased (9 %) following mSAD. The mean heart rate level was not affected. Short-term BP variability was elevated following AD (81 %), SAD (144 %) and mSAD (146 %), but not after CD. Baroreflex heart rate responses to phenylephrine were attenuated in all denervation groups. 3. Significant RVH occurred only following CD and SAD. These procedures also produced high mortality (CD and SAD) and significant increases in right ventricular pressures and haematocrit (CD). 4. Significant left ventricular hypertrophy occurred following CD, SAD and mSAD. Normalized left ventricular weight was significantly correlated with indices of BP variability. 5. These results suggest that SAD-induced RVH is a consequence of chemoreceptor, not baroreceptor, denervation. Our results also demonstrate that a mSAD procedure designed to spare the carotid chemoreceptors produced profound baroreflex dysfunction and significant left, but not right, ventricular hypertrophy. (+info)
Modification of the effects of histamine and norepinephrine on the sinoatrial node pacemaker by potassium and calcium
Modification of the effects of histamine and norepinephrine on the sinoatrial node pacemaker by potassium and calcium Academic Article ...
Difference between revisions of Detailed Cardiac - Sinus Node - Embryology
Computational analysis of the human sinus node action potential: model development and effects of mutations The sinoatrial node (SAN) is the normal pacemaker of the mammalian heart. Over several decades, a large amount of data on the ionic mechanisms underlying the spontaneous electrical activity of SAN pacemaker cells has been obtained, mostly in experiments on single cells isolated from rabbit SAN. This wealth of data has allowed the development of mathematical models of the electrical activity of rabbit SAN pacemaker cells. Our aim was to construct a more comprehensive model of the electrical activity of a human SAN pacemaker cell, using recently obtained electrophysiological data from human SAN pacemaker cells. We based our model on the recent Severi-DiFrancesco model of a rabbit SAN pacemaker cell. The action potential and calcium transient of the resulting model are close to the experimentally recorded values: the model has a much smaller funny current (If ) than do rabbit cells, but ...
Sinoatrial Node Dysfunction and Early Unexpected Death of Mice With a Defect of klotho Gene Expression | Circulation
Background- Homozygous mutant mice with a defect of klotho gene expression (kl/kl) show multiple age-related disorders and premature death from unknown causes.. Methods and Results- The kl/kl mice subjected to 20-hour restraint stress showed a high rate (20/30) of sudden death, which was associated with sinoatrial node dysfunction (conduction block or arrest). Heart rate and plasma norepinephrine of kl/kl mice, unlike those of wild-type (WT) mice, failed to increase during the stress. Intrinsic heart rate after pharmacological blockade of autonomic nerves in kl/kl mice was significantly lower than that in WT mice (380±33 versus 470±44 bpm; n=7). The sinus node recovery time after an overdrive pacing (600 bpm, 30 seconds) in kl/kl mice was significantly longer than in WT mice (392±37 versus 233±24 ms; n=6). In isolated sinoatrial node preparations, the positive chronotropic effect of isoproterenol was significantly less, whereas the negative chronotropic effect of acetylcholine was ...
Aging and Sinoatrial Node Dysfunction | Circulation
In the century since the discovery by Keith and Flack of the sinoatrial node in the mole heart, a detailed mosaic of its cellular, anatomic, and electrophysiological properties has emerged. The human sinus node has been found to be anatomically constant and well localized, occupying an approximately 10-mm subepicardial region on the sulcus terminalis at the superior cavo-atrial junction.1 Histologically, its ultrastructure of central P cells (likely corresponding to the leading pacemaker site) and outer transitional zone merging with surrounding atrial myocardium have been well characterized.1 Great progress also has been made in defining the ionic mechanisms responsible for the sinoatrial action potential and its spontaneous pacemaker activity, including important contributory roles for ICa,L, Ik, and the funny current, If.1 This morphologically discrete, unifocal sinus node is not the exclusive force behind clinical sinus rhythm, however. Detailed animal and human mapping has demonstrated that ...
Nerves projecting from the intrinsic cardiac ganglia of the pulmonary veins modulate sinoatrial node pacemaker function
Rationale: Autonomic nerves from sinoatrial node (SAN) ganglia are known to regulate SAN function. However, it is unclear whether remote pulmonary vein ganglia (PVG) also modulate SAN pacemaker rhythm. Objective: To investigate whether in the mouse heart PVG modulate SAN function. Methods and Results: In hearts from 45 C57BL and 7 Connexin40+/GFP mice, we used tyrosine-hydroxylase (TH) and choline-acetyltransferase (ChAT) immunofluorescence labeling to characterize adrenergic and cholinergic elements, repectively, within the PVG and SAN. PVG project postganglionic nerves to the SAN. TH and ChAT stained nerves, enter the SAN as an extensive, dense mesh-like neural network. Neurons in PVG are biphenotypic, containing ChAT and TH positive neurons. In Langendorff-perfused hearts, we compared effects of electrical stimulation of PVG, posterior (PRCVG) and anterior right vena cava ganglia (ARCVG) using 200-2000 ms trains of pulses (300μs, 0.2-0.6mA, 200Hz). Sympathetic and/or parasympathetic ...
Modulation of the hyperpolarization-activated current (I(f)) by calcium and calmodulin in the guinea-pig sino-atrial node. -...
The aim of this study was to investigate possible regulation of the hyperpolarization-activated current (I(f)) by cytosolic calcium in guinea-pig sino-atrial (SA) node cells. Isolated SA node cells were superfused with physiological saline solution (36 degrees C) and the perforated patch voltage-clamp technique used to record I(f) activated by hyperpolarizing voltage steps. A 10-min loading of SA node cells with the calcium chelator BAPTA (using 10 microM BAPTA-AM) significantly reduced the amplitude of I(f) at all potentials studied (69+/-8% at -80 mV, n=6). BAPTA loading also shifted the voltage of half-activation (V(h)) of the conductance from -83+/-2 mV in control to -93+/-2 mV in BAPTA (n=6) without significantly altering the slope of activation. The calmodulin antagonists W-7 (10 microM), calmidazolium (25 microM) and ophiobolin A (20 microM) caused similar reductions in I(f) amplitude (73+/-4, 86+/-9 and 59+/-6% at -80 mV, n=6, 5 and 4, respectively) and shifts in V(h) (11+/-3, 14+/-3 and 8+/-2
Distribution and functional role of inositol 1,4,5-trisphosphate receptors in mouse sinoatrial node. - Department of...
RATIONALE: Inositol 1,4,5-trisphosphate receptors (IP(3)Rs) have been implicated in the generation of arrhythmias and cardiac muscle nuclear signaling. However, in the mammalian sinoatrial node (SAN), where the heart beat originates, the expression and functional activity of IP(3)Rs have not been investigated. OBJECTIVES: To determine whether SAN express IP(3)Rs and which isoforms are present. To examine the response of the SAN to IP(3)R agonists and antagonist, and the potential role played by IP(3)Rs in cardiac pacemaking. METHODS AND RESULTS: The expression and distribution of IP(3)Rs were studied by reverse-transcription polymerase chain reaction, Western blotting, and immunolabeling. Ca(2+) signaling and electric activity in intact mouse SAN were measured with Ca(2+)-sensitive fluorescent dyes. We found that although the entire SAN expressed three IP(3)R mRNA isoforms, the type II IP(3)R (IP(3)R2) was the predominant protein isoform detected by Western blot using protein extracts from the SAN,
Synergistic dual automaticity in sinoatrial node cell and tissue models<...
TY - JOUR. T1 - Synergistic dual automaticity in sinoatrial node cell and tissue models. AU - Zhang, Hong. AU - Joung, Boyoung. AU - Shinohara, Tetsuji. AU - Mei, Xi. AU - Chen, Peng-Sheng. AU - Lin, Shien-Fong. PY - 2010. Y1 - 2010. N2 - Background: The mechanism of sinoatrial node (SAN) automaticity is traditionally attributed to membrane ion currents. Recent evidence indicates spontaneous sarcoplasmic reticulum (SR) Ca2+ cycling also plays an important role. Methods and Results: A computer simulation on SAN cell and 1D tissue model was performed. In the SAN cells, SR Ca2+ cycling broadly modulated the sinus rate from 1.74 Hz to 3.87 Hz. Shortening of the junctional SR refilling time and increase of SR Ca2+ release were responsible for sinus rate acceleration. However, under the fast SR Ca2+ cycling, decreased L-type Ca2+ current (ICaL) resulted in irregular firing. When Ca2+ cycling was suppressed, If and ICaT both acted to stabilize the pacemaker rhythm, but ICaT had less effect than If. At ...
Rhythmic Ryanodine Receptor Ca2+ Releases During Diastolic Depolarization of Sinoatrial Pacemaker Cells Do Not Require Membrane...
The advent of Ca2+ sensitive indicators, coupled to confocal imaging with simultaneous measurement of membrane potential, has permitted the detection of LCRs beneath the cell membrane during diastolic depolarization. Recent studies1,2,12 have shown that LCRs during diastolic depolarization activate NCX, which produces a large inward current1,9,19 in pacemaker cells, and enhances the rate of the later part of the diastolic depolarization.. The first novel finding of the present study is that the occurrence of LCRs during diastolic depolarization in rabbit sinoatrial nodal cells does not require the concomitant change in membrane potential. Thus, local LCRs occur in saponin skinned cells bathed at physiological [Ca2+] and during acute voltage clamp of spontaneously beating cells (Figures 1 and 3⇑). During the initial stage of voltage clamp, ie, the first would-be cycle, when SR Ca2+ load and RyR inactivation are the same as during the prior spontaneous beating, the LCR characteristics are ...
The calcium and voltage clocks in sinoatrial node automaticity<...
TY - JOUR. T1 - The calcium and voltage clocks in sinoatrial node automaticity. AU - Joung, Boyoung. AU - Ogawa, Masahiro. AU - Lin, Shien Fong. AU - Chen, Peng Sheng. PY - 2009/6/1. Y1 - 2009/6/1. N2 - Recent evidence indicates that the voltage (cyclic activation and deactivation of membrane ion channels) and Ca2+ clocks (rhythmic spontaneous sarcoplasmic reticulum Ca2+ release) jointly regulate sinoatrial node (SAN) automaticity. Since the intact SAN is a heterogeneous structure that includes multiple different cell types interacting with each other, the relative importance of the voltage and Ca2+ clocks for pacemaking may be variable in different regions of the SAN. Recently, we performed optical mapping in isolated and Langendorff-perfused canine right atria. We mapped the intracellular calcium (Cai) and membrane potentials of the intact SAN simultaneously. Using previously described criteria of the timing of the late diastolic Cai elevation (LDCAE) relative to the action potential upstroke ...
Localization of Islet-1-Positive Cells in the Healthy and Infarcted Adult Murine Heart | Circulation Research
Methods and Results: Distribution of Islet-1+ cells in adult heart was investigated using transgenic mice with nuclear β-galactosidase inserted into the Islet-1 locus. nLacZ-positive cells were only present in 3 regions of the adult heart: clusters in the interatrial septum, scattered within the wall of the great vessels, and a strictly delimited cluster between right atrium and superior vena cava. Islet-1+ cells in the first type of clusters coexpressed markers for parasympathetic neurons. Positive cells in the great arteries coexpressed smooth muscle actin and β-myosin heavy chain, indicating a smooth muscle cell identity. Very few Islet-1+ cells within the outflow tract expressed the cardiomyocyte marker α-actinin. Islet-1+ cells in the right atrium coexpressed the sinoatrial node pacemaker cell marker HCN4. Cell number and localization remained unchanged between 1 to 18 months of age. Consistently Islet-1 mRNA was detected in human sinoatrial node. Islet-1+ cells could not be detected in ...
Garny, Kohl, Hunter, Boyett, Noble, 2003 - Physiome Model Repository
ABSTRACT: INTRODUCTION: Cardiac multicellular modeling has traditionally focused on ventricular electromechanics. More recently, models of the atria have started to emerge, and there is much interest in addressing sinoatrial node structure and function. METHODS AND RESULTS: We implemented a variety of one-dimensional sinoatrial models consisting of descriptions of central, transitional, and peripheral sinoatrial node cells, as well as rabbit or human atrial cells. These one-dimensional models were implemented using CMISS on an SGI Origin 2000 supercomputer. Intercellular coupling parameters recorded in experimental studies on sinoatrial node and atrial cell-pairs under-represent the electrotonic interactions that any cardiomyocyte would have in a multidimensional setting. Unsurprisingly, cell-to-cell coupling had to be scaled-up (by a factor of 5) in order to obtain a stable leading pacemaker site in the sinoatrial node center. Further critical parameters include the gradual increase in ...
