CHI Memorial Hospital Chattanooga. Guerry Heart and Vascular Center patient rooms: Entrance A from 5 a.m. to 9 p.m. South tower patient rooms: Entrance B from 4 a.m. to 7 p.m. Mon-Fri; 6:30 a.m. to 7 p.m. Sat-Sun. 4 East patient rooms: Entrance F from 7 a.m. to 5 p.m. Critical Care Unit patient rooms: Entrance A; MICU and CVICU patient rooms ....