Right ventricular work increase during strenuous exercise is greater than for the left ventricle: results from a real-time exercise cardiac magnetic resonance study

Abstract

Background: Exercise-induced augmentation of cardiac output demands an increase in ventricular work. We sought to quantify the relative increases of right and left ventricular work using gold standard pressure and volume measures during strenuous exercise. Methods: 10 male athletes (35±9 years, VO2=55±9ml/min/kg) and 10 male non-athletes (37±10 years, VO2=39±8ml/min/kg) underwent real-time cardiac magnetic resonance (CMR) imaging at rest and during 3 stages of increasing exercise to maximal exertion. After compensation for respiratory motion, left and right ventricular stroke volumes (LVSV and RVSV) were quantified from endocardial traces on bi-plane cine stacks (12-18 x8mm slices) using in-house developed software. Simultaneous mean pulmonary and radial artery pressures (mPAP and mBP) were measured invasively, and ventricular work was calculated as SV x mean pressure. Results: Cardiac output was greater in athletes than non-athletes at maximal exercise (25.8±4.4 vs. 20.6±4.0 L/min, p=0.014), as was mPAP (32±9 vs. 24±4 mmHg, p=0.021) and mBP (129±14 vs. 117±10, p=0.014). During exercise, the proportional increase in RV work was far greater than for LV work. This was true for athletes, non-athletes and in the combined cohort (figure). ![Figure][1] Greater RV than LV work during exercise Conclusion: As compared with the LV, strenuous exercise imposes a considerably greater workload on the RV. During exercise, the RV and pulmonary circulation may be a far more important determinant of cardiac performance than has previously been realized. [1]: pending:yes