Sinoatrial node - Wikipedia
The sinoatrial node (SA node), also known as sinus node, is a group of cells located in the wall of the right atrium of the heart. These cells have the ability to spontaneously produce an electrical impulse (action potential; see below for more details), that travels through the heart via the electrical conduction system (see figure 1) causing it to contract. In a healthy heart, the SA node continuously produces action potential, setting the rhythm of the heart and so is known as the hearts natural pacemaker. The rate of action potential production (and therefore the heart rate) is influenced by nerves that supply it. The sinoatrial node is a banana-shaped structure that varies in size, usually between 10-30 millimeters (mm) long, 5-7 mm wide, and 1-2 mm deep. The SA node is located in the wall (myocardium) of the right atrium, laterally to the entrance of the superior vena cava in a region called the sinus venarum (hence sino- + atrial). It is positioned roughly between a groove called the ...
SA - isolated rabbit sino-atrial | AcronymAttic
How is isolated rabbit sino-atrial abbreviated? SA stands for isolated rabbit sino-atrial. SA is defined as isolated rabbit sino-atrial very rarely.
Heart failure differentially modulates natural (Sinoatrial node) and ectopic (pulmonary veins) pacemakers: Mechanism and...
TY - JOUR. T1 - Heart failure differentially modulates natural (Sinoatrial node) and ectopic (pulmonary veins) pacemakers. T2 - Mechanism and therapeutic implication for atrial fibrillation. AU - Chan, Chao Shun. AU - Lin, Yung Kuo. AU - Chen, Yao Chang. AU - Lu, Yen Yu. AU - Chen, Shih Ann. AU - Chen, Yi Jen. PY - 2019/7/1. Y1 - 2019/7/1. N2 - Heart failure (HF) frequently coexists with atrial fibrillation (AF) and dysfunction of the sinoatrial node (SAN), the natural pacemaker. HF is associated with chronic adrenergic stimulation, neurohormonal activation, abnormal intracellular calcium handling, elevated cardiac filling pressure and atrial stretch, and fibrosis. Pulmonary veins (PVs), which are the points of onset of ectopic electrical activity, are the most crucial AF triggers. A crosstalk between the SAN and PVs determines PV arrhythmogenesis. HF has different effects on SAN and PV electrophysiological characteristics, which critically modulate the development of AF and sick sinus syndrome. ...
Abnormal response of superior sinoatrial node to sympathetic stimulation is a characteristic finding in patients with atrial...
TY - JOUR. T1 - Abnormal response of superior sinoatrial node to sympathetic stimulation is a characteristic finding in patients with atrial fibrillation and symptomatic bradycardia. AU - Joung, Boyoung. AU - Hwang, Hye Jin. AU - Pak, Hui Nam. AU - Lee, Moon Hyoung. AU - Shen, Changyu. AU - Lin, Shien Fong. AU - Chen, Peng Sheng. PY - 2011/12. Y1 - 2011/12. N2 - Background-We hypothesized that unresponsiveness of superior sinoatrial node (SAN) to sympathetic stimulation is strongly associated with the development of symptomatic bradycardia in patients with atrial fibrillation (AF). Methods and Results-We performed 3D endocardial mapping in healthy controls (group 1, n=10) and patients with AF without (group 2, n=57) or with (group 3, n=15) symptomatic bradycardia at baseline and during isoproterenol infusion. Corrected SAN recovery time was abnormal in 0%, 11%, and 36% of groups 1, 2, and 3, respectively (P=0.02). At baseline, 90%, 26%, and 7% (P,0.001) of the patients had multicentric SAN ...
Computational analysis of the human sinus node action potential: model development and effects of mutations - Physiome Model...
You are here: Home / Exposures / Computational analysis of the human sinus node action potential: model development and effects of mutations ...
Measurement of funny current (I(f)) channel mRNA in human atrial tissue: Correlation with left atrial filling pressure and...
TY - JOUR. T1 - Measurement of funny current (I(f)) channel mRNA in human atrial tissue. T2 - Correlation with left atrial filling pressure and atrial fibrillation. AU - Lai, Ling Ping. AU - Su, Ming Jai. AU - Lin, Jiunn Lee. AU - Tsai, Chang Her. AU - Lin, Fang Yue. AU - Chen, Yih Sharng. AU - Hwang, Juey Jen. AU - Stephen Huang, Shoei K.. AU - Tseng, Yung Zu. AU - Lien, Wen Pin. PY - 1999/1/1. Y1 - 1999/1/1. N2 - Introduction: The funny current (I(f)) contributes to phase IV spontaneous depolarization in cardiac pacemaker tissue. Enhanced I(f) activity in myocardial tissue may lead to increased automaticity and therefore tachyarrhythmia. We measured the amount of I(f) activity in the messenger ribonucleic acid (mRNA) in human atrial tissue and correlated the mRNA amount to left atrial filling pressure and atrial fibrillation (AF). Methods and Results: A total of 34 patients undergoing open heart surgery were included (15 men and 19 women, aged 55 ± 10 years). Atrial tissue was obtained from ...
2012 ICD-9-CM Diagnosis Code 427.81 : Sinoatrial node dysfunction
Free, official information about 2012 (and also 2013-2015) ICD-9-CM diagnosis code 427.81, including coding notes, detailed descriptions, index cross-references and ICD-10-CM conversion.
Developmental Patterning of the Sinoatrial Node - Michael Bressan
Cardiac pacemaker cells of the sinoatrial node initiate and maintain the rhythmic beating of the heart. This function requires that pacemaker cells be insulated...
Cholinergic inhibition of slow delayed-rectifier K+ current in guinea pig sino-atrial node is not mediated by muscarinic...
We studied the effects of cholinergic agonists on slow delayed-rectifier K+ current (IKs) in isolated cells from the sino-atrial node (SAN) region of guinea pig heart, using patch-clamp procedures. Carbachol (5 nM to 10 microM) inhibited IKs in guinea pig SAN cells in the absence of previous beta-adrenergic stimulation and in cells pretreated with 8-(4-chlorophenylthio)-cAMP. Neither the muscarinic antagonist atropine nor the nicotinic antagonist hexamethonium antagonized carbachol inhibition of the current. Similar results were obtained with other cholinergic agonists. Cholinergic stimulation of the muscarinic K+ current was successfully antagonized by atropine in SAN cells where inhibition of IKs persisted. Therefore, the lack of antagonist effects on inhibition of IKs cannot be attributed to either an absence of muscarinic cholinoceptors on SAN cells or a loss of antagonist activity under our experimental conditions. These data demonstrate that cholinergic agonists, including the endogenous ...
Effect of Pindolol and Propranolol on Sinus Node Recovery Time and Atrioventricular Conduction Intervals
In a randomized, observer-blind study, the effect of incremental doses of pindolol 0.001, 0.002, 0.003, and 0.004 mg/kg IV and propranolol 0.01, 0.02, 0.03, and 0.04 mg/kg IV on SA nodal recovery time (SNRT) and atrioventricular conduction interval (AH) was assessed in 20 patients (15 men and 5 women age range thirty to seventy-two, mean age fifty-three). AH and His bundle-to-ventricle (HV) intervals and SNRT were measured at spontaneous heart rate and at incremental atrial pacing rates (80, 100, 120, 140 bpm). Both drugs caused significant beta blockade as estimated by the percentage suppression of heart rate increment induced by 3 mcg isoproterenol administered intravenously (pindolol 67.6Â±5.3%, ...
Sinoatrial node artery arising from posterolateral branch of right coronary artery: definition by screening consecutive 1500...
Free Online Library: Sinoatrial node artery arising from posterolateral branch of right coronary artery: definition by screening consecutive 1500 coronary angiographies/Sag koroner arter posterolateral dalindan cikan sinoatriyal nod arteri: Ardisik 1500 koroner anjiyografi taramasi ile tanimlama.(Original Investigation/Ozgun Arastirma) by The Anatolian Journal of Cardiology (Anadolu Kardiyoloji Dergisi); Health, general Angiography
The Bradyarrhythmias: Disorders of the Sinoatrial Node | Harrisons Principles of Internal Medicine, 20e | AccessPharmacy |...
Spontaneous activation and contraction of the heart are a consequence of the specialized pacemaking tissue in these anatomic locales. As described in Chap. 238, action potentials in the heart are regionally heterogeneous. The action potentials in cells isolated from nodal tissue are distinct from those recorded from atrial and ventricular myocytes (Fig. 239-1). The complement of ionic currents present in nodal cells results in a less negative resting membrane potential compared with atrial or ventricular myocytes. Electrical diastole in nodal cells is characterized by slow diastolic depolarization (phase 4), which generates an action potential as the membrane voltage reaches threshold. The action potential upstrokes (phase 0) are slow compared with atrial or ventricular myocytes, being mediated by calcium rather than sodium current. Cells with properties of SA and AV nodal tissue are electrically connected to the remainder of the myocardium by cells with an electrophysiologic phenotype between ...
Facilitation of the L-type calcium current in rabbit sino-atrial cells: effect on cardiac automaticity. - Physiology, Anatomy...
OBJECTIVE: The L-type Ca(2+) current (I(Ca,L)) contributes to the generation and modulation of the pacemaker action potential (AP). We investigated facilitation of I(Ca,L) in sino-atrial cells. METHODS: Facilitation was studied in regularly-beating cells isolated enzymatically from young albino rabbits (0.8-1 kg). We used the whole-cell patch-clamp technique to vary the frequency of the test depolarizations evoked at -10 mV or the conditioning diastolic membrane potential prior to the test pulse. RESULTS: High frequencies (range 0.2-3.5 Hz) slowed the decay kinetics of I(Ca,L) evoked from a holding potential (HP) of -80 mV in 68% of cells resulting in a larger Ca(2+) influx during the test pulse. The amount of facilitation increased progressively between 0.2 and 3.0 Hz. When the frequency was changed from 0.1 to 1 Hz, the averaged increase in the time integral of I(Ca,L) was 27+/-7% (n=22). Application of conditioning voltages between -80 and -50 mV induced similar facilitation of I(Ca,L) in 73% of
SA node cell to atrial cardiac muscle cell communication Antibodies | Invitrogen ...
Antibodies for proteins involved in SA node cell to atrial cardiac muscle cell communication pathways, according to their Panther/Gene Ontology Classification
MCBeng.it - Ion channels
The sinoatrial node (SAN) is the normal pacemaker of the mammalian heart. Over several decades, a large amount of data on the ionic mechanisms underlying the spontaneous electrical activity of SAN pacemaker cells has been obtained, mostly in experiments on single cells isolated from rabbit SAN. This allowed the development of comprehensive mathematical models of ...
Enhanced cardiac automaticity
Enhanced cardiac automaticity refers to the accelerated generation of an action potential by either normal pacemaker tissue (enhanced normal automaticity) or by abnormal tissue within the myocardium (abnormal automaticity). The discharge rate of norm
ible dose of sildenafil during 1 month. In patients with Since endothelial dysfunction is associated with vas- CHF, sildenafil significantly reduced blood pressure, cular inflammation, platelet activation, and rapid pro- resting heart rate and attenuated the heart rate incre- gression of atherosclerosis and its adverse events, strate- ment (6-min treadmill-walking test and maximal exer- gies that enhance NO bioavailability may have a positive cise test, Figure 3) which was attributed to the modula- impact on outcomes in patients with coronary artery dis- tion of the effects of the NO-cGMP pathway on the ease (CAD). Therefore, Halcox et al.  hypothesized pacemaker activity of sinoatrial node cells . More- that PDE 5 inhibition with sildenafil may abrogate coro- nary and peripheral vascular endothelial dysfunction in cise and increased the maximal exercise capacity. Treat- patients with CAD, inhibit platelet activation, and ame- ment was associated with more adverse symptoms, liorate ...
The atherosclerosis of the sinus node artery is associated with an increased history of supra-ventricular arrhythmias: a...
