Effects of long-term xamoterol in idiopathic dilated cardiomyopathy.

: In prospective study, the beta 1-partial agonist xamoterol (200 mg daily) was given to 26 patients with idiopathic dilated cardiomyopathy (DCM) in addition to conventional therapy with digitalis, diuretics and vasodilators. The patients were followed for 35 +/- 15 months (6-53 months). Cardiothoracic ratio (CTR), left ventricular end-diastolic dimension (LVDD) and exercise heart rate decreased, and exercise duration, fractional shortening (FS) and ejection fraction (EF) increased after xamoterol therapy. Twenty-one patients survived and one patient dropped out at 7 months. Twelve of the 20 patients improved their NYHA functional class. Blood norepinephrine concentration (NE), LVDD, FS, EF and pulmonary capillary wedge pressure (PCWP) after xamoterol were significantly better in survivors than in non-survivors. Survival rate at 3 years was 83%. The results suggest that adjunctive xamoterol therapy in DCM has a beneficial effect on hemodynamics and symptoms. Prognosis will be satisfactory if improvement in parameters such as NE, LVDD, FS, EF and PCWP is seen during xamoterol therapy.