Circulation, Vol 63, 70-79, Copyright © 1981 by American Heart Association
M Naito, EL Michelson, JJ Kmetzo, E Kaplinsky and LS Dreifus
Ninety-nine adult mongrel dogs underwent acute ligation of the proximal
left anterior descending coronary artery. Thirty minutes later, the
occlusion was released to evaluate the effectiveness of five antiarrhythmic
protocols in eliminating reperfusion ventricular fibrillation. The five
protocols included: protocol 1 --i.v. lidocaine, preligation and prerelease
(n = 19); protocol 2 -- i.v. lidocaine, prereperfusion only (n = 22);
protocol 3 -- chronic, oral, daily amiodarone for 2 weeks preligation (n =
19); protocol 4 -- i.v. procainamide, preligation and prereperfusion (n =
21); and protocol 5 -- i.v. verapamil, prereperfusion (n = 18). Each
regimen was evaluated with respect to the incidence of reperfusion
ventricular fibrillation in dogs that survived to reperfusion, and the
results were compared to 77 control dogs that underwent identical coronary
artery occlusion and release procedures without drug therapy. The incidence
of reperfusion ventricular fibrillation was as follows: protocol 1 -- seven
of 15 dogs (47%); protocol 2 -- six of 18 (33%); protocol 3 -- 11 of 16
dogs (69%); protocol 4 -- eight of 17 dogs (47%); and protocol 5 -- 10 of
17 dogs (59%), compared with 36 of 60 (60%) in control dogs. Using chi-
square analysis, protocol 2 was beneficial (p < 0.05). The dogs were
then stratified into high- and low-risk subgroups based on the arrhythmic
events of the antecedent coronary artery ligation periods, and predictive
risk indexes for the occurrence of reperfusion ventricular fibrillation
were developed. the Mantel-Haenszel method of statistical analysis revealed
that none of these protocols resulted in a statistically significant
reduction in the incidence of reperfusion ventricular fibrillation. Thus,
use of these predictive indexes plus appropriate statistical methods has
revealed, unexpectedly, limitations in the efficacy of a spectrum of
antiarrhythmic agents in preventing reperfusion ventricular fibrillation.
ARTICLES
Failure of antiarrhythmic drugs to prevent experimental reperfusion ventricular fibrillation
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