Different effects of amiodarone and dofetilide on the dispersion of repolarization between well-coupled ventricular and Purkinje fibers1.

Canadian Journal of Physiology and Pharmacology
Tamás Árpádffy-LovasLászló Virág

Abstract

Increased transmural dispersion of repolarization is an established contributing factor to ventricular tachyarrhythmias. In this study, we evaluated the effect of chronic amiodarone treatment and acute administration of dofetilide in canine cardiac preparations containing electrotonically coupled Purkinje fibers (PFs) and ventricular muscle (VM) and compared the effects to those in uncoupled PF and VM preparations using the conventional microelectrode technique. Dispersion between PFs and VM was inferred from the difference in the respective action potential durations (APDs). In coupled preparations, amiodarone decreased the difference in APDs between PFs and VM, thus decreasing dispersion. In the same preparations, dofetilide increased the dispersion by causing a more pronounced prolongation in PFs. This prolongation was even more emphasized in uncoupled PF preparations, while the effect in VM was the same. In uncoupled preparations, amiodarone elicited no change on the difference in APDs. In conclusion, amiodarone decreased the dispersion between PFs and VM, while dofetilide increased it. The measured difference in APD between cardiac regions may be the affected by electrotonic coupling; thus, studying PFs and VM separately m...Continue Reading

References

Nov 1, 1990·Journal of Cardiovascular Pharmacology·A VarróB Surawicz
Nov 1, 1994·The American Journal of Cardiology·G CuiB N Singh
Sep 1, 1996·Japanese Heart Journal·I KodamaJ Toyama
Dec 12, 1997·Journal of Cardiovascular Electrophysiology·S SicouriC Antzelevitch
Apr 16, 1998·Journal of Electrocardiology·C AntzelevitchS Sicouri
Oct 13, 1998·Journal of the American College of Cardiology·E DrouinF Charpentier
Nov 22, 2000·Circulation·J P Mounsey, J P DiMarco
Sep 21, 2002·Drug Safety : an International Journal of Medical Toxicology and Drug Experience·Bente BrendorpLars Køber
May 12, 2006·Journal of Cardiovascular Electrophysiology·David FedidaAlan M Ezrin
Jun 27, 2009·Cardiovascular Research·Tamás BányászPéter P Nánási
Jan 18, 2011·Journal of Cardiovascular Electrophysiology·Toshiyuki OsakaItsuo Kodama
Mar 18, 2011·Pacing and Clinical Electrophysiology : PACE·Akihiko Nogami
Jun 16, 2011·Pacing and Clinical Electrophysiology : PACE·Akihiko Nogami
Jul 6, 2014·Cardiovascular Research·Richard D WaltonEdward J Vigmond
May 1, 2015·Canadian Journal of Physiology and Pharmacology·Balázs HorváthPéter P Nánási
Sep 21, 2019·Heart Rhythm : the Official Journal of the Heart Rhythm Society·Hans Friedrich StabenauJonathan W Waks

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