Hemodynamic changes during dynamic exercise in patients after mitral valve replacement for chronic mitral regurgitation.

To evaluate hemodynamic changes during dynamic exercise, we investigated 13 patients after mitral valve replacement (MVR) for chronic mitral regurgitation (MR) and 5 control subjects by right heart catheterisation during supine bicycle exercise. According to the sizes of the St. Jude Medical (SJM) prosthesis during MVR, patients were divided into group A (n = 8) with SJM 31mm and group B (n = 5) with SJM 29mm. Significant rise in cardiac index (CI) was noted during exercise in both groups A and B (from 3.3 +/- 0.8 to 5.5 +/- 0.9 l/min/m2, p < 0.01 and from 3.0 +/- 0.6 to 5.6 +/- 0.6 l/min/m2, p < 0.01 respectively) and also in control subjects (from 3.4 +/- 0.7 to 6.2 +/- 0.6 l/min/m2, p < 0.01). Mean pulmonary artery and pulmonary capillary wedge pressure were significantly higher during exercise in patients of both groups A and B than control subjects (p < 0.05 and p < 0.01 respectively). Total pulmonary vascular resistance was significantly higher during exercise in both groups A and B than control subjects (p < 0.05 and p < 0.01 respectively). No difference in hemodynamics were noted between the patients of group A and B during exercise. It is concluded that response of CI to exercise in patients after MVR for chronic MR was adequate in comparison to control subjects irrespective of two different valve sizes.