A 52-year-old man presented to our emergency department with shortness of breath. He reported exertional dyspnea for the past five years which had worsened recently. He reported no weight loss, fever or poor appetite. His past medical history was noncontributory. The physical exam revealed a diastolic murmur best heard in the aortic area. Echocardiography showed a mildly enlarged left ventricle with normal contraction. Severe aortic regurgitation (AR) and holodiastolic flow reversal in the abdominal aorta were present (Figures 1–4). No vegetation was seen on the aortic valve. There was an aneurysmal sac on the anterior leaflet of the mitral valve, corresponding to the site of the high velocity AR jet (video 1 and video 2 in the Supplementary material). Laboratory tests including complete blood cell count, liver and kidney function tests, erythrocyte sedimentation rate and C-reactive protein were normal. The patient refused surgical intervention and was lost to follow-up.

Figure 1.

Transthoracic echocardiogram, 4-chamber apical view, showing the aneurysmal sac of the anterior mitral valve leaflet.

Figure 2.

Transthoracic echocardiogram, long-axis parasternal view, showing the mitral valve anterior leaflet aneurysm.

Figure 3.

Continuous wave spectral Doppler recording through the aortic valve. Pressure half time is noted to be 334 ms.

Figure 4.

Holodiastolic flow reversal in the descending thoracic aorta indicative of significant aortic valve regurgitation.

Acquired mitral valve aneurysm is a rare entity which has generally been reported in the context of endocarditis. Aneurysm of the anterior mitral valve leaflet due to the regurgitant flow of AR is a plausible mechanism in the absence of evidence for endocarditis.