Maintain a high degree of suspicion of cardiac tamponade for oncology patients who fit the clinical signs and symptoms of tamponade.



Acute idiopathic
Post–myocardial infarction







If a pericardial effusion compromises hemodynamics, pericardiocentesis can be lifesaving. 



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You are caring for a 45-year-old man in the cardiac intensive care unit. He presented with chest pain and initially was thought to have acute coronary syndrome, prompting initiation of antiplatelet agents and IV heparin. After complete assessment and the return of negative serial cardiac enzymes, it became clear that he instead had acute pericarditis. Shortly after admission to the cardiac intensive care unit, he becomes hypotensive with elevated neck veins. His lungs are clear to auscultation. His extremities are cool, and you note that his brachial pulse is only palpable during expiration. What is the most likely diagnosis?


The answer is B. This patient has physical examination findings consistent with cardiac tamponade, likely caused by bleeding into the pericardial space induced by anticoagulation in the setting of acute pericarditis. Acute myocardial infarction has been ruled out, so left main coronary artery occlusion, ruptured chordae tendineae (which would be associated with mitral regurgitation and acute pulmonary edema), and ventricular septal defect are unlikely. Acutely, a minimal amount of supranormal pericardial fluid (often ~200 mL) is required to rapidly increase intrapericardial pressure and cause cardiac tamponade. This is a medical emergency, and prompt evaluation with echocardiography and preparation for emergent pericardiocentesis are warranted. The paradoxical pulse (as noted in the question by the vanishing arterial pulse with inspiration) is an important clue to the presence of cardiac tamponade and consists of a greater than normal (10 mmHg) inspiratory decline in systolic arterial pressure. Because both ventricles share a tight incompressible covering (i.e., the pericardial sac), the inspiratory enlargement of the right ventricle in cardiac tamponade compresses and reduces left ventricular volume; leftward bulging of the interventricular septum reduces further the left ventricular cavity as the right ventricle enlarges during inspiration. Thus, in cardiac tamponade, the normal inspiratory augmentation of right ventricular volume causes an exaggerated reduction of left ventricular volume, stroke volume, and systolic pressure. Because immediate treatment of cardiac tamponade may be lifesaving, prompt measures to establish the diagnosis by echocardiography should be undertaken. When pericardial effusion causes tamponade, Doppler ultrasound shows that tricuspid and pulmonic valve flow velocities increase markedly during inspiration, whereas pulmonic vein, mitral, and aortic flow velocities diminish. In tamponade, there is late diastolic inward motion (collapse) of the right ventricular free wall and the right atrium.



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