Another "not bad, but different" question

• by SteveE
• 2014-08-05 05:08:59
• Checkups & Settings
• 1448 views
• 3 comments

This may be a long story, but please stay with me – I need to set the stage for my current questions.

My pacemaker (Boston Scientific S603, DDDR) was implanted 3 ½ years ago when I went into complete heart block following aortic valve replacement. At time of implant, I was 100% paced. Over then next couple of years, my intrinsic pacing grew stronger and more dependable, so my EP began carefully lengthening my A-V delay step-by-step to allow for whatever underlying intrinsic pacing I might have. At his last adjustment, atrial pacing was down to less than 25% of the time, ventricular was about 35%, and feeling fine. This was great, but I live about 20 miles of city traffic away from the EP’s office, and had to take half a day off work each time I went there.

About a year ago, at my “local” cardio’s recommendation, I moved my semi-annual PM interrogation to their local EP, rather than the big downtown clinic I had been going to. At the first interrogation at the local clinic, the EP and tech made some setting changes – supposedly turning on something like “auto-voltage sensing” to try to improve battery life. About an hour later I concluded that I felt just terrible. I made it through the night but went to the emergency room first thing the next morning, demanding that they bring in a Boston Scientific rep to “put everything back just the way it was.” As soon as the tech adjusted the PM, I immediately felt “back to normal.” I crossed this EP off my list.

Fast forward 6 months to my next interrogation at the downtown clinic. Interrogation was fine, I felt fine, but was surprised to find that although my atrial pacing rate was still about 15%, I was being paced over 90% in my ventricle. Since I felt fine, we went with it.

Now, after another 6 months, I have had another interrogation downtown. This time I got the “Alpha Tech.” She is Device Coordinator for the entire clinic; she really knows this stuff. She asked if I knew why they had my A-V delay set so short when my intrinsic pacing was strong and regular. I had no idea, nor did she. She lengthened my A-V delay about 30 msec to allow for intrinsic pacing. She said that I would not feel or notice anything due to this minimal change, but that my battery life should show improvement at the next interrogation. She said very clearly “You are NOT pacemaker dependent. As we speak, your heart is pacing naturally and the PM is just there in case of missed pulses or slow rate (I had bradycardia prior to valve surgery).”

Since this last adjustment, I feel fine, just as normal as I have ever been since having valve surgery, BUT I occasionally feel short periods of “hard” or “pounding” heartbeats, especially after exertion like climbing a couple of flights of stairs. I do fine in the gym, but occasionally have these episodes. No light-headedness or fainting, etc. Just “bump-bump-bump.”

So (finally) these are my questions:
1. Any ideas what could be causing this “pounding?” As far as I know, the A-V delay is the only adjustment made.
2. Is this likely to subside? Will I (or my heart) just “get used to it” and stop noticing it?
3. Should I worry about it and/or demand a re-check?

I feel normal (for me), so I’m just looking for some reassurance, but since I don’t know what the cause might be, I’m anxious.