Page 192 - Assessing right ventricular function and the pulmonary circulation in pulmonary hypertension Onno Anthonius Spruijt

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Characterization of myocardium using native T1-mapping
As described in chapter 7, native-T1 values of the right ventricular free wall could only be accurately assessed in small parts of the myocardium [4]. Presence of pericardial fat at the border of the frequently irregularly shaped right ventricular free wall can make it difficult to quantify native T1- values of the total right ventricular free wall. A voxel at the border of the right ventricular free wall can contain a partial volume of pericardial fat. Due to the fact that fat has a high signal intensity and very short T1-value, such a partial volume effect can already dominate the T1-value of the total voxel. This phenomenon can bias the quantification of native T1-values of the right ventricular free wall. By inserting a fat saturation pulse in the T1 mapping pulse sequence the effects of fat can be eliminated [5]. Future studies should test whether insertion of the fat saturation pulse can improve the quantification of the right ventricular free wall using T1-mapping.
Effect of exercise training on the right ventricle in patients with pulmonary hypertension
Several studies showed that exercise training progams can improve exercise capacity and quality of life in patients with pulmonary hypertension [6-11]. The mechanisms for the improvement in exercise capacity are yet incompletely understood. It has been shown that exercise training programs can increase capillarization of muscles [9] and can improve hemodynamics at rest and during exercise [6].
Handoko et al. evaluated the effects of exercise training on right ventricular function in a pulmonary hypertension rat model and showed that TAPSE decreased in rats with progressive pulmonary hypertension while an increased TAPSE was seen in rats with stable pulmonary hypertension [12]. In the same study exercise training did not affect right ventricular contractility at rest.
Currently, studies on the effects of exercise training on the right ventricle in patients with pulmonary hypertension are lacking. Randomized controlled trails are needed that investigate the effects of exercise training on the function of the right ventricle, not only at rest but also on the right ventricular contractile reserve. Ideally, assessment of right ventricular contractile reserve in such studies should combine pressure-volume loop analysis to assess the effects of exercise training on the load-independent contractile reserve (Chapter 10) and cardiac magnetic resonance imaging to assess the effects on the load-dependent contractile reserve [13-18], both measured during maximal incremental exercise protocols.