Left stellectomy in the prevention of ventricular fibrillation caused by acute myocardial ischemia in conscious dogs with anterior myocardial infarction.

Abstract

The potential of left stellectomy in reducing the incidence of ventricular fibrillation associated with acute myocardial ischemia was investigated in a new animal model for sudden death. Thirty-two dogs had an anterior myocardial infarction produced by ligation of the left descending coronary artery. One week later they were randomly allocated to a control or to an experimental group that underwent left stellectomy. One month after ligation while the dogs were conscious, a balloon occluder previously positioned around the circumflex coronary artery was inflated and the ensuing coronary occlusion was maintained for 10 minutes. Ventricular fibrillation occurred in 11 of 17 (65%) control dogs, compared with five of 15 (33%) (p < 0.05) in the experimental group. Among the survivors the incidence of arrhythmias was less in the experimental group compared with the control group. Infarct size (21 +/- 2% vs 20 +/- 2%), resting heart rate (143 beats/min vs 127 beats/min) and QTc (347 +/- 11 msec vs 349 +/- 13 msec) were similar between control and experimental groups. The dogs that died had a greater increase in heart rate at 1 minute postocclusion than survivors and also had significantly longer QT intervals. Our study indicates that left stellectomy exerts a major protective effect in reducing the incidence of ventricular fibrillation when conscious dogs with a previous anterior myocardial infarction undergo acute myocardial ischemia. This simple and safe surgical procedure may be considered for a clinical trial in subgroups of patients with ischemic heart disease at very high risk for sudden death.