Effects of a novel class III antiarrhythmic agent, E-4031, on reentrant tachycardias in rabbit right atrium.
Effects of a new antiarrhythmic agent, E-4031, on reentrant types of tachycardias in rabbit right atrial preparations were studied using the microelectrode technique. E-4031 at concentrations of 0.1 and 1.0 microM prolonged the refractory period (RP) of the atrium and atrioventricular node (AVN) without affecting the intraatrial conduction time. In 13 of 17 preparations, premature stimulation repeatedly induced tachycardias lasting more than 10 beats. Twelve of 13 preparations exhibited a smooth AV conduction curve and showed activation patterns compatible with intraatrial reentry (IAR) during tachycardias, whereas the remaining preparation started tachycardia with a jump on the AV conduction curve, indicating dual AVN reentrant tachycardia (AVNRT). Application of 0.1 and 1.0 microM E-4031 completely prevented the initiation of both types of tachycardias by producing intraatrial conduction block due to prolonged effective refractory period (ERP) of the atrium. The results indicated that E-4031 exhibiting pure class III antiarrhythmic properties is effective for prevention of reentrant type of supraventricular tachycardias (SVTs).
Adaniya
H
H
Department of Cardiovascular Diseases, Tokyo Medical and Dental University, Japan.
Hiraoka
M
M
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D001283:Atrioventricular Node / Q000187:drug effects; D004558:Electric Stimulation; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006325:Heart Atria / Q000187:drug effects; D066298:In Vitro Techniques; D015425:Myocardial Reperfusion; D010880:Piperidines / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D011817:Rabbits; D012032:Refractory Period, Electrophysiological / Q000187:drug effects; D013610:Tachycardia / Q000139:chemically induced / Q000503:physiopathology
D000889:Anti-Arrhythmia Agents; D010880:Piperidines; D011725:Pyridines; C063968:E 4031