Exercise Doppler echocardiography in patients with mitral prosthetic valves.

Submaximal supine exercise was done by 17 patients with mitral prostheses. Eleven had Björk-Shiley (BS) and six had Starr-Edwards (SE) valves. In 15 patients with normally functioning prostheses, valve area at rest was 2.4 +/- 0.25 cm2 in the BS patients and 1.8 +/- 0.35 cm2 in the SE group (p less than 0.01). In the SE group, peak and mean gradients increased from 8 +/- 1 and 5 +/- 1 mm Hg, respectively, at rest to 22 +/- 5 and 13 +/- 4 mm Hg at peak exercise (mean +/- 1 SD). In the BS group, peak and mean gradients increased from 10 +/- 3 and 5 +/- 2 mm Hg, respectively, at rest to 16 +/- 3 and 10 +/- 3 mm Hg at peak exercise. Peak pressure gradient at peak exercise and the increase in peak gradient with exercise (exercise-resting gradient) were significantly higher in the SE group (p less than 0.05). By plotting the heart rate versus the transmitral gradient during the recovery period, a heart rate-gradient curve was obtained for each type of prosthesis. Doppler echocardiography with moderate supine exercise can be performed in most patients with mechanical prosthesis. Hemodynamic properties (the occlusive character of the SE prosthesis) were brought out by exercise. Doppler echocardiographic measurements during exercise can provide important information, particularly in patients with borderline measurements at rest.