Cor triatriatum with unroofed coronary sinus and persistent left superior vena cava associated with atrial tachycardia.

A 2-year-old girl with cor triatriatum with unroofed coronary sinus and persistent left superior vena cava underwent preoperative radiofrequency catheter ablation for atrial tachycardia attack that developed after admission to our hospital. The procedure was not successful. Cryoablation was successfully performed during corrective surgery. Cutting back from the coronary sinus orifice, resection of the fibrous tissue above the mitral valvular orifice, closure of the excised fossa ovalis and coronary sinus orifice with a Gore-Tex patch, and ligation of the persistent left superior vena cava resulted in an excellent hemodynamic outcome. At 2-year follow-up, the patient was free from tachycardia attack.