Right Ventricular-Pulmonary Arterial Coupling and Outcomes in Heart Failure and Valvular Heart Disease

Right ventricular (RV) intrinsic contractility and its response to afterload defined as pulmonary arterial (PA) elastance, is referred to as RV-PA coupling. RV contractility can be estimated by end-systolic elastance (E-es), the slope of the line through the end-systolic pressure-volume point. Afterload or arterial elastance (Ea) can be estimated from RV end-systolic pressure divided by stroke volume. A ratio of E-es/Ea of 1.5-2 reflects an optimal balance between RV mechanical work and oxygen consumption. In left-sided heart failure (HF), chronically elevated left-sided filling pressures result in secondary pulmonary hypertension (PH). In the early stages of PH, RV contractility and load are adequately coupled through mainly RV hypertrophy, but as the disease advances, ventricular dilatation and failure takes place. The degree of RV coupling (or lack thereof) to the pulmonary circulation can be measured either invasively or through noninvasive imaging. Several non-invasive surrogate indexes for E-es and Ea have been associated with decreased functional status and mortality in patients with HF and valvular disease.