[Acute aortic regurgitation due to localized aortic dissection adjacent to the commissure of the aortic valve].

A 78-year-old male with a sudden loss of consciousness and chest pain was transferred to our hospital. He presented heart failure due to severe aortic regurgitation. Cardiac ultrasonography and computed tomography (CT) scanning did not lead to an established diagnosis of acute aortic dissection. Aortic valve replacement was performed 24 days after the onset of the disease. The surgical findings showed prolapse of the aortic valve due to localized dissection adjacent to the commissure of the aortic valve.