Has anyone been switched from one make or model pacemaker to another and found it made a significant difference? I had my pacemaker implanted four years ago, when I was 68. I have never felt really well since, even though I felt generally quite well before the surgery. I had a few episodes of syncope but was overall quite energetic. Since the implant I´m tired a lot. I´ve seen several cardiologists. They´ve all insisted the pacemaker is working perfectly. Well, perhaps it is -- but I´m NOT. I´ve wondered if a different pacemaker would have produced better results. Are there pacemaker ratings anywhere? Have they been measured against one another? Is it possible that some are in fact superior to the rest?