Rate Responsive Max Not Working

Hi!

I'm 29 years old, and I had a St. Jude rate responsive dual chamber pacemaker placed in 2007 after a total sinus node ablation due to supraventricular tachycardia, after several failed partial ablations. Over the past few days I have felt my heart rate racing during exercise. My max is set to 110bpm, and no higher because the doctor is concerned of a triggering of SVT if the ablation were to fail again.

I can count it beating near 140bpm during simple exercise, with some shortness of breath, and then it slows quickly as the pacemaker would if it were beating 110bpm, and returning to the set min of 60bpm. I'm concerned since I have never counted a heart rate over 110bpm at anytime since implantation.

Does anyone know the reasoning's for this. A sensor, or lead issue? I'm not concerned about the ablation wearing off since it only happens during exercise, and am still needing to be paced at rest. The battery seemed to have 1 1/2 years left 6 months ago. I see the doctor next month, I'm out of town for the holidays, and unable to see my doctor, but will go home if needed. Any help would be appreciated. Thanks!

5 Comments

Thanks!

by tactheemt - 2012-12-12 06:12:40

Thanks snitch! Sorry to hear that you have a pacemaker at a younger age as well. I had 6 sinus node modifications that all failed. However, the complete sinus node ablation was nearly complete since my heart rate was in the teens after the ablation. I should have added I also had the AV node ablation done as well. During my last check-up when the pacer was turned off the rate was the same it had been since the ablation which suggested to the doctor there was minimal failing of the total ablation since the procedure which was good.

Rate responsive pacemakers using the accelerometer sensor works very poorly during bicycling because it involves minimal movement of the upper body, so if you have a pacer that has other sensor methods it may bring you better results during that activity. I'm sorry to hear you have poor exercise results with your pacemaker.

I have event warnings that go off at 120bpm that triggers recording so, you're right the doctor will see the increased rate, however I am on a high dose of beta blockers for inappropriate heart arrhythmia's PVC's, & PAC's.

The medications I take do control rate as well, so it wouldn't be possible for the heart to beat that fast on it's own during exercise. The rate also declines at the same rate as the pacer is set to lower the heart rate back to 60 after exercise, which is set fairly fast, which makes things uncomfortable when beating so fast. If my heart were beating on it's own at that rate, it would have an appropriate recovery time, and wouldn't slow to 60bpm under the same recovery time that is set on the pacemaker. Which is what makes me think it is not my heart, but the pacemaker instead. The last check up showed that I am being paced at 100%, and my resting rate is never any higher than 60. I am keeping faith in this last ablation. ;)

I've also recently achieved a 100 pound weight loss, I wonder if the pacemaker being closer to the skin, and not under a layer of fat is causing an increased sensitivity, since it now moves more during exercise than before which triggers increase. Honestly, I have no clue why it is happening. Thanks again!

I'm just going to wait to go in next month, and am avoiding strenuous exercise due to shortness of breath. If anything interesting is the cause, I'll be sure to share it.

Thanks TraceyE!

Your advice of waiting until vacation is over made my decision (and others approval of it) so much easier! ;)

pacing

by Tracey_E - 2012-12-12 07:12:40

If your pm is only set to 110, then that's your heart going over that on its own, not pacing. As long as you don't feel bad or have very high rate at rest, it can probably wait until after your vacation is over to be checked. Write down the day/times you have episodes so they can check the reports.

Sinus rhythm or other kind of supraventricular rhythm

by golden_snitch - 2012-12-12 07:12:43

Hi!

Having had sinus node ablations myself, I would guess that the sinus node has recovered a bit or that some other atrial rhythm is able to go faster than the pacer is set. However, I'd not worry too much, because of max. heart rate of 110bpm at your age is way too slow. I often have around 120-130bpm when going for a walk, and my cardio says that's perfectly normal at my age (31). So, 140bpm should not be a problem, as long as you don't get this at rest. Not a sensor or lead problem, I'd say, just your own heart rhythm.

Also, my experience is the other way around from what your doctor says: If I exercise and the pacer does not increase the heart rate enough, this triggers all kinds of other rhythms to take over and go faster. For example, my pacemaker adjust very slowly, if at all, when I ride a bike. So, when I do a bicycle ergometry what used to kick in, before my AV-node ablation, was a junctional rhythm.

Your pacer will probably have recorded some episodes of atrial tachycardia when you go for your next check-up. If not, you can get a holter monitor to find out what kind of rhythm is kicking in when you exercise.

Best wishes
Inga

P.S. A sinus node recovery is not unheard of, I have had it again and again. You cannot ablate the whole sinus node because it's actually not a node, not a clearly defined structure within your right atrium, but covers an area - looks different in everyone - with lots of heart cells with an increased electrical activity. No EP gets them all.

Sensors

by golden_snitch - 2012-12-13 03:12:37

Hi!

I know about the bicycling problem. I actually do have a pacemaker with two sensors, accelerometer plus minute ventilation. However, ever since I've got epicardial pacemaker leads, the minute ventilation sensor has stopped working. It cannot sense properly with leads outside of the heart. So, it's accelerometer only.

Six sinus node ablations?! Did you ever have a venography/phlebography to check your vena cava superior. I ended up with superior vena cava syndrome after four sinus node ablations due to all the scar tissue caused by the ablations. Needed open-heart surgery to correct it. Now, my cardio wants all patients that undergo sinus node modifications to have a venography about six months after the ablation to check for stenosis. I got to meet to other patients here in the forum who also had superior vena cava syndrome after sinus node ablations. My first symptoms were shortness of breath and pressure in my head/neck when lying down or bending over.

Best wishes
Inga

Thanks!

by tactheemt - 2012-12-13 10:12:52

Oh my Igna, you have really been through a lot! I wish you the best with your heart! I haven't heard talk of superior vena cava syndrome, and never had the procedures venography or phlebography, but with the info will speak to the doctor about it. I only see an electrophysiologist, and left the cardiologist after he missed a CHD thankfully the electrophysiologist caught, and never went to another one. I think I will have to get back in with a cardio to be sure everything else besides the pacer/ablations is doing well too, but will mention it to the electro next month. I don't have many of the symptoms seen with the syndrome though, which is great.

I do have frequent echos because of the CHD, and low ejection fraction, but not sure if that catches this you are speaking about caused by an excess of scarring, which I have heard the doctor mention with multiple ablations. ;)

Again, I wish you the best with things, and I'm so sorry you have been through so much!! Thanks so much for your info and help!

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