Large right atrial pacemaker lead thrombus diagnosed by chest CT angiography

A 74-year-old woman presented with chest tightness and progressive dyspnoea for 1 week. She had past history of cardiac surgery for tricuspid annuloplasty and mitral valve replacement 2 years previously. A ventricular rate responsive pacemaker was implanted for atrial fibrillation 3 months previously. Physical examination revealed a grade 3/6 holosystolic murmur at the left heart apex. Lab examination showed elevation of D-dimer level. Chest radiograph showed severe cardiomegaly (figure 1). Chest CT angiography was performed for suspected pulmonary embolism. Chest CT showed a large ovoid 62 mm mass only attached to the wire of the pacemaker lead (figure 2B–D; white arrow indicating thrombus adherent to pacemaker lead) in the right atrium and a crescent-shaped area of hyperdensity (figure 2A, black arrows) on unenhanced CT. Right atrial pacemaker lead thrombus was diagnosed. Anticoagulant therapy with international normalised ratio (INR) within the range of 2–3 was administered. However, the patient died of cardiovascular collapse 5 days later. Pacemaker-related intra-cardiac thrombus is rare but has a high mortality rate due to sudden cardiovascular collapse.1 2 Patients present with congestive heart failure, shortness of breath, chest pain, pyrexia or malaise acutely or subacutely.2 The risk factors predisposing patients to pacemaker-related thrombus are hypercoagulable states, heart failure, infective endocarditis and pacemaker lead material. Therapeutic modalities include anticoagulation, thrombolysis and surgery for thrombus removal.3