[Myocardial protection by dilazep in myocardial ischemia and reperfusion]

Myocardial protection of dilazep HCl, which is an antianginal drug and a potent calcium antagonist against myocardial damage following acute ischemia and reperfusion, was studied on myocardial contractility in isolated blood perfused canine left ventricular muscle. Myocardial function was expressed by percent recovery rate of maximum net developed tension. 1. The coronary infusion of dilazep revealed significant myocardial protection during normothermic ischemic arrest of 45 min and reperfusion. 2. The i.v. administration of dilazep to the donor dog and Young's infusion also showed significant myocardial protection during normothermic ischemic arrest of 45 min and reperfusion. 3. The combination of i.v. administration of dilazep to the donor dog, Young's infusion, and hypothermia showed significant myocardial protection during prolonged ischemia and reperfusion even in hypertrophied ventricle. 4. Dilazep prevents abnormal calcium accumulation in myocardial cells during reperfusion. These results demonstrate that dilazep provides effective myocardial protection during ischemic arrest and reperfusion, and they may support its clinical application as a myocardial protective agent for open-heart surgery.