Sinoatrial Node: 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).Vena Cava, Superior: The venous trunk which returns blood from the head, neck, upper extremities and chest.Superior Vena Cava Syndrome: A condition that occurs when the obstruction of the thin-walled SUPERIOR VENA CAVA interrupts blood flow from the head, upper extremities, and thorax to the RIGHT ATRIUM. Obstruction can be caused by NEOPLASMS; THROMBOSIS; ANEURYSM; or external compression. The syndrome is characterized by swelling and/or CYANOSIS of the face, neck, and upper arms.Heart Conduction System: An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Sinoatrial Block: Disturbance in the atrial activation that is caused by transient failure of impulse conduction from the SINOATRIAL NODE to the HEART ATRIA. It is characterized by a delayed in heartbeat and pauses between P waves in an ELECTROCARDIOGRAM.Vena Cava, Inferior: The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs.Heart Atria: The chambers of the heart, to which the BLOOD returns from the circulation.Tachycardia, Sinoatrial Nodal Reentry: Abnormally rapid heartbeats caused by reentry circuit in or around the SINOATRIAL NODE. It is characterized by sudden onset and offset episodes of tachycardia with a HEART RATE of 100-150 beats per minute. The P wave is identical to the sinus P wave but with a longer PR interval.Venae Cavae: The inferior and superior venae cavae.Lymph Nodes: They are oval or bean shaped bodies (1 - 30 mm in diameter) located along the lymphatic system.Atrioventricular Node: A small nodular mass of specialized muscle fibers located in the interatrial septum near the opening of the coronary sinus. It gives rise to the atrioventricular bundle of the conduction system of the heart.Biological Clocks: The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.Brachiocephalic Veins: Large veins on either side of the root of the neck formed by the junction of the internal jugular and subclavian veins. They drain blood from the head, neck, and upper extremities, and unite to form the superior vena cava.Bradycardia: Cardiac arrhythmias that are characterized by excessively slow HEART RATE, usually below 50 beats per minute in human adults. They can be classified broadly into SINOATRIAL NODE dysfunction and ATRIOVENTRICULAR BLOCK.Azygos Vein: A vein which arises from the right ascending lumbar vein or the vena cava, enters the thorax through the aortic orifice in the diaphragm, and terminates in the superior vena cava.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Atrial Function: The hemodynamic and electrophysiological action of the HEART ATRIA.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Arrhythmia, Sinus: Irregular HEART RATE caused by abnormal function of the SINOATRIAL NODE. It is characterized by a greater than 10% change between the maximum and the minimum sinus cycle length or 120 milliseconds.Vena Cava Filters: Mechanical devices inserted in the inferior vena cava that prevent the migration of blood clots from deep venous thrombosis of the leg.Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels: A subgroup of cyclic nucleotide-regulated ION CHANNELS of the superfamily of pore-loop cation channels that are opened by hyperpolarization rather than depolarization. The ion conducting pore passes SODIUM, CALCIUM, and POTASSIUM cations with a preference for potassium.Models, Cardiovascular: Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.Vagus Nerve: 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.Vascular Malformations: A spectrum of congenital, inherited, or acquired abnormalities in BLOOD VESSELS that can adversely affect the normal blood flow in ARTERIES or VEINS. Most are congenital defects such as abnormal communications between blood vessels (fistula), shunting of arterial blood directly into veins bypassing the CAPILLARIES (arteriovenous malformations), formation of large dilated blood blood-filled vessels (cavernous angioma), and swollen capillaries (capillary telangiectases). In rare cases, vascular malformations can result from trauma or diseases.Phlebography: Radiographic visualization or recording of a vein after the injection of contrast medium.Electrophysiology: The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Coronary Sinus: A short vein that collects about two thirds of the venous blood from the MYOCARDIUM and drains into the RIGHT ATRIUM. Coronary sinus, normally located between the LEFT ATRIUM and LEFT VENTRICLE on the posterior surface of the heart, can serve as an anatomical reference for cardiac procedures.Electrocardiography: 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.Cyclic Nucleotide-Gated Cation Channels: A subgroup of cyclic nucleotide-regulated ION CHANNELS within the superfamily of pore-loop cation channels. They are expressed in OLFACTORY NERVE cilia and in PHOTORECEPTOR CELLS and some PLANTS.Pacemaker, Artificial: