Regional right ventricular deformation in patients with open and closed atrial septal defect

Abstract

This study aimed at (i) evaluating regional right ventricular (RV) deformation in patients with an atrial septal defect (ASD)-type secundum using strain and strain rate imaging and (ii) investigating the relation of regional deformation with functional capacity using cardiopulmonary exercise testing (CPET) in order to identify subclinical changes in RV function. Forty-five patients with ASD-type secundum (18 open, 27 closed) and 20 age-matched controls were included. All underwent standard echocardiography and colour-Doppler myocardial velocity imaging. Longitudinal deformation was measured in the RV free wall divided in two segments. ASD patients underwent symptom-limited CPET. When compared with controls, apical strain was higher (-38.2 ± 9.9 vs. -29.9 ± 6.6%; P= 0.004) and lower (-25.2 ± 6.1 vs. -29.9 ± 6.6%; P= 0.006) in patients with an open and a closed ASD, respectively. Apical strain was higher (-38.2 ± 9.9 vs. -27.9 ± 6.6%; P= 0.001) and lower (-25.2 ± 6.1 vs. -28.7 ± 7.4%; P= 0.022) than basal strain in patients with an open and a closed ASD, respectively. In patients with an open ASD, apical strain correlated with shunt-ratio (R = -0.78; P< 0.0001), RV end-diastolic area (R = -0.68; P= 0.002), and RV stroke volume (R = -0.67; P= 0.002). Peak oxygen consumption (peak vO₂) was below average in patients with an open (79 ± 19% predicted; P< 0.0001) and a closed ASD (89 ± 18% predicted; P= 0.002). After ASD repair, apical strain correlated with peak vO₂ (R = -0.49; P= 0.01) and with ventilatory efficiency (R = 0.62; P= 0.001). Volume overload of the right ventricle in patients with ASD-type secundum causes a regional deformation pattern with higher apical strain, related to parameters of volume load severity. After ASD repair, lower apical strain values correlated with functional capacity. Measurement of apical strain seems sensitive for detecting mild RV dysfunction.