Emergency Percutaneous Closure of an Iatrogenic Atrial Septal Defect Causing Right-to-Left Shunt and Severe Refractory Hypoxemia After Pulmonary Vein Isolation.

A 60-year-old man with arrhythmogenic right ventricular dysplasia, dilated right heart chambers, moderate tricuspid regurgitation, and mild pulmonary hypertension (systolic pulmonary pressure of 45 mm Hg) underwent pulmonary vein isolation (PVI) under general anesthesia due to symptomatic atrial fibrillation. Using a single transseptal puncture–double transseptal approach, a 12-F FlexCath Advance steerable sheath (Medtronic, Heerlen, the Netherlands) and an 8.5-French SL1 long sheath (St. Jude Medical, Plymouth, Minnesota) were placed into the left atrium. PVI and radiofrequency ablation were performed. The patient developed severe hypoxemia (SpO2, 65%) after the removal of the sheaths from the left atrium. A transesophageal echocardiogram showed a continuous right-to-left (R-L) jet through an iatrogenic atrial septal defect (iASD) (Figure 1, Online Video 1). The hypoxemia improved partially as the 12-French sheath was replaced across the iASD, supporting the