Reduced mitral regurgitation in heart failure patients submitted to cardiac resynchronization therapy: a short-term prospective study.

BACKGROUND

The intraventricular delay is a determinant of functional mitral regurgitation (MR). MR contributes to the progression of congestive heart failure (CHF) and represents a marker of a worse outcome. The aim of this study was to test the hypothesis that cardiac resynchronization therapy (CRT) significantly reduces MR in CHF patients with ventricular conduction defects.

METHODS

We studied 45 consecutive patients (37 males, 8 females, mean age 72 +/- 9 years) in NYHA class III-IV, with left ventricular ejection fraction < 35%, QRS duration > 150 ms with left bundle branch block or already paced in the right ventricle, and MR score > or = 1. We compared the QRS duration and the basal peak of the V-wave before and 15 min after CRT. Before implantation and 1 week after we measured ejection fraction, systolic mitral annulus diameter, MR area, left atrial area, MR area expressed as the percentage of the left atrial area (%MR area), and MR score (range 1-4).

RESULTS

The QRS duration before and after CRT was 195 +/- 30 and 156 +/- 17 ms (p < 0.01) respectively. Significant decreases were observed in the systolic mitral annulus diameter (-7.9%, p < 0.001), MR area (-38%, p < 0.001), MR score (-33.4%, p < 0.001), left atrial area (-5.9%, p < 0.05), and %MR area (-36.2%, p < 0.001). The peak of the V-wave decreased by 33%. The ejection fraction increased by 46% (p < 0.001).

CONCLUSIONS

CRT significantly reduces MR and improves cardiac function in patients with CHF and ventricular conduction defects. The combination of the degree of MR and a low ejection fraction and large QRS duration may contribute to a more reliable patient selection for CRT.