Hospital sources, however, said, "he was fine and it was just a routine check-up."
Mr Thakur, 64, did not attend court today.
"The CJI visited the hospital earlier in the day. He has been coming to Fortis Escorts Heart Institute for medical check-ups for the past couple of years, and today's visit was also a regular visit. He is doing fine and has returned home.
There is nothing to worry about," a source said.
Mr Thakur is the 43rd Chief Justice of India and due to to retire on January 4 next year.
Mr Thakur was appointed as a permanent judge in September, 1995 and transferred as a judge of the High Court of Delhi in July 2004.
He was appointed as the Acting Chief Justice of Delhi High Court in 2008 and took over as Chief Justice of the High Court of Punjab and Haryana on August 11, 2008.
Elevated as a judge of Supreme Court in 2009, he was appointed as the Chief Justice of India on December 3 last year.
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