Bidirectional Dynamic Change in Shunt Flow across Small Ventricular Septal Defect in a Patient with Left Ventricular Assist Device

Summary Ventricular septal defect (VSD) was identified in a patient with left ventricular assist device, which was not documented before implantation. As the pump speed was raised during echocardiographic ramp test, VSD flow changed from left-to-right shunt to right-to-left shunt with systemic hypoxemia. High LVAD pump speed raises the risk of hypoxemia and paradoxical thromboembolism under even small residual intracardiac shunt.