Enhanced induction of ventricular arrhythmias during sympathetic stimulation before and during coronary artery...

We used programmed electrical stimulation to examine the arrhythmogenic influence of the sympathetic nervous system before and during coronary artery occlusion. In 29 anesthetized dogs the left and/or right stellate ganglia were stimulated at 2-8 hertz. Program-induced ventricular arrhythmias included single premature ventricular depolarizations, doublets, triplets, ventricular tachycardia and ventricular fibrillation. Both the number of extrastimuli and the duration of coronary occlusion significantly influenced ventricular arrhythmia induction. After pooling the number of extrastimuli, type of artery occluded, and the duration of occlusion, the influences of unilateral and bilateral stellate stimulations were evaluated. The incidence of induced ventricular arrhythmias was 54% during control conditions (prior to sympathetic stimulation). Right stellate stimulation had no influence on arrhythmogenesis, causing ventricular arrhythmia induction in 52% (NS) of the trials. Left stellate stimulation resulted in increased ventricular arrhythmias (68%; P less than 0.05) in response to programmed electrical stimulation. Bilateral stellate stimulation elevated program-induced ventricular arrhythmias (63%; P less than 0.05). The effects of the stellate stimulations on arrhythmia induction were similar during and up to 180 minutes of coronary occlusion. Thus, the arrhythmogenic influence of sympathetic stimulation was present before and during coronary artery occlusion.