Cardiovascular responses to exercise in children and adolescents with myocardial dysfunction

Objectives The objective of this study was to understand the expected hemod ynamic responses to exercise in children and adolescents with myocardial dy sfunction. Methods and Results with the use of Doppler and M-mode echocardiography, ca rdiovascular changes during maximal semisupine exercise in 11 patients (7 t o 17 years old) with myocardial dysfunction were compared with those of a h ealthy control group (n = 11). Endurance fitness and mean values for maxima l cardiac index, stroke index, heart rate, peak aortic velocity, and left v entricular shortening fraction were all significantly lower in the patients (P < .05). Stroke volume rose at the onset of exercise in both groups; whe reas values were subsequently stable in the control subjects, stroke volume declined at high-intensity exercise in the patients. Conclusions These findings imply that augmented myocardial contractility is necessary to sustain stroke volume during exercise. Moreover, the results suggest that pattern of stroke volume response to exercise may serve as a u seful marker of myocardial function in children with heart disease.