Introduction
Atrioventricular septal defect is a group of diverse malformations unified by having the same characteristic morphology at their atrioventricular septal junction. It account for about 7-17% of congenital heart disease [1]. Most patients undergo operation in childhood and the long-term survival after operation is favorable. However, a few patients with incomplete atrioventricular septal defect are diagnosed in adulthood. It is suggested that the delayed operations rise ratio to additional preoperative complications and influences cardiac function [2]. Here, we report a rare case of adult patient with incomplete atrioventricular septal defect that were incidentally detected without symptom.