Br Heart J 1986; 55: 391-9 Afterload reduction: a comparison of captopril and nifedipine in dilated cardiomyopathy PIER G AGOSTONI, NICOLETTA DE CESARE, ELISABETTA DORIA, ALVISE POLESE, GLORIA TAMBORINI, MAURIZIO D GUAZZI From Istituto di Cardiologia, Centro di Studio Ricerche Cardiovascolari del Consiglio Nazionale delle Ricerche, University of Milan, and Fondazione "I. Monzino" and Istituto Ricerche Cardiovascolari "G. Sisini", Milan, Italy SUMMARY Nifedipine and captopril are potent vasodilators and may be expected to help left ventricular failure by reducing afterload. Nifedipine (20mg three times a day) and captopril (50 mg three times a day) were added to an optimal regimen of digitalis and diuretics in a double blind crossover trial in 18 cases of dilated cardiomyopathy. New York Heart Association func- tional class rating symptoms and exercise tolerance times improved on captopril but not on nifedipine. The reduction in pulmonary capillary wedge pressure and the increase of cardiac output on captopril indicated that the augmented functional capacity may have resulted in part from an improved performance of the left ventricle. Although there were comparable decreases in systemic vascular resistance and presumably in impedence to ejection by the left ventricle on both drugs, the dimensions of the ventricular cavity were found to be reduced by captopril and augmented by nifedipine, and only captopril reduced the afterload (wall stress). In addition, the force-length relation (between left ventricular end systolic stress and end systolic diameter) was shifted to the left of baseline by captopril and to the right by nifedipine, suggesting that muscle contractility was reduced by nifedipine and not by captopril. These results suggest that nifedipine and captopril have different effects on afterload and contractility and these may account for the different effects of these drugs on the performance of the heart and clinical responses. Most vasodilators may be beneficial in both hyper- tension and cardiac decompensation. The angio- tensin converting enzyme inhibitor, captopril, is such an example.'`3 The antihypertensive proper- ties of the calcium channel blocking agents are well established,4 and nifedipine has been used to reduce ventricular afterload.5-8 Treatment of cardiac insufficiency in the advanced stage of dilated cardiomyopathy is still one of the most challenging tasks in clinical cardiology, and the poor prognosis justifies a search for more efficient methods of treatment. Although the combination of captopril with conventional treatment has been of benefit in many series of patients with refractory chronic congestive heart failure,9 - 12 these series did Requests for reprints to Professor Maurizio D Guazzi, Istituto di Cardiologia, Via Bonfadini 214, 20138 Milan, Italy. Accepted for publication 3 December 1985 not include many cases of dilated cardiomyopathy and the specific response of such patients may have been obscured. Acute pulmonary oedema due to dilated cardiomyopathy can be relieved by nifedipine"6 but long term studies are lacking. For these reasons we have studied the effects of these two agents in dilated cardiomyopathy. We per- formed a detailed haemodynamic study of the different effects of captopril and nifedipine on blood vessels (in terms of arterial and venous muscle relax- ation) and on the myocardium (in terms of changes in heart rate and contractility) in a crossover trial. Patients and methods PATIENTS Twenty six patients with chronic congestive heart failure caused by dilated cardiomyopathy of un- known cause were considered to be eligible, but 391 group.bmj.com on June 21, 2017 - Published by http://heart.bmj.com/ Downloaded from