• In the case of dobutamine, this increase is usually not accompanied by marked increases in heart rate (although tachycardia is occasionally observed), and the cardiac stroke volume is usually increased. (drugs.com)
  • The most common cause of cardiac arrest is an irregular heart rhythm (arrythmia), usually ventricular fibrillation (V-fib), or ventricular tachycardia (V-tach). (wikipedia.org)
  • Previous adverse cardiac events, non-sustained ventricular tachycardia (NSVT), syncope, and left ventricular hypertrophy (LVT) have been shown to predict sudden cardiac death in children. (wikipedia.org)
  • [ 1 ] Currently, Wolff-Parkinson-White (WPW) syndrome is defined as a congenital condition involving abnormal conductive cardiac tissue between the atria and the ventricles that provides a pathway for a reentrant tachycardia circuit, in association with supraventricular tachycardia (SVT). (medscape.com)
  • Tachyarrhythmia is used to describe tachycardia in the presence of cardiac rhythm abnormality. (mims.com)
  • Michiel J. Janse, MD, PhD Background Atrioventricular junctional (AV nodal) reentrant tachycardia can be cured by catheter ablation of the slow pathway, which is part of the reentrant circuit. (pdfkul.com)
  • HL double potentials were found along the Atrioventricular junctional reentrant tachycardia ~4 (AVJRT) can be cured by catheter ablation of 1k sites near the coronary sinus orifice.1-3 This technique damages the slow pathway, part of the reentrant circuit used by this tachycardia. (pdfkul.com)
  • Key Words * atrioventricular node * tachycardia reentry * action potentials * radiofrequency ablation tissues of origin of these potentials. (pdfkul.com)
  • OBJECTIVE To assess the efficacy and safety of intravenous dofetilide in preventing induction of atrioventricular re-entrant tachycardia. (bmj.com)
  • Fifty one patients with electrically inducible atrioventricular re-entrant tachycardia were allocated to one of five doses of dofetilide (1.5, 3, 6, 9, and 15 μg/kg), two thirds of the dofetilide dose being given over a 15 minute loading period and the remainder over a 45 minute maintenance period. (bmj.com)
  • MAIN OUTCOME MEASURE Responders were defined as patients in whom dofetilide prevented reinduction of atrioventricular re-entrant tachycardia at the end of the infusion. (bmj.com)
  • In non-responders, dofetilide increased the cycle length of induced atrioventricular re-entrant tachycardia. (bmj.com)
  • CONCLUSIONS Dofetilide shows promise as an agent for the prevention of atrioventricular re-entrant tachycardia in patients without structural heart disease. (bmj.com)
  • Atrioventricular re-entrant tachycardia is currently treated with various pharmacological agents. (bmj.com)
  • While class I antiarrhythmic drugs are effective in treating this form of tachycardia, there is a reluctance to use these agents, especially in patients with structural heart disease, because of potential proarrhythmia or undesirable side effects-as seen in the cardiac arrhythmia suppression trial (CAST). (bmj.com)
  • 14-16 However, to date there have been no studies on the dose dependent effects of dofetilide on atrioventricular re-entrant tachycardia. (bmj.com)
  • Our goal in this study was to assess the efficacy of intravenous dofetilide, in five different dosing regimens, for treating patients with inducible atrioventricular re-entrant tachycardia, by determining its ability to prevent reinduction of the tachycardia. (bmj.com)
  • However, current techniques for ablating complex arrhythmias such as atrial fibrillation and ventricular tachycardia are associated with sub-optimal success rates and prolonged radiation exposure. (rmmj.org.il)
  • Radiofrequency (RF) catheter ablation has advanced over the last 25 years from an experimental procedure to the first-line treatment for a number of cardiac arrhythmias including atrioventricular re - entrant tachycardia, accessory pathway-associated tachycardias, and typical atrial flutter. (rmmj.org.il)
  • Cardiac Pacemakers The need for treatment of arrhythmias depends on the symptoms and the seriousness of the arrhythmia. (msdmanuals.com)
  • Surgery for cardiac arrhythmias The normal heart beats in a regular, coordinated way because electrical impulses generated and spread by myocytes with unique electrical properties trigger a sequence of organized myocardial. (msdmanuals.com)
  • The majority of sudden cardiac death events in athletes are due to ventricular arrhythmias as a result of underlying molecular and/or structural level pathologic substrate. (scienceopen.com)