Background. The ischemic damage of the sinus node (SN) is a well known cause of cardiac arrhythmias and can be a consequence of any flow abnormality in the sinus node artery (SNA). Accordingly we aimed this retrospective study to: (1) evaluate the suitability of the standard coronary angiography to study the SNA and (2) determine if the percentage of subjects with a positive retrospective history of supra-ventricular arrhythmias (SVA) differs in patients with normal and diseased SNA ascertained at the time of coronary angiography.Methods and Results. Out of the 541 coronary angiograms reviewed the SNA was visible for its entire course in 486 cases (89.8%). It was found to arise from the right side of the coronary circulation in 266 cases (54.7%) slightly more often than from the left, 219 cases (45.1%). One patient had 2 distinct SNA arising from either side of the coronary circulation. For the second objective, we studied the 333 patients with: (a) coronary artery disease (CAD), (b) properly evaluable
Anesthetics and Automaticity in Latent Pacemaker Fibers:IV. Effects of Isoflurane and Epinephrine or Norepinephrine on...
Mladen Boban, John L. Atlee, Martin Vicenzi, John P. Kampine, Zeljko J. Bosnjak; Anesthetics and Automaticity in Latent Pacemaker Fibers: IV. Effects of Isoflurane and Epinephrine or Norepinephrine on Automaticity of Dominant and Subsidiary Atrial Pacemakers in the Canine Heart. Anesthesiology 1993;79(3):555-562. Download citation file:. ...
Arrhythmia - Wikipedia
Automaticity refers to a cardiac muscle cell firing off an impulse on its own. All of the cells in the heart have the ability to initiate an action potential; however, only some of these cells are designed to routinely trigger heart beats. These cells are found in the conduction system of the heart and include the SA node, AV node, Bundle of His and Purkinje fibers. The sinoatrial node is a single specialized location in the atrium that has a higher automaticity (a faster pacemaker) than the rest of the heart and, therefore, is usually responsible for setting the heart rate and initiating each heart beat. Any part of the heart that initiates an impulse without waiting for the sinoatrial node is called an ectopic focus and is, by definition, a pathological phenomenon. This may cause a single premature beat now and then, or, if the ectopic focus fires more often than the sinoatrial node, it can produce a sustained abnormal rhythm. Rhythms produced by an ectopic focus in the atria, or by the ...
Wandering pacemaker - Wikipedia
Wandering atrial pacemaker (WAP) is an atrial arrhythmia that occurs when the natural cardiac pacemaker site shifts between the sinoatrial node (SA node), the atria, and/or the atrioventricular node (AV node). This shifting of the pacemaker from the SA node to adjacent tissues is identifiable on ECG Lead II by morphological changes in the P-wave; sinus beats have smooth upright P waves, while atrial beats have flattened, notched, or diphasic P-waves. It is often seen in the very young, very old, and in athletes, and rarely causes symptoms or requires treatment. Wandering pacemaker is usually caused by varying vagal tone. With increased vagal tone the SA Node slows, allowing a pacemaker in the atria or AV Nodal area, which may briefly become slightly faster. After vagal tone decreases, the SA Node assumes its natural pace. A wandering atrial pacemaker, also termed multifocal atrial rhythm, is present when there are three or more ectopic foci within the atrial myocardium that ...
Frontiers | The Autonomic Nervous System Regulates the Heart Rate through cAMP-PKA Dependent and Independent Coupled-Clock...
Sinoatrial nodal cells (SANCs) generate spontaneous action potentials (APs) that control the cardiac rate. The brain modulates SANC automaticity, via the autonomic nervous system, by stimulating membrane receptors that activate (adrenergic) or inactivate (cholinergic) adenylyl cyclase (AC). However, these opposing afferents are not simply additive. We showed that activation of adrenergic signaling increases AC-cAMP/PKA signaling, which mediates the increase in the SANC AP firing rate (i.e., positive chronotropic modulation). However, there is a limited understanding of the underlying internal pacemaker mechanisms involved in the crosstalk between cholinergic receptors and the decrease in the SANC AP firing rate (i.e., negative chronotropic modulation). We hypothesize that changes in AC-cAMP/PKA activity are crucial for mediating either decrease or increase in the AP firing rate and that the change in rate is due to both internal and membrane mechanisms. In cultured adult rabbit pacemaker cells infected
Conduction System Tutorial
Under normal physiologic conditions, the dominant pacemaker cells of the heart lie within the sinoatrial node; in adults, these pacemaker cells fire at rates between 60 to 100 beats per minute (i.e., faster than cells in any other cardiac region, See Figure 3). Even at rest, modulation by the autonomic nervous system dominates, with the primary drive from the parasympathetics; at rest or during sleep, the sinoatrial nodal rate decreases to about 75 beats per minute (bpm) or even slower.. In addition to pacemaker cells of the sinoatrial node, other cells within the conduction system are capable of developing autorhythmicity, specifically those within the atrioventricular node (junction region) and His-Purkinje system. Yet, rhythms generated within these cells are in a much lower range (25 to 55 bpm), hence not altering the intrinsic atrial rates (Figure 2). These lower rate rhythms are commonly referred to as ventricular escape rhythms and are important for patient survival, since they maintain ...
北京大学医学部机构知识库([email protected]): Effect of Ibutilide on the Canine Cardiac Conduction System
The objective of the study was to evaluate the effect of ibutilide on canine cardiac sinoatrial and atrioventricular nodes (AVNs). For this purpose, 18 mongrel dogs were injected intravenously with ibutilide and the changes in heart rate, sinus node recovery time, and AVN were measured. Our data show that ibutilide administration caused significant suppression of the sinus atrial node, the peak response time was 20-30 min, and the heart rate was restored to pre-drug administration level. After receiving ibutilide, 1 animal had a 5 s sinus pause, and after 5 min of ibutilide administration, 1 dog showed 2:1 atrioventricular conduction. Therefore, it was concluded that ibutilide had a suppressive effect on the sinoatrial node and AVN. ...
KIT-Über Uns - Team - Wissenschaftliche Mitarbeiter
Abstract:. Background: For chronic kidney disease patients undergoing maintenance hemodialysis (HD), the risk to die from sudden cardiac death (SCD) is 14x higher compared to patients with a history of cardiovascular disease and normal kidney function. Traditional SCD risk factors cannot explain this high rate. Two recent human studies using implantable loop recorders surprisingly point towards bradycardia and asystole as the prevailing arrhythmias causing SCD in HD patients. This suggests a decisive role of the sinus node. Objective: To identify the effect of altered electrolyte levels (as systematically occurring in HD patients) on pacemaking in a computational model of human sinus node cells. Methods: We enhanced the Fabbri et al. model of human sinus node cells to account for the dynamic intracellular balance of all considered electrolytes. The model was exposed to clinically relevant extracellular electrolyte concentrations of potassium, sodium, and calcium to study their effect on ...
Nodal artery | Article about nodal artery by The Free Dictionary
Looking for nodal artery? Find out information about nodal artery. blood vessel that conveys blood away from the heart heart, muscular organ that pumps blood to all parts of the body. The rhythmic beating of the heart is a... Explanation of nodal artery
aena.noor.janna: Cardiac Conduction System
Properties of the cardiac muscle AUTOMATICITY CONDUCTIVITY CONTRACTILITY EXCITABILITY REFRACTORY PERIODS 1. AUTOMATICITY is the unique ability of the cells in the SA node (pacemaker cells) to generate an action potential without being stimulated.
Modelling the electrical activity of a cardiac pacemaker cells - mcbeng.it
The sinoatrial node (SAN) is the normal pacemaker of the mammalian heart. Over several decades, a large amount of data on the ionic mechanisms underly...
Evidence suggesting time-dependent recovery of excitability in the in vivo human sinus node | Meta
Cardiovascular disease is a significant health concern. Risk factors include hypertension, obesity, dyslipidemia and smoking. Women who are postmenopausal are at an increased risk of heart disease. Here is the latest research for risk factors of cardiovascular disease. ...
We have investigated the concentration-dependent modulation, by the novel class III antiarrhythmic compound NE-10064, of the delayed potassium channel current Iks in isolated guinea pig sinoatrial nodal (SAN) and ventricular cells. At concentrations greater than 1 micron, the drug potently inhibited Iks in each of the cell types investigated. The concentration-dependent inhibition of Iks (IC50 = 700 nM) was the same in ventricular and SAN cells. At near-threshold drug concentrations, we also observed increases of Iks activity in both SAN and ventricular cells. The NE-10064-induced enhancement of Iks was more pronounced at voltages near the Iks activation threshold (0 mV), than at more positive voltages in both cell types. Furthermore, the agonistic effects of the drug were more prominent before steady-state effects of the compound were attained, which suggests parallel agonistic and antagonistic pathways. Our results demonstrate that Iks channels in cells of the sinoatrial node region of the ...
Interaction of oscillatory processes: the effects of subthreshold A.C. current on sinoatrial nodal rhythm.
In this study of interactions occurring within the heart, isolated superfused strips of rabbit atria, containing the sinoatrial (s.a.) node, were subjected to sinusoidal subthreshold current pulses of varied frequencies and intensities. A.C. current
Impact of manipulation of energy substrates on sinus nodal rhythm<...
TY - JOUR. T1 - Impact of manipulation of energy substrates on sinus nodal rhythm. AU - Maruyama, Hiroko. AU - Ito, Masanori. AU - Goda, Nobuhito. AU - Adachi-Akahane, Satomi. PY - 2014/1. Y1 - 2014/1. N2 - Background: The high energy demand of the heart is supported by metabolic flexibility in the utilization of energy substrates for adenosine triphosphate (ATP) synthesis. To investigate the roles of glucose and long-chain fatty acids (FA) as energy substrates in sinus nodal rhythm, we developed an isolated mouse atrial preparation and studied the effects of manipulating these energy substrates on atrial beating rate. Methods: The spontaneous beating rate of isolated atria from mouse was measured at resting tension in a modified Tyrode solution that was gassed with 100% O2 at 37°C and contained 1 of the following sets of energy substrates: 10 mM glucose plus 0.4 mM palmitate (control), 5 mM glucose plus 0.4 mM palmitate (low glucose), or 10 mM glucose without palmitate (FA (-)). Atria were ...
Comparison of ion channel gene expression in the sinus node of the human, rabbit, rat and mouse - Department of Pharmacology
© 2016 CCAL. Small animal species (e.g. mouse) have a faster heart rate than large animal species (e.g. human). We have looked for the reason from the functional level to the gene level in the human, rabbit, rat and mouse using a metaanalysis approach. For example, review of the literature shows that, in isolated sinus node cells, the spontaneous rate is 4.6× faster and the action potential is 2.4 × shorter in mouse than in human. Although data on ionic currents are limited, data suggests that the density of the funny current (If) is ∼5× higher in mouse than in human, (Q10 of 1.38 was used to correct temperature differences among studies). Data on ion channel mRNA expression (qPCR) in the sinus node for the four species were collected from different research groups. To compare data, we either normalised to the Nav1.5 mRNA level (in atrial muscle) or the Cav1.2 mRNA level (in sinus node). Although different housekeeper genes were used (18S, 28S, HPRT), comparison of different data sets on the
Function of the heart
0:06Skip to 0 minutes and 6 secondsWere going to look at the function of the heart. The main function of the heart is to supply blood to the tissues of the body, delivering oxygen and nutrients to them. Now, the heart is able to function because it is able to generate its own electrical activity. And this starts in the region known as the pacemaker, or the sinoatrial node, that is located in the right atrium. The electrical activity begins in the sinoatrial node, then spreads across the rest of the atrium, through to the other atrium, and then down into the ventricles. This causes the atria to contract before the ventricles.. 0:49Skip to 0 minutes and 49 secondsNow, the electrical activity of the heart can be measured using the electrocardiogram, or the ECG, that can measure the electrical activity of the heart, and this is depicted by letters of the alphabet P, QRS, and T. Now when the electrical activity of the heart passes through the atria, this causes the atria to contract and, as a result ...
Sinus node dysfunction - WikiProjectMed
Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms caused by malfunction of the sinoatrial node, the hearts primary pacemaker. Early on symptoms may be few. As the disease progresses syncope may occur. Other symptoms may include lightheadedness, palpitations, or chest pain. The heart may beat insufficiently fast during exercise. Complications may include atrial fibrillation. It involves a slow heart rate with or without periods of a faster heart rate. The slow heart rate may be a sinus bradycardia, sinus pause, or sinoatrial exit block. When periods of a fast heart rate is present it is known as tachy-brady syndrome. The underlying mechanism may include fibrosis, ion channel dysfunction, or remodeling of the sinoatrial node. Other factors that can worsen the condition include medications such as beta blockers or calcium channel blockers, electrolyte abnormalities, low oxygen, and low thyroid. Diagnosis is ...
