Endocardial flap of left atrial dissection following radiofrequency ablation.

This report describes an unusual mobile strand found by transesophageal echocardiography prior to a patient's second radiofrequency ablation for paroxysmal atrial fibrillation. This structure arose from the limbus of the left upper pulmonary vein, a location where radiofrequency energy bursts were delivered during the first ablation procedure. After seven months of therapeutic anticoagulation, there was no evidence of change in the size of the mass or of thromboembolism and the patient underwent radiofrequency ablation without complication. We believe this structure most likely represents an endocardial flap of left atrial dissection temporally related to radiofrequency ablation.