Kitty, Monitors are not "bad" to have on board. Even now, at 2 years post-op, I use one. In fact, I used one for the 4 or 5 years before surgery as well. I don't obsess about how high my heart rate goes any more, although in those first 6 to 12 months I did. Now I realize that I can't "break" my heart, and it just will not go any faster than it can. Now I use the monitor to gauge just how hard to "push" myself. Some days I feel better than others, and if my heart rate goes up to the 150's at low effort level, I dial it back that day. Most days, given my bike/walk routine, I only get up to the low 130's, but if it goes higher I don't worry.
For me, as a pacemaker patient, the monitor serves an additional purpose. Under some circumstances, if my heart is being paced electronically but the pacer senses the need to go really fast (above the top speed setting), I am told that the pacer will start to skip beats - actually dropping to half the "required" speed. If I see this happen, I need to slow down and let things settle back to normal before proceeding. I've never seen this happen to me, but others have experienced it, so I watch.