Abstract
BACKGROUND: Intracardiac thrombi are a complication of cardiac implantable electronic devices (CIEDs) and device leads. While the risk of pulmonary embolism exists, clinically significant pulmonary embolism is rare, possibly because of low embolism rates or small embolic material. Larger thrombi pose greater concern, yet guidelines regarding investigation and management are limited. CASE SUMMARY: We describe the investigation of a large and mobile CIED-related thrombus in a patient with previous infectious endocarditis and myeloproliferative neoplasm, including serial multimodal imaging assessment, individualized management considerations, and anticoagulation. DISCUSSION: Large intracardiac thrombi have the potential to cause significant morbidity and mortality. The investigation and management of large intracardiac thrombi is an area of cardiology that is largely evidence free. Current literature suggests strategies may involve medical or procedural approaches, but evidence is restricted to case reports. TAKE-HOME MESSAGES: Large intracardiac CIED-related thrombi remain clinically significant but poorly studied. Anticoagulation is the mainstay of treatment, however decisions are highly individualized.