Late-onset transvenous pacemaker lead-associated thrombosis

A man in his eighties presented with a two-week history of left-arm swelling and bruising. Twelve years earlier, he had undergone dual-chamber pacemaker implantation for bradycardia and syncope. His past medical history included hypertension, paroxysmal atrial fibrillation (pAF), and coronary artery bypass grafting (CABG) 15 years prior. Upon further investigation with ultrasound Doppler, and computerised tomography (CT) of his chest, a thrombus was confirmed in the left subclavian vein, associated with a pacing lead. He was initiated on a three-week course of low molecular weight heparin (LMWH). Although his symptoms initially improved, traces of the thrombus remained on his follow-up CT after commencing treatment, and he was continued on lifelong direct oral anticoagulant (DOAC). Pathogenesis, incidence, investigations and management of pacemaker-induced thrombosis are discussed. This case illustrates a rare, delayed presentation of pacemaker-induced thrombosis in the context of a symptomatic presentation and highlights the potential need for prolonged anticoagulation.