Pulmonary artery (PA) band is done in a variety of congenital heart diseases (CHDs) with the primary goal of reducing pulmonary overcirculation. Its use has declined during the last two decades, however, its role still exists in classic univentricular heart with unrestricted pulmonary blood flow. PA banding in univentricular morphology with transposition of great arteries (TGA) can be extremely morbid. Our patient had ST segment elevation in inferior leads after banding, indicating acute ischemia in right coronary artery territory. We hypothesize that, the cause for this was sudden shift of volume to the rudimentary camber through the bulboventricular foramen after PA banding, causing subendocardial ischemia. Interpretation of electrocardiogram (ECG) and subsequent management is not straightforward in this scenario .We hereby describe successful management of sudden ST segment changes observed in immediate post-operative period after PA banding for univentricular, TGA heart in an 8 month old infant.