Contribution of exercise-induced mitral regurgitation to exercise stroke volume and exercise capacity in patients with left ventricular systolic dysfunction.
BACKGROUND
Functional mitral regurgitation (MR) is common in patients with heart failure and left ventricular (LV) dysfunction, and its severity may vary over time, depending primarily on the loading conditions. Because dynamic changes in the severity of functional MR may affect forward stroke volume, we hypothesized that exercise-induced changes in MR severity influence the stroke volume response of patients with LV dysfunction to exercise, and hence their exercise capacity.


RESULTS
Heart failure patients (n=25; mean age 53+/-12 years) with LV dysfunction underwent dynamic bicycle exercise at steady-state levels of 30%, 60%, and 90% of predetermined peak VO2. During each exercise level, right heart pressures, cardiac output, VO2, and MR severity were measured simultaneously. During exercise, MR severity, as evaluated by the ratio of MR jet over left atrium area, increased from 15+/-8% to 33+/-15%. Peak VO2, exercise-induced changes in stroke volume, and those in capillary wedge pressure correlated with the changes in MR (r=-0.55, -0.87, and 0.62, respectively, P<0.01). The changes in MR severity also correlated with those in end-diastolic (r=-0.75, P<0.01) and end-systolic (r=-0.72, P<0.01) sphericity indexes and those in the coaptation distance (r=0.86, P<0.01).


CONCLUSIONS
Our data indicate that in patients with LV dysfunction, exercise-induced changes in MR severity limit the stroke volume adaptation during exercise and therefore contribute to limitation of exercise capacity.
Lapu-Bula
Rigobert
R
Division of Cardiology, Université Catholique de Louvain, Brussels, Belgium.
Robert
Annie
A
Van Craeynest
David
D
D'Hondt
Anne-Marie
AM
Gerber
Bernhard L
BL
Pasquet
Agnès
A
Melin
Jacques A
JA
De Kock
Martine
M
Vanoverschelde
Jean-Louis
JL
D000328:Adult; D000368:Aged; D015150:Echocardiography, Doppler; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D015203:Reproducibility of Results; D013318:Stroke Volume; D013599:Systole; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000503:physiopathology*