ESC Congress 2010 edition:2010 location:Stockholm, Sweden date:28 August - 01 September
Progressive right ventricular dilatation due to left-to-right shunt in patients with atrial septal defect (ASD) type secundum may eventually lead to RV failure. This study aimed at evaluating regional RV deformation based on strain rate imaging in order to detect subclinical changes in RV systolic function.
Eighteen patients with open ASD (mean age 39.2±18.5), 28 patients with closed ASD (mean age 41.1±16.6) and 18 age-matched controls (mean age 39.4±13.6) underwent standard echocardiography and color-Doppler myocardial imaging. Regional longitudinal deformation was measured in the RV free wall divided in two segments. Patients with ASD underwent cardiopulmonary exercise testing.
Patients with open ASD had significantly higher apical strain (-38.2±9.9 versus -29.6±4.8 % ; P=0.003), whereas patients after ASD repair had significantly lower apical strain when compared to controls (25.2±6.1 versus -29.6±4.8 % ; P=0.013). Apical strain was higher (38.2±9.9 versus -27.9±6.6 % ; P=0.001) and lower (25.2±6.1 versus -28.7±7.4 % ; P=0.022) than basal strain in patients with open and closed ASD respectively. However, in the control group there was no regional difference in deformation parameters. Apical strain correlated with RV end-diastolic area (R= -0.68; P=0.002), stroke volume (R= -0.67; P=0.003), cardiac index (R= -0.76; P<0.0001) and ventilatory efficiency (R= 0.53; P=0.030) in patients with open ASD and with peak oxygen consumption (R= -0.49; P=0.011) and ventilatory efficiency (R= 0.616; P=0.001) in patients with closed ASD.
Volume overload of the right ventricle causes higher apical RV strain, possibly related to lower wall thickness or increased curvature in the apical segment. After ASD repair, decreased apical strain is related with exercise capacity, indicating the apical segment as the vulnerable segment of the RV free wall.