Background: The aim of this study was to evaluate the effects of carvedilol therapy on left atrial (LA) function in patients with heart failure from nonischemic dilated cardiomyopathy.
Methods and results: Thirty-five patients (42.4 +/- 13.5 years) in New York Heart Association functional Class II-III have been studied. A low-dose (20 mug.kg.min) echo-dobutamine study has been performed, before and 12 months after carvedilol therapy. Twelve months after carvedilol therapy, a significant improvement in LA and left ventricular (LV) function was observed. To investigate the beneficial effects of carvedilol, patients were separated into 2 groups according to the presence of pretreatment LV contractile reserve (CR) (ejection fraction [EF] increases >20% after dobutamine infusion): Group A consisted of 18 patients with CR and Group B of 17 patients without CR. After carvedilol treatment, both the LV and LA function were improved in group A (P < .01 for all). However, in group B, only the LA function was significantly improved (left atrial ejection volume increased from 10.4 +/- 3 mL to 15.4 +/- 6.7, P < .01 and LA ejection fraction from 19.6 +/- 45.3% to 29.4 +/- 12.5%, P < .01), whereas the LV contractile reserve has partially reappeared (EF from 29.9 +/- 4.5% at baseline, increased after dobutamine infusion to 35.8 +/- 6.8%, P < .0001).
Conclusions: In conclusion, carvedilol therapy is associated with improvement in both LV and LA functions in nonischemic dilated cardiomyopathy. In a subgroup of these patients, carvedilol may act differently on LV and LA function.