Three-time Delhi chief minister from Congress, Dikshit was brought to Fortis Escorts Heart Institute, Okhla in early hours of the day, in a critical condition with a cardiac arrest," the hospital said in a statement.
"A multi-disciplinary team of doctors, led by Dr Ashok Seth, chairman, Fortis Escorts Heart Institute, carried out advanced resuscitative measures. Her condition stabilised temporarily. However, she had another cardiac arrest and despite all the resuscitative efforts, passed away at 3:55 pm on July 20," it added.
Confirming the development, Congress party tweeted, "We regret to hear of the passing of Sheila Dikshit.
Lifelong Congresswoman and as three-time CM of Delhi, she transformed the face of Delhi. Our condolences to her family and friends. Hope they find strength in this time of grief."
Eighty one-year-old Sheila Dikshit
underwent a heart surgery in France last year. Ashok Seth, chairman of Fortis Escorts Heart institute had advised that the procedure be performed at University Hospital in Lille, France under the care of Dr Thomas Modine.
Sources said Dikshit had been undergoing treatment at Fortis Escorts hospital under the supervision of Dr Seth for the past few years. She had undergone angioplasty in November 2012 and was also treated for infection some time ago.
She was president of Delhi Congress. She served as Delhi's chief minister for 15 years from 1998-2013 and also served as the governor of Kerala.
She unsuccessfully fought the recent Lok Sabha elections from the North-East Delhi constituency. She represented New Delhi constituency in Delhi Vidhan Sabha.
Dikshit became an MP for the first time from Kannauj Lok Sabha seat in Uttar Pradesh in 1984. She was also a close associate of former prime minister Rajiv Gandhi and a minister in his cabinet.
President Ram Nath Kovind, Vice President Venkaiah Naidu, Prime Minister Narendra Modi, Congress leader Rahul Gandhi and Delhi Chief Minister Arvind Kejriwal were among those who condoled her death.