A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external).Cardiac Pacing, Artificial: Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.Catheterization, Central Venous: Placement of an intravenous CATHETER in the subclavian, jugular, or other central vein.Impulse Control Disorders: Disorders whose essential features are the failure to resist an impulse, drive, or temptation to perform an act that is harmful to the individual or to others. Individuals experience an increased sense of tension prior to the act and pleasure, gratification or release of tension at the time of committing the act.Heart: The hollow, muscular organ that maintains the circulation of the blood.Atrial Function, Right: The hemodynamic and electrophysiological action of the RIGHT ATRIUM.Heart Block: 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.Membrane Potentials: 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, 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.Connexins: A group of homologous proteins which form the intermembrane channels of GAP JUNCTIONS. The connexins are the products of an identified gene family which has both highly conserved and highly divergent regions. The variety contributes to the wide range of functional properties of gap junctions.Potassium Channels: Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.Pulmonary Veins: The veins that return the oxygenated blood from the lungs to the left atrium of the heart.Calcium Channels, T-Type: A heterogenous group of transient or low voltage activated type CALCIUM CHANNELS. They are found in cardiac myocyte membranes, the sinoatrial node, Purkinje cells of the heart and the central nervous system.Connexin 43: A 43-kDa peptide which is a member of the connexin family of gap junction proteins. Connexin 43 is a product of a gene in the alpha class of connexin genes (the alpha-1 gene). It was first isolated from mammalian heart, but is widespread in the body including the brain.Tachycardia, Sinus: Simple rapid heartbeats caused by rapid discharge of impulses from the SINOATRIAL NODE, usually between 100 and 180 beats/min in adults. It is characterized by a gradual onset and termination. Sinus tachycardia is common in infants, young children, and adults during strenuous physical activities.Ion Channels: Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.Catheter Ablation: Removal of tissue with electrical current delivered via electrodes positioned at the distal end of a catheter. Energy sources are commonly direct current (DC-shock) or alternating current at radiofrequencies (usually 750 kHz). The technique is used most often to ablate the AV junction and/or accessory pathways in order to interrupt AV conduction and produce AV block in the treatment of various tachyarrhythmias.Isoproterenol: Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.Jugular Veins: Veins in the neck which drain the brain, face, and neck into the brachiocephalic or subclavian veins.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Electrophysiologic Techniques, Cardiac: Methods to induce and measure electrical activities at specific sites in the heart to diagnose and treat problems with the heart's electrical system.Microelectrodes: Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)Patch-Clamp Techniques: 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.Myocytes, Cardiac: Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).Arrhythmias, Cardiac: Any disturbances of the normal rhythmic beating of the heart or MYOCARDIAL CONTRACTION. Cardiac arrhythmias can be classified by the abnormalities in HEART RATE, disorders of electrical impulse generation, or impulse conduction.Tachycardia, Supraventricular: A generic expression for any tachycardia that originates above the BUNDLE OF HIS.Heart Bypass, Right: Diversion of the flow of blood from the entrance to the right atrium directly to the pulmonary arteries, avoiding the right atrium and right ventricle (Dorland, 28th ed). This a permanent procedure often performed to bypass a congenitally deformed right atrium or right ventricle.Lymph Node Excision: Surgical excision of one or more lymph nodes. Its most common use is in cancer surgery. (From Dorland, 28th ed, p966)Mediastinal Diseases: Disorders of the mediastinum, general or unspecified.Myoblasts, Cardiac: Precursor cells destined to differentiate into cardiac myocytes (MYOCYTES, CARDIAC).Mediastinal Neoplasms: Tumors or cancer of the MEDIASTINUM.Guinea Pigs: A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.Aminophylline: A drug combination that contains THEOPHYLLINE and ethylenediamine. It is more soluble in water than theophylline but has similar pharmacologic actions. It's most common use is in bronchial asthma, but it has been investigated for several other applications.