MYOCARDIAL-ISCHEMIA - TREATMENT WITH DILTIAZEM

Many patients with coronary artery disease develop attacks of regional myocardial ischemia with pain, ECG-changes and dyskinesia (angina pectoris), or with ECG-changes and dyskinesia without pain (silent ischemia), or with only dyskinesia (supersilent ischemia). In most cases ischemic attacks occur both spontaneously and induced by exercise. Medical therapy is indicated not only in patients suffering from anginal; it has been demonstrated that patients in whom anti-ischemic therapy fails, suffer from significantly more major coronary events than those who were treated successfully. In all patients with ischemic episodes, however detected, diltiazem raises the ischaemic threshold, reduces severity and duration of attacks and lowers the rate of spontaneous attacks. Diltiazem does not reduce the working capacity, it may even raise it slightly. Simultaneously, maximal myocardial oxygen consumption, as estimated from the product of heart rate and systolic pressure, is only slightly reduced. This demonstrates that the anti-anginal effect of diltiazem is based not only on coronary vasodilation, but also on reduction of oxygen myocardial oxygen uptake. A beta-blocker reduces myocardial oxygen uptake for more effectively than diltiazem in an equipotent anti-anginal dose, but as a result it reduces the aerobic working capacity more than diltiazem does.