Three-dimensional echocardiography-based analysis of right ventricular shape in pulmonary arterial hypertension

Abstract

Aims: Right ventricular (RV) remodelling involves changes in size, function, and shape. Although three-dimensional echocardiography (3DE) allows imaging of RV morphology, regional RV shape analysis has not been evaluated using 3DE. We developed a technique to quantify RV shape and tested its ability to differentiate normal from pressure overloaded right ventricles. Methods Transthoracic 3DE RV images were acquired in 54 subjects, including 39 patients with pulmonary artery hypertension (PAH) and 15 normal controls (NL). 3D RV surfaces were reconstructed (TomTec) at end-diastole and end-systole (ED, ES) and processed using custom software to calculate mean curvature of the inflow and outflow tracts (RVIT, RVOT), apex, and body (both divided into free wall and septum).

Methods and results: Septal segments (apical and body) in NLs were characterized by concavity (curvature < 0) in ED and slight convexity (curvature > 0) in ES. In PAH, however, the septum remained convex, bulging into the left ventricle throughout the cardiac cycle. In keeping with the 'bellows-like' action of RV contraction in the NL group, the body free wall transitioned from a convex surface at ED to a more flattened surface at ES, while the apex free wall progressed from a less convex surface at ED to a more convex surface at ES. In contrast, in PAH, both RV free-wall segments (apical and body) remained equally convex throughout the cardiac cycle.

Conclusions: Curvature analysis using 3D echocardiography allows quantitative evaluation of RV remodelling, which could be used to track differential changes in regional RV shape, as a way to assess disease progression or regression.

Keywords: curvature; pulmonary hypertension; remodelling; right ventricle.