Geert Kleinnibbelink

RV Function after Preload Manipulation 7 167 The non-invasive nature of the RV strain-area loop and its potential in assessing RV function and mechanics may contribute in evaluating and adjusting pharmacological therapy in pulmonary arterial hypertension patients, whereas right heart catherization is not ideal given its expensive, time-consuming and invasive nature. Further studies are warranted to better understand our observations, and to explore its potential (clinical) value. Some caution must be taken when interpreting our results. The small sample size and limitations in deriving RV-area, further studies are warranted to explore and validate assessment of RV strain-area loops. Furthermore, this study is limited to patients with suspicion of PAH, therefore caution is needed in extrapolating findings to other populations. Importantly, also changes in pulmonary vascular resistance (because of preload manipulation) may contribute to our observations. For example, a decreased RV afterload (or pulmonary vascular resistance) is associated with an increase in RV longitudinal strain and vice versa . Measurement of pulmonary vascular resistance was not performed in this study. In conclusion, this explorative study shows that a reduction in preload leads to a larger contribution of longitudinal myocardial strain to facilitate systolic volume ejection and vice versa . Most importantly, following comparison of the invasive RV strain-area and pressure- area loop, we found a strong correlation in the assessment of cardiac contractility. This suggests that both loops provide similar information, at least related to identification of loop shifts and cardiac contractility.