Na(+)‐Ca2+ exchange current in latent pacemaker cells isolated from cat right atrium.<...
TY - JOUR. T1 - Na(+)‐Ca2+ exchange current in latent pacemaker cells isolated from cat right atrium.. AU - Zhou, Z.. AU - Lipsius, S. L.. N1 - Copyright: Copyright 2016 Elsevier B.V., All rights reserved.. PY - 1993/7/1. Y1 - 1993/7/1. N2 - 1. Single latent pacemaker cells were isolated from cat right atrium, and studied in a whole‐cell configuration using a nystatin‐perforated patch recording method. The nystatin method avoids alterations in intracellular Ca2+, cellular constituents and run‐down of ionic currents. 2. Depolarizing voltage clamp pulses from ‐40 mV elicited L‐type Ca2+ current (ICa) that exhibited an initial rapid phase of inactivation followed by a secondary slower inward current component that decayed over about 100 ms. The secondary inward component appeared as a slowly decaying inward tail current following short (10‐40 ms) depolarizing clamp steps. 3. Slowly decaying inward currents were abolished by internally dialysing pacemaker cells with 2 mM EGTA using a ...
IJMS | Free Full-Text | Heart Failure Differentially Modulates Natural (Sinoatrial Node) and Ectopic (Pulmonary Veins)...
Heart failure (HF) frequently coexists with atrial fibrillation (AF) and dysfunction of the sinoatrial node (SAN), the natural pacemaker. HF is associated with chronic adrenergic stimulation, neurohormonal activation, abnormal intracellular calcium handling, elevated cardiac filling pressure and atrial stretch, and fibrosis. Pulmonary veins (PVs), which are the points of onset of ectopic electrical activity, are the most crucial AF triggers. A crosstalk between the SAN and PVs determines PV arrhythmogenesis. HF has different effects on SAN and PV electrophysiological characteristics, which critically modulate the development of AF and sick sinus syndrome. This review provides updates to improve our current understanding of the effects of HF in the electrical activity of the SAN and PVs as well as therapeutic implications for AF.
The key to getting this to work is to control the timing. One way to do this is to have the main task set some variables which tell the subsidiary task whether or not to run. In order to do this, have the stimulus variable set as a global variable in both tasks. Set two stimulus subfields as flags, e.g. stimulus.startSubsidiary and stimulus.endSubsidiary, in order to control the subsidiary task. Then have the subsidiary task check the status of these flags, and start or stop accordingly. In order to get the subsidiary task to start and stop when the appropriate flags are set, you will need to do the following: Set the first segment of the subsidiary task to have infinite length. That makes the subsidiary wait in the first segment until the main task calls it. When the main task wants to start the subsidiary task, it will set the stimulus.startSubsidary flag to 1, and this will cause the subsidiary to jump to the next segment as follows: In the screenUpdate callback of the subsidiary task, have a ...
Adani Enterprises incorporates new subsidiary for cement biz
Adani Enterprises Ltd (AEL) on Saturday said it has incorporated a wholly-owned subsidiary, Adani Cement Industries Limited (ACIL), to manufacture all types of cements.In a filing to BSE, the company said it incorporated the wholly-owned subsidiary on June 11, 2021 and the subsidiary company yet to
Sinus Node Dysfunction - Cardiovascular Disorders - Merck Manuals Professional Edition
Sinus Node Dysfunction - Etiology, pathophysiology, symptoms, signs, diagnosis & prognosis from the Merck Manuals - Medical Professional Version.
Novel coronavirus 19 (COVID-19) associated sinus node dysfunction: A case series - Fingerprint - Northwestern Scholars
Fingerprint Dive into the research topics of Novel coronavirus 19 (COVID-19) associated sinus node dysfunction: A case series. Together they form a unique fingerprint. ...
Heart Disease of the Sinus Node in Dogs | PetMD
The sinoatrial node (SA Node, or SAN), also called the sinus node, is the initiator of electrical impulses within the heart, triggering the heart to beat, or contract, by firing off electrical surges. Sick sinus syndrome (SSS) is a disorder of the hearts electrical impulse formation within the sinus node.
Heart Disease of the Sinus Node in Cats | petMD
The sinoatrial node (SA Node, or SAN), also called the sinus node, is the initiator of electrical impulses within the heart, triggering the hearts contractions by firing off electrical surges. One of the disorders that can affect the hearts electrical impulse formation within the sinus node is called sick sinus syndrome (SSS).
Multilevel determinants of foreign direct investment entry mode strategies and subsidiary survival of multinationals in China:...
TY - BOOK. T1 - Multilevel determinants of foreign direct investment entry mode strategies and subsidiary survival of multinationals in China: an analysis of Nordic firms.. AU - Wang, Yi. PY - 2014. Y1 - 2014. M3 - Ph.D. thesis. BT - Multilevel determinants of foreign direct investment entry mode strategies and subsidiary survival of multinationals in China: an analysis of Nordic firms.. PB - Vaasan yliopisto. ER - ...
Innoval Döhler becomes a 100% Döhler subsidiary | FDBusiness.com
Innoval Döhler, based in Mexico City, will become a 100% Döhler subsidiary in January 2014 and thus will be fully integrated into the globally active Döhler group. Headquartered in Darmstadt, Germany, Döhler is a leading manufacturer of technology-based natural ingredients, ingredient systems and integrated solutions for the food and beverage industry. The Mexican ingredient specialist Innovación Alimentaria was founded in 1992 by Gustavo León. Döhler acquired close to 40% of the company back in 2006. Managed jointly by Innovación Alimentarias founder and Döhler, the company has since developed into Döhlers most important hub in Central America under its new name, Innoval Döhler. Doehler Mexico S.A. de C.V., as the 100% Döhler subsidiary will now be called, will also be increasingly active in the United States and Canada markets. An additional expertise of Doehler Mexico is the development of tailored sweetening systems and innovative low-calorie food and beverage ...
IFM Therapeutics Launches IFM Due, Its Second Subsidiary Aimed at Parkinsons and NASH | BioSpace
IFM Therapeutics LLC is launching its second subsidiary in less than a year. This morning, the Boston-based company, launched IFM Due (pronounced du-way), a subsidiary company developing a suite of cGAS inhibitors and STING antagonists that can target diseases like NASH, lupus and Parkinsons.
LifeMap Sciences, a Subsidiary of BioTime, Signs Definitive Distribution Agreement with ProSpec-Tany - AOL Finance
LifeMap Sciences, a Subsidiary of BioTime, Signs Definitive Distribution Agreement with ProSpec-Tany TechnoGene ALAMEDA, Calif.--(BUSINESS WIRE)-- LifeMap Sciences, Inc. a subsidiary of
BioTime Subsidiary OrthoCyte Corporation Announces the Appointment of Francois Binette as Vice President
ALAMEDA, Calif.---- BioTime, Inc. and its subsidiary OrthoCyte Corporation today announced the appointment of Francois Binette, PhD, as OrthoCyte s Vice President of Research and Business Development. OrthoCyte is a wholly owned subsidiary of BioTime, Inc. that develops cellular therapeutics for orthopedic repair, diseases, and injuries.
Acetylcholine, acetyl-β-methylcholine and carbamylcholine inhibited sinoatrial pacemaker activity in atria isolated from chick embryos on the 6th, 12th and 18th incubation days. Cardioinhibition persisted throughout the 5-minute exposure to cholinergic agonists in sinoatrial preparations from the 12th and l8th incubation days whereas automaticity recovered completely within 1 to 2 minutes in preparations from the 6th incubation day. Neither hydrolysis by acetylcholinesterase nor release of catecholamines from cardiac stores accounted adequately for the brevity of pacemaker inhibition by choline esters on the 6th incubation day. Evidence suggested that desensitization, most prominently observed with carbamylcholine, restricted the duration of cholinergic inhibition of the pacemaker on the 6th incubation day. Although automaticity recovered completely within 2 minutes after initial application of acetylcholine and carbamylcholine, pacemaker cells were not inhibited by a second application until ...
Noticed yellow urine while on sinus medicine. Why am I getting lack of lubrication?
Question - Noticed yellow urine while on sinus medicine. Why am I getting lack of lubrication?. Ask a Doctor about Glans penis, Ask a Psychiatrist
Congenital Defects Tutorial - Normal Cardiac Development | Atlas of Human Cardiac Anatomy
Conduction System. Development of the conduction system. Cardiomyocytes form the conduction system of the heart. Molecular genetic studies have revealed the requirement of a functional network of transcription factors to determine whether a myocardial precursor cell turns into either a working cell or a cell belonging to the conduction system. Contrary to previous assumptions, the conduction system itself has no neural crest influence during development. The innervation of the conduction system in adults though is ensured through cardiac ganglia originating from the neural crest. In embryos, the innervation of this system is still missing.. Cells located in the caudal heart tube, derived from the common cardinal vein or right sinus venosus in the sinoatrial region, differentiate to form the sinoatrial node near the left venous valve. This node acts as a pacemaking component of the cardiac conduction pathway. During early development, the entire sinus venosus has a pacemaker activity. In fact, ...
Pitx2-microRNA pathway that delimits sinoatrial node development and inhibits predisposition to atrial fibrillation
The molecular mechanisms underlying atrial fibrillation, the most common sustained cardiac arrhythmia, remain poorly understood. Genome-wide association studies uncovered a major atrial fibrillation susceptibility locus on human chromosome 4q25 in close proximity to the paired-like homeodomain trans …
Funny Videos Of Cats And Babies Compilation 2014 [NEW] | Funny Meme Gags
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Stewies Blood Vessel - FG - ComicBeat.Com - Funny Videos - Funny Video Clips - Funny Video - Funny Clips
Stewies Blood Vessel - FG ComicBeat is your one stop source for funny videos, funny video, funny clips, funny clip, funny video clips, funny movies and more.
Maximum Rate of Depolarization of Single Muscle Fiber in Normal and Low Sodium Solutions | JGP
The values of membrane action potentials and maximum depolarization rates of single muscle fibers in normal Tyrode solution and in low sodium solutions containing as little as 20 per cent of the sodium chloride were measured with intracellular microelectrodes. Under these conditions the membrane potential remains unchanged up to 36 per cent of [Na+]out concentration, whereas the overshoot of the action potential varies linearly with the logarithm of the external sodium concentration. The maximum depolarization rate is a linear function of the external sodium concentration. The results obtained support the ionic theory for sodium and the independence principle for sodium current related to the external sodium concentration.. ...
KIT-Über Uns - Team - Wissenschaftliche Mitarbeiter
Abstract:. Each heartbeat is initiated by cyclic spontaneous depolarization of cardiomyocytes in the sinus node forming the primary natural pacemaker. In patients with end-stage renal disease undergoing hemodialysis, it was recently shown that the heart rate drops to very low values before they suffer from sudden cardiac death with an unexplained high incidence. We hypothesize that the electrolyte changes commonly occurring in these patients affect sinus node beating rate and could be responsible for severe bradycardia. To test this hypothesis, we extended the Fabbri et al. computational model of human sinus node cells to account for the dynamic intracellular balance of ion concentrations. Using this model, we systematically tested the effect of altered extracellular potassium, calcium, and sodium concentrations. Although sodium changes had negligible (0.15 bpm/mM) and potassium changes mild effects (8 bpm/mM), calcium changes markedly affected the beating rate (46 bpm/mM ionized calcium without ...
Funny Cide relaxed in work | Daily Racing Form
Email. ELMONT, N.Y. - Kentucky Derby and Preakness winner Funny Cide got down to serious business Friday at Belmont Park when he had his first work since Aug. 19. Under exercise rider Robin Smullen, Funny Cide covered a half-mile in 48.26 seconds, breezing, over the main track, which was listed as fast. The early fractions on Funny Cides work, according to the clockers, were 12.60 for the first furlong and 24.40 for the opening quarter-mile. Funny Cide galloped out five furlongs in 1:01.30. Unlike in some of his works before the Belmont Stakes that took place when the track opened at 5:30 a.m., Funny Cide was one of the first workers when the track reopened after the renovation break at 8:45. Barclay Tagg, Funny Cides trainer, said he was happy with the work because Funny Cide was relaxed. During the Triple Crown, the New York-bred Funny Cide was headstrong in many of his breezes. Weve been galloping him in draw reins to relax him, Tagg said. We spend all our time trying to keep him ...
natriuretic peptides Protocols and Video...
