Results
From December 2005 (start of the hybrid program at this institution) to May 2015, 20/66 (30.3%) patients with left heart hypoplasia underwent an atrial intervention after HP.  Two patients in the early era were excluded as their echocardiographic data was not available, two were excluded as they underwent a septal intervention at the time of HP, and one was excluded as they underwent a biventricular repair.  Six patients had critical aortic stenosis with forward flow through the left heart, and 9 had classical HLHS.  Five control patients were included. The patient characteristics are shown in table 1.
Eleven patients had a septal intervention as the sole intervention. Three had additional intervention on the ductal stent (one patient had a septostomy due to concern over gradient and two as it was felt septostomy should be performed during the catheter) and one had an aortic valve balloon (septostomy was performed as the gradient was 34mmHg with clinical evidence of elevated left atrial pressures). Pre-procedural invasive gradient was measured in 7 patients, median (range) 9mmHg (4-34mmHg).