Born with a cyanotic congenital heart defect, Tanisha started suffering from frequent bouts of respiratory illness from two months onward. Her heart was positioned in the right side of her rib cage, which led to increased blood pressure in the right lung.

After being treated at the NRS Medical College and Hospital and the Rabindranath Tagore International Institute of Cardiac Sciences, Tanisha's parents, Deepa and Subhro Shah, brought her to Dr KR Balakrishnan, director of Cardiac Sciences of Malar Hospital.

Dr Balakrishnan said the surgery was a complicated process, "She had cyanotica congenital heart defect, which affects only one in a lakh. Her heart was on the right side with a hole in it coupled with an ineffective and underdeveloped right lung," he added at a press meet.

The doctors used Viagra in oral form to reduce blood pressure in the lungs during the operation. Malar Hospital also helped raise funds for the surgery, which cost Rs 4 lakh.

Tanisha suffered from a condition called cyanotic heart disease, which is a heart defect, present at birth that results in low blood oxygen levels. There may be more than one defect as was the case with Tanisha who had dextrocardia in which the heart is located in the right side of the chest instead of the left.

In this condition, babies turn blue often and experience breathing problems. This was what caught the attention of Tanisha's parents in the first place.