Mumbai, Aug. 27 - Rashtriya Janata Dal chief Lalu Prasad is undergoing two major heart surgeries - one to replace an aortic valve and the other to repair the aorta, at a hospital in Mumbai today.

An Asian Heart Institute spokesman said that the former Bihar chief minister had been diagnosed with 'aortic stenosis' and that he was being operated upon since the morning.

Asian Heart Institute Medical Director Vijay D'Silva has said that the surgical procedure will take over five hours.

Lalu, 67, was hospitalized on Monday; the day bye-election results were being counted in Bihar and three other states.

The RJD-Janata Dal (United)-Congress combine won six of the 10 seats in the state's bye-election.

It is expected that JD-U leader Nitish Kumar might visit Lalu in hospital today. (ANI)