Programmed electrical stimulation induced sustained ventricular tachycardia in 11 of 20 dogs an average of 20 days after experimental myocardial infarction.
To study recurrent ventricular tachycardia in the late phase or myocardial infarction (MI), transmural anteroapical infarcts were created by ligation of the left anterior descending (LAD) coronary artery in 25 dogs. Twenty dogs survived LAD ligation and underwent an open-chest electrophysiologic study an average of 20 days after MI. Programmed electrical stimulation was carried out using the extrastimulus technique and short bursts of rapid ventricular pacing via bipolar electrodes positioned at multiple left ventricular endocardial sites. Sixteen dogs had electrically induced ventricular tachycardia, and in 11, sustained ventricular tachycardia was reproducibly initiated and terminated by programmed ventricular stimulation. Short bursts of rapid left ventricular pacing from areas in periinfarct zone was the most effective technique for initiating ventricular tachycardia. The electrophysiologic phenomena in this model of sustained ventricular tachycardia in 3-week-old MI included electrically induced changes in rate and morphology and biventricular capture without termination during tachycardia.
Garan et al. (Sat,) conducted a other in Myocardial infarction and ventricular tachycardia (n=25). Programmed electrical stimulation and rapid ventricular pacing was evaluated on Electrically induced ventricular tachycardia. Programmed electrical stimulation induced sustained ventricular tachycardia in 11 of 20 dogs an average of 20 days after experimental myocardial infarction.