Reduced biventricular contractility during exercise in adults with small, unrepaired ventricular septal defects: an echocardiographic study

OBJECTIVES: Small ventricular septal defects are often considered to be without long-term haemodynamic consequences and so the majority remains unrepaired. However, we recently showed reduced functional capacity and altered right ventricular morphology in adults with small, unrepaired ventricular septal defects. The underlying mechanisms behind these findings remain unclear, and so, biventricular contractility during exercise was evaluated. METHODS: Adults with small, unrepaired ventricular septal defects and healthy controls were examined with echocardiography during supine bicycle exercise with increasing workload. Tissue velocity Doppler was used for evaluating isovolumetric acceleration and systolic velocities during exercise. RESULTS: In total, 34 patients with ventricular septal defects, a median shunt- ratio of 1.2 (266 years), and 28 healthy peers (27 +/- 5 years) were included. Right ventricular isovolumetric acceleration was lower in patients as compared with controls at rest (97 +/- 40 vs 158 +/- 43 cm/s(2), P = 0.01) and at peak heart rate (222 +/- 115 vs 410 +/- 120 cm/s(2), P < 0.01). Peak systolic velocities were similar at rest, but differed with exercise (13 +/- 3 vs 16 +/- 3 cm/s, P = 0.02). Left ventricular isovolumetric acceleration was lower in patients as compared with controls throughout the test (P < 0.01). Septal isovolumetric acceleration was similar at rest, but reduced during increasing exercise as compared with controls (220 +/- 108 vs 303 +/- 119 cm/s(2), P = 0.03). Left ventricular isovolumetric acceleration was negatively correlated with the shunt- ratio, and right ventricular and septal peak systolic velocities were positively correlated with lower functional capacity. CONCLUSIONS: Altered biventricular contractility is present during exercise in adults with small, unrepaired ventricular septal defects. These results add to the growing number of studies showing that long-term outcome in unrepaired ventricular septal defects may not be benign.