A transthoracic echocardiogram of a 72-year-old woman who was admitted to the hospital complaining of dyspnea at rest and peripheral edema showed severe pericardial effusion with right chamber and left atrial collapse, as well as left ventricular hypertrophy with systolic anterior movement of the septal mitral leaflet and systolic gradient through the left ventricular outflow tract (peak gradient of 70 mm Hg; online-only Data Supplement Movie I and Figure 1). A grade 3/6 systolic murmur was heard. The ECG showed sinus rhythm and respiratory phasic changes in QRS amplitude ( Figure 2). The patient was referred to the catheterization laboratory for pericardiocentesis.