Beta-blockade therapy in chronic heart failure: diastolic function and mitral regurgitation improvement by carvedilol.

BACKGROUND

In patients with chronic heart failure, the use of carvedilol therapy induces clinical and hemodynamic improvement. However, although the benefits of this beta-blocker have been established in patients with chronic heart failure, the mechanisms underlying them and the changes in left ventricular systolic function, diastolic function, and mitral regurgitation during long-term therapy remain unclear.

OBJECTIVE

To identify the clinical and functional effects of carvedilol, focusing on diastolic function and mitral regurgitation variations.

METHODS

Forty-five consecutive patients with chronic heart failure (ejection fraction 24% +/- 7%), 17 with dilated ischemic and 28 with nonischemic cardiomyopathy, were treated with carvedilol (mean dose 44 +/- 30 mg) and matched for clinical (New York Heart Association functional class and heart failure duration) and hemodynamic (cardiac index and pulmonary wedge pressure) characteristics to a control group. Clinical and echocardiographic variables were measured in the 2 groups at baseline and after 6 months and the results compared.

RESULTS

After 6 months of treatment with carvedilol, left ventricular ejection fraction had increased from 24% +/- 7% to 29% +/- 9% (P <.0001); this change was caused by a reduction in end-systolic volume index (106 +/- 41 vs 93 +/- 37 mL/m(2); P <. 0001). Deceleration time of early diastolic filling increased (134 +/- 74 vs 196 +/- 63 ms; P <.0001). Seventeen of the 27 patients with demonstrated improvement of left ventricular diastolic filling moved from having a restrictive filling pattern to having a normal or pseudonormal left ventricular filling pattern. In the control group, no significant changes in deceleration time of early diastolic filling were found (139 +/- 74 vs 132 +/- 45 ms; P = not significant). The effective regurgitant orifice area decreased significantly in the carvedilol group but not in the control group. These changes were associated with a significant reduction of the mitral regurgitant stroke volume in the carvedilol group (50 +/- 25 vs 16 +/- 13 mL; P <.0001) but not in the control group (57 +/- 29 vs 47 +/- 24 mL; P = not significant). These changes of mitral regurgitation were closely associated with significant improvement of forward aortic stroke volume (r = -.57, P <.0001). These findings were not observed in patients in the control group.

CONCLUSIONS

The results of this study show that long-term carvedilol therapy in patients with chronic heart failure was able to prevent or partially reverse progressive left ventricular dilatation. The effects on left ventricular remodeling were associated with a concomitant recovery of diastolic reserve and a decrease of mitral regurgitation, which have been demonstrated to be powerful prognostic predictors in such patients. Overall these findings provide important insights into the pathophysiologic mechanisms by which carvedilol improves the clinical course of patients with chronic heart failure.