ON THE COVER A 25-year-old male was referred for evaluation of fatigue and decreased exercise tolerance. On physical examination, he was noted to have a grade III/VI diastolic murmur heard best at the left upper sternal border, consistent with at least a moderate degree of aortic regurgitation (AR). Transthoracic echocardiography (TTE) identified a quadricuspid aortic valve (QAV) with 4 equal size cusps and a moderate degree of aortic regurgitation (A and B, Video 1). The patient underwent cardiac magnetic resonance (CMR) imaging confirming the QAV with a moderate degree of AR (regurgitant fraction 30%) and a dilated ascending aorta (C, Video 2). 64-slice multidetector computed tomography (MDCT) revealed normal coronary anatomy, a QAV, and a moderate degree of AR with a regurgitant orifice area of 0.18 cm² (D, Video 3). QAV is a rare congenital anomaly of the aortic valve, with an incidence ranging between 0.0125%; and 0.033%;. QAVs have been reported in association with other cardiac abnormalities, such as anomalies of coronary artery origin, pulmonary valve stenosis, atrial septal defect, ventricular septal defect, fibromuscular subaortic stenosis, and supravalvular stenosis with left coronary atresia. Aortic valvular insufficiency usually develops due to fibrous thickening with incomplete coaptation of the cusps. Although a rare congenital anomaly, QAVs may be associated with significant AR as well as other cardiac anomalies, requiring thorough evaluation by the use of complementary cardiac imaging, including echocardiography, MDCT, and CMR, prior to surgical intervention. For accompanying videos, please see the online version of the issue. Images provided by Negareh Mousavi, MD, MHSc, FRCPC,* James W. Tam, MD, FRCPC,* Iain D. C. Kirkpatrick, MD, FRCPC,† Bruce Maycher, MD, FRCPC,† Davinder S. Jassal, MD, FRCPC,*†‡ from the *Section of Cardiology, Department of Cardiac Sciences, †Department of Radiology, and the ‡Institute of Cardiovascular Sciences, St. Boniface Research Centre, University of Manitoba, Winnipeg, Manitoba, Canada.

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