  • In this article, we will review the physiologic cardiac adaptations to exercise along with arrhythmias seen in athletes with a focus on those commonly associated with sudden cardiac death. (scienceopen.com)
  • Pattern recognition can help physicians detect and diagnose cardiac arrhythmias, ischemic heart disease, electrolyte imbalances, and structural heart disease. (ecgedu.com)
  • Cardiac arrhythmias are irregular heart rhythms that can manifest as a heartbeat that's too slow, fast, or irregular. (ecgedu.com)
  • Catheter ablation is a first-line treatment for many cardiac arrhythmias and is generally performed under X-ray fluoroscopy guidance. (rmmj.org.il)
  • Radiofrequency catheter ablation techniques are safe and effective as well, especially for patients with poor tolerance to drugs (see figure figure 3b radiofrequency ablation in WPW, as well as in the treatment of atrial flutter and fibrillation by identifying tract carrying the excitation impulse). (rjmatthewsmd.com)
  • Both radiofrequency catheter ablation and cryoablation are widely performed, rapidly developing techniques. (aerjournal.com)
  • Radiofrequency catheter ablation (RFA) of the pulmonary veins was the first and most widely performed ablation procedure and cryoablation is a newer and rapidly progressing technique which has resulted in shorter procedure times and reduced treatment costs. (aerjournal.com)
  • Facilitation of atrioventricular conduction has been observed in human electrophysiologic studies and in patients with atrial fibrillation. (drugs.com)
  • MAs may be manifested either in hemodynamic collapse or in cardiac arrest: The sudden loss of effective blood flow due to atrial fibrillation (AF) with rapid VT leads to hemodynamic collapse, and VT and VF result in cardiac arrest necessitating CPR or electric defibrillation. (medscape.com)
  • Dr. Olgin's clinical research has focused on atrial fibrillation and sudden cardiac death mechanisms, epidemiology, genetics and interventions. (ucsf.edu)
  • Atrial fibrillation (AF) is the most common form of cardiac arrhythmia in clinical practice and causes significant morbidity and mortality [ 1 ]. (e-arrhythmia.org)
  • Pulsed electrical field ablation uses a train of high voltage, short duration electrical impulses that kill cardiac myocytes in a non-thermal method. (msdmanuals.com)
  • Basing on the presence of If current in ventricular myocytes isolated from severely hypertrophied rat hearts, the current arrhythmogenic role in cardiac hypertrophy and failure has been inferred [25] , and its density is larger in human ventricular myocytes isolated from the hearts of patients with ischemic than in those with dilated cardiomyopathy [21] . (bjcvs.org)
  • Sympathetic efferent nerves are present throughout the atria, ventricles (including the conduction system), and myocytes in the heart and also the sinoatrial (SA) and atrioventricular (AV) nodes. (medscape.com)
  • Based on the Cardiac Arrhythmia Suppression Trial study results, flecainide is not recommended in patients with structural heart disease due to high proarrhythmic risk. (wjgnet.com)
  • Based on the Cardiac Arrhythmia Suppression Trial study results, flecainide is contraindicated for patients with structural heart disease due to high proarrhythmic risk. (wjgnet.com)
  • The hyperpolarization-activated funny current (If ) is a major determinant of cardiac diastolic depolarization and plays a key role in controlling heart rate [4] . (bjcvs.org)
  • Left bundle branch block is associated with anatomic malformations and abnormalities of the conduction system (eg, as is observed in Lenegre disease). (medscape.com)
  • However, especially in the presence of congenital or acquired structural or conduction abnormalities, a subset of dysrhythmias (ie, sustained VT and VF) may pose an immediate threat to life by causing profound hemodynamic instability. (medscape.com)
  • Important points to cover when one obtains a history from a child with left bundle branch block (LBBB) include known congenital heart disease, previous cardiac surgery, or both. (medscape.com)
  • Convergent ablation is a novel hybrid technique combining an endocardial radiofrequency ablation with a minimally invasive epicardial surgical ablation. (aerjournal.com)
  • With looping and growth of the cardiac septi, the rings are brought together and develop into the sinus node, the AV node, and the penetrating bundle. (medscape.com)
  • Because of its selective class III antiarrhythmic effect, dofetilide has no effect on atrioventricular conduction or sinus node function. (bmj.com)