Video articles in JoVE about natriuretic peptides include High Efficiency Differentiation of Human Pluripotent Stem Cells to Cardiomyocytes and Characterization by Flow Cytometry, Methods for the Isolation, Culture, and Functional Characterization of Sinoatrial Node Myocytes from Adult Mice, Assessing Endothelial Vasodilator Function with the Endo-PAT 2000, Semi-automated Biopanning of Bacterial Display Libraries for Peptide Affinity Reagent Discovery and Analysis of Resulting Isolates, Development of a Backbone Cyclic Peptide Library as Potential Antiparasitic Therapeutics Using Microwave Irradiation, Distinguishing Allosteric Effects from Orthosteric Binding in Protein-Ligand Interactions, Technique of Minimally Invasive Transverse Aortic Constriction in Mice for Induction of Left Ventricular Hypertrophy, Combining Chemical Cross-linking and Mass Spectrometry of Intact Protein Complexes to Study the Architecture of Multi-subunit Protein Assemblies, Microwave-assisted Functionalization
Action potentials in pacemaker cells - Osmosis
Learn and reinforce your understanding of Action potentials in pacemaker cells through video. The action potentials of the heart are usually initiated in the cells of the sinoatrial node
Time-Dependent Changes in the Chronotropic Response to Vagal Stimulati by Shirou Yamasakj, Adrienne Stolfi et al.
We characterized changes in the vagal chronotropic response during 3-min trains of vagal stimulation at 3, 5, and 8 Hz in anesthetized, chemically sym-pathectomized (6-hydroxydopamine) newborn canines (|15 d of|age). In response to vagal stimulation, the sinus cycle length gradually increased (within 30 s) to a maximum value that was dependent upon the stimulation frequency (p | 0.001). The chronotropic response then attenuated over the remainder of the vagal train. However, unlike in adult dogs, the degree of attenuation of the vagal chronotropic response (fade) was also highly dependent upon the frequency of vagal stimulation in the range 3-8 Hz (p | 0.002). We then compared the maximum change in sinus cycle length and fade in a group of neonates while stimulating the vagus at 3 Hz before and after the administration of physostigmine (0.2 mg/kg i.v.). Physostigmine resulted in a significant increase not only in the maximum percent change in sinus cycle length but in the magnitude of attenuation of the
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JCI - Popeye domain containing proteins are essential for stress-mediated modulation of cardiac pacemaking in mice
In this report, we demonstrated that loss of function mutations in Popdc1 and Popdc2 genes in mice are associated with stress-induced SND, resulting in chronotropic incompetence and long sinus pauses. The Popdc genes displayed overlapping myocardial expression patterns and similar biochemical properties, and the cardiac phenotypes of the null mutants were nearly identical. Our data suggest that Popdc proteins represent a novel class of cAMP binding proteins that interact with TREK-1 channels and may be involved in channel trafficking. Age-dependent decline in cardiac pacemaking in Popdc null mutants. Both mouse mutants developed SND at advanced age. Assuming that Popdc genes act in the same pathway, loss of a single gene might not have a significant impact on function in the young, since both Popdc genes might be able to substitute for each other. Obviously, the compensation became less efficient when the null mutants aged, possibly due to an age-dependent decline of Popdc expression. ...
What Are The 4 Lethal Heart Rhythms? - mcafee online activation
Common Abnormal Heart RhythmsAtrial fibrillation, irregular contraction of atria. … Atrial tachycardia, a fast heart rate that starts in the atriums.Premature atrial contractions, early extra heart beats that start in ventricles.Sinus node disease or dysfunction, abnormal heart rhythms by malfunction of the hearts primary pacemaker, sinus node.More items… ...
Health Article | Health & Wellness Library | University Hospitals | Cleveland, OH
Ablation is a procedure to treat atrial fibrillation. It uses small burns or freezes to cause some scarring on the inside of the heart to help break up the electrical signals that cause irregular heartbeats. This can help the heart maintain a normal heart rhythm.. The heart has 4 chambers. There are 2 upper chambers called atria and 2 lower chambers called ventricles. Normally, a special group of cells begin the signal to start your heartbeat. These cells are in the sinoatrial (SA) node in the upper right atrium of the heart. During atrial fibrillation, the signal to start the heartbeat doesnt begin in the sinoatrial node the way it should. Instead, the signal is sidetracked and begins somewhere else in the atria, triggering a small region at a time. The atria cant contract normally to move blood to the ventricles. This causes the atria to quiver or fibrillate. The disorganized signal spreads to the ventricles, causing them to contract irregularly and sometimes more quickly than they ...
Royal Holdings Inc. Through Its Royal Specialty Packaging Subsidiary Has Acquired Adhesives Packaging Specialties Inc. -...
Royal Holdings Inc. (Royal), a holding company of Arsenal Capital Partners (Arsenal), announced that it has through its Royal Packaging Specialties subsidiary, acquired the stock of Adhesives Packaging Specialties Inc. (APS) Based
Caribbean International Holdings Wholly Owned Subsidiary Announces It Has Begun Processing Applicants for Treatments Via Its...
Strategy is to Screen and Qualify Viable Applicants/Patients for Treatment in DR Through Regenerative BioScience, Inc.. Treatments Have Already Commenced. SARASOTA, Fla., May 5, 2014 (GLOBE NEWSWIRE) -- Caribbean International Holdings (Pink Sheets:CIHN) through its subsidiary, Regenerative BioScience, Inc., (RBS) previously announced on May 2, 2014, that it had appointed Dr. Leonel Liriano as its Medical Director, today announced, in a further development, that via the Companys new website (http://www.regenerativebioscience.com/index.html) is now fully operational and it has begun processing initial requests for its no-cost cost complimentary consultations regarding the applicants suitability to qualify for Companys revolutionary stem cell procedures.. Adult stem cells work as the repairmen of the body by replenishing and regenerating damaged tissues and cells. Certain conditions have shown marked improvement when treated with adult stem cells taken from the patients own body. ...
F321. CHEMISTRY A Atoms, Bonds and Groups ADVANCED SUBSIDIARY GCE. Monday 23 May 2011 Afternoon. Duration: 1 hour - PDF
ADVANCED SUBSIDIARY GCE CHEMISTRY A Atoms, Bonds and Groups F321 *F * Candidates answer on the question paper. OCR supplied materials: Data Sheet for Chemistry A (inserted) Other materials required:
Scilex Holding Company, a Subsidiary of Sorrento Therapeutics, Announces Continuous Sales Growth in ZTlido® and Expects to...
Scilex Holding Company, a Subsidiary of Sorrento Therapeutics, Announces Continuous Sales Growth in ZTlido® and Expects to Complete Enrollment on its SP-102 (SEMDEXA™) Phase 3 Pivotal Trial Program in 2020 - read this article along with other careers information, tips and advice on BioSpace
Advanzeon Solutions, Inc.s Wholly Owned Subsidiarys SleepMaster Solutions(TM) Sleep Apnea Program Extended by Prominent...
TAMPA, FL / ACCESSWIRE / July 24, 2019 / Advanzeon Solutions, Inc. (OTC PINK: CHCR) (Advanzeon) announced today the extension of its wholly-owned Subsidiarys (collectively, the
Advanced Pain Remedies, a Subsidiary of Cato BioVentures, Announces a Three Million Dollar Award from the National Cancer...
...DURHAM N.C. Jan. 10 2011 /- Advanced Pain Remedies (AP...SP-SAP is a conjugate of the pain-processing peptide Substance P and t...Following discussions and input from the Food and Drug Administration ... I am pleased that the National Cancer Institute has recognized the im...,Advanced,Pain,Remedies,,a,Subsidiary,of,Cato,BioVentures,,Announces,a,Three,Million,Dollar,Award,from,the,National,Cancer,Institute,for,SP-SAP,biological,advanced biology technology,biology laboratory technology,biology device technology,latest biology technology
AppYeas Subsidiary The Diagnostic Centers Signs First New Client
FORT WORTH, TX--(Marketwired - Nov 2, 2017) - AppYea Inc. (OTC PINK: APYP) announced today that its subsidiary The Diagnostic Centers has signed its first new client, Pacific Pain & Regenerative Medicine, with locations in Los Angeles and Irvine, California and has started shipping PGx samples for testing. Under this new...
Short: HP to create subsidiary - CNET
Hewlett-Packard announced that it will convert its Mechanical Design Division into a subsidiary company, CoCreate, focusing on software for mechanical design and product-data management. CoCreate will market globally under its own brand and identity, and is scheduled to start operations in November.
Amarantus Subsidiary MANF Therapeutics Announces Publication in Science Magazine of Positive Animal Data for MANF in Treatment...
View complete news release for Amarantus+Subsidiary+MANF+Therapeutics+Announces+Publication+in+Science+Magazine+of+Positive+Animal+Data+for+MANF+in+Treatment+of+Retinal+Damage+and+Issuance+of+Retinal+Patent+in+Japan+Covering+MANF+and+CDNF - OTCMarkets.com
Mozilla Opens Thunderbird Email Subsidiary - Slashdot
alphadogg is one of several readers to note the opening of the Mozilla Foundations new subsidiary, Mozilla Messaging, charged with developing the free, open source Thunderbird email software. Mozilla Messaging will initially focus on Thunderbird 3, which aims at improving several aspects of the sof...
The transfer pricing considerations of Suzukis 100% subsidiary in India | International Tax Review
Car manufacturer, Suzuki, has decided to set up a 100% subsidiary in Gujarat, India, in addition to its majority-owned listed-entity, Maruti Suzuki. Wider business decisions aside, there are transfer pricing implications, which must be considered by any multinational in this position.
MOL announces name changes of wholly owned subsidiary in Europe
Mitsui O.S.K. Lines, Ltd. today announced that effective April 3, 2017, its wholly owned subsidiary Mitsui O.S.K Bulk Shipping (Europe) Ltd. will change its name to MOL (Europe Africa) Ltd., in line with the MOL Groups efforts to promote its comprehensive service lineup under the One MOL concept.. ...
100-year-old distributor purchased by large subsidiary
Multiregional veterinary distributor Miller Vet has been purchased by Patterson Veterinary Supply, a subsidiary of Patterson Companies.
Methanexs shipping subsidiary orders new methanol-powered vessels | Chemical Week
Waterfront Shipping (Vancouver, BC), the marine transportation subsidiary of Methanex, said on Monday that it has reached an agreement with Mitsui O.S.K. Lines (MOL; Tokyo), Westfal-Larsen & Co. (WL;...
The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is an oval shaped region of special cardiac ... although in some cases there have been either 2 or 3 sinoatrial node arteries supplying the SA node. Also, the SA node artery ... The sinoatrial node receives its blood supply from the sinoatrial nodal artery. This blood supply, however, can differ hugely ... This can disrupt the electrical pacemaker function of the SA node, and can result in sinus node dysfunction. If the SA node ...
Pacemaker cells in the sinoatrial node, and atrioventricular node are smaller and conduct at a relatively slow rate between the ... ISBN 0-13-193480-5. Kashou AH, Basit H, Chhabra L (January 2020). "Physiology, Sinoatrial Node (SA Node)". StatPearls. PMID ... They are located in the sinoatrial node (the primary pacemaker) positioned on the wall of the right atrium, near the entrance ... Other pacemaker cells are found in the atrioventricular node (secondary pacemaker). Pacemaker cells carry the impulses that are ...
It causes tachycardia by blocking vagal effects on the sinoatrial node. Acetylcholine hyperpolarizes the sinoatrial node; this ... In the atrioventricular node, the resting potential is lowered, which facilitates conduction. This is seen as a shortened PR- ...
The right vagus branch innervates the sinoatrial node. In healthy people, parasympathetic tone from these sources is well- ... When hyperstimulated, the left vagal branch predisposes the heart to conduction block at the atrioventricular node. At this ...
Wahl-Schott C, Fenske S, Biel M (Apr 2014). "HCN channels: new roles in sinoatrial node function". Current Opinion in ... HCN1 channel expression is found in the sinoatrial node, the neocortex, hippocampus, cerebellar cortex, dorsal root ganglion, ...
