are these settings typical for bradycardia?

Hi all. I have either a sinus node problem or a vasovagal issue (they're not sure) where my heart spontaneously slows way down and I experience syncope. I had a dual-chamber pm implanted a few months ago and understood that it was set to kick in if my heart rate drops below 50bpm. Indeed it is, but it's apparently also set for other kinds of interventions as well. I discovered this when I repeatedly experienced a tickle when exercising and asked the tech to look at the data I uploaded. Apparently it is set for two additional things:

(A) If I experience tacycardia (>180) it "stands by in case of pause".

(B) If the heartbeat signal isn't propagating from my atrium to ventricle it will pace the ventricle according to the atrium beat up to 150bpm. This was the tickle I was experiencing because (I'm told) I'm young and in good shape so the atrial lead was sensing the very strong beat of my ventricle and the PM was counting 2x atrial beats, leading the PM to go into "mode switch" (http://www.medtronicfeatures.com/browse-features/all/CDF_DF_MODE-SWITCH). I *think* this means I was ventricly paced while exercising (?).

I have no history of heart block so I find it weird that this intervention is enabled. The tech assures me that it's totally standard and "just in case". However I've already experienced the unintended consequences of this "protection", and knowing little about it I'm not excited about having interventions enabled that I don't need. So: is this a normal thing to have enabled for someone like me?

Thanks so much!

2 Comments

Bradycardia then syncope

by Runningmama - 2014-11-19 06:11:25

My heart slows down the same way, like out of nowhere bradycardia happens, then comes the presyncope ( I spent a while learning to avoid full syncope). I have stage 2 av block type 2, my longest pause is like 3.5 seconds while sleeping, the lowest rate is 37.

All that being said, I had a Micra TPS pm implanted 9 days ago. It is a single chamber device that is set to only "react" when my heart rate goes below 50 . My EP advised this is the "fix" for my condition and that I didn't need help when my heart rate was elevated during exercise even though I have sudden symptoms. The device will keep me from experiencing the "episodes" when my heart rate drops, like during a random bout of bradycardia, pause, etc. regardless of the ambient conditions....

I'd love to hear what you come up with. While I am happy that I have minimal interference so to speak, I do worry that I may have needed a bit more "hardware".

Best Wishes and please do keep me posted. Thanks!!!!

Thanks for finding info

by Theknotguy - 2014-11-19 09:11:12

Thanks for finding the web address of Medtronics that goes into detail about how decisions are made for various heartbeat issues. It is really helpful especially since the APP feature has been turned on in my PM. It's given me a great reference point. Especially since my
online searches with Medtronic usually end up in a dead end.

I feel, however, your question is beyond the scope of this forum. It should be discussed with your EP, an EP with your medical insurance, and Medtronic.

While I'd love to see the decision flowchart as to how they arrived at the various heartbeat scenarios I'm pretty sure they'll tell you it's proprietary information and leave it at that.

Some of the things we see with our newer PM's are on the leading / bleeding edge of medical science. To some extent we are all guinea pigs but each advance helps thousands of other people. When they first turned on APP with my Medtronic PM the EP said the jury was
still out on whether or not APP would help with afib. Since APP has reduced the number and intensity of afib sessions for me I'm grateful I've had it turned on. Medtronic did just recently advise EP's their APP software function did help patients with afib but that was through an internal survey by Medtronic.

As for question "A" - it has been standard settings for the PM to go into a standby mode if your heartbeat goes above a certain level. I think mine is set at 120. So when I went into afib with RVR the PM just sat there and observed. While lying in bed, having a heartbeat go up to
140 is uncomfortable enough let alone having the PM jump in and intensify the situation. Why they have decided to do that is a good question for you EP. I'll ask mine the next time I see him.

Question "B" - that's really for your EP, your medical insurance EP, and Medtronic. Why that particular decision tree goes that way is far beyond me. Should the setting be changed? That's between you and your EP. Reminds me of the old joke where the auto mechanic compares himself to a doctor. The doctor agreed what the mechanic did was similar to what doctors did. "But.", he said "Did you ever
try to fix a car with the engine running?" While you may not like the settings, changing them could have consequences resulting in your engine not running. Want to take a chance?

Another item to consider is that my heart went wacko right after the PM implant. When I go back and look a the PM graph you can see where my heart gradually gave up trying to keep any kind of regular heartbeat rhythm. Kinda scary to think I went from a natural heart beat to an artificial heartbeat but that's what the PM does. So your heart may not have had time to settle down into the new situation. Just because they stick a PM in doesn't mean it's an instantaneous fix.

I sense frustration on your part where, "They didn't get it right! Fix it!" Sorry but heart problems and heart medicine aren't an exact science. While there have been huge strides made in just the last year since I've gotten my PM there still is a very big area for which they have no answers. They aren't going to be able to "Fix it" and you'll have to live with the situation for now.

For example, got into a discussion with my EP about my afib. The discussion boiled down to - your grandparents swam in the wrong gene pool. They don't have an answer as to why I have afib. As far as they are concerned what triggers it is random. The only "fix" is medication and ablation. Some of the medication wasn't available ten years ago. Some of the ablation techniques weren't available five years ago. The
APP software function programmed into my PM I don't think was available until this year. If it weren't for those recent medical advances my life would be very grim. I'd be doomed to living most of my life lying in bed with afib. My only hope would be to get a heart transplant, or die quickly so I wouldn't have to live in pain.

I hope you can get some answers from your EP or Medtronic. I'd really like to see what they say. My best wishes for you.

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