Evaluation of left ventricular ejection fraction as a measure of pump performance in patients with chronic mitral regurgitation

Abstract

Left ventricular (LV) ejection fraction may not adequately detect a reduction in LV systolic performance resulting from chronic mitral regurgitation (MR), due to ventricular unloading into the low-impedance left atrium. To determine whether LV ejection fraction sufficiently gauges myocardial function in MR, nine patients were studied using micromanometer- measured LV pressures and biplane cineventriculography before and 1 year after mitral valve surgery. Six control patients were also studied. LV ejection fraction was normal in MR patients, despite an increase in LV end- systolic volume index. LV endsystolic pressure-volume and stress-volume ratios in MR patients were lower than in controls (P < 0.05 and P < 0.01), suggesting that LV systolic performance fell. One year after mitral valve surgery, LV ejection fraction decreased (P < 0.05) even though LV end- systolic volume index (P < 0.05), pressure-volume (P < 0.05), and stress- volume ratios (P < 0.01) all improved. Thus, LV ejection fraction inadequately reflected LV systolic function in MR patients before and after mitral valve surgery. (C) 2000 Wiley-Liss, Inc.