Comparative left ventricular functional and neurohumoral effects of chronic treatment with carvedilol versus metoprolol in patients with dilated cardiomyopathy

The efficacy of treating dilated cardiomyopathy with metoprolol was compare d with that of carvedilol. Metoprolol was administered to 29 patients, and carvedilol to 62. Patients who could not be dosed with up to 40 mg daily of metoprolol or 20 mg daily of carvedilol were defined as intolerant. As wel l as the tolerability of these beta -blockers, the effects on left ventricu lar end-diastolic dimension (LVDd), fractional shortening (FS), plasma atri al natriuretic peptide (ANP) and brain natriuretic peptide (BNP) concentrat ions, the delayed heart and mediastinum (HIM) ratio determined from metaiod obenzylguanidine imaging were compared. Drug intolerance occurred in 24% of patients in the metoprolol group and 19% in the carvedilol group. Among th e drug-tolerant patients, LVDd, FS and plasma BNP concentration improved in both groups and to the same degree. Only 25% of drug-tolerant patients in the metoprolol group had a delayed H/M ratio below 1.9 compared with 57% in the carvedilol group. Both metoprolol and carvedilol, when tolerated, impr ove cardiac function and neurohumoral factors to the same degree. However, carvedilol is preferable to metoprolol for patients with a low delayed HIM ratio.