Former India cricket captain M A K Pataudi underwent successful bypass surgery -- the second in five years.

Inquiries with the Board of Control for Cricket in India to find out why Pataudi did not honour an invitation to visit Pakistan for the just-concluded series between the two countries revealed that the former captain is ailing.

"He couldn't go to Pakistan because he was preparing for his second bypass surgery," a BCCI source said.

He added that the operation was carried out successfully, but couldn't confirm if it was done at a hospital in Britain or the United States.

"We know the operation was done abroad, most probably in the US," the source said.

Pataudi had given his consent to travel to Pakistan with other former India captains to watch the Islamabad Test.

It is learnt that his actress wife Sharmila Tagore was with him during the operation.

India's youngest captain had undergone bypass surgery four years ago.