RESUMEN
The transcatheter left atrial appendage occluding device, WATCHMAN, can be used to prevent thromboembolism in patients with nonvalvular atrial fibrillation who are at high risk of bleeding during anticoagulation. We report an emergent surgical case of cardiac tamponade due to the left atrial appendage perforation with the WATCHMAN device implantation. An 83-year-old woman with recurrent paroxysmal atrial fibrillation (CHA2DS2-VASc score 4, HAS-BLED score 3) after catheter ablation was scheduled for the WATCHMAN device implantation. During implantation, the patient developed cardiac tamponade and underwent emergent surgery with cardiopulmonary bypass for active bleeding despite pericardial drainage. The bleeding was caused by the left atrial appendage perforation, and suture exclusion of the left atrial appendage was performed.