Resolution of Right Atrial Pacemaker Lead Thrombosis After Rivaroxaban Failure: A Case Report.

Background: Pacemaker lead thrombosis is a rare but serious complication of cardiac implantable electronic devices (CIEDs) that often mimics infection; its management, given the lack of standardized treatment strategies, requires individualized anticoagulation and dynamic imaging. Case Presentation: A 65-year-old woman with heart failure and diabetes mellitus had previously undergone dual-chamber pacemaker implantation following radiofrequency catheter ablation. After the subsequent occurrence of ventricular tachycardia, the device was upgraded to a cardiac resynchronization therapy defibrillator (CRT-D). She later experienced recurrent atrial flutter accompanied by worsening heart failure. The timing of atrial flutter recurrence was uncertain, and the patient had not received anticoagulation therapy. Preoperative transesophageal echocardiography (TEE) revealed a mobile mass measuring 10 × 3.5 mm attached to the right atrial lead. Comprehensive clinical and laboratory evaluation showed no evidence of infection. Anticoagulation with rivaroxaban at 20 mg once daily was initiated; however, no reduction in thrombus size was observed after 1 month. The treatment regimen was therefore switched to warfarin, with an initial target international normalized ratio (INR) of 2.0-3.0. Follow-up TEE performed 3 months later demonstrated enlargement of the thrombus to 18 × 3.8 mm. The target INR was subsequently intensified to 2.5-3.0, after which the thrombus gradually regressed. Serial TEE examinations confirmed complete thrombus resolution by 6 months. No embolic or bleeding complications occurred during the treatment course. Conclusion: This case underscores the inadequacy of NOAC monotherapy in selected high-risk patients with lead-associated thrombus, and demonstrates that INR-guided warfarin therapy with individualized adjustment was effective in achieving thrombus resolution.