Assessment of left ventricular contractility during supine exercise in children with left-sided cardiac disease.

Exercise stresses the cardiovascular system and causes it to use its reserve capacities. Exercise assessment may unmask abnormalities of left ventricular contractility not suspected from or detected by resting measurements. We have studied the following indices of left ventricular contractility in 21 children with left-sided congenital heart disease: maximum dP/dt, Vmax, Vpm, Vcf, and peak meridional wall stress. Studies were performed in the supine posture at rest, and at 25 per cent, and 50 per cent of a predetermined maximal upright workload on a bicycle ergometer. The method of measurement used simultaneous high fidelity catheter pressure tracings and M-mode echocardiography. There were no complications and the technique appeared practical and safe. The measurements of contractility differentiated patients with left ventricular volume or pressure overload from each other and from patients with either volume plus pressure overload, or myocardial dysfunction. These measurements can be used to measure the functional reserve capacity of patients with left-sided lesions, and may be useful in follow-up studies, especially before and after operation.