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Atrial Fibrillation: Abnormal cardiac rhythm that is characterized by rapid, uncoordinated firing of electrical impulses in the upper chambers of the heart (HEART ATRIA). In such case, blood cannot be effectively pumped into the lower chambers of the heart (HEART VENTRICLES). It is caused by abnormal impulse generation.Electrophysiological Phenomena: The electrical properties, characteristics of living organisms, and the processes of organisms or their parts that are involved in generating and responding to electrical charges.Delayed Rectifier Potassium Channels: A group of slow opening and closing voltage-gated potassium channels. Because of their delayed activation kinetics they play an important role in controlling ACTION POTENTIAL duration.Adrenergic beta-Agonists: Drugs that selectively bind to and activate beta-adrenergic receptors.Subclavian Vein: The continuation of the axillary vein which follows the subclavian artery and then joins the internal jugular vein to form the brachiocephalic vein.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Benzazepines: Compounds with BENZENE fused to AZEPINES.Sodium Channels: Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.Sentinel Lymph Node Biopsy: A diagnostic procedure used to determine whether LYMPHATIC METASTASIS has occurred. The sentinel lymph node is the first lymph node to receive drainage from a neoplasm.Acetylcholine: A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.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.Cardiac Myosins: Myosin type II isoforms found in cardiac muscle.Anti-Arrhythmia Agents: 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.Calcium: 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.Cardiotonic Agents: Agents that have a strengthening effect on the heart or that can increase cardiac output. They may be CARDIAC GLYCOSIDES; SYMPATHOMIMETICS; or other drugs. They are used after MYOCARDIAL INFARCT; CARDIAC SURGICAL PROCEDURES; in SHOCK; or in congestive heart failure (HEART FAILURE).Heart Ventricles: The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.Ryanodine: 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.Superior Colliculi: The anterior pair of the quadrigeminal bodies which coordinate the general behavioral orienting responses to visual stimuli, such as whole-body turning, and reaching.Device Removal: Removal of an implanted therapeutic or prosthetic device.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.Incidental Findings: Unanticipated information discovered in the course of testing or medical care. Used in discussions of information that may have social or psychological consequences, such as when it is learned that a child's biological father is someone other than the putative father, or that a person tested for one disease or disorder has, or is at risk for, something else.Aging, Premature: Changes in the organism associated with senescence, occurring at an accelerated rate.Heart Defects, Congenital: Developmental abnormalities involving structures of the heart. These defects are present at birth but may be discovered later in life.Sarcoplasmic Reticulum: A network of tubules and sacs in the cytoplasm of SKELETAL MUSCLE FIBERS that assist with muscle contraction and relaxation by releasing and storing calcium ions.Sodium-Calcium Exchanger: An electrogenic ion exchange protein that maintains a steady level of calcium by removing an amount of calcium equal to that which enters the cells. It is widely distributed in most excitable membranes, including the brain and heart.Cardiovascular Abnormalities: Congenital, inherited, or acquired anomalies of the CARDIOVASCULAR SYSTEM, including the HEART and BLOOD VESSELS.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.Atropine: An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.Constriction, Pathologic: The condition of an anatomical structure's being constricted beyond normal dimensions.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Myocardial Contraction: Contractile activity of the MYOCARDIUM.Calcium Signaling: 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.Chylothorax: The presence of chyle in the thoracic cavity. (Dorland, 27th ed)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.Lymphatic Metastasis: Transfer of a neoplasm from its primary site to lymph nodes or to distant parts of the body by way of the lymphatic system.Vascular Neoplasms: Neoplasms located in the vasculature system, such as ARTERIES and VEINS. They are differentiated from neoplasms of vascular tissue (NEOPLASMS, VASCULAR TISSUE), such as ANGIOFIBROMA or HEMANGIOMA.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.Echocardiography, Transesophageal: Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus.4-Aminopyridine: One of the POTASSIUM CHANNEL BLOCKERS, with secondary effect on calcium currents, which is used mainly as a research tool and to characterize channel subtypes.Phosphodiesterase 3 Inhibitors: Compounds that specifically inhibit PHOSPHODIESTERASE 3.
