Background: Several reports from controlled and uncontrolled studies, mainly in the setting of heart failure due to dilated cardiomyopathy (DCM), indicate that chronic betablockade may improve hemodynamics and clinical function. There are few reports on the effects of betablockers in patients with severe heart failure.
Methods: Thirty-five patients (27 M; 8 F; mean age 44.3 +/- 16.7 years; range 14-66 years) with DCM, advanced functional (NYHA III-IV) and severe left ventricular dysfunction (LVEF < or = 25%) underwent a test dosage with metoprolol (5 mg b.i.d.). Five patients (14%) did not tolerate the drug; 30 were chronically treated with metoprolol (mean dosage 127 +/- mg/die). No differences in baseline characteristics were observed between tolerant and not tolerant patients, except for the E-deceleration time (103 +/- 42 ms vs 84 +/- 17 ms; p<0.05). Seven alive patients did not reach a minimum follow up of 18 months. Nineteen patients (54.3%) had a follow up of at least 18 months. They were classified as ¿improved¿ (11 pts; and ¿not improved¿ (8 pts; 42%) on the basis of a score, which included left ventricular ejection fraction (> or = 0.10), left ventricular end diastolic diameter (> or = 10%), regression of restrictive filling pattern, NYHA functional class (> or = 1), cardio-thoracic ratio (> or = 10%) and exercise time (> or = 2 min). No differences were observed at baseline between ¿improved¿ and ¿not improved¿ patients, with exception for a history of slight hypertension (p<0.01), congestive heart failure score (p<0.04) and right ventricular function (p<0.05).
Results: An overall improvement of all the main clinical-instrumental parameters were observed in the 19 long term treated patients. At the end of follow up 16 long term treated patients were in NYHA class > or = 2 and in 9 LVEF was > or = 40%. During follow up, among the 30 patients who tolerated the drug, 1 pt died suddenly after 12 months of betablocker therapy and 5 pts were transplanted. No major events occurred among ¿improved¿ patients, after 24 +/- 6 months of follow-up. The actuarial survival curve of our study population shows that survival at 1, 2, 3 and 4 years was respectively 87%, 75%, 67% and 66%. These results confirm previous trials evidence that a progressively increasing dose of beta-blockers confers functional benefit in DCM with severe heart failure.