Sinoatrial nodal artery
... or sinuatrial nodal artery or sinoatrial artery) is an artery of the heart which supplies the sinoatrial node, the natural ... The sinoatrial node surrounds the sinoatrial artery, which can run centrally (in 70% of individuals) or off-center within the ... The origin of the sinoatrial node artery is not related to coronary artery dominance, which means the side (right or left) that ... July 2008). "Anatomical Aspects of the Arterial Blood Supply to the Sinoatrial and Atrioventricular Nodes of the Human Heart". ...
Hund, TJ; Mohler, PJ (2008). "Ankyrin-based targeting pathway regulates human sinoatrial node automaticity". Channels (Austin, ... Robaei, D; Ford, T; Ooi, SY (February 2015). "Ankyrin-B syndrome: a case of sinus node dysfunction, atrial fibrillation and ... Glukhov, AV; Fedorov, VV; Anderson, ME; Mohler, PJ; Efimov, IR (August 2010). "Functional anatomy of the murine sinus node: ... ANK2 mutations have also been identified in patients with sinus node dysfunction. Mechanistic studies on effects of these ...
In a healthy sinoatrial node (SAN, a complex tissue within the right atrium containing pacemaker cells that normally determine ... In the pacemaking cells of the heart (e.g., the sinoatrial node), the pacemaker potential (also called the pacemaker current) ... ISBN 978-0-07-366175-9. Verkerk AO, van Ginneken AC, Wilders R (January 2009). "Pacemaker activity of the human sinoatrial node ... SA node → ,block, atrial foci → junctional foci → ventricular foci The other foci will not see the SA node firing; however, ...
Right axis deviation
It is measured using an electrocardiogram (ECG). Normally, this begins at the sinoatrial node (SA node); from here the wave of ... Pre-excitation refers to early activation of the ventricles due to impulses bypassing the AV node via an accessory pathway. ...
Cardiac action potential
In the sinoatrial node, this phase is also due to the closure of the L-type calcium channels, preventing inward flux of Ca2+ ... Joung B, Chen PS, Lin SF (March 2011). "The role of the calcium and the voltage clocks in sinoatrial node dysfunction". Yonsei ... In healthy hearts, these cells form the cardiac pacemaker and are found in the sinoatrial node in the right atrium. They ... In pacemaker cells (e.g. sinoatrial node cells), however, the increase in membrane voltage is mainly due to activation of L- ...
Larsson HP (Sep 2010). "How is the heart rate regulated in the sinoatrial node? Another piece to the puzzle". The Journal of ... "Phosphorylation and modulation of hyperpolarization-activated HCN4 channels by protein kinase A in the mouse sinoatrial node". ... Nof E, Antzelevitch C, Glikson M (Jan 2010). "The Contribution of HCN4 to normal sinus node function in humans and animal ... "Pacemaker channel dysfunction in a patient with sinus node disease". The Journal of Clinical Investigation. 111 (10): 1537-45. ...
Pacemaker cells develop in the primitive atrium and the sinus venosus to form the sinoatrial node and the atrioventricular node ... SA node), and the vagus nerve provides parasympathetic input to the heart by releasing acetylcholine onto sinoatrial node cells ... The normal resting heart rate is based on the at-rest firing rate of the heart's sinoatrial node, where the faster pacemaker ... The heart rate is rhythmically generated by the sinoatrial node. It is also influenced by central factors through sympathetic ...
Beta-2 adrenergic receptor
Increases heart rate in sinoatrial node (SA node) (chronotropic effect). Increases atrial cardiac muscle contractility. ( ...
Cyclic nucleotide-gated ion channel
The significance of this in the sinoatrial node (and, as backup, in the atrioventricular node) is that as the heart resets, or ... ISBN 978-0-12-065310-2. Larsson, H. P. (2010). "How is the heart rate regulated in the sinoatrial node? Another piece to the ...
HCN4 is the main isoform expressed in the sinoatrial node, but low levels of HCN1 and HCN2 have also been reported. The current ... Larsson, H. P. (2010). "How is the heart rate regulated in the sinoatrial node? Another piece to the puzzle". The Journal of ...
In short, they generate action potentials, but at a slower rate than the sinoatrial node. This capability is normally ... The electrical origin of atrial Purkinje fibers arrives from the sinoatrial node. Given no aberrant channels, the Purkinje ... They are influenced by electrical discharge from the sinoatrial node. During the ventricular contraction portion of the cardiac ... The Purkinje fibers do not have any known role in setting heart rate unless the SA node is compromised (when they can act as ...
Monfredi, O; Dobrzyński, H; Mondal, T; Boyett, MR; Morris, GM (2010). "The Anatomy and Physiology of the Sinoatrial Node-A ...
Anatomy of the human heart
At the upper end of sulcus terminalis lies the sinoatrial node. The sinoatrial node receives blood supply from a branch of the ... is named node of Arantius. The aortic leaflets are hinged at the beginning of the aorta, at very first part of aortic sinus. ... they end up in a brachiocephalic node. In approximately 1% of humans, coronary arteries originate in a not typical position. ...
These results showed that the mechanism of pacemaker generation in Purkinje fibres and in sinoatrial node cells was the same, ... Bucchi, Annalisa; Baruscotti, Mirko; DiFrancesco, Dario (2002-06-10). "Current-dependent Block of Rabbit Sino-Atrial Node If ... DiFrancesco, D. (December 4-10, 1986). "Characterization of single pacemaker channels in cardiac sino-atrial node cells". ... in cells isolated from the rabbit sino-atrial node". The Journal of Physiology. 377: 61-88. doi:10.1113/jphysiol.1986.sp016177 ...
The sinoatrial node (SA node) is the primary pacemaker of the heart. It is a region of cardiac muscle on the wall of the upper ... Kashou AH, Basit H, Chhabra L (January 2020). "Physiology, Sinoatrial Node (SA Node)". StatPearls. PMID 29083608. Retrieved 10 ... Impulses from the sinus node reach the atrioventricular node which acts as the secondary pacemaker. The cells of the AV node ... In most humans, the highest concentration of pacemaker cells is in the sinoatrial (SA) node the natural and primary pacemaker, ...
In contrast, expression is low in the sinoatrial node and atrioventricular node. Within the heart, a transmural expression ...
The sinus venosus also forms the sinoatrial node and the coronary sinus; in (most) mammals only. In the embryo, the thin walls ...
Pacemaker cells develop in the primitive atrium and the sinus venosus to form the sinoatrial node and the atrioventricular node ... These cells form an ovoid sinoatrial node (SAN), on the left venous valve. After the development of the SAN, the superior ... the sinoatrial node and the coronary sinus. The central part of cardiogenic area is in front of the oropharyngeal membrane and ... But this pacemaker activity is actually made by a group of cells that derive from the sinoatrial right venous sinus. ...
Caution is recommended when using ticagrelor in people with advanced sinoatrial node disease. Allergic skin reactions such as ...
Normal sinus rhythm is established by the sinoatrial (SA) node, the heart's pacemaker. The SA node is a specialized grouping of ... Without the SA node, the AV node would generate a heart rate of 40-60 beats per minute. If the AV node were blocked, the ... the sinoatrial node, the atrioventricular node, the bundle of His (atrioventricular bundle), the bundle branches, and the ... that lead directly from the SA node to the next node in the conduction system, the atrioventricular node. The impulse takes ...
"On the ionic mechanism of cyproheptadine-induced bradycardia in a rabbit sinoatrial node preparation". European Journal of ... sinoatrial automaticity (level of sinoatrial self-activation). Takahara A, Uneyama H, Sasaki N, Ueda H, Dohmoto H, Shoji M, ... and conductance through the atrioventricular node. In addition AH-1058 has been shown to decrease systolic blood pressure while ...
Peter Kohl (scientist)
Kohl, P; Kamkin, AG; Kiseleva, I S.; Noble, D (1994). "Mechanosensitive fibroblasts in the sino-atrial node region of rat heart ... Camelliti, P; Green, CR; LeGrice, I; Kohl, P (2004). "Fibroblast network in rabbit sinoatrial node: structural and functional ... axial stretch increases spontaneous pacemaker activity in rabbit isolated sinoatrial node cells". Journal of Applied Physiology ...
Sinoatrial node activity is modulated, in turn, by nerve fibres of both the sympathetic and parasympathetic nervous systems. ... These systems act to increase and decrease, respectively, the rate of production of electrical impulses by the sinoatrial node ... Specialized cardiomyocytes in the sinoatrial node generate electrical impulses that control the heart rate. These electrical ...
The sinoatrial node (S-A Node) is the heart's natural pacemaker, issuing electrical signaling that travels through the heart ... These electrical pathways contain the sinoatrial node, the atrioventricular node, and the Purkinje fibers. (Exceptions such as ... Systole of the heart is initiated by electrically excitable cells situated in the sinoatrial node. These cells are activated ... competes with the sinoatrial node for electrical control of the atrial chambers and thereby diminishes the performance of the ...
... the sinoatrial node (also known as the sinus node or the SA node). Here an electrical signal is created that travels through ... The right coronary artery also supplies blood to the atrioventricular node (in about 90% of people) and the sinoatrial node (in ... The sinoatrial node is found in the upper part of the right atrium near to the junction with the superior vena cava. The ... The sinoatrial node is found in all amniotes but not in more primitive vertebrates. In these animals, the muscles of the heart ...
A wave of excitation spreads out from the sinoatrial node through the atria along specialized conduction channels. This ... The AV node is quite compact (~1 x 3 x 5 mm). The AV node lies at the lower back section of the interatrial septum near the ... The AV node's normal intrinsic firing rate without stimulation (such as that from the SA node) is 40-60 times/minute. This ... The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of ...
List of ICD-9 codes 390-459: diseases of the circulatory system
... right 426.6 Sinoatrial heart block 426.7 Atrioventricular excitation, anomalous Wolff-Parkinson-White syndrome 427 Cardiac ... Acute febrile mucocutaneous lymph node syndrome 446.5 Giant Cell arteritis(Temporal Arteritis) 447 Other disorders of arteries ...
... and the sinoatrial node, via the vagus nerve Chemically and mechanically sensitive neurons of the general visceral afferent ...
2007). "Tbx3 controls the sinoatrial node gene program and imposes pacemaker function on the atria". Genes & Development. 21 (9 ... However, in the instance of either a malfunctioning SA node or an ectopic focus bearing an intrinsic rate superior to SA node ... which can cause the rate of impulse to slow SA node blockage so that impulses never leave the atria AV node blockage (3rd ... the SA node usually suppresses the ectopic pacemaker activity due to the higher impulse rate of the SA node. ...
... which run from the sinoatrial node to the atrioventricular node, converging in the region near the coronary sinus. Atrial ... The normal cardiac rhythm originates in the sinoatrial node, which is located in the right atrium near the superior vena cava. ... Because it originates close to the sinoatrial node and consists of long parallel fibers, Bachmann's bundle is, during sinus ... James, Thomas N. (1 October 1963). "The connecting pathways between the sinus node and A-V node and between the right and the ...
AVRT may involve orthodromic conduction (where the impulse travels down the AV node to the ventricles and back up to the atria ... Presented in order of most to least common, they are: Narrow complex Sinus tachycardia, which originates from the sino-atrial ( ... SA) node, near the base of the superior vena cava Atrial fibrillation Atrial flutter AV nodal reentrant tachycardia Accessory ... is a rare but benign type of cardiac arrhythmia that may be caused by a structural abnormality in the sinus node. It can occur ...
Wandering atrial pacemaker
This is different from normal pacemaking activity, where the sinoatrial node (SA node) is responsible for each heartbeat and ... Kashou, Anthony H.; Basit, Hajira; Chhabra, Lovely (2021), "Physiology, Sinoatrial Node", StatPearls, Treasure Island (FL): ... This is unusual because the SA node, AV node, bundle of His, bundle branches, and Purkinje fibers are the structures that have ... For elderly individuals, the rhythm may be caused by sinus node dysfunction. This is where the heart's pacemaker, the SA node, ...
Myocardial infarction complications
... when the impulse from the sinoatrial node, the normal cardiac pacemaker, does not reach the heart chambers). As a reaction to ...
Cardiology diagnostic tests and procedures
... typically from the sinoatrial or SA node) following down the bundle of HIS and ultimately stimulating the ventricles to ...
This condition, called tachycardia-bradycardia syndrome, is usually caused by sinoatrial node dysfunction or block or ... Sick sinus syndrome, a sinus node dysfunction, causing alternating bradycardia and tachycardia. Often there is a long pause ( ...