The sinoatrial node (SA node) is a group of cells positioned on the wall of the right atrium, near the entrance of the superior ... If the SA node does not function, or the impulse generated in the SA node is blocked before it travels down the electrical ... vena cava. These cells are modified cardiomyocytes. They possess rudimentary contractile filaments, but contract relatively ... Because the sinoatrial node is responsible for the rest of the heart's electrical activity, it is sometimes called the primary ...
If the SA node does not function, or the impulse generated in the SA node is blocked before it travels down the electrical ... Finally, the SA node artery commonly passes behind the superior vena cava, before reaching the SA node, however in some ... These grooves run between the entrance of the superior vena cava and the inferior vena cava. The cells of the SA node are ... 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 ...
... that lead directly from the SA node to the next node in the conduction system, the atrioventricular node. The impulse takes ... from the body via the superior vena cava, inferior vena cava and from the coronary sinus and pump it, through the tricuspid ... Normal sinus rhythm is established by the sinoatrial (SA) node, the heart's pacemaker. The SA node is a specialized grouping of ... and the electrical impulse reaches all of the ventricular muscle cells in about 75 ms. Since the electrical stimulus begins at ...
Once electrical impulse goes through the atrio-ventricular node (AV Node). The AV Node makes the impulse slow down. Slowing ... The veins going into the right atrium are the superior vena cava and inferior vena cava. These bring blood from the body to the ... The electricity starts in the sino-atrial node (acronym SA Node) The SA Node is a group of cells in the right atria. These ... After the electrical impulse goes through the AV Node, the electrical impulse will go through the conduction system of the ...
The right vagus then crosses anterior to the right subclavian artery, runs posterior to the superior vena cava, descends ... The right vagus branch innervates the sinoatrial node. In healthy people, parasympathetic tone from these sources are well- ... The second heart slowed down without an electrical stimulation. Loewi described the substance released by the vagus nerve as ... When stimulated, these chemoreceptors relay impulses throughout the vagus nerves in order to enable a vasoconstrictor response ...
I-SA Node liqela lee-cells kwi-atria yangasekunene. ezi cells ziqala i-electrical impulse. Le electrical impulse ibeka umyinge ... Oonobuyisa ohamba ne-atrium yangasekunene zii-superior vena cava kunye ne-inferior vena cava. Yomibini le mithambo izisa igazi ... Zilandelelana ngolu hlobo: I-Sino-Atrial Node → i-Atria (systole) → i-Atrio-Ventricular Node → i-Bundle of His → i-Bundle ... Iyakuthi ke yakuhamba i-electrical impulse nge-atrio-ventricular node (Xa eli gama lishunqulwe lithi- eyi-AV Node). I-AV Node ...
SA node blockage so that impulses never leave the atria.[1]. *AV node blockage (3rd degree block) prevents normal conduction ... Haghjoo, Majid (2007). "Efficacy, safety, and role of segmental superior vena cava isolation in the treatment of atrial ... "Tbx3 controls the sinoatrial node gene program and imposes pacemaker function on the atria". Genes & Development. 21 (9): 1098- ... "Electrical Activity in the Heart." Lecture at the University of Florida College of Pharmacy, 23-Oct-2007.[verification needed] ...
SA node dysfunction, (1st degree block) which can cause the rate of impulse to slow. SA node blockage so that impulses never ... 96-8. ISBN 978-1-58255-701-4. Haghjoo, Majid (2007). "Efficacy, safety, and role of segmental superior vena cava isolation in ... 2007). "Tbx3 controls the sinoatrial node gene program and imposes pacemaker function on the atria". Genes & Development. 21 (9 ... "Electrical Activity in the Heart." Lecture at the University of Florida College of Pharmacy, 23-Oct-2007.[verification needed] ...
