The Journal of Thoracic and Cardiovascular Surgery, Vol 82, 127-135, Copyright © 1981 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Effect of valve replacement for chronic mitral insufficiency on left ventricular function during rest and exercise
CA Peter, EH Austin and RH Jones
In this study we measured left ventricular function at rest and during
exercise before and after operation in 18 patients who underwent mitral
valve replacement (MVR) for chronic mitral insufficiency. First-transit
radionuclide angiocardiography was employed a week before operation and 5
to 19 months after operation to calculate left ventricular ejection
fraction, volumes, output, filling, and emptying rates. Preoperatively,
left ventricular ejection fraction increased from 0.56 +/- 0.09 (mean +/-
S.D.) at rest to 0.62 +/- 0.11 during exercise, and this response was not
altered for the group after operation. After valve replacement, there was
no consistent change in end-diastolic volume (EDV), and cardiac function
was not related to an alteration in filling rates of the left ventricle.
After operation, the patient group achieved a maximal ventricular filling
rate during exercise comparable to that measured before operation. In
addition, postoperative maximal filling rates did not correlate with
prosthetic valve size. These data suggest that the hemodynamic changes
elicited by MVR for chronic insufficiency are primarily related to the
elimination of the regurgitant flow but no attributable to alterations of
the myocardium. It is suggested that limitation in exercise performance
after operation may be primarily related to the functional status of the
myocardium prior to operation.
