Circulation, Vol 81, 334-342, Copyright © 1990 by American Heart Association
M Talajic, D Papadatos, C Villemaire, M Nayebpour and S Nattel
The purpose of this study was to determine if the known frequency-
dependent effects of diltiazem on inward calcium current result in
selective actions during supraventricular tachycardia. These effects were
evaluated by use of an experimental model of orthodromic atrioventricular
reentrant tachycardia (AVRT). AVRT was induced in 15 dogs over a wide range
of retrograde conduction times before and after two doses of diltiazem.
Diltiazem produced a tachycardia-related suppression of atrioventricular
nodal conduction resulting in greater efficacy for faster than for slower
AVRTs. The degree of slowing for tachycardias that remained inducible after
diltiazem administration was greater for AVRTs with a rapid initial rate
(dose 1, 29%; dose 2, 40%) than for slower AVRTs (dose 1, 11%, p less than
0.01; dose 2, 18%, p less than 0.001). Rate-dependent AVRT slowing occurred
because of a time-dependent phase of AH interval prolongation after the
onset of tachycardia, which was observed only after diltiazem
administration. to further clarify the mechanism of diltiazem's selective
actions against faster tachycardias, its effects on the minimum pathway for
reentry, or wavelength, were examined in four dogs. The ratio of refractory
period to revolution time (RP/RT), an index of wavelength, was measured for
each AVRT before and after diltiazem administration. Diltiazem increased
the positive slope of the relation between RP/RT and the AVRT rate
threefold compared with control (p less than 0.05). This rate- dependent
effect prevented AVRT when RP/RT became greater than unity. In conclusion,
rate-dependent atrioventricular node depression by diltiazem results in
greater tachycardia slowing and higher rates of termination during
atrioventricular reentrant tachycardias with faster initial rates and
shorter retrograde conduction intervals.
ARTICLES
Antiarrhythmic actions of diltiazem during experimental atrioventricular reentrant tachycardias. Importance of use-dependent calcium channel-blocking properties
Department of Medicine, Montreal Heart Institute, Quebec, Canada.
This article has been cited by other articles:
 |
|
 |
|
  L. Rivard, H. Sinno, A. Shiroshita-Takeshita, G. Schram, T.-K. Leung, and S. Nattel The pharmacological response of ischemia-related atrial fibrillation in dogs: Evidence for substrate-specific efficacy Cardiovasc Res, April 1, 2007; 74(1): 104 - 113. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. N. Wijeysundera, W. S. Beattie, V. Rao, J. Ivanov, and K. Karkouti Calcium antagonists are associated with reduced mortality after cardiac surgery: a propensity analysis J. Thorac. Cardiovasc. Surg., March 1, 2004; 127(3): 755 - 762. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. N. Wijeysundera, W. S. Beattie, V. Rao, and J. Karski Calcium antagonists reduce cardiovascular complications after cardiac surgery: A meta-analysis J. Am. Coll. Cardiol., May 7, 2003; 41(9): 1496 - 1505. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Sticherling, H. Tada, W. Hsu, A. C. Bares, H. Oral, F. Pelosi, B. P. Knight, S. A. Strickberger, and F. Morady Effects of Diltiazem and Esmolol on Cycle Length and Spontaneous Conversion of Atrial Fibrillation Journal of Cardiovascular Pharmacology and Therapeutics, June 1, 2002; 7(2): 81 - 88. [Abstract] [PDF]
|
|
|
|
|
|
R. Seitelberger, W. Hannes, M. Gleichauf, M. Keilich, M. Christoph, R. Fasol, Sponsored by, and E. Wolner Effects of diltiazem on perioperative ischemia, arrhythmias, and myocardial function in patients undergoing elective coronary bypass grafting J. Thorac. Cardiovasc. Surg., March 1, 1994; 107(3): 811 - 821. [Abstract] [Full Text]
|
|