Biventricular response to supine physical exercise in young adults assessed with ultrafast magnetic resonance imaging

Simultaneous assessment of left ventricular (LV) and right ventricular (RV) response to exercise is limited with the current imaging modalities, Magne tic resonance imaging (MRI) techniques are now under development that allow near reel-time evaluation of biventricular function under physical stress. This approach may open new avenues to study heart function in response to exercise in health and disease. The aim of this study was to evaluate biven tricular response to supine physical exercise using ultrafast MRI, Biventri cular volumes and function were examined in 16 healthy volunteers (mean age 18 +/- 2 years) using an ultrafast MRI sequence at rest and during an exer cise protocol on a MRI compatible bicycle ergometer. Exercise level was ind ividualized at the workload corresponding to 60% of the maximal oxygen upta ke. All subjects completed the exercise MRI examination, allowing functiona l evaluation. Stroke volume of both ventricles increased from rest to exerc ise (left ventricle, 89 +/- 14 ml vs 102 +/- 19 ml, p <0.05; right ventricl e, 88 +/- 14 ml vs 101 +/-/ 16 ml, p <0.05). Ejection fraction also increas ed in both ventricles from rest to exercise (left ventricle, 63 +/- 6% vs 7 4 +/- 6%, p <0.05; right ventricle, 61 +/- 6% vs 70 +/- 6%, p <0.05). End-s ystolic volume of the left and right ventricles decreased from rest to exer cise (left ventricle, -33 +/- 12%, p <0.05; right ventricle, -25 +/- 12%, p <0.05), whereas LV and RV end-diastolic volumes remained unchanged. The re sults fit well with current concepts of cardiac physiology, and therefore w e conclude that ergometer-induced exercise MRI is a valid approach to asses s physiologic changes in LV and RV function simultaneously. (C) 2001 by Exc erpta Medico, Inc.