Recent Advances in Antiarrhythmic Drug Research: Studies in Chronic Canine Myocardial Infarction‐Ventricular Tachyarrhythmia Models

Several chronic canine myocardial infarction‐ventricular tachyarrhythmia models are now available for the evaluation of new antiarrhythmic drugs The available models ful‐fill many, but not all of the requirements for an ideal chronic arrhythmia model Sustained arrhythmias can be initiated in these animals using routine methods of programmed pacing. Presumably, the mechanism for these arrhythmias is localized re‐entry, similar to that in patients with previous myocardial infarction and chronic coronary artery disease However, these models are not suitable for determining whether a new drug will abolish spontaneously‐occurring ventricular extrasystoies In addition, these models are of unproven value in the study of acute spontaneously‐occurring sudden death, although recently initiated, provocative work may shed further light on this subject Most important, the available models do seem well‐suited to the evaluation of new drugs intended for use of chronic coronary artery disease patients at risk for sustained re‐entrant ventricular tachycardia or fibrillation Notably, the results of preliminary electropharmacologic studies in these canine models parallel closely those findings reported in human patients with sustained life‐threatening ventricular tachyarrhythmias. Therefore, increased use of these chronic models for new antiarrhythmic drug testing appears promising