2.4 Echocardiography
All echocardiographic procedures were performed using an echocardiography platform equipped with a 2.5 MHz phased-array transducer (Vivid 3, GE Healthcare, Piscataway, NJ). Per heart failure clinic protocol, all examinations were performed by the members of advanced heart failure team that are competent in echocardiographic procedures. Stored images and 3-beat loops that were acquired from parasternal long-axis, parasternal short-axis and apical views were analyzed to repeat all measurements and calculations. Right ventricular PDI was calculated using the following equation:
Eq 1. PASP / RVMD2
where RVMD is right ventricular minor diameter as measured immediately above the tricuspid valve at end-diastole and PASP is the systolic pulmonary artery pressure (Figure 1). Echocardiographic PASP was calculated according to relevant guidelines (7). Right ventricular contraction pressure index was calculated as defined before (8). For the purposes of the present study, images were used from the echocardiographic examination that immediately preceded left ventricular assist device implantation, and this is done two days before planned implantation date. None of the patients were on inotropes or vasoactive drugs when echocardiographic examination was performed. All measurements and calculations were performed according to relevant guidelines.