A 62-year-old woman was brought to the emergency department after she was found unresponsive on the ground with a presumed cardiac arrest. She had pulseless electrical activity. After resuscitation, the return of spontaneous circulation was achieved. She remained comatose and was intubated for airway protection. She had a history of deep vein thrombosis 3 years prior but was not receiving long-term anticoagulation. A physical examination revealed a rapid irregular pulse, no jugular venous distension, clear lung fields, and no cardiac murmurs. There was no peripheral edema. Laboratory findings were notable only for a troponin T level of 2.41 ng/mL (to convert to micrograms per liter, multiply by 1). An electrocardiogram (ECG) and a point-of-care transthoracic echocardiogram (TTE) were obtained (Figure 1; Video).