Junctional escape beat
It occurs when the rate of depolarization of the sinoatrial node falls below the rate of the atrioventricular node. This ... It is a protective mechanism for the heart, to compensate for the SA node no longer handling the pacemaking activity, and is ... dysrhythmia also may occur when the electrical impulses from the SA node fail to reach the AV node because of SA or AV block. ... A junctional escape complex is a normal response that may result from excessive vagal tone on the SA node (e.g. digoxin ...
Index of anatomy articles
... short ciliary nerves shoulder shoulder blade shin sight sigmoid colon sigmoid sinus Simian crease simian shelf sinoatrial node ... hypothalmotegmental axon hypothenar muscles ileal vessels ileocecal valve ileocolic artery ileum iliac crest iliac lymph nodes ... enlargement lumbar spine lumbar vertebrae lumbosacral enlargement lumbosacral plexus lumbrical lunate lung lymph lymph nodes ... neuromuscular junction neuron neuropil nevus nictitating membrane nigrostriatal axon nipple Nissl body nociception nodes of ...
Third-degree atrioventricular block
... is a medical condition in which the electrical impulse generated in the sinoatrial node (SA node) in the atrium of the heart ... This type of device typically listens for a pulse from the SA node via lead in the right atrium and sends a pulse via a lead to ... Atropine works by reducing vagal stimulation through the AV node but will not be effective in those who have had a previous ... An inferior wall myocardial infarction may cause damage to the AV node, causing third-degree heart block. In this case, the ...
The M2 muscarinic receptors decrease the heart rate by inhibiting depolarization of the sinoatrial node via Gi protein-coupled ... AV node). However, M2 receptors have no effect on the contractile forces of the ventricular muscle. Stimuli causing reflex ... reduce the contractile forces of the atrial cardiac muscle and reduce the conduction velocity of the atrioventricular node ( ...
... is a medical condition wherein the sinoatrial node of the heart transiently ceases to generate the electrical ... If a pacemaker other than the sinoatrial node is pacing the heart, this condition is known as an escape rhythm. If no other ... as a brief period of irregular length with no electrical activity before either the sinoatrial node resumes normal pacing, or ... not sinus node (normal P morphology is lost). Junctional escape (rate 40-60): originates near the AV node; a normal P wave is ...
In AF, the normal regular electrical impulses generated by the sinoatrial node are overwhelmed by disorganized electrical waves ... Fibrosis is not limited to the muscle mass of the atria and may occur in the sinus node (SA node) and atrioventricular node (AV ... the sinoatrial node) to spread to and stimulate the muscular layer of the heart (myocardium) in both the atria and the ... Rate control is achieved with medications that work by increasing the degree of the block at the level of the AV node, ...
T-type calcium channel
This is important in the aforementioned depolarization events in the pace-making activity of the sinoatrial (SA) Node in the ... T-type calcium channels function to control the pace-making activity of the SA Node within the heart and relay rapid action ... its ability to generate potentials that allow for rhythmic bursts of action potentials in cardiac cells of the sinoatrial node ... These channels allow for continuous rhythmic bursts that control the SA Node of the heart. Pharmacological evidence of T-type ...
This is due to the presence of "pacemaker cells," which originate from the sinoatrial node. This structure allows for ... tissue throughout the heart whereas T-type calcium channels are more concentrated in the pacemaker cells of the sinoatrial node ...
... since the sinoatrial node (SAN) is discharging at an abnormally fast rate. Atrial ectopic tachycardia, in which the focus or ... Junctional ectopic tachycardia, in which the focus is in the atrioventricular node (AVN), and Accelerated idioventricular ...
He is also famous for discovering the sinoatrial node, the component of the heart which makes it beat, with his student Martin ... Silverman, M. E; Hollman, A. (1 October 2007). "Discovery of the sinus node by Keith and Flack: on the centennial of their 1907 ...
or Miss Sinoatrial node San people, indigenous people of southern Africa Standard algebraic notation, in chess Senior Advocate ...
... of which increased stimulation leads to decreased output of the sinoatrial node. This reflex is especially sensitive in ...
... is an elevated sinus rhythm characterized by an increase in the rate of electrical impulses arising from the sinoatrial node. ... Patients who are unresponsive to such treatment can undergo catheter ablation to potentially repair the sinus node. Sinus ... ISBN 978-0-7216-8677-6. Choudhury SR, Sharma A, Kohli V (February 2005). "Inappropriate sinus node tachycardia following ...
Two distinct pathways of muscarinic current responses in rabbit sino-atrial node myocytes
... slows the heart rate by acting on sino-atrial node currents. Low ACh concentrations act on muscarinic receptors to inhibit the ... Two distinct pathways of muscarinic current responses in rabbit sino-atrial node myocytes Pflugers Arch. 1998 Dec;437(1):164-7. ... Acetycholine (ACh) slows the heart rate by acting on sino-atrial node currents. Low ACh concentrations act on muscarinic ...
British Library EThOS: A Mathematical Model of Action Potentials of Mouse Sinoatrial Node cells with Molecular Bases
Electrophysiological study of cibenzoline in voltage-clamped rabbit sinoatrial node preparations. | Journal of Pharmacology and...
Electrophysiological study of cibenzoline in voltage-clamped rabbit sinoatrial node preparations.. H Kotake, S Matsuoka, K ... Electrophysiological study of cibenzoline in voltage-clamped rabbit sinoatrial node preparations.. H Kotake, S Matsuoka, K ... Electrophysiological study of cibenzoline in voltage-clamped rabbit sinoatrial node preparations.. H Kotake, S Matsuoka, K ... Electrophysiological study of cibenzoline in voltage-clamped rabbit sinoatrial node preparations. Message Subject (Your Name) ...
Sino-Atrial Nodes Definition & Meaning | ClusterMed.info
Sino-Atrial Nodes defined and explained for easy understanding at the Medical Dictionary from ClusterMed.info. ... Find the definition of the medical term Sino-Atrial Nodes. ... Sino-Atrial Nodes. Sino-Atrial Nodes Definition And Meaning. ... Find the definition of the medical term Sino-Atrial Nodes. Sino-Atrial Nodes defined and explained for easy understanding at ... Whats The Definition Of Medical Term Sino-Atrial Nodes?. The small mass of modified cardiac muscle fibers located at the ...
Parasympathetic modulation of sinoatrial node pacemaker activity in rabbit heart: a unifying model - Physiome Model Repository
You are here: Home / Exposures / Demir, Clark, Giles, 1999 / Parasympathetic modulation of sinoatrial node pacemaker activity ... Parasympathetic modulation of sinoatrial node pacemaker activity in rabbit heart: a unifying model. License and Citation. This ... Parasympathetic modulation of sinoatrial node pacemaker activity in rabbit heart: a unifying model ...
Role of slowly activating delayed rectifier current, IKs, in pacemaker activity of rabbit sino-atrial node cells - Department...
Expression of Kir2.1 and Kir6.2 transgenes under the control of the α-MHC promoter in the sinoatrial and atrioventricular nodes...
Expression of Kir2.1 and Kir6.2 transgenes under the control of the α-MHC promoter in the sinoatrial and atrioventricular nodes ... Expression of Kir2.1 and Kir6.2 transgenes under the control of the α-MHC promoter in the sinoatrial and atrioventricular nodes ... Expression of Kir2.1 and Kir6.2 transgenes under the control of the α-MHC promoter in the sinoatrial and atrioventricular nodes ... Expression of Kir2.1 and Kir6.2 transgenes under the control of the α-MHC promoter in the sinoatrial and atrioventricular nodes ...
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Electrophysiological effect of the maze procedure on canine sinoatrial node function<...
Electrophysiological effect of the maze procedure on canine sinoatrial node function. D. E. McLoughlin, A. Blitz, J. Simmons, R ... This procedure includes several right atrial incisions that may interrupt the integrity of the sinoatrial node or its arterial ... Electrophysiological effect of the maze procedure on canine sinoatrial node function. / McLoughlin, D. E.; Blitz, A.; Simmons, ... This procedure includes several right atrial incisions that may interrupt the integrity of the sinoatrial node or its arterial ...
Calcium transients in guinea-pig sino-atrial node cells imaged by confocal microscopy. - Oxford Cardiovascular Science
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Nkx2-5 defines a subpopulation of pacemaker cells and is essential for the physiological function of the sinoatrial node in...
keywords = "Cardiac conduction system, Nkx2-5, Shox2, Sinoatrial node, Sinus node dysfunction", ... The sinoatrial node (SAN), the primary cardiac pacemaker, consists of a head domain and a junction/tail domain that exhibit ... N2 - The sinoatrial node (SAN), the primary cardiac pacemaker, consists of a head domain and a junction/tail domain that ... AB - The sinoatrial node (SAN), the primary cardiac pacemaker, consists of a head domain and a junction/tail domain that ...
Sick sinus syndrome: MedlinePlus Medical Encyclopedia
... sinus node or SA node. Its role is to keep the ... It is called the sinoatrial node, sinus node or SA node. Its ... Sick sinus syndrome is a group of heart rhythm problems due to problems with the sinus node, such as:. *The heartbeat rate is ... Bradycardia-tachycardia syndrome; Sinus node dysfunction; Slow heart rate - sick sinus; Tachy-brady syndrome; Sinus pause - ...
Frontiers | Heart Rhythm Insights Into Structural Remodeling in Atrial Tissue: Timed Automata Approach
Coster, A. C., and Celler, B. G. (2003). Phase response of model sinoatrial node cells. Ann. Biomed. Eng. 31, 271-283. doi: ... Two clusters of specific and specially organized cells: the sinoatrial node (SAN)-the thin and elongated piece of cardiac ... A simple model of the right atrium of the human heart with the sinoatrial and atrioventricular nodes included. J. Clin. Monit. ... Computational assessment of the functional role of sinoatrial node exit pathways in the human heart. PLoS ONE 12:e0183727. doi ...
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b. Sinoatrial node. c. Autorhythmic cardiac muscle cells. d. All of the above. ... a. SA node - internodal pathway - AV node - interventricular bundle - bundle branches -purkinje fibers ... b. AV node- internodal pathway - SA node - interventricular bundle - bundle branches -purkinje fibers ... c. SA node - interventricular bundle - AV node - internodal pathway -bundle branches -purkinje fibers ...
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SA node cell action potential - Ontology Browser - Rat Genome Database
SA node cell action potential + An action potential that occurs in a sinoatrial node cardiac muscle cell. ... SA node cardiac muscle cell action potential ; SAN cardiac muscle cell action potential ; sinoatrial node cardiac muscle cell ... SA node cell action potential (GO:0086015). Annotations: Rat: (10) Mouse: (13) Human: (13) Chinchilla: (10) Bonobo: (10) Dog: ( ...
Atrial Fibrillation - AHealthyMe - Blue Cross Blue Shield of Massachusetts
These cells are referred to as the sinoatrial (SA) node. The signal quickly travels down the hearts conducting system. From ... In some cases when atrial fibrillation cant be controlled, the conduction node between the atria and the ventricles (AV node) ... it passes through another node of tissues call the AV node, to reach the left and right ventricle, the two lower pumping ... During AFib, the heart receives electrical signals that come from outside the SA node causing the atria to contract in a ...
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The sinus (or sinoatrial) node is a small area of tissue in the wall of the right atrium. It sends out an electrical signal to ... This node is called the pacemaker of the heart because it sets the rate of the heartbeat and causes the rest of the heart to ... Then the impulses travel down to the atrioventricular (or AV) node, which acts as a kind of relay station. From here, the ...
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Reverse re-modelling chronic heart failure by reinstating heart rate variability<...
Sinoatrial Node Medicine & Life Sciences 9% * Apnea Medicine & Life Sciences 7% View full fingerprint ... Despite this, current pacemakers either pace the heart in a metronomic fashion or sense activity in the sinus node. If RSA has ... Despite this, current pacemakers either pace the heart in a metronomic fashion or sense activity in the sinus node. If RSA has ... Despite this, current pacemakers either pace the heart in a metronomic fashion or sense activity in the sinus node. If RSA has ...
