Free-floating left ventricular thrombus after rapid improvement of cardiac function related to mechanical hemodynamic support.

The incidence of acute complications is high in patients presenting late with acute myocardial infarction (AMI). We describe the case of a patient who presented late with anterior AMI that was complicated by left ventricular (LV) thrombus and electrical storm (ES). Temporary right ventricular pacing suppressed ES under extracorporeal membrane oxygenation support but reduced cardiac function. Immediately after returning to sinus rhythm (i.e. increase in cardiac function), free-floating LV thrombus was detected by echocardiography, resulting in cerebral embolism. Rapid improvement in cardiac function related to mechanical hemodynamic support may become a trigger for embolization in patients with LV thrombus. < Patients presenting late with acute myocardial infarction have a high incidence of complications. In patients with severe left ventricular (LV) dysfunction who require venoarterial extracorporeal membrane oxygenation, right ventricular (RV) pacing can advocate cardiac dysfunction with insufficient aortic valve opening. When patients have LV thrombus in this situation, rapid improvement in cardiac function by the interruption of RV pacing can dislodge LV thrombus, leading to systematic embolism.>.