• tissue
  • Ablation, or cardiac ablation, is a therapeutic method used to destroy a small section of heart tissue causing abnormal electrical activity or irregular heartbeat. (heart.org)
  • Connexin40 is expressed in atrial tissue and the fast-conducting tissue of the His-Purkinje system but not in the compact AV node or in the ventricular myocytes. (ahajournals.org)
  • Aminophylline causes bronchodilation, diuresis†, central nervous system and cardiac stimulation, and gastric acid secretion by blocking phosphodiesterase which increases tissue concentrations of cyclic adenosine monophosphate (cAMP) which in turn promotes catecholamine stimulation of lipolysis, glycogenolysis, and gluconeogenesis, and induces release of epinephrine from adrenal medulla cells. (wikipedia.org)
  • It is a G-protein coupled receptor associated with the Gs heterotrimeric G-protein and is expressed predominantly in cardiac tissue. (wikipedia.org)
  • Junctional" is used as the abnormal tissue driving the ventricular rate is located close junction between the atria and ventricles, known as the AV node. (wikipedia.org)
  • The cause of JET is felt to be due to manipulation of the tissue surrounding the AV node during surgery, however debate exists regarding the exact cause, as it is seen after procedures even without significant manipulation of this area. (wikipedia.org)
  • Treatment of non-post-operative JET is typically with antiarrhythmic medications or a cardiac catheterization with ablation (removal of affected tissue). (wikipedia.org)
  • citation needed] The use of radiofrequency energy is infrequently associated with damage to the normal conduction due to the close proximity to the AV node, the normal conduction tissue. (wikipedia.org)
  • Transthyretin cardiac amyloidosis diagnosed by analyzing a prostatic tissue sample: a case report. (wikipedia.org)
  • Cardiac muscle tissue has autorhythmicity, the unique ability to initiate a cardiac action potential at a fixed rate - spreading the impulse rapidly from cell to cell to trigger the contraction of the entire heart. (wikipedia.org)
  • SCN5A is mainly expressed in the heart, where expression is abundant in working myocardium and conduction tissue. (wikipedia.org)
  • Mutations
  • Due to changes in amino acids and binding domains, mutations may also affect the ability of these channels to respond to physiological changes in cardiac demand. (wikipedia.org)
  • Mutations resulting in loss of function of K+ channels can result in delayed repolarization of the cardiac muscle cells. (wikipedia.org)
  • Pressure-volume relationships in patients with transthyretin (ATTR) cardiac amyloidosis secondary to V122I mutations and wild-type transthyretin. (wikipedia.org)
  • A vast number of cardiac diseases is associated with mutations in NaV1.5 (see paragraph genetics). (wikipedia.org)
  • Mutations in SCN5A, which could result in a loss and/or a gain-of-function of the channel, are associated with a spectrum of cardiac diseases. (wikipedia.org)
  • cell membranes
  • Movement of ions, particularly Na+, Ca2+ and K+, causes depolarizations of cell membranes in node cells, which are then transmitted to cardiac muscle cells to induce contraction. (wikipedia.org)
  • contraction
  • Cardiac muscle cells branch freely and are connected by junctions known as intercalated discs which help the synchronized contraction of the muscle. (wikipedia.org)
  • In cardiac muscle cells, on the other hand, an initial fast sodium spike provides a "primer" to provoke the rapid onset of a calcium spike, which then produces muscle contraction[citation needed]. (wikipedia.org)
  • decrease
  • In reflex bradycardia, blood pressure is reduced by decreasing cardiac output (CO) via a decrease in heart rate (HR). An increase in blood pressure can be caused by increased cardiac output, increased total peripheral resistance, or both. (wikipedia.org)
  • connexin43
  • Conduction defects were correlated with dephosphorylation of connexin40 and connexin43 and upregulation of protein phosphatase 1β (PP1β). (ahajournals.org)
