An Autopsy Case of Bicuspid Aortic Valve with First Presentation as Sudden Cardiac Death

The prevalence of bicuspid aortic valve (BAV) is approximately 0.5%-2% and is the most common congenital heart valve disease in adulthood. It is present at birth but may be asymptomatic initially, and symptoms can appear over time as various complications, such as dystrophic calcification, infective endocarditis, aortic stenosis, aortic regurgitation, and aortic dissection, occur. However, in some cases, sudden cardiac death may be the first presentation; this case will be introduced. This case report describes a 63-year-old woman with no known underlying conditions or history of heart disease, except for hypertension, who suddenly collapsed and died. Autopsy results confirmed a severely calcified BAV, and histological examination revealed calcification not only in the valve leaflets but also in the sinus wall, with interstitial fibrosis observed in the hinge of the leaflet extending downward to the interventricular septum. This anatomical distribution suggests the potential involvement of the cardiac conduction system, which could lead to fatal arrhythmias, such as atrioventricular block or ventricular tachyarrhythmia. BAV should be recognized as a potentially life-threatening condition, even in the absence of clinically apparent cardiac disease, as observed in this case. Additionally, a thorough histological examination of the heart valves and conduction system at autopsy should not be overlooked, as this will allow for clinicopathological correlations and an understanding of the mechanisms of sudden cardiac death.