EVALUATION OF RIGHT-VENTRICULAR SYSTOLIC PRESSURE DURING INCREMENTAL EXERCISE BY DOPPLER-ECHOCARDIOGRAPHY IN ADULTS WITH ATRIAL SEPTAL-DEFECT

Study objectives: Pulmonary hypertension is the most important complic ation in patients with atrial septal defect (ASD), but its role in lim iting exercise has not been examined. This study sought to evaluate ex ercise performance in adults with ASD and determine the contribution o f elevated pulmonary artery pressure in limiting exercise capacity. De sign: We used Doppler echocardiography during exercise in 10 adults (a ged 34 to 70 years) with isolated ASD (New York Heart Association clas s I, II) and an equal number of matched control subjects. Incremental exercise was performed on an electrically braked upright cycle ergomet er. Expired gases and (V) over dot E were measured breath-by-breath. T wo-dimensional and Doppler echocardiographic images were obtained at r est prior to exercise to determine ASD size, stroke volume (SV), shunt ratio (Qp:(Q) over dot s), right ventricular outflow tract (RVOT) siz e, and right ventricular systolic pressure at rest (RVSPr). Doppler ec hocardiography was repeated at peak exercise to measure right ventricu lar systolic pressure during exercise (RVSPex). Results: Resting echoc ardiography revealed that RVOT was larger (21+/-4 vs 35+/-8 mm, mean+/ -SD; p=0.0009) and RVSPr tended to be higher (17+/-8 vs 31+/-8 mm Hg; p=0.08) in ASD; however, left ventricular SV was not different (64+/-2 3 vs 58+/-23 mL; p>0.05), compared with control subjects. Despite norm al resting left ventricular function, ASD patients had a significant r eduction in maximum oxygen uptake ((V) over dot O(2)max) (22.9+/-5.4 v s 17.3+/-4.2 mL/kg/min; p=0.005), RVSPex was higher (19+/-8 vs 51+/-10 mm Hg; p=0.001) and the mean RVSP-(V) over dot O-2 slope (1+/-2 vs 18 +/-3 mm Hg/L/min; p=0.003) and intercept (17+/-4 vs 27+/-4 mm Hg; p=0. 05) were higher in the ASD group. (V) over dot O(2)max correlated inve rsely with both RVSPr (r=-0.69; p=0.007) and RVSPex (r=-0.61; p=0.01). Conclusion: These findings suggest that adults with ASD have reduced exercise performance, which may be associated with an abnormal increas e in pulmonary artery pressure during exercise.