  • Confocal microscopy revealed increased levels of dephosphorylated connexin43 at the cardiac gap junctions in RTEF-1 mice, suggesting that defective conduction is a result of impaired gap-junction conductance rather than assembly. (ahajournals.org)
  • Transcription
  • Methods and Results- Transgenic mice were generated with cardiac-specific overexpression of the transcription factor RTEF-1 (transcription enhancer factor-1-related factor), which mediates α 1 -adrenergic signaling in cardiac myocytes. (ahajournals.org)
  • 7 In addition, disrupting transcription factor function or protein processing leads to downregulated connexin expression and defects in cardiac conduction. (ahajournals.org)
  • α 1 -Adrenergic signaling targets the transcription factor RTEF-1 (transcription enhancer factor-1-related factor) to upregulate gene expression in cultured cardiac myocytes. (ahajournals.org)
  • muscle
  • Actions of the β1 receptor include: stimulate viscous, amylase-filled secretions from salivary glands Increase cardiac output Increase heart rate in sinoatrial node (SA node) (chronotropic effect) Increase atrial cardiac muscle contractility. (wikipedia.org)
  • Cardiac muscle (like skeletal muscle) is characterized by striations - the stripes of dark and light bands resulting from the organised arrangement of myofilaments and myofibrils in the sarcomere along the length of the cell. (wikipedia.org)
  • In cardiac muscle the T-tubules are only found at the Z-lines. (wikipedia.org)
  • SCN5A is part of a family of 10 genes that encode different types of sodium channels, i.e. brain-type (NaV1.1, NaV1.2, NaV1.3, NaV1.6), neuronal channels (NaV1.7, NaV1.8 and NaV1.9), skeletal muscle channels (NaV1.4) and the cardiac sodium channel NaV1.5. (wikipedia.org)
  • The bundle of His or His bundle is a collection of heart muscle cells specialized for electrical conduction. (wikipedia.org)
  • electrical
  • The AV node serves as a sort of electrical relay station that slows the current before the signal passes to the lower chambers. (heart.org)
  • Gap junctions are the membrane channels that mediate direct electrical coupling between cardiac myocytes. (ahajournals.org)
  • sudden
  • Changes in the sinoatrial node represent the major mechanism of sudden death in humans, and because of the sparse knowledge about the effects of aging on this structure, light microscopic and quantitative studies of the sinoatrial node were undertaken. (ebscohost.com)
  • It can help save the life of someone who has suffered sudden cardiac arrest, the abrupt loss of heart function. (heart.org)
  • contractility
  • Similarly, gain of function of Na+ and Ca2+ channels results in delayed repolarization, and Ca2+ overload causing increased Ca2+ binding to cardiac troponin C, more actin-myosin interactions and causing an increased contractility, respectively. (wikipedia.org)
  • adenosine
  • Transient cardiac arrest was induced by intravenous adenosine injection enabling accurate valve implantation. (hindawi.com)
  • however, this dose was not adequate, and thereafter cardiac arrest was induced with bolus injection of 18 mg of adenosine through a peripheral vein access. (hindawi.com)
  • Aminophylline competitively antagonizes the cardiac actions of adenosine at the cell surface receptors. (wikipedia.org)
  • stimulation
  • The AV node's normal intrinsic firing rate without stimulation (such as that from the SA node) is 40-60 times/minute. (wikipedia.org)
  • Normally, vagal stimulation predominates as, left unregulated, the SA node would initiate a sinus rhythm of approximately 100 bpm. (wikipedia.org)
  • Sympathetic stimulation causes the release of the neurotransmitter norepinephrine (also known as noradrenaline) at the neuromuscular junction of the cardiac nerves. (wikipedia.org)
  • interval
  • 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). (ebscohost.com)
  • rhythms
  • Studies have shown celivarone is capable of cardioversion and of maintaining normal sinus cardiac rhythms and that it is effective in hypokalemic, vasotonic, and stretch-induced atrial fibrillation, as well as ischemic and reperfusion ventricular fibrillation. (wikipedia.org)