... node, near the base of the superior vena cava Atrial fibrillation Atrial flutter AV nodal reentrant tachycardia Accessory ... AVRT may involve orthodromic conduction (where the impulse travels down the AV node to the ventricles and back up to the atria ... Heart rates above the resting rate may be normal (such as with exercise) or abnormal (such as with electrical problems within ... Presented order of most to least common, they are: Narrow complex Sinus tachycardia, which originates from the sino-atrial (SA ...
The sinoatrial node is found in the upper part of the right atrium near to the junction with the superior vena cava.[42] The ... waves of electrical impulses originate in the sinus node before spreading to the rest of the atria, the atrioventricular node, ... Superior vena cava, inferior vena cava,[d] right and left pulmonary veins,[e] great cardiac vein, middle cardiac vein, small ... The right coronary artery also supplies blood to the atrioventricular node (in about 90% of people) and the sinoatrial node (in ...
Sinus tachycardia, which originates from the sino-atrial (SA) node, near the base of the superior vena cava ... AVRT may involve orthodromic conduction (where the impulse travels down the AV node to the ventricles and back up to the atria ... such as with electrical problems within the heart). ... which the impulse travels down the accessory pathway and back ... up to the atria through the AV node). Orthodromic conduction usually results in a narrow complex tachycardia, and antidromic ...
Once electrical impulse goes through the atrio-ventricular node (AV Node). The AV Node makes the impulse slow down. Slowing ... The veins going into the right atrium are the superior vena cava and inferior vena cava. These bring blood from the body to the ... The electricity starts in the sino-atrial node (acronym SA Node) The SA Node is a group of cells in the right atria. These ... After the electrical impulse goes through the AV Node, the electrical impulse will go through the conduction system of the ...
The most common symptoms of superior vena cava is shortness of breath. ... Read about superior vena cava syndrome, a condition caused by tumors or cancer in the chest area, blood clots, or infection ( ... A pacemaker can be a natural pacemaker of the heart (the sinoatrial node) or it can be an electronic device that serves as an ... A pacemaker is a device or system that sends electrical impulses to the heart in order to set the heart rhythm. ...
SA Node). The sinoatrial node is found right at the top of the wall of the right atrium, near where the superior vena cava ... The electrical impulses (action potentials) from the sinoatrial node trigger co-ordinated contraction of both atria by causing ... The impulse travels on to the atrioventricular node.. Atrioventricular Node (AV Node). The atrioventricular node is found on ... Its function is to hold up the electrical impulse from the sinoatrial node. This provides a delay that allows the atria to ...
An electrical impulse from the sinoatrial (SA) node tells the atrium to contract and push in the remaining blood and signals to ... The right atrium takes in deoxygenated blood from the body through the superior and inferior vena cava. Since the right atrium ... The right atrium takes in deoxygenated blood from the body through the superior and inferior vena cava.. ...
... the sinoatrial node (SAN) is responsible for generating spontaneous electrical impulses and conducting the impulses to the ... lateral superior/middle/inferior, superior vena cava, and septal pathways) (fig. S1). However, because of heart-specific ... Abnormal response of superior sinoatrial node to sympathetic stimulation is a characteristic finding in patients with atrial ... Human sinoatrial node structure: 3D microanatomy of sinoatrial conduction pathways. Prog. Biophys. Mol. Biol. 120, 164-178 ( ...
... node (sinus node), which is near the junction of the superior vena cava and the right atrium. ... In a healthy heart, electrical impulses are generated in the sinoatrial (SA) ... electrical impulses are generated in the sinoatrial (SA) node (sinus node), which is near the junction of the superior vena ... the AV node in the upper part, and the bundle of His in the lower part. In a healthy heart, the AV node is the only electrical ...
The sinoatrial node (SA node) is a group of cells positioned on the wall of the right atrium, near the entrance of the superior ... If the SA node does not function, or the impulse generated in the SA node is blocked before it travels down the electrical ... vena cava. These cells are modified cardiomyocytes. They possess rudimentary contractile filaments, but contract relatively ... Because the sinoatrial node is responsible for the rest of the hearts electrical activity, it is sometimes called the primary ...
