Impact of Right Ventricular Dilatation in Patients with Atrial Septal Defect

Objective. The aim of this study was to examine the relationship between right ventricular (RV) volume and exercise capacity in adult patients with atrial septal defect (ASD) and to determine the degree of RV dilatation for transcatheter ASD closure. Background. RV dilatation is an indication of transcatheter ASD closure; however, few studies have reported the clinical significance of RV dilatation. Methods. We enrolled 82 consecutive patients (mean age, 49 +/- 18 years; female, 68%) who underwent cardiac magnetic resonance imaging and symptom-limited cardiopulmonary exercise test before ASD closure. The relationship between RV volume and peak oxygen uptake (VO2) was evaluated. Results. The mean RV end-diastolic volume index was 108 +/- 27 ml/m(2) (range, 46 to 180 ml/m(2)). The mean peak VO2 was 24 +/- 7 ml/min/kg (range, 14 to 48 ml/min/kg), and the mean predicted peak VO2 was 90 +/- 23%. There were significant negative relationships of RV end-diastolic volume index with peak VO2 (r = -0.28, p<0.01) and predicted peak VO2 (r = -0.29, p<0.01). The cutoff value of RV end-diastolic volume index <80% of predicted peak VO2 was 120 ml/m(2), with the sensitivity of 49% and the specificity of 89%. Conclusions. There was a relationship between RV dilatation and exercise capacity in adult patients with ASD. RV end-diastolic volume index >= 120 ml/m(2) was related to the reduction in peak VO2. This criterion of RV dilatation may be valuable for the indication of transcatheter ASD closure.