Protection of ischemic rat heart by cardioplegic doses of pentobarbital

We examined the ability of pentobarbital in extremely high concentrations (over 10 times the anesthetic dose) to act as a cardioplegic agent. Isolated rat hearts treated with 500 mg/liter of pentobarbital showed excellent recovery of heart function (heart rate and aortic pressure) after 25 min of global ischemia at 37°C. The effect of 375 mg/liter of pentobarbital was marginal, and lower concentrations of pentobarbital (125–250 mg/liter) did not improve the recovery of heart function even though the drug prevented ventricular tachycardia which is frequently observed upon reperfusion of ischemic heart.