Herz
-
Vasodilators have been shown to improve hemodynamics of the failing heart as a short-term effect and to decrease mortality as a long-term result. We therefore studied the effect of different vasodilators on myocardial mechanics and energetics in patients with idiopathic dilated cardiomyopathy (IDC) NYHA II to III. In these patients undergoing routine heart catheterization myocardial oxygen consumption was measured using the argon method, and left ventricular pressure and geometry were obtained from left ventricular angiography using a Millar tip microcatheter. ⋯ In conclusion, vasodilators decrease left ventricular pressure and chamber size and thereby proportionally reduce MVO2/beat. The reduction of energy needed for myocardial contraction may partially explain the long-term effects of the ACE-inhibitors and combinations of vasodilators. Pure positive inotropic substances, especially beta 1-agonists, increase myocardial oxygen consumption with minor changes of systolic stress-time integral.(ABSTRACT TRUNCATED AT 250 WORDS)