Abstract
Electrocautery-assisted transseptal puncture offers clinical advantages but is associated with potential complications. Herein, we describe a case encountered during radiofrequency ablation for atrial fibrillation, in which intracardiac echocardiography detected a thrombus that formed after electrocautery and guidewire traversal of the interatrial septum. The thrombus appeared as a hyperechoic, cord-like structure adherent to the right atrial side of the interatrial septum. Prompt heparin administration led to thrombus resolution without embolization, enabling the procedure to continue safely. This case underscores the thrombotic risk of electrocautery transseptal puncture and highlights the need for further research on optimal anticoagulation strategies.