... of the superior vena cava and high lateral right atrium is a cluster of cells that generates the initial electrical impulse of ... each normal heart beat, called the sinoatrial (SA) or sinus node. Electrical discharge of these pacemaker cells stimulates ... coordinated way because electrical impulses generated and spread by myocytes with unique electrical properties trigger a ... The AV node is located on the right side of the interatrial septum. It has a slow conduction velocity and thus delays impulse ...
The sinoatrial node creates and sends electrical signals throughout the heart to pump blood. Click here to learn more. Ask an ... The sinoatrial node is located in the center of the heart on the right atrial wall. It is near the opening of the superior vena ... The signal starts in the sinoatrial node. The tissue contracts rhythmically, creating and releasing electrical impulses. This ... What is the Sinoatrial Node?. The sinoatrial node (SA node) is a bundle of nerve cells that function as a natural pacemaker for ...
... it is normally in response to an electrical impulse. In normal physiologic behavior, this impulse starts in the sino-atrial (SA ... node where a collection of cells are located at the junction of the right atrium and superior vena cava. These specialized ... approximately 0.2 seconds after the initial impulse has arisen in the sino-atrial node. Depolarization of the myocardial cell ... The LIMD 1200 has been placed through the superior vena cava and tricuspid valve into the RV 1237, such as by utilizing one of ...
... refers to abnormalities in SN impulse formation and propagation and includes sinus bradycardia, sinus pause/arrest, ... chronotropic incompetence, and sinoatrial exit block. (See Workup. ... The sinus node (SN) is a subepicardial structure normally located in the right atrial wall near the superior vena cava entrance ... Electrical impulses generated in the SN must then be conducted outside the SN in order to depolarize the rest of the heart. ...
If the SA node does not function, or the impulse generated in the SA node is blocked before it travels down the electrical ... Finally, the SA node artery commonly passes behind the superior vena cava, before reaching the SA node, however in some ... These grooves run between the entrance of the superior vena cava and the inferior vena cava. The cells of the SA node are ... 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 ...
... pacemaker is found in a group of cells called the sinoatrial or sinus node located near the junction of the superior vena cava ... and to the atrioventricular node. Upon leaving the atrioventricular node, the electrical impulse continues to propagate down ... The electrical impulse is conducted out of the sinus node to the atria, where it stimulates atrial muscle cells to contract, ... The right bundle spreads the electrical impulse to the right ventricle and the left bundle branch propagates the impulse to ...
SA node or Sinoatrial node is the dominant pacemaker in a healthy normal heart. When the normal atrial electrical impulses are ... This structure lies at the junction of the superior vena cava and the right atrium. It works as an electrical impulse generator ... When there is a structural change in the atria, SA node or AV node and abnormal triggering of impulses occur, the electrical ... The electrical impulse also travel from the atria to the ventricles through the atrioventricular (AV) node. The optimal ...
SA Node The sinoatrial node (abbreviated SA node or SAN, also called the sinus node) is the impulse generating (pacemaker) ... SA node (located in the right atrium near the entrance of the superior vena cava) • AV node (located at the base of right ... If the SA node doesnt function, or the impulse generated in the SA node is blocked before it travels down the electrical ... The SA node emits a new impulse before either the AV or purkinje fibers reach threshold. The sinoatrial node (SA node) is a ...
The external electrical contacts may detect bioelectric energy or may deliver electrical or thermal energy to a target site. ... The traces and contacts may assist in diagnosis and/or detection of bio-electrical signals emitted by organs, and may transmit ... Each trace may be in electrical connection with one or more external electrical contacts. More specifically, each trace is ... Normally, initial electric impulses are generated at the SA node and conducted to the AV node. The AV node lies near the ostium ...
The SA node (sinoatrial node) lies in the right atrium beneath the opening of the superior vena cava. See figure 18-2a. Each ... The SA node is the pacemaker of the heart. The SA node initiates electrical impulses that spread out over both atria causing ... When something disrupts the SA node the AV node takes over to initiate a basic pace for the heart rate. When both the SA node ... The impulse then passes to the AV (atrioventricular node) located near the bottom of the interatrial septum. (Between the ...
