Effects of Left Heart Loading on the Right Ventricular-Pulmonary Arterial Circulatory Unit

The right ventricle (RV) and pulmonary vasculature (PV) form a circulatory unit which is sensitive to downstream left atrial (LA) function. Exercise may significantly stress the RV-PV circulatory unit, even in healthy individuals. This thesis aimed to characterize normal hemodynamic mechanisms through which RV-PV circulatory unit function is influenced in-series by LA function during exercise. Healthy males and females >45 years old were recruited. Right heart catheterization was used to measure cardiac output, RV and PV pressures, and pulmonary artery wedge pressure (PAWP). Echocardiography was used to measure LA volumes. Participants were studied at rest and during 7-10 minute stages of Light- and Moderate-intensity cycle-ergometry. Project one described the PAWP and PV pressure response as exercise was initiated, sustained, and escalated in intensity. PAWP was 11 ± 3 mmHg at rest, increased to 22 ± 5 mmHg at early-Light exercise (pPh.D