Feeling a Little Blue After Ablation: Iatrogenic Atrial Septal Defect With Right-to-Left Shunt Following Atrial Fibrillation Ablation.

Atrial fibrillation is the most common cardiac arrhythmia. Cardiac ablation is indicated for patients refractory to medical management. During the ablation process, a transseptal puncture is utilized to access and isolate the pulmonary veins, which results in a temporary iatrogenic atrial septal defect (iASD). Generation of an iASD is considered unavoidable and is a generally accepted risk due to high rates of spontaneous closure. Studies have shown that persisting iASD may occur in 5%-20% of patients for up to nine to 12 months after undergoing radiofrequency ablation and that spontaneous rates of closure are high in patients with normal intracardiac pressures. Patients with preexisting elevated right intracardiac pressures from pulmonary hypertension or other right-sided cardiac pathology are at an increased risk of complications from iASD. These increased pressures can lead to clinically significant hypoxemia from right-to-left shunting following a transseptal puncture. Intervention with closure is considered in high-risk settings such as right atrial or ventricular enlargement, right-to-left shunting with hypoxemia, and intraseptal defect greater than 8 mm. This case vignette describes a 67-year-old female who developed clinically significant right-to-left shunting intraoperatively from iASD with ongoing hypoxemia for several months but with spontaneous closure. We highlight this case as it demonstrates spontaneous closure in a high-risk iASD. We also provide a review of the literature on iASD after cardiac ablations.