Determinants of Subsequent Late Postoperative Left Ventricular Function and Reversal of Ventricular Dilatation after Mitral Valve Replacement for Chronic Mitral Regurgitation.

We studied 16 patients with chronic mitral regurgitation by echocardiography before, and at 3 weeks, at 6-8 months and at 1-9 years after mitral valve replacement (MVR) to investigate serial changes in left ventricular (LV) function and reversal of ventricular dilatation. All patients at an average of 2.6 years after, and 8 patients before MVR were also studied by echocardiography and, except for 3 patients by measuring plasma catecholamines from the right atrium during bicycle exercise. Before operation, all patients were divided into group A (n = 12) with end-systolic dimension (ESD) < 4 cm and systolic blood pressure (SBP)/ESD > 3, and group B (n = 4) with ESD > 4 cm and SBP/ESD < 3. Maximum reduction in end-diastolic dimension (EDD) occurred at 3 weeks in all patients after MVR (from 60.5 +/- 3.7 to 49.0 +/- 4.5 mm, p < 0.05). ESD was reduced significantly (p < 0.5) only in group A. LV function was normal in group A, but it was depressed in group B at early and late periods after MVR. The slopes of the relationship between the mean velocity of circumferential fiber shortening (Vcf) and plasma norepinephrine (NE) during exercise in all patients in group B decreased along with the depression in LV function. After operation, all patients in group A reached New York Heart Association (NYHA) functional class I, while patients in group B were in NYHA class II. It is concluded that the surgical outcome after MVR for chronic MR will be better if preoperative ESD < 4 cm and SBP/ESD > 3. The relationship between mean Vcf and plasma NE during exercise seemed to be a useful index to evaluate the inotropic reserve of the LV.