Balloon atrial septostomy (BAS), which involves artificially creating a communication across the interatrial septum following trans-septal puncture and repetitive balloon dilatation, is known to be associated with therapeutic benefit in patients with severe pulmonary artery hypertension (PAH). Adult patients with large shunts and consequent severe PAH are not uncommon in the developing world, since they often seek medical attention late in the course of the disease. Often PAH in such cases is reversible with amelioration of symptoms after closure of the defect. We report a case of large atrial septal defect (ASD) with severe PAH who developed gross right heart failure following surgical closure of the ASD. A successful bail out BAS was performed using an Inoue balloon, avoiding the need for a redo surgery. The case highlights for the first time the use of Inoue balloon for performing a successful BAS.