Mihali K, Markus B, Schieffer B, Bauer M, Kreutz J. Thinking Outside the Box: Case Report of a Rare Quadricuspid Aortic Valve as an Underrecognized Cause of Heart Failure and Atrial Fibrillation. J Med Cases. 2025;16(8):277-281. doi:10.14740/jmc5153