Changes in mitral regurgitation and left ventricular geometry during exercise affect exercise capacity in patients with systolic heart failure

Abstract

Aims: Exercise may dramatically change the extent of functional mitral regurgitation (MR) and left ventricular (LV) geometry in patients with chronic heart failure (CHF). We hypothesized that dynamic changes in MR and LV geometry would affect exercise capacity.Methods and resultsThis study included 30 CHF patients with functional MR who underwent symptom-limited bicycle exercise stress echocardiography and cardiopulmonary exercise testing for quantitative assessment of MR (effective regurgitant orifice; ERO), and pulmonary artery systolic pressure (PASP). LV sphericity index was obtained from real-time three-dimensional echocardiograms. The patients were stratified into exercised-induced MR (EMR; n 10, an increase in ERO by <13 mm2) or non-EMR (NEMR; n 20, an increase in ERO by <13 mm2) group. At rest, no differences in LV volume and function, ERO, and PASP were found between the two groups. At peak exercise, PASP and sphericity index were significantly greater (all P < 0.01) in the EMR group. The EMR group revealed lower peak oxygen uptake (peak VO2; P 0.018) and greater minute ventilation/carbon dioxide production slope (VE/VCO2 slope; P 0.042) than the NEMR group. Peak VO2 negatively correlated with changes in ERO (r -0.628) and LV sphericity index (r -0.437); meanwhile, VE/VCO2 slope was well correlated with these changes (r 0.414 and 0.364, respectively). A multivariate analysis identified that the change in ERO was the strongest predictor of peak VO2 (P 0.001). ConclusionDynamic changes in MR and LV geometry contributed to the limitation of exercise capacity in patients with CHF. © The Author 2010.