An 87-year-old man with a history of rheumatoid arthritis and associated interstitial lung disease was transferred to our ED after presentation to an outside hospital with the chief complaint of increasing dyspnea on exertion as well as new left-sided chest pain. CT of the chest performed prior to transfer was notable for a circumferential pericardial effusion as well as a large pulmonary embolus (PE) in the left main pulmonary artery (Fig 1). On presentation to our ED, his BP was 114/91 mm Hg and oxygen saturation was 98% on 2 L/min via nasal cannula. ECG showed a heart rate of 133 beats/min in atrial fibrillation with low voltages in all leads as well as electrical alternans. Transthoracic echocardiogram performed by cardiology in the ED was concerning for pretamponade physiology with right ventricular (RV) diastolic collapse, and he was admitted to the medical ICU for further management.