Zee Media Bureau Mumbai: Rashtriya Janata Dal (RJD) chief Lalu Yadav, who is currently under medical observation in a Mumbai hospital, is likely to undergo heart surgery, reports said on Tuesday. “Laluji is fundamentally a healthy person, as can be seen from the intense campaigning he has done. Based on the preliminary reports, we can confirm that cardiac surgery is required,” said Dr. Vijay D`Silva, Medical Director, Asian Heart Institute. He further added that the date and details related to what kind of surgery is required will be finalised by the doctors after his pending medical reports are received by today evening. Meanwhile, Congress president Sonia Gandhi called up the former Bihar chief minister to ask about his health. The 66-year-old RJD leader was rushed to Mumbai`s Asian Heart Institute (AHI) yesterday for `routine` check up. He has been said to suffering from heart-related ailments, it was reported.