... it is normally in response to an electrical impulse. This impulse starts in the sinoatrial (SA) node, a collection of pacemaker ... the superior and inferior vena cava, which empty into the left atrium. Answer each statement true or false. If the statement is ... The whole cycle then repeats following another impulse from the sinoatrial node. Teaching Point The electrocardiogram (ECG) ... approximately 0.2 seconds after the initial impulse has arisen in the sinoatrial node. Depolarisation of the myocardial cell ...
The SA node (pacemaker of the heart) sits in the upper portion of the R atria near the entrance of the superior vena cava. ... The specific set of cells that regulates the heart rate (in most people) are called the Sinoatrial node or SA node for short. ... When the SA node sends out and electrical shock, it immediately shocks the atria. The pulse then gets "held up" in another set ... of cells called the Atrioventricular node, or AV node for short. This then transmits the impulse down to the bundle of His and ...
The sinoatrial node, or SA node, located in the right atrium near the entrance of the superior vena cava. This is the natural ... The AV node serves as electrical gateway to the ventricles. It delays the passage of electrical impulses to the ventricles. ... Electrical impulses from the SA node spread throughout both atria and stimulate them to contract. - The atrioventricular node, ... 7. What is mean by electrical axis or cardiac axis of heart. 8. How does electrical impulse travels through the heart. 9. ...
SA node generates cardiac action potential while AV node receives the action potential from the SA node... ... What is the difference between SA node and AV node? ... Electrical impulses from the atria to ventricles are generated ... SA node is located in the superior lateral wall closer to the opening of the superior vena cava of the heart.. AV node is ... SA node Definition, SA node Function, SA node Location, SA node Role, SA node vs AV node, Sino atrial node ...
During this phase, the atria relax.• Blood will come in from the superior vena cava, inferior vena cava and pulmonary veins, ... This generates the heartbeat by sending out tiny electrical impulses.• These impulses stimulate another special patch of tissue ... Embedded in the wall of the right atrium is the sino-atrial node or SA node. ... SA Node AV Node * 25. • Increased levels of CO2 in blood During exercise, CO2 in blood increases. This results in an increase ...
... the sinoatrial node. Lying in the right atrium at the recess of the vena cava superior, this node beats the fastest of all ... The generator controls the rate and amplitude of impulses, which may be fixed or may change according to the needs of the heart ... men have known about the ability of muscle to respond to electrical stimulation. The fibers of the myocardium (the middle ... If the sinoatrial node fails, the atrioventricular node takes over, causing the heart to beat about 50 to 60 times per minute, ...
... known as the sinoatrial (SA) node [2]. A coordinated series of electrical conductions regulate contraction of the atria to ... Blood carrying carbon dioxide returns to the right atria from the body via both the superior and inferior vena cava, then upon ... The heart beats without external nerve supply because the heart muscle generates the electrical impulse responsible for ...
... heart cells of the cardiac conduction system me-thodically generate and coordinate the transmission of electrical impulses to ... The sinoatrial (SA) node, referred to as the primary pace-maker of the heart, is located at the junction of the superior vena ... Excitability: ability to respond to an electrical impulse. Conductivity: ability to transmit an electrical impulse from onecell ... The AV node coordinates the incoming electrical im-pulses from the atria and, after a slight delay (allowing the atria time to ...
... located in the right atrium beneath the opening of the superior vena cava; also called the sinuatrial node or pacemaker ... The SA node is a group of specialized cells in the top of the right atrium which produces the electrical impulses that travel ... The sinoatrial node (abbreviated SA node or SAN, also called the sinus node) is the impulse generating (pacemaker) tissue ... The sinoatrial node sends one electrical signal telling the atrium to contract and another signal to the AV node for relay to ...
  • There are three bundles of atrial fibers that contain Purkinje-type fibers and connect the SA node to the AV node: the anterior, middle (tract of Wenckebach), and posterior (tract of Thorel) tracts. (mhmedical.com)