Tissue Doppler assessment of ventricular function during cycling in 7- to 12-yr-old boys

Purpose: Studies utilizing submaximal supine exercise have indicated that tissue Doppler imaging (TDI) may be useful for assessing ventricular systolic and diastolic function during exercise and might offer a means of detecting patients with early myocardial dysfunction. This investigation of 14 healthy boys ages 7-12 yr was designed to assess measures of inotropic and lusitropic function during maximal upright cycle exercise. Methods: Color tissue Doppler imaging (S and E′ waves, indicative of systolic and diastolic function, respectively), stroke volume, and mitral peak inflow velocity (E wave) were recorded at rest and during a progressive upright cycle test to exhaustion. Results: Values of TDI-S and TDI-E′ were obtained at exhaustive exercise in all but one subject. Mean value of S rose 163% (3.8 ± 1.2 to 10.0 ± 2.5 cm·s^-1), and average E′ increased by 92% (-6.3 ± 2.2 to -12.1 ± 3.2 cm·s^-1). No significant changes were observed in the ratio of E′ to mitral peak flow velocity (E), suggesting that left ventricular end-diastolic pressure remained stable. Conclusions: These data indicate that measurement of TDI is feasible during maximal upright exercise, and velocities obtained may provide insights into ventricular systolic and diastolic functional capacity.