Effects of Intravenous Captopril on Inducible Sustained Ventricular Tachycardia One Week After Experimental Infarction in the Anaesthetized Pig

The effect of captopril on inducible sustained ventricular tachycardia (VT) one week after myocardial infarction was studied in 6 Yorkshire swine. In 24 pigs, controlled myocardial infarction (MI) was produced by reversible occlusion of the left anterior descending artery during 60 minutes using an inflatable balloon catheter. Four animals died during this procedure and another 4 during the first week. After 7 days, programmed electrical stimulation (PES) was performed in the surviving animals. Seven animals showed inducible VT, which could not be terminated in one. Subsequently, intravenous captopril (0.6-1.2 mg/kg) was administered as a rapid bolus injection. PES was repeated after 5 minutes and VT was no longer inducible in all 6 pigs (P less than 0.05). Right ventricular refractoriness decreased from 253 to 228 ms (n.s.). Blood pressure and heart rate were not significantly changed. We conclude that captopril can protect the heart against PES-induced VT late after MI. It is suggested that inhibition of angiotensin II and subsequent inhibition of noradrenaline may be responsible for this effect