Abstract
Background and Clinical Significance: Mechanical complications and intracavitary thrombus are both recognized causes of clinical deterioration following acute myocardial infarction, yet they require fundamentally different therapeutic approaches. Distinguishing between these entities is critical, as misdiagnosis may lead to unnecessary surgical intervention or delayed anticoagulation with serious consequences. Left ventricular (LV) thrombus typically appears as a well-defined mass; however, atypical and highly mobile morphologies may closely mimic catastrophic post-infarction mechanical complications, creating significant diagnostic uncertainty. This case highlights the pivotal role of contrast-enhanced echocardiography in resolving such ambiguity and guiding appropriate management in a high-stakes clinical setting. Case Presentation: A 60-year-old man presented with acute dyspnea and pulmonary edema ten days after an anterior myocardial infarction treated with percutaneous coronary intervention, complicated by ischemic stroke. Transthoracic echocardiography demonstrated severe LV systolic dysfunction with moderate-to-severe mitral regurgitation and an unexpected, highly mobile, irregular mass protruding into the LV apex. The mass exhibited a shredded, tissue-like appearance, raising urgent concern for post-infarction mechanical complications, including papillary muscle rupture or apical myocardial disruption, and prompting immediate consideration of surgical intervention. Contrast-enhanced echocardiography was performed and revealed a mobile LV apical thrombus. Surgical management was avoided, and systemic anticoagulation was initiated, followed by transition to rivaroxaban in combination with ongoing dual antiplatelet therapy. The patient demonstrated rapid clinical improvement with optimized heart failure treatment and was discharged after four days, with planned follow-up imaging to assess thrombus resolution. Conclusions: Left ventricular thrombus may present with atypical, misleading morphologies that closely resemble life-threatening mechanical complications after myocardial infarction.