[Acute aortic regurgitation by spontaneous rupture of a fibrous strand in fenestrated aortic valve; report of a case].

Although fenestration of the aortic valve cusps is a common anatomic finding, it rarely causes aortic regurgitation. We describe acute aortic regurgitation by spontaneous rupture of a fibrous strand in fenestrated aortic valve. A 65-year-old man was referred with sudden onset of dyspnea and cough. He diagnosed acute heart failure due to severe aortic valve regurgitation. After medical therapy, the aortic valve replacement was performed. Operative findings reviewed that a fibrous strand in the fenestrated non-coronary cusp was ruptured, which caused severe aortic regurgitation. Pathological examination showed the myxomatous degeneration. The postoperative course was uneventful, and the patient was discharged on postoperative day 11 with good health.