  • This study has been led by science at the molecular level as well as by advances in imaging that allow us to "look inside the heart" using electrocardiography, echocardiography, cardiac computed tomography, and cardiac magnetic resonance imaging techniques. (scienceopen.com)
  • Knowledge of the anatomy and electrophysiology of cardiac conduction system from the atrioventricular (AV) junction to the Purkinje fibers is essential to understanding the pathophysiology of right bundle branch block (RBBB). (medscape.com)
  • Sudden cardiac death related to athletic competition is a rare but tragic event. (scienceopen.com)
  • The occurrence of sudden cardiac death (SCD) in an athlete is a tragic event that deeply affects family members, teammates, and at times, an entire community. (scienceopen.com)
  • Cardiac arrest, also known as sudden cardiac arrest, is when the heart suddenly and unexpectedly stops beating. (wikipedia.org)
  • Without immediate intervention such as cardiopulmonary resuscitation (CPR), and possibly defibrillation, death will occur (sudden cardiac death) within minutes. (wikipedia.org)
  • CPR and defibrillation can reverse a cardiac arrest, leading to the return of spontaneous circulation (ROSC), but without such intervention, it will prove fatal, known as sudden cardiac death. (wikipedia.org)
  • A prior episode of sudden cardiac arrest also increases the likelihood of future episodes. (wikipedia.org)
  • 828 Sudden cardiac arrest, or sudden cardiac death, occurs when the heart abruptly begins to beat in an abnormal or irregular rhythm (arrhythmia). (wikipedia.org)
  • Background It is unclear whether early initiation of low-dose pravastatin therapy can reduce the occurrence of major adverse cardiac events after acute myocardial infarction (AMI). (go.jp)
  • Conclusion For patients with AMI, early and low-dose pravastatin therapy (10 mg/daily) reduces recurrent major adverse cardiac events, mostly the requirement for revascularization. (go.jp)
  • The conduction system can be divided into distinct anatomic segments, and each segment is described in sequence beginning at the AV junction and ending with the Purkinje fibers. (medscape.com)
  • Thus, the right ventricle depolarizes by means of cell-to-cell conduction that spreads from the interventricular septum and left ventricle to the right ventricle. (medscape.com)
  • [ 4 ] Wolff-Parkinson-White Syndrome (when the abnormal conduction pathway enters the right ventricle), and acute pulmonary embolism. (medscape.com)
  • The left bundle branch block pattern, or rather, left ventricular conduction delay, also occurs in patients with Wolff-Parkinson-White Syndrome in whom the abnormal conduction pathway enters the right ventricle. (medscape.com)
  • Strength-based sporting activities (e.g., track and field throwing events, weightlifting, karate/judo, American football) result in a normal or slightly increased cardiac output, an increase in peripheral vascular resistance, and transient hypertension, imposing a significant pressure load on both the left ventricle and the right ventricle. (scienceopen.com)
  • In the healthy adult heart, HCN channels are predominantly expressed in the conduction system, especially in the sinoatrial node, HCN4 has been determined as the principal HCN isoform in sinoatrial node cells. (bjcvs.org)
  • Cardiac pacemakers were implanted in accordance with European Society of Cardiology guidelines. (revespcardiol.org)
  • Mutations in the human cardiac sodium channel ( SCN5A ) cause one type of long-QT syndrome (LQT3), and these individuals may also have sinus pauses and sinus bradycardia in addition to the characteristic prolongation of the QT interval. (medilib.ir)
  • Functional states of the sodium channel (closed, open, and inactivated) and their structure help to understand the cardiac regulation processes. (bvsalud.org)
  • Finally, it seems appropriate to consider the "sodium channel syndrome" (mutations in the gene of the α subunit of the sodium channel, SCN5A gene) as a single clinical entity that may manifest in a wide range of phenotypes, to thus have a better insight on these cardiac syndromes and potential outcomes for their clinical treatment. (bvsalud.org)
  • Conditions that produce these functional changes can be acquired following previous cardiac injury or inherited through familial history of arrhythmogenic disorders. (wikipedia.org)
