Right to left shunt following radiofrequency catheter ablation of atrial fibrillation in a patient with complex congenital heart disease.

We report a case of an iatrogenic atrial septal defect following left atrial ablation for persistent atrial fibrillation in a patient with a Fontan circulation. Transseptal puncture was performed with two sheaths across a single puncture and left atrial ablation undertaken. Post procedure the patient became cyanosed with right to left shunting. Transcatheter closure immediately improved symptoms and oxygen saturation.