Aortic regurgitation (AR) is characterized by regurgitation of blood from the aorta to the left ventricle (LV) during diastole and is attributable to diverse congenital and acquired abnormalities of the aortic valve or the wall of the aortic root. AR can be either chronic or acute. The classic features of chronic AR have been known to clinicians for nearly 2 centuries. Corrigan described chronic AR in 1832 in his text “On Permanent Patency of the Mouth of the Aorta, or Inadequacy of the Aortic Valves.”1 Patients with chronic AR remain asymptomatic for many years as the LV becomes gradually enlarged; cardiac symptoms and clinical congestive heart failure then develop. On the other hand, acute severe AR, if untreated, leads to advanced heart failure and early death. Acute severe AR may be difficult to recognize clinically and is often erroneously diagnosed as another acute condition such as sepsis, pneumonia, or nonvalvular heart disease. Acute or subacute infective endocarditis, aortic dissection, and aortic valve damage caused by trauma are known causes of acute AR. We present 2 cases of acute AR (case 1, infective endocarditis; case 2, Stanford type A aortic dissection), and we propose management plans for each case (Figure 1A and 1B). Figure 1. Proposed management plan for acute aortic regurgitation (AR) due to infective endocarditis ( A ) and aortic dissection ( B ). CHF indicates congestive heart failure; TTE, transthoracic echocardiogram; TEE, transesophageal echocardiogram; IE, infective endocarditis; AR, aortic regurgitation; PMVC, premature mitral valve closure; DMR, diastolic mitral regurgitation; ESMR, early systolic mitral regurgitation; ICU, intensive care unit; EKG, electrocardiogram; LVOT, left ventricular outflow tract; and AV, aortic valve. A 23-year-old man admitted to an intensive care unit with Staphylococcus bacteremia presented with soft heart sounds and a to-and-fro murmur, which progressed to a silent precordium within 24 hours. Bedside transthoracic …