[Effect of physical exercise on the function of prosthetic heart valves--evaluation by doppler echocardiography]

Although considerable data exist regarding the function of prosthetic heart valves (PHV) at rest, few data exist regarding the response to exercise. Thus, we studied by Doppler echocardiography 81 asymptomatic patients with PHV (46 mitral, 45 aortic) of varying type and 20 normal persons before and after symptom limited upright bicycle exercise. Rest and exercise hemodynamics (blood velocity, gradients, heart rate, stroke volume and cardiac output) was examined. In patients with mitral PHV maximal (Gmax) and mean (Gmean) gradients increased from 9.9 to 17.8 mmHg and from 4.4 to 7.8 mmHg (both p < 0.001), respectively. In patients with aortic PHV Gmax and Gmean increased from 27 to 42 mmHg and from 16 to 24 mmHg (both p < 0.001), respectively. Linear regression analysis demonstrated a relationship between the % change in gradient with exercise nd % change in stroke volume and cardiac output. Importantly, the largest gradient produced by exercise is related and predicted by the rest gradient. In comparison with normal valves, maximal and mean blood velocity were significantly (p < 0.001) greater across PHV, but % change in velocity with exercise did no differ significantly between prosthetic and normal valves. In conclusion, exercise Doppler echocardiography provides a good method to assess PHV function.