I would definitely go see another doctor; they may not have answers either and you may have to find a larger practice with alot of types of patients to find the right answer, it may be something as small as a setting or rate response not being on or it may be something else entirely; maybe related to the surgery he had.
I still haven't found my answers but will keep looking until someone can tell me WHY I'm still having problems =) when a PM/ICD was supposed to correct alot of my problems. My FiL is 78; had 3 heart attacks years ago; fainted 2 years ago and needed a PM/ICD also and he's not had 1 problem - but I'm 43, had mine implanted 1 year ago and have had nothing but problems - so it's not always the same for everyone.
good luck and I hope you find the answers for your husband
I do not have any personal experience with a pacemaker but I know two people (both older than you, and me for that matter) who wear a pacemaker and they seem to get along well. As said, they are older, and so have no "need" for high aerobic activity... still from what you say your husband's problems are at rest or just moving around (walking). This isn't as it should be, if the doctor can't suggest something to help you may want to seek a "second opinion".
This post will push your post back to the top of the list, you may yet get more helpful input here.
Wishing the best and soon.
Gosh, I am so sorry that your husband is still feeling under the weather. I have a pacemaker and have had it for many years. I had a difficult time with the settings initially and kept going back to have it interrogated and settings changed. I was lightheaded prior to the pacer due to low bpm (i was pacing about 38 bpm) . At best, work with the pacing clinic to see if some settings can be changed to help him out.
ksig