gms | German Medical Science

33rd International Congress on Electrocardiology

International Society of Electrocardiology

Efficacy of Bepridil on Rapid Atrial Pacing-induced Canine Atrial Fibrillation Model

Meeting Abstract

  • corresponding author presenting/speaker K. Nishida - University of Toyama, Toyama, Japan
  • A. Fujiki - University of Toyama, Toyama, Japan
  • T. Sakamoto - University of Toyama, Toyama, Japan
  • J. Iwamoto - University of Toyama, Toyama, Japan
  • K. Mizumaki - University of Toyama, Toyama, Japan
  • H. Inoue - University of Toyama, Toyama, Japan

33rd International Congress on Electrocardiology. Cologne, 28.06.-01.07.2006. Düsseldorf, Köln: German Medical Science; 2007. Doc06ice028

The electronic version of this article is the complete one and can be found online at:

Published: February 8, 2007

© 2007 Nishida et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Background: Bepridil converts effectively long lasting atrial fibrillation (AF) into sinus rhythm, but the mechanism is still unclear.

Method: Ten dogs were subjected to rapid atrial pacing (400bpm) for six weeks after atrioventricular block was created to control ventricular rate (80bpm). Five dogs were paced for six weeks with placebo (Group P). The remaining five dogs were paced for the first three weeks with placebo and for another three weeks under bepridil administration (10 mg/kg/day)(Group B). Atrial effective refractory period (ERP) and P wave duration during right atrial pacing at basic cycle lengths form 400ms (CL400) to 150ms (CL150), inducibility of AF by burst pacing, and duration of AF were determined every week.

Results: Data are before pacing, and 3 and 6 weeks after starting pacing. In Group P, ERP was abbreviated (150±8ms, 84±11ms, and 77±8ms at CL400; 119±12ms, 80±11ms, and 73±7ms at CL150) and P wave duration prolonged (73±5ms, 76±7ms, and 80±9ms at CL 400; 82±13ms, 80±8ms, and 84±10ms at CL150). AF inducibility increased (0%, 34±40%, and 60±40%), and AF duration prolonged (0sec, 39±40sec, and 396±786sec) after 6 weeks of pacing. In Group B, bepridil reversed these changes; ERP was prolonged (145±16ms, 77±10ms, and 105±14ms, p<0.05 vs. Group P at CL400; 114±21ms, 77±9ms, and 106±9ms, p<0.05 vs. Group P at CL150). AF inducibility was suppressed (0%, 60±38%, and 8±18%, p<0.05 vs. Group P), and AF duration was shortened (0sec, 377±797sec, and 5±11sec, p<0.05 vs. Group P). P wave duration in Group B continued to prolong and did not differ as compared with Group P (73±6ms, 78±8ms, and 83±4ms at CL400; 77±6ms, 81±5ms, and 88±7ms at CL150). AF inducibility and duration correlated most strongly with ERP at CL150 (r=0.7, p<0.01, and r=0.58, p<0.01, respectively), but not with P wave duration.

Conclusion: In this model, emergence of AF correlated strongly with ERP abbreviation and bepridil suppressed AF by prolonging ERP.