Although pacing-induced ventriculo-atrial (VA) Wenckebach conduction has been previously described, the occurrence of this phenomenon during ventricular tachycardia has received little attention. The latter is defined as 2:1 VA block in which the conducted beats show progressive lengthening of VA conduction until the sequence is terminated by two or three blocked ventricular beats. This phenomenon was observed in a 16-year-old boy who underwent electrophysiologic study for ventricular tachycardia as a late complication of surgical correction of tetralogy of Fallot. During pacing-induced ventricular tachycardia with a morphology similar to that of the spontaneous tachycardia, 8:4 alternating VA block was observed. This sequence suggested that the AV node was the site of block, the 2:1 block being located at the upper level, and the VA Wenckebach block at the lower level. Alternate VA Wenckebach conduction appears as a possible cause of variation in atrial depolarization intervals during ventricular tachycardias with short cycle lengths.
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http://dx.doi.org/10.1111/j.1540-8159.1985.tb05861.x | DOI Listing |
J Interv Card Electrophysiol
January 2025
Rooney Heart Institute, 311 9th St N #201, Naples, FL, 34102, USA.
Introduction: The role of the sympathetic nervous system in the initiation and continuation of ventricular tachyarrhythmias (VTA) is well established. However, whether CSD reduces implantable cardioverter-defibrillator (ICD) shocks and recurrent VTA is still uncertain.
Methods: A comprehensive literature search was performed at Medline and Embase until March 2023.
Pharmacol Res Perspect
February 2025
Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Ventricular arrhythmias induced by ischemia/reperfusion injury limits the therapeutic effect of early reperfusion therapy for acute myocardial infarction. This study investigated the protective effects of the β2-adrenergic receptor (β2-AR) agonist clenbuterol against ischemia/reperfusion-induced arrhythmias and the underlying mechanism. Anesthetized rats were subjected to 10-min left coronary artery occlusion and 10-min reperfusion in vivo.
View Article and Find Full Text PDFArrhythm Electrophysiol Rev
December 2024
Heart Rhythm Research Group, Division of Biomedical Sciences, Warwick Medical School, Clinical Sciences Research Laboratory Coventry, UK.
Functional substrate mapping has emerged as an essential tool for electrophysiologists, overcoming many limitations of conventional mapping techniques and demonstrating favourable long-term outcomes in clinical studies. However, a consensus on the definition of 'functional substrate' mapping remains elusive, hindering a structured approach to research in the field. In this review, we highlight the differences between 'functional mapping' techniques (which assess tissue response to the 'electrophysiological stress' using short coupled extrastimuli) and those highlighting regions of slow conduction during sinus rhythm.
View Article and Find Full Text PDFCardiol Young
January 2025
Department of Medical Education and Clinical Sciences, Elson S Floyd College of Medicine, Washington State University, Spokane, WA, USA.
Sudden cardiac death poses a significant risk in patients with surgically repaired tetralogy of Fallot. Despite extensive research, risk stratification practices vary. This study surveyed the Pediatric and Adult Congenital Electrophysiology Society to identify these differences.
View Article and Find Full Text PDFInt J Cardiol
January 2025
Department of Cardiology, Cardiovascular Institute, Thorax Center, Erasmus MC, Rotterdam, the Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart), Amsterdam, the Netherlands.
Background: Little is known about the very long-term outcome in Tetralogy of Fallot (ToF) patients.
Objectives: To prospectively evaluate clinical outcome and quality-of-life after surgical repair of ToF.
Methods: Single-centre, longitudinal cohort-study evaluating every decade 144 ToF patients who underwent surgical repair <15 years of age between 1968 and 1980.
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