Mechanisms and clinical implications of asymptomatic mitral regurgitation in patients with left ventricular dysfunction.

BACKGROUND Functional mitral regurgitation (MR) is common in patients with chronic heart failure (CHF). During exercise, hemodynamic changes such as elevation of blood pressure and an increase in the left ventricular end-diastolic dimension may increase MR. Severity of CHF is reflected by exercise tolerance and, therefore, MR during exercise is supposed to indicate the severity of heart failure. The degree of MR increase and left ventricle (LV) shape was quantified during exercise in CHF patients and were compared with exercise tolerance. METHODS AND RESULTS Twenty patients with CHF (mean age: 63 years) underwent dynamic cycle exercise at steady-state levels of 80% and 150% of the anaerobic threshold (AT). The MR jet area and left atrial (LA) area were measured during exercise and the ratio of MR/LA was calculated. The LV shape was assessed by calculating the ratio of the major to the minor axis. The MR/LA ratio increased during exercise (rest: 16.9+/-6.5%, 80% AT: 21.9+/-8.9%, 150% AT: 30.9+/-11.2%; p<0.01) and the LV shape became more spherical (rest: 1.34+/-0.10, 80% AT: 1.31+/-0.10, 150% AT: 1.23+/-0.11; p<0.05). There was a negative correlation between MR/LA ratio and the ratio of the major to the minor axis (-0.722, r<0.01). CONCLUSIONS MR during exercise increases as the severity of CHF increases. Functional MR is correlated with the shape of the LV.