Director of RMLIMS Dr Deepak Malviya said that Tiwari was admitted at 9AM at the cardiology department of the institute, following illness.
Doctors have conducted various test on Tiwari, he said in a health bulletin.
The 91-year-old former CM was also give high antibiotic. Tiwari was earlier admitted to the hospital on March 28 following complaints of an infection. He was discharged on March 31.
While he was undergoing treatment at the hospital, Uttar Pradesh Chief Minister Yogi Adityanath visited him and enquired his well being.