A case misdiagnosed as hyperthyroid heart disease: Surgical repair of unroofed coronary sinus syndrome with severe tricuspid regurgitation

Unroofed coronary sinus syndrome (URCS), also known as coronary sinus septal defect, is a rare congenital heart disease. Because of its special anatomy and the lack of typical clinical symptoms, the disease is easily missed and misdiagnosed. This case report particularly describes a middle‐aged male patient with URCS misdiagnosed for more than 19 years, covered by hyperthyroid heart disease, who subsequently developed uncontrollable symptoms such as chest tightness and shortness of breath and came to our hospital. After a clear diagnosis in our hospital, the patient was successfully cured after treatment with coronary sinus repair and tricuspid valvuloplasty under extracorporeal circulation.