Reproducibility of the model of induced ventricular tachycardia in conscious dogs with infarction.
The canine model of ventricular tachycardias (VT) induced by programmed stimulation is used routinely in several laboratories to test antiarrhythmic drugs. The aim of the present study was to determine the rate of success and reproducibility of this model. We analyzed a group of 58 dogs that underwent a 2-hr occlusion and were submitted to programmed electrical stimulation at least 4 days after the surgery. Only 29 dogs (50%) were inducible and included in the study, as 22 dogs died following myocardial infarction, and seven dogs were never inducible. Out of 130 trials, 92 (70%) performed on inducible dogs were positive with 11% of nonsustained ventricular tachycardias, 63% of sustained monomorphic ventricular tachycardias, and 26% of ventricular fibrillation. Inducibility decreased over time in a subgroup of 19 dogs that was submitted to four trials during the first month after the infarction (68% of inducible dogs versus 46% in trials 1 and 4, respectively). Ventricular effective refractory period decreased significantly from 146 +/- 7 msec at trial 1 to 114 +/- 6 msec at trial 4, and the severity of the induced ventricular tachycardias increased. This variability should be considered when planning studies on antiarrhythmic drugs in this model.
Chézalviel-Guilbert
F
F
Laboratoire de Pharmacologie, CHU Saint Antoine, Paris, France.
Weissenburger
J
J
Davy
J M
JM
Vernhet
L
L
Guhennec
C
C
Cheymol
G
G
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D004195:Disease Models, Animal; D004285:Dogs; D004558:Electric Stimulation; D004594:Electrophysiology; D005260:Female; D008297:Male; D009203:Myocardial Infarction / Q000188:drug therapy / Q000503:physiopathology; D015203:Reproducibility of Results; D017180:Tachycardia, Ventricular / Q000188:drug therapy / Q000503:physiopathology*; D013997:Time Factors
D000889:Anti-Arrhythmia Agents