Shiv Sena executive president Uddhav Thackeray was admitted to Lilavati hospital in suburban Bandra for an angioplasty procedure here this morning.
This would be the second phase of the procedure as the 51-year-old leader had undergone the first angioplasty operation at the same hospital in July.
Doctors had discovered multi-vessel blockages in Uddhav's heart and suggested that he undergo two operations.
"Today's second angioplasty had been advised when he was admitted for the first surgery," Sena sources said.
As Uddhav arrived at the hospital early morning, he was accompanied by wife Rashmi and children Aditya and Tejas.
His estranged cousin and MNS chief Raj Thackeray was also present.
Meanwhile, singer Lata Mangeshkar visited Uddhav's father, Shiv Sena supremo Bal Thackeray at his residence 'Matoshri' in Bandra today. The Sena chief has not been keeping well for the past few months.