  • Functional changes in the heart such as reduced ejection fraction or cardiac arrhythmia have been shown to increase the risk of cardiac arrest and act independently from the aforementioned risk factors. (wikipedia.org)
  • See "Cardiac excitability, mechanisms of arrhythmia, and action of antiarrhythmic drugs", section on 'Action potential in slow response tissues' . (medilib.ir)
  • They may have their onset at any time from childhood to middle age, and they can vary in severity from mild chest discomfort or palpitations with or without syncope to severe cardiopulmonary compromise and cardiac arrest. (medscape.com)
  • Patients with chronic bifascicular block (BFB) can progress to advanced atrioventricular block (AVB), especially when syncope or a prolonged HV interval is present. (revespcardiol.org)
  • Acute myocardial infarctions are recognized by ST-segment elevation, particularly in a patient presenting with classic cardiac chest pain. (ecgedu.com)
  • 221 Implantable Cardiac Defibrillators: Who Needs Them and Who Does Not? (scienceopen.com)
  • In post-resuscitation care, an implantable cardiac defibrillator may be considered to reduce the chance of death from recurrence. (wikipedia.org)
  • G. There is a slow conduction pathway as well as a fast one. (rjmatthewsmd.com)
  • When there is a disturbance in the normal conduction through the fast pathway, the slow pathway may be activated to conduct the excitation wave to the bundle of His, as well as retrograde back to the fast one, and then back again down the slow pathway continuously to produce the PSVT (see Figure 1). (rjmatthewsmd.com)
  • The specialized conduction system of the heart is composed of cells that conduct electrical impulses faster than the surrounding myocardium. (medscape.com)
  • Since that time there has been intense scientific interest in the study of cardiac adaptation to repetitive bouts of vigorous activity, athletic performance, and the pathophysiology of structural, functional, and electrical cardiac diseases in competitive athletes. (scienceopen.com)
  • Creation of sufficient ablation lesions was assessed by the absence of a conduction gap. (authorea.com)
  • 23-25 Linear ablation combined with PVI may result in reentrant ATs because of conduction gaps and non-transmural lesions caused by ablation lesions. (aerjournal.com)
  • Treatment for cardiac arrest includes immediate CPR and, if a shockable rhythm is present, defibrillation. (wikipedia.org)
  • This can present in the form of new or worsening: chest pain fatigue blackouts dizziness shortness of breath weakness vomiting When cardiac arrest is suspected by a layperson due to signs of unconsciousness and abnormal breathing, it should be assumed that the victim is in cardiac arrest, and CPR should be initiated. (wikipedia.org)
  • Conduction down the left bundle branch proceeds normally, and the interventricular septum and left ventricle rapidly depolarize in the normal fashion. (medscape.com)
  • However the technique is limited by difficult implantation, long fluoroscopic exposure time, high capture threshold and fails to provide adequate pacing in patients with infrahisian block or proximal left bundle branch block4. (romanianjournalcardiology.ro)
  • By providing a stable and low capture threshold, left bundle branch pacing has emerged to be a potential altenative to His bundle pacing in heart failure patients with left bundle branch block and furthermore an attractive option for pacing in patients with infranodal conduction disease5-7. (romanianjournalcardiology.ro)
  • Two protocols have been established for CPR: basic life support (BLS) and advanced cardiac life support (ACLS). (wikipedia.org)
  • There are areas in the cardiac muscle with anatomical and functional differentiation that present automatism, thus subjecting the rest of the fibers to their own rhythm. (bvsalud.org)
  • 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. (bvsalud.org)
  • Cardiac arrest is diagnosed by the inability to find a pulse. (wikipedia.org)
  • In some cases, cardiac arrest is an anticipated outcome of serious illnesses where death is expected. (wikipedia.org)
  • Of these, 326,000 (61%) experience cardiac arrest outside of a hospital setting, while 209,000 (39%) occur within a hospital. (wikipedia.org)
  • Cardiac arrest becomes more common with age and affects males more often than females. (wikipedia.org)
  • Twice as many black men die from a cardiac arrest than white men. (wikipedia.org)
  • Cardiac arrest is not preceded by any warning symptoms in approximately 50 percent of people. (wikipedia.org)
