Atrial septal defect closure in children at young age is beneficial for left ventricular function

Atrial septal defects (ASD) lead to volume-loaded right ventricles (RV). Atrial septal defect closure does not always improve symptoms or exercise capacity, possibly explained by impaired left ventricular (LV) hemodynamics. The study evaluated the effect of ASD closure in children using non-invasive LV pressure-volume (PV) loops derived from cardiac magnetic resonance imaging (CMR) and brachial blood pressure, compared with controls. Twenty-three children with ASD underwent CMR, 17 of these were re-examined 7 [6–9] months after ASD closure. Twelve controls were included. Hemodynamic variables were derived from PV loops by time-resolved LV volumes and brachial blood pressure. After ASD closure, LV volume increased (76 [70–86] ml/m2 vs 63 [57–70] ml/m2, p=0.0001), however was still smaller than in controls (76 [70–86] ml/m2 vs 82 [78–89] ml/m2, p=0.048). Compared to controls, children with ASD had higher contractility (2.6 [2.1–3.3] mmHg/ml vs 1.7 [1.5–2.2] mmHg/ml, p=0.0076) and arterial elastance (2.1 [1.4–3.1] mmHg/ml vs 1.4 [1.2–2.0] mmHg/ml, p=0.034). After ASD closure, both contractility (2.0 [1.4–2.5] mmHg/ml, p=0.0001) and arterial elastance (1.4 [1.3–2.0] mmHg/ml, p=0.0002) decreased. Despite the left-to-right atrial shunt that leads to low LV filling and RV enlargement, the LV remains efficient and there is no evidence of impaired LV hemodynamics in children. Closure of ASD at young age while the ventricle is compliant is thus beneficial for LV function. Left ventricular volumes however remained small after ASD closure, which may impact long-term cardiovascular risk and exercise performance.