Right ventricular function in adults with pulmonary hypertension with and without atrial septal defect

Using equilibrium (gated) radionuclide ventriculography, right ventricular (RV) function was studied in 22 adults with pulmonary hypertension and in 16 patients without evidence of cardiac disease. To assess the effect of volume overload on RV performance in pulmonary hypertension, RV ejection fractions were compared in patients with and without left-to-right shunts due to atrial septal defect (ASD). In addition, the effect of ASD repair on RV function was examined. In 14 patients with pulmonary hypertension without RV volume overload (group I), the RV ejection fraction (0.35 ± 0.11, mean ± standard deviation [SD]) was significantly lower than in the normal group (0.47 ± 0.11, p < 0.01). In 8 patients with left-to-right shunts due to ASD (group II) and with RV systolic pressures similar to those in group I, the mean RV ejection fraction (0.53 ± 0.15) was normal and was significantly higher than in group I (p < 0.01). Right ventricular end-diastolic volumes, estimated from combined radionuclide and hemodynamic data, were higher (p < 0.01) in group II patients (171 ± 70 ml/m2) than in group I patients (70 ± 13 ml/m2). In 5 patients who underwent isolated shunt repair, mean RV ejection fraction decreased postoperatively from 0.57 ± 0.17 to 0.40 ± 0.12 (p < 0.05). It is concluded that (1) pulmonary hypertension frequently causes a decrease in RV systolic function due to abnormal afterload; (2) in patients with RV volume overload due to left-to-right shunt, systolic function, as measured by the ejection fraction, remains normal despite pulmonary hypertension, possibly through the Starling mechanism; and (3) RV systolic function often decreases after repair of an ASD.