Sino-atriAtrioventricular nodesRight atriumSinus node dysfunctionDysfunctionAction PotentialsCalled the atrioventricular nodeImpulsesHeart'sConduction systemAtrialAtriumAtrio-ventricular nodeAtria to contractBranchesAbnormalFibrosisImpulseAbnormalitiesClustersCellsHeartbeatVentriclesSick sinusElectrophysiologicalArrhythmiaMiceMuscarinicOccursDescribeActivityHeart rateChambersVentricleBloodSignalEffects
- Acetycholine (ACh) slows the heart rate by acting on sino-atrial node currents. (nih.gov)
- Calcium transients in guinea-pig sino-atrial node cells imaged by confocal microscopy. (ox.ac.uk)
- Effects on the heart - Beta 1 receptors are present on the sino-atrial node, which is responsible for generating the impulses that make the heart beat. (news-medical.net)
- Blocking the sino-atrial node therefore reduces heart rate. (news-medical.net)
- The electricity starts in the sino-atrial node ( acronym SA Node) The SA Node is a group of cells called pacemaker cells in the right atria. (wikipedia.org)
- ECG is considered superior because it provides a clear waveform, which makes it easier to exclude heartbeats not originating in the sino-atrial node. (bartleby.com)
- Decreases conduction through sinoatrial and atrioventricular nodes. (medscape.com)
- The sinus (or sinoatrial) node is a small area of tissue in the wall of the right atrium. (kidshealth.org)
- The signal begins in the sinoatrial node, or SA node, located in the right atrium. (merckmanuals.com)
- And this starts in the region known as the pacemaker, or the sinoatrial node, that is located in the right atrium. (futurelearn.com)
- The electrical activity of the heart originates in a tissue located in the right atrium called the sinoatrial node, which is the innate pacemaker. (rigging.top)
- The atrio-ventricular node is located at the base of the right atrium, just above the junction of the atria and ventricles. (wordpress.com)
Sinus node dysfunction7
- Sinus node dysfunction was corroborated by all studies. (elsevier.com)
- The maze procedure results in significant acute sinus node dysfunction. (elsevier.com)
- Modifications of the maze procedure that avoid the sinus node or its blood supply area may reduce procedure related sinus node dysfunction. (elsevier.com)
- Although Nkx2-5 inactivation in the SAN junction did not cause a malformed SAN at birth, the mutant mice manifested sinus node dysfunction. (mssm.edu)
- Sinus node dysfunction is a related term that describes an inappropriately low heart rate (either sinus or nonsinus) due to abnormal activity of the normal SA node. (medscape.com)
-   Bradyarrhythmias are due to sinus node dysfunction or atrioventricular conduction disturbances . (wikipedia.org)
- Similarly, SAN-specific CRISPR/Cas9-mediated gene silencing of ACI results in sinus node dysfunction. (bvsalud.org)
- Causes of SA or AV node dysfunction can be divided into two distinct categories: congenital and acquired. (medscape.com)
- Congenital causes include congenital AV block and congenital SA node dysfunction, which is notably less common. (medscape.com)
- Acquired forms of heart block or SA node dysfunction are caused by infection or injury, whereas other forms are idiopathic. (medscape.com)
- SA node dysfunction with symptoms during age-inappropriate bradycardia (The definition varies with the patient's age and expected heart rate. (medscape.com)
- Sinoatrial node myocytes (SAMs) act as the natural pacemakers of the heart, initiating each heart beat by generating spontaneous action potentials (APs). (vectorbiolabs.com)
Called the atrioventricular node2
- This means that electrical activity can only pass from the atria to the ventricles through a small region called the atrioventricular node. (futurelearn.com)
- The electrical signal from the sinoatrial node is first transmitted to the entire atrium, and then, through a tissue called the atrioventricular node, it is divided into left and right branches and transmitted to the entire ventricle, thereby causing the heart to repeatedly beat rhythmically. (rigging.top)
- Contraction impulses probably start in this node, spread over the atrium and are then transmitted by the atrioventricular bundle to the ventricle. (clustermed.info)
- Second degree: Not all impulses are conducted through the AV node. (medscape.com)
- Third degree: AV block is complete, and none of the impulses are conducted across the AV node. (medscape.com)
- Then the impulses travel down to the atrioventricular (or AV) node , which acts as a kind of relay station. (kidshealth.org)
- These electrical impulses are controlled by the heart's sinoatrial (SA) node, or sinus node, the heart's natural pacemaker. (ottawaheart.ca)
- The sinoatrial node (SAN), the leading pacemaker region, generates electrical impulses that propagate throughout the heart. (bvsalud.org)
- The signal arrives at the AV node near the ventricles, where it slows for an instant to allow your heart's right and left ventricles to fill with blood. (smartdraw.com)
- Sinoatrial node (SAN) cells are the heart's primary pacemaker. (bvsalud.org)
- The conduction system includes a gateway called the AV node (atrioventricular node). (msdmanuals.com)
- Find the definition of the medical term Sino-Atrial Nodes. (clustermed.info)
- Sino-Atrial Nodes defined and explained for easy understanding at the Medical Dictionary from ClusterMed.info. (clustermed.info)
- This procedure includes several right atrial incisions that may interrupt the integrity of the sinoatrial node or its arterial supply. (elsevier.com)
- Other arrhythmias arising outside of the SA node may occur, and among the most serious of these is atrial fibrillation. (petplace.com)
- The signal from the SA node is delayed at the AV (slow conduction) to allow atrial systole to precede ventricular systole. (wordpress.com)
- After excitation reaches the AV node and atrial systole has ended, it spreads rapidly down the ventricles via specialised cells that form the Bundle of His (of which there is a left and a right bundle) and to the rest of the myocardium via similar Purkinje fibres. (wordpress.com)
- From the right atria, it travels to the upper-left filling chamber of the heart (left atrium) and from there, it passes through another node of tissues call the AV node, to reach the left and right ventricle, the two lower pumping chambers of the heart. (ahealthyme.com)
- The electrical activity begins in the sinoatrial node, then spreads across the rest of the atrium, through to the other atrium, and then down into the ventricles. (futurelearn.com)
- Once electrical impulse goes through the atrio-ventricular node (AV Node). (wikipedia.org)
Atria to contract2
- During AFib, the heart receives electrical signals that come from outside the SA node causing the atria to contract in a disorganized fashion. (ahealthyme.com)
- The SA node triggers the atria to contract, pushing blood into the ventricles. (merckmanuals.com)
- Interventricular septal branches sternocostal surface sinuatrial node: The pacemaker of the. (psm.edu)
- Irregular HEART RATE caused by abnormal function of the SINOATRIAL NODE. (umassmed.edu)
- The death certificate, completed by the County Coroner, listed "probable arrhythmia due to hypertrophic cardiomyopathy, fibrosis of sinoatrial node" as the immediate cause of death. (cdc.gov)
- First degree: The impulse is conducted through the AV node, albeit delayed. (medscape.com)
- After the cycle is complete, the nodes repolarize , stopping the nerve impulse. (howtogeek.com)
- Each heartbeat originates as an electrical impulse in the upper right chamber of the heart (sinoatrial [SA] node). (petplace.com)
- The impulse then travels across the upper chambers of the heart (atria), to an intermediate station (atrioventricular [AV] node), and finally to the lower chambers of the heart (ventricles). (petplace.com)
- The pacemaker or sinoatrial (SA) node generates an impulse that is spread throughout the atria, causing those two chambers to contract, sending blood into the ventricles. (gradesaver.com)
- Pediatric pacemaker implantation is performed primarily to treat abnormalities of sinoatrial (SA) node (ie, sinus node) or atrioventricular (AV) node function that lead to an insufficient heart rate. (medscape.com)
- Although indications for pacing in children differ from those in adults, both include abnormalities in sinoatrial (SA) node and atrioventricular (AV) node function. (medscape.com)
- While abnormalities of the sinus node are typically a consequence of a systemic disorder, such as hypo- or hyperthyroidism, primary sinus disease is common and can lead to an arrhythmia known as sick sinus syndrome. (petplace.com)
- Two clusters of specific and specially organized cells: the sinoatrial node (SAN)-the thin and elongated piece of cardiac tissue built of self-exciting cells, and the atrioventricular node (AVN)-which collects excitations wandering on the atria, and then uniformly transmits them downwards to cause the contraction of ventricles, are crucial elements for the electrophysiology of the heart. (frontiersin.org)
- The slow delayed rectifier K+ current (IKs) is present in sinoatrial node (SAN) cells of various species, but both in vitro and in silico data on the contribution of IKs to SAN pacemaker activity are not consistent. (cinc.org)
- These cells are referred to as the sinoatrial (SA) node. (ahealthyme.com)
- There are special pacemaker cells in a part of your heart called the SA node (sinoatrial node). (msdmanuals.com)
- The AV node cells are unique in that they are smaller in diameter and thus have a smaller conduction velocity. (wordpress.com)
- This node is called the pacemaker of the heart because it sets the rate of the heartbeat and causes the rest of the heart to contract in its rhythm. (kidshealth.org)
- This is the start of your heartbeat, where the SA node is depolarizing. (howtogeek.com)
- The AV node controls how signals pass from the upper chambers of your heart (atria) to the lower chambers (ventricles). (msdmanuals.com)
- The electrical signal then travels through the atrioventricular node, or AV node, and into the ventricles. (merckmanuals.com)
- As the electrical activity passes through the node and into the rest of the ventricles, there is depolarisation of the ventricles which causes them to contract. (futurelearn.com)
- The latter directs this excitation towards the atrioventricular node, which (because there is a layer of fibrous, non-conducting tissue between ventricles and atria) is the only point of electrical communication between the atria and ventricles. (wordpress.com)
- The AV node is the ONLY point of contact between atria and ventricles i.e. in order from SA activity to reach the ventricles, it must go through the AV node. (wordpress.com)
- Sick sinus syndrome is an abnormality that affects the SA node: It most commonly occurs in Miniature Schnauzers, Dachshunds, Cocker Spaniels, and West Highland White Terriers. (petplace.com)
- You suspect sick sinus node at the properties may be? (sawanschool.com)
- Electrophysiological study of cibenzoline in voltage-clamped rabbit sinoatrial node preparations. (aspetjournals.org)
- Kodituwakku S, Lazar SW, Indic P, Brown EN, Barbieri R. Point process time-frequency analysis of respiratory sinus arrhythmia under altered respiration dynamics. (umassmed.edu)
- In this study, we have investigated the expression (at protein and mRNA levels) of GFP-tagged Kir2.1 and Kir6.2 transgenes under the control of the α-MHC promoter in the sinoatrial node (SAN), atrioventricular node (AVN), His bundle and working myocardium of transgenic mice. (wustl.edu)
- Beta-adrenergic and muscarinic receptor mRNA accumulation in the sinoatrial node area of adult and senescent rat hearts. (cdc.gov)
- An action potential that occurs in a sinoatrial node cardiac muscle cell. (mcw.edu)
- Chronotropic incompetence is the term used to describe the inability of the SA node to increase heart rate adequately as needed for the degree of activity. (medscape.com)
- Despite this, current pacemakers either pace the heart in a metronomic fashion or sense activity in the sinus node. (bath.ac.uk)
- The contractile function of the heart is controlled by the electrical activity initiated in the pacemaker sinoatrial node and conducted throughout the heart. (upstate.edu)
- The pacemaker activity of the AV node produces a slower firing rate (around 40-60/min compared with the SA node's 70-80/min). (wordpress.com)
- To assess the effect of the maze procedure on sinus node function (SNF), the following studies were performed: sinus node recovery times (SNRT), corrected SNRT (CSNRT), CSNRT under autonomic blockade maximal heart rate and intrinsic heart rates. (elsevier.com)
- The muscles surrounding these two chambers are triggered by two nodes: the sinoatrial ( SA) node and the atrioventricular (AV) node. (howtogeek.com)
- The AV node acts as a delay circuit, pausing until the ventricle is full. (howtogeek.com)
- The atrioventricular node then receives the signal, and after a short delay, initiates the contraction of the muscles in the ventricle, thus sending blood into the aorta and pulmonary artery. (gradesaver.com)
- Because the Apple Watch only has one lead, it can't diagnose heart attacks due to an inadequate blood supply, structural defects, or other conditions that may involve more subtle problems with the nerves and nodes in the heart. (howtogeek.com)
- Each beat of your heart begins with an electrical signal from the sinoatrial node, called SA node. (smartdraw.com)
- However, the signal generated by the SA node, if it reaches the AV node, overrides this. (wordpress.com)
- Python and MATLAB scripts for studying the dual effects of SCZ-related genes on layer 5 pyramidal cell firing and sinoatrial node cell pacemaking properties. (yale.edu)