Cardiorespiratory exercise tolerance in asymptomatic children with Ebstein's anomaly

The aim of the study was to evaluate cardiorespiratory exercise tolerance i n asymptomatic children with Ebstein's anomaly. Eleven children with a mean age of 9.6 years were prospectively studied by spirometry, cardiopulmonary exercise testing (bicycle ergometer n = 8, treadmill test n = 3), and cont rast echocardiography. A right-to-left atrial shunt was detected by contras t echocardiography in 7 children (group I), whereas no shunt was found in 4 (group 2), VO2 max was decreased [84.5 (SD = 16.8)] and was strongly corre lated to oxygen saturation in group 1 (p < 0.0001). Oxygen saturation at pe ak uptake was significantly decreased compared to baseline [97.4 (SD = 2.0) vs 90% (SD = 9.5%), p = 0.02] and was significantly lower in group 1 than in group 2 [85.7 (2.2) vs 98.2% (SD = 1.2%), p = 0.03]. Oxygen desaturation was related to a right-to-left atrial shunt (p = 0.01), Decreased VO2 max was also correlated to the small size of the left ventricle (p = 0.05), We concluded that decreased exercise tolerance in children with asymptomatic E bstein's anomaly is related to a right-to-left atrial shunt and to a small left ventricle. In case of poor exercise tolerance, a contrast echocardiogr aphy should be performed to detect an atrial septal defect.