Thrombus formation at the site of radiofrequency catheter ablation.

A 55-year-old woman with a history of resected atrial myxoma with residual patched atrial septal defect (ASD) underwent a successful radiofrequency (RF) ablation of reentry atrial tachycardia. She presented with progressive dyspnea 5 days later. Transesophageal echocardiography revealed a 1-cm right atrial mass attached to the intraatrial septum at the ablation site. Repeat study after anticoagulation for 5 weeks showed complete resolution of the thrombus. Thrombus formation at the site of RF ablation is a potential complication that may require aggressive anticoagulation. Patients with patched ASD might be at higher risk.