Transseptal Puncture Through an Interatrial Septum With Lipomatous Hypertrophy: A False Perception of Success and Failure.

Transseptal puncture is a standard procedure to access the left atrium during catheter ablation of arrhythmias. It is associated with high success and a meager complication rate in the contemporary era. The potential complications of transseptal puncture include aortic puncture, perforation of the right/left atrial free wall resulting in pericardial effusion/tamponade, and systemic thromboembolism. The dissection of the interatrial septum (IAS) is a rare complication of transseptal puncture, reported in less than 1% of the procedures. We report a case of a dissection of the IAS during an attempted transseptal puncture in a 72-year-old man with lipomatous hypertrophy of the interatrial septum.