Iatrogenic inferior vena cava (IVC)-left atrium (LA) shunt is a rare complication in atrial septal defect (ASD) surgery, caused by mistaking the Eustachian valve for the lower margin of the ASD. In this report, we describe the case of a 45-year-old woman who experienced circulatory collapse at termination of cardiopulmonary bypass during surgical IVC-LA shunt repair. Transesophageal echocardiography helped identify stenosis between the IVC and the right atrium, caused by a residual original incorrectly placed ASD patch. Removal of most of the patch led to improvement in circulatory failure.