Acute aortic regurgitation due to aortic dissection confined to the sinus of Valsalva.

A 34-year-old man with severe heart failure was diagnosed with acute aortic regurgitation (AR) by transthoracic echocardiography (TTE). However, this differential diagnosis was incomplete. Only transesophageal echocardiography (TEE) revealed an intimal flap, leading to a diagnosis of Stanford type A aortic dissection. No abnormal findings were observed in the ascending aorta by contrast-enhanced computed tomography (CT). Aortic dissection confined to the sinus of Valsalva has rarely been reported; however, TEE should still be considered for the differential diagnosis of acute AR, even if there is no evidence of dissection by TTE or contrast-enhanced CT.