Prospectives for angiotensin converting enzyme inhibition in heart diseases.

Angiotensin converting enzyme (ACE) inhibitors are not known to have a direct effect on the myocardium. However, there is some evidence to suggest that they can play an important role in protecting the heart during the evolution of hypertensive and coronary arterial disease, both acutely and on a long term basis. Reduction of afterload by balanced arterial and venular dilatation has led to a sustained improvement of cardiac performance both in hypertension and heart failure. Reversal of cardiac hypertrophy has been shown to restore inotropic responsiveness to stimulators of the adenylate cyclase system. Following myocardial infarction, captopril has prevented undue ventricular dilatation and normalized left ventricular chamber stiffness; this prevented deterioration of cardiac function and improved long term survival after infarction. Control of secondary aldosteronism and prevention of hypokalaemia can play an important role in the prevention of cardiac arrhythmias. The lack of reflex sympathetic stimulation during long term captopril therapy can also play a favourable role in that respect. Although highly speculative, evidence is accumulating that ACE inhibition could have a cardioprotective effect in acute myocardial ischaemia. It is based on the demonstration that renin can be produced by myocardial cells, that angiotensin is liberated by the ischemic myocardium and that angiotensin in high renin conditions plays an active constrictor role in regulating the coronary circulation.