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It has been suspected that the increased sympathetic activity seen in patients with chronic congestive heart failure from dilated cardiomyopathy may be harmful. We therefore tested the long-term effect of metoprolol on eight patients in a double-blind, randomized protocol and 12 patients in an unblinded, crossover protocol who were treated for 12 months (range 10 to 24), and compared them with 16 similar subjects who were treated with placebo for 10 months (range 6 to 12) in a doubleblind, randomized protocol. Patients were followed by serial clinical assessment, treadmill testing, radionuclide ventriculography, and echocardiography. Metoprolol-treated patients had an improvement in mean exercise capacity by 3 mets (p < .0001) while experiencing a significant improvement in functional classification (p < .001) during both the double-blind and open-label crossover studies and had an improved ejection fraction during the double-blind study (p < .02). These improvements were not seen in matched control subjects receiving placebo. Seven of 20 patients receiving long-term metoprolol therapy had resolution of nearly all symptoms of heart failure, doubled their exercise capacity, and had progressive improvement in resting radionuclide left ventricular ejection fraction (12.6 3% to 26.9 + 6%) and echocardiographic left ventricular end-diastolic dimension (7.7 0.5 to 6.5 0.5 cm). Only one of 21 patients treated was intolerant of metoprolol. We conclude that metoprolol can be given safely to a select group of patients with dilated cardiomyopathy in doses that substantially reduce both resting and exercise heart rates. Long-term /3-blockade improved functional class and exercise capacity in 14 of 20 patients while producing an exceptional clinical response in seven that was accompanied by improved resting parameters of left ventricular function. Circulation 72, No. 3, 536-546, 1985. DILATED CARDIOMYOPATHY is a disease of heart muscle characterized by left ventricular dilatation and congestive heart failure. ' It affects a younger population than does ischemic heart disease and frequently results in functional impairment and premature death. The reflex neurohumoral responses that accompany the syndrome of congestive heart failure are useful in maintaining short-term compensation of cardiac function.2' 3 Norepinephrine is released from sympathetic nerve endings to activate myocardial /3-receptors that increase both the heart rate and force of ventricular contraction.4 Stimulation of a-receptors results in peripheral vasoconstriction to help maintain critical end-

Peripartum cardiomyopathy is defined as left ventricular dilation and failure, first developing during the third trimester of pregnancy or in the first 6 months postpartum. In an effort to characterize this syndrome in a middle class population, 14 consecutive patients with peripartum cardiomyopathy underwent a detailed history and physical examination, right heart catheterization, M-mode and two-dimensional echocardiography, radionuclide ventriculography and right ventricular endomyocardial biopsy. These patients were then observed with sequential noninvasive studies to determine prognostic indicators. Eight (57%) of these 14 patients were primiparous and an equal number first presented with heart failure concomitant with or immediately before the onset of labor. When these women were compared with 55 patients with idiopathic dilated cardiomyopathy, only mean age at onset of symptoms (28.7 +/- 5.7 versus 48.2 +/- 13.6 years, p less than 0.001) and symptom duration (4.1 +/- 7.7 versus 19.0 +/- 18.4 months, p less than 0.001) differed between the groups. There was no difference in ventricular arrhythmia, left ventricular chamber size, ejection fraction or hemodynamics. Myocyte histologic findings were similar; however, myocarditis was identified in 29% of patients with peripartum cardiomyopathy and in only 9% of those with idiopathic dilated cardiomyopathy. In all patients with peripartum cardiomyopathy and myocarditis, the myocardial biopsy was performed within 1 week of onset of symptoms. Seven (50%) of the patients with peripartum cardiomyopathy had dramatic improvement within 6 weeks of follow-up, and 6 (43%) died.(ABSTRACT TRUNCATED AT 250 WORDS)

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