Massive Left Ventricular Thrombus Complicating Anterior STEMI in a Patient Recently Started on Tamoxifen: A Case Report and Brief Review of the Literature

Background Left ventricular thrombus (LVT) is a known complication of large anterior STEMI, especially with severe LV dysfunction and apical akinesis. Tamoxifen is associated mainly with venous thrombosis, whereas arterial and intracardiac thrombosis are rare. Detection of a very large LVT early during anterior STEMI care in a patient recently started on tamoxifen represents an unusual clinical presentation. Case Presentation A 77-year-old man with recently treated right-sided invasive ductal carcinoma of the breast, status post mastectomy and adjuvant radiotherapy, presented with anterolateral STEMI 10 days after starting tamoxifen. Emergent PCI of the proximal left anterior descending artery was successfully performed with placement of a drug-eluting stent, but was complicated by severe no-reflow and cardiogenic shock requiring intra-aortic balloon pump support. Bedside TTE revealed severe left ventricular systolic dysfunction with an ejection fraction of 25%–30% and a large fixed apical thrombus measuring 3.2 × 2.9 cm. He was treated with intravenous heparin, tirofiban, dual antiplatelet therapy, and inotropic support. His hospital course was complicated by paroxysmal atrial fibrillation, recurrent cardiogenic shock, flash pulmonary edema, and renal failure. Despite escalation of care, he ultimately chose comfort-focused treatment and died on hospital day 17. Conclusion This case describes a very large fixed LVT detected during anterior STEMI in a patient who had recently started tamoxifen. The large infarct burden, severe LV systolic dysfunction, no-reflow, and cardiogenic shock provide a strong mechanistic explanation for thrombus formation. Recent tamoxifen exposure may have represented an additional prothrombotic cofactor, but causality cannot be established from this case.