Case study:
The case study involves a 73 year-old asymptomatic Caucasian male with a previous history of aortic root and bioprosthetic aortic valve replacement (AVR) for a 5.8cm ascending aortic aneurysm in 2018 recently attended a routine follow-up transthoracic echocardiography (TTE) at their local hospital. A transvenous dual chamber pacemaker was implanted following the aortic root and AVR for postsurgical transient atrial fibrillation with permanent atrioventricular heart block. The TTE showed a well seated bioprosthetic aortic valve with normal peak and mean gradients and good biventricular function. However, the TTE also clearly demonstrated a ventricular pacing lead originating from the superior aspect of the right atrium, crossing both the atrial septum and mitral valve embedding into the lateral left ventricular (LV) wall (figure one ).
The patient was transferred to a tertiary centre for a transoesophageal echocardiogram (TOE) to assess the risk of lead derived intra-cardiac thrombus and discussion at the multi-disciplinary team meeting for potential lead extraction. A 12-lead electrocardiogram (figure two ) and chest x-ray (figure three ) was performed following admission to the tertiary centre showed underlying atrial fibrillation with a VVI pacemaker induced right bundle branch block morphology. During the TOE three-dimensional imaging was obtained which demonstrated the right ventricular lead crossing the atrial septum through a patent patent foremen ovale and crossing the anterolateral aspect of the mitral valve between A1 and P1/2 scallops with mild mitral regurgitation. A small sessile mass attached to the lead in the left atrium measuring 11 x 5mm was visualised consistent with thrombus (Figures four - seven ). Infective endocarditis was initially considered as a differential diagnosis especially in the context of an AVR but excluded as the patient did not exhibit any major findings on the Duke criteria such as positive blood cultures or signs of pyrexia. As the patient was high risk for systemic emboli, anticoagulation with warfarin (5mg) and subcutaneous Tinzaparin (16,000 units) was offered and advised that a repeat TOE was required prior to lead removal in six months.