Oral metoprolol therapy in dilated cardiomyopathy: hemodynamic evidence for improved diastolic function accompanying amelioration of symptoms

Twenty patients with dilated cardiomyopathy (11 males and 9 females) aged from 14 to 54 (37.3 +/- 10.5) years were treated orally with metoprolol (dose 37.5 mg-100 mg/day, mean 91 +/- 18.6 mg/day) after a baseline hemodynamic study. On follow-up, all patients showed improvement in symptomatic status by at least one NYHA class within 2 to 4 weeks of the initiation of therapy. Repeat right heart study and left ventricular angiography (venous digital subtraction angiography) afer 3 to 6 months of treatment in 10 patients showed a fall in the mean pulmonary arterial wedge pressure from 24.4 +/- 9.6 to 12.8 +/- 7.7 mm Hg (P = 0.025), right ventricular end-diastolic pressure from 8.8 +/- 4.7 mm Hg to 4.5 +/- 1.9 mm Hg (P = 0.025) and mean pulmonary arterial pressure from 34.2 +/- 12.4 mm Hg to 25.9 +/- 10.9 mm Hg (P less than 0.01). There was no significant change in the left ventricular ejection fraction (18.7 +/- 1.6% vs. 22 +/- 0.48%, P = NS) or cardiac index (2.2 +/- 0.48 l/m/m2 to 2.12 +/- 0.68 l/m/m2, P = NS). These hemodynamic results indicate that the improvement in symptoms and congestive cardiac failure produced by treatment with metoprolol in patients having dilated cardiomyopathy is related to improvement in diastolic function of the myocardium.