Maybe a Dumb Question, But I was Wondering
Is it possible for the rate response feature in a pacemaker to overcome the chronotropic incompetence caused by ( or is contributed to) medications such as beta blockers or calcium channel blockers in a patient with sick sinus syndrome who takes those medications?
That's me. I've taken metoprolol for over 19 years, and diltiazem for most of those 19 years, to control atrial tachycardia and hypertension. Side effects from these drugs only lasted a couple months when I first took them, and they did a fairly decent job of controlling the tachycardia and my heart rate was within the normal range till about 3 yrs ago. But I noticed pretty much from the get-go that I had a hard time when I exercised getting anywhere near my target heart rate, I'd get exhausted before that happened, so I just did the best I could.
So many years later, after the gradual, then accelerated ( it seemed) onset of bradycardia, increased incidents of the tachycardia (including some atrial flutter), and medication adjustments, I ended up with the pacemaker, and medication ( 50mg/day metoprolol and 360mg/day diltiazem) to control the tachycardia and blood pressure. I don't feel any side effects and the combination of these meds seems to work better than either alone for the tachycardia, and the blood pressure has responded to the increased diltiazem as well.
Before they turned on the rate response when I first got the pacemaker, I again couldn't get the heart rate up to close to the target rate ( that's about 130, I couldn't get it above 90 no matter what I did) during exercise. It was better after they turned on the rate response, though this still seems to be a challenge sometimes, though I have exercised for a number of years ( nothing like an athlete, though, but about 30-40 minutes six days/week on an elliptical/recumbant bike combination thing and arm exercises with weights, I'm almost 73 years old).
It might be my imagination, but I think it's getting better the harder I work at it, though that's to be expected with any exercise. It's certainly improved with the pacemaker. Still have to fight hard to get my heart rate to 120 ( that's the upper setting limit, lower is 55)- they set a tachycardia alert at 140, hence the upper pacing rate at 120 ( guess they assumed I was a old lady couch potato). If I get into tachycardia I can get the heart rate up to well above 140, but that's not exercise related.
I assumed all along that it had to be the medication that caused the bradycardia over time, as well as the chronotropic incompetence. But responses to changes in meds, varying dosages and the timing of the bradycardia indicated ( according to the EPs I saw) that I had an underlying "sick sinus" issue that was uncovered ( and maybe aggrevated) by the medication I needed to control the tachycardia. So I figure it's half me and half those meds, but whatever, the pacemaker seems to be doing most of the atrial pacing at around 91% at my last report.
So, I wonder if the rate control set on my pacemaker ( which does a great job at increasing the rate during activity) can also override the chronotropic incompetence that may be caused by medication, or will I always have to work through at least some of that. I'm just curious, I can certainly live with this.