  • For individuals who do experience symptoms, the symptoms are usually nonspecific to the cardiac arrest. (wikipedia.org)
  • Coma can result from a cardiac arrest when the brain has been without oxygen for too long. (wikipedia.org)
  • Near-death experiences are reported by 10 to 20 percent of people who survived cardiac arrest, which demonstrates that a certain level of cognition is still active during resuscitation. (wikipedia.org)
  • The risk factors for cardiac arrest are similar to those of coronary artery disease and include age, cigarette smoking, high blood pressure, high cholesterol, lack of physical exercise, obesity, diabetes, family history, and cardiomyopathy. (wikipedia.org)
  • The cardiac conduction system develops from rings of specialized tissue found in the embryonic heart tube. (medscape.com)
  • In contrast, isoproterenol increases the cardiac index primarily by increasing the heart rate while stroke volume changes little or declines. (drugs.com)
  • Endurance-based sports activities (e.g., rowing, swimming, cycling, and long-distance running) result in sustained elevations in cardiac output and normal or decreased peripheral vascular resistance, and importantly, impose significant volume challenges to all cardiac chambers and vessels leading away from the heart. (scienceopen.com)
  • Without organized electrical activity in the heart muscle, there is no consistent contraction of the ventricles, which results in the heart's inability to generate an adequate cardiac output (forward pumping of blood from the heart to the rest of the body). (wikipedia.org)
  • Using (HBP) the native conduction system, His bundle pacing has been proved to be the most physiologic form of ventricular pacing, than can correct wide QRSd, ensure the ventricular electrical activation synchrony and improves the clinical outcomes in heart failure patients1-3. (romanianjournalcardiology.ro)
  • Another electrical property is conductivity, which is characterized by a conduction and activation process, where the action potential, by the all-or-nothing law, travels throughout the heart. (bvsalud.org)
  • Chien SJ, Liang CD, Lin IC, Lin YJ, Huang CF. Myocarditis complicated by complete atrioventricular block: nine years' experience in a medical center. (medscape.com)
  • Evidence exhibits that HCN channels play critical roles in the generation and conduction of the electrical impulse and the physiopathological process of some cardiac diseases. (bjcvs.org)
  • They may constitute promising drug targets in the treatment of these cardiac diseases. (bjcvs.org)
  • Under normal conditions, HCN channels are poorly expressed outside the cardiac pacemaking and conduction system [11,18-20] , but it changes during cardiac disease. (bjcvs.org)
  • As a result of prolonged ventricular conduction time and dyssynchronous activation of the ventricles, systolic dysfunction may occur in patients with LBBB1. (romanianjournalcardiology.ro)
  • Accordingly, these cardiac rhythm disturbances are labeled as MAs. (medscape.com)
  • Three isoforms (HCN1, HCN2, HCN4) are expressed in cardiac tissues, with HCN2 and HCN4 the dominant subtypes. (bjcvs.org)
  • His lab is translational in that he utilizes a spectrum of techniques and studies that span from mouse, large animal physiologic models, human tissue, human biomarkers and genetic approaches to understanding the disease. (ucsf.edu)
  • In patients with depressed cardiac function, both dobutamine and isoproterenol increase the cardiac output to a similar degree. (drugs.com)
  • In the limited number of patients who were studied for 24, 48, and 72 hours, a persistent increase in cardiac output occurred in some, whereas output returned toward baseline values in others. (drugs.com)
  • Retrospective chart review identified 114 consecutive patients without a history of AF or prior cardiac surgery who underwent typical CTI dependent AFL ablation between December 2013 to November 2018, who also had a complete preoperative transthoracic echocardiogram, and at least 1 year of follow-up at our medical center. (jafib.com)
  • However, it has limitations, such as higher capture thresholds, lower R wave amplitudes, atrial oversensing, and increased risk for lead revisions from late threshold increase with subsequent premature battery depletion, which has prevented a wider adoption of this technique in routine clinical practice. (romanianjournalcardiology.ro)
  • The mechanisms of cellular excitability and propagation of electrical signals in the cardiac muscle are very important functionally and pathologically. (bvsalud.org)