Geert Kleinnibbelink

Chapter 10 214 direct link between exercise-based CR and mortality. This may suggest that the additional “relative” load faced by the RV during exercise could have a positive effect on its function. Furthermore, this stresses the urgency of appropriately powered randomized controlled trials to investigate the causal effect of exercise as medicine for patients with PH. 10.5 – Conclusion and future perspectives The present thesis provides novel insights into acute and chronic effects of load challenges on the RV in healthy individuals, elite athletes and patient with PH. The most important findings are; First, cardiac function is traditionally measured under resting conditions whilst in supine position. We showed that cardiac function measured during exercise (i.e. stress echocardiography) yields additional information compared to resting conditions only. Namely, EICF after short duration high-intensity exercise is only present when evaluated with stress echocardiography. This observation fits with some recent observations of other athletes’ heart studies, where exercise-induced responses show added (clinical) value compared to evaluation at rest alone. Therefore, we recommend the use of stress echocardiography in research, and to explore its potential in the diagnosis or prognosis of cardiovascular diseases in clinical settings. Second, acute cardiovascular responses to exercise and altered haemodynamics are related to subsequent chronic responses (within each side of the ventricle). This highlights the need to measure and evaluate both ventricles to understand the entire heart. Third, following the current body of evidence, including those presented in this thesis, we conclude that the RV does not simply mirror the LV in both acute and chronic responses to exercise. EICF may vary between the RV and LV. Furthermore, integration of our findings with existing literature, we hypothesize the presence of a distinct pathway of structural remodelling for the RV and LV related to the level of training of an individual. Fourth, evolving technology in echocardiography has led to the development of novel strain-area loops, which provide a comprehensive overview of cardiac function. In this thesis, we showed that the strain-area loop detects changes in RV function following interventions to alter haemodynamics. This novel technique, therefore, may serve as a