Longitudinal strain of systemic right ventricle correlates with exercise capacity in adult with transposition of the great arteries after atrial switch

Abstract

Background: Systemic right ventricle (sRV) dysfunction in d-transposition of the great arteries following atrial switch (d-TGA) is associated with increased mortality. We aimed to characterize maladaptive sRV mechanisms in d-TGA patients, analyzing relation of echocardiographic parameters of sRV systolic function to objective measurements of exercise capacity.

Methods: Forty-seven adult patients with d-TGA and atrial switch (mean age 31.6±4.2years) underwent conventional echocardiography, bidimensional strain (2D-strain), cardiac magnetic resonance (CMR) imaging and cardiopulmonary exercise evaluation on the same day. Those with median peak oxygen uptake (VO2)>64.5% (n=23) constituted group A, those with VO2≤64.5% (n=24) constituted group B and 23 healthy age and gender matched subjects constituted the control group.

Results: In group A, global longitudinal peak systolic 2D-strain (GLS) of sRV was significantly reduced compared to GLS of normal RV and LV in the healthy control group (p<0.01), however peak longitudinal 2D strain was similar at basal and mid-segment of sRV free wall than normal LV. In group B, GLS was significantly reduced compared to group A (-10.9±2.9% vs -13.1±2.3%, p<0.05), mostly due to significant decrease of interventricular septum longitudinal strain. Other echocardiographic systolic parameters were not significantly different between groups A and B. Only sRV GLS showed significant correlation with functional capacity as measured by VO2 (r=0.42, p<0.01), while CMR RVEF did not.

Conclusion: GLS of sRV predicts functional capacity and may be more sensitive than CMR RVEF in detecting early myocardial damage of sRV in patients with d-TGA and atrial switch.

Keywords: Magnetic resonance imaging; Strain; Systemic right ventricle; Transposition of the great arteries.