Pulmonary arterial hypertension: A two-dimensional echocardiographic approach from screening to prognosis

An elevated pulmonary artery pressure (PAP) from any cause is associated with increased mortality, especially in cases of primary pulmonary arterial hypertension (PAH). One of the many reasons behind a bad prognosis is the inherent difficulty in assessing right ventricular (RV) function with reproducible methods. Intensive research involving the left heart has made it relatively easy to assess left ventricular (LV) systolic and diastolic functions in many centers around the world. As for the RV, however, although increasing attention has been focused on the right-sided heart in the recent times, neither global longitudinal strain nor right ventricular ejection fraction (RVEF) has been studied well in relation to the outcome (unlike in the LV). Another issue is that the right heart functions in a circuitry involving the right atrium (RA), the RV, and the pulmonary artery. Hence, all 3 components of this circuit have important roles in unison to eject a cardiac output equivalent to the left-sided heart. In this review, we sought to discuss the ways to quantity the function of the entire circuit using both standard and advanced echocardiographic imaging modalities. As primary PAH is the classic form of pathology causing the RV to face an afterload with which it is not destined to cope, this review is mainly based on the assessment of the right heart as a circuit in idiopathic primary PAH.