Vanzara was admitted to U N Mehta Institute of Cardiology and Research Centre here in the morning, according to a source in the hospital.
Vanzara is an accused in the cases relating to alleged fake encounter killing of Soharabuddin Sheikh, Tulsi Prajapati and college student Ishrat Jahan.
After spending nearly seven months at Navi Mumbai's Taloja jail in Sohrabuddin Sheikh fake encounter killing case, Vanzara was recently shifted to Sabarmati Central Jail in Ahmedabad in connection with Ishrat fake encounter case.
The four were gunned down on June 15, 2004 allegedly in a staged encounter on the outskirts of the city by Ahmedabad police on the suspicion that they were on a mission to kill Gujarat chief minister Narendra Modi.
CBI is expected to file its chargesheet in the case by July 4.