I, too, had my surgery with Dr. McCarthy at NMH. Due to all sorts of complications, I was not ready to start rehab until 12 weeks post-op. (I went back to work at 6 weeks, but wasn't cleared for rehab until later.) I did not even look into rehab at NMH due to the rigors of the commute that would be necessary, and the fact that I work out in the suburbs. Also, we live out on the Northwest corner of the city.
I did my cardio rehab at Advocate Lutheran General Hospital in Park Ridge. I cannot say enough good things about the program there and the staff. In my case, it was a 1-hour session, 3 days a week. They encouraged self-managed activity on the "other" 2 week days. Since I had been a 5-days-a-week gym rat before surgery, I was right at home doing rehab on 3 and my own gym on the other 2.
The rehab center at LGH has room for 8 or 9 patients in each hourly session. The staff consisted of 3 cardio rehab technicians and one administrator. They kept a close watch on all of us, both visually and electronically. The "class" of each session bonded together, and we had a great time. It is true that the patients in your class may be in rehab for a variety of reasons (stents, bypass, valve or other heart surgery), and we compared notes quite a bit. They had weekly discussion sessions on the lifestyle management aspects of rehab, but most of the time was monitored physical activity.
For me, it was wonderful. After the valve surgery, complications, bypass and surprise pacemaker, I was a bit unsure of my body. They helped me to realize just how tough the human body is and how far I could push mine. It was such a great experience that I still go back to visit occasionally, just to thank them for their support.