Former prime minister P V Narasimha Rao, who is admitted at the All India Institute of Medical Science in New Delhi, on Wednesday underwent a surgical procedure for his heart problem.
An intracardiac defibrillator device was implanted on him, which will help cut short heart rhythm disturbances before they attain a life-threatening magnitude, an AIIMS release said.
The device also performs as a pacemaker when required, it said.
The 83-year-old Congress leader stood the procedure well and has shown slow improvement, the release added.
Though he is on partial support for heart and kidney, his vital functions are stable, it said.
Rao was admitted on December 9 following breathlessness. He has also been suffering from diabetes, coronary heart and vascular diseases, besides pulmonary fibriosis.