Are night "episodes" of increased HR normal?

A month after implant surgery, mostly at night but sometimes during the day, I'm experiencing episodes of elevated pulse with no physiological cause. 

My pulse abruptly goes from 65 (base rate) to 90-100 for periods of 2-5 mins, perhaps 8-10 X a night. These episodes involve more than just increased BPM: it feels like my heart is 'pounding' and it wakes me up. Subjectively, it feels like my ventricle goes rogue and disassociates from my atrium, beating at it's own pace - but I could be wrong, of course. It stops just as abruptly.

This is definitely me, not my PM - it's set to rate response (motion detection only), and I'm laying still when this happens.

I'd appreciate any thoughts on what this might be?

Thanks for your advice/opinions,




Same here at first

by Gemita - 2021-11-05 15:43:44

Jerry my first post here was about "nocturnal tachycardia".  It was very uncomfortable but my doctors were not overly concerned.  My heart rate would suddenly race from 70 bpm (my set base rate) to well over 120 bpm in a flash (flutter like sensation and a regular beat).  Yes it used to wake me and it did scare me especially since I thought my pacemaker might have caused this.

All I can say is that for me it was normal to experience sudden, intermittent fast heart beats lasting for seconds to minutes, at worse for a few hours.  But this all settled down after a few months.  Unfortunately I do have arrhythmias which as you know cannot be controlled by the pacemaker, so I am very used to this happening.  Since implant in May 2018, I can honestly say that my pacemaker is helping me to stay in normal sinus rhythm and helping me to keep my rhythm disturbances under firm control, but this is quite unusual and some are not quite as lucky.

All you can do Jerry is perhaps to ask your doctors whether you could have some additional "external" event monitoring to try to capture exactly what is going on, although a heart rate of up to 100 bpm would still be within the normal range of (60-100 bpm).   Anything over 100 bpm would be classified as "tachycardia"

Chronotropic Incompetence?

by AgentX86 - 2021-11-05 18:52:47

If you're not chronotropically incompetent (your SI node is still functional during exercise), it could be sleep apnea.  If your PM is not running everything, no, there is another explination.

When you say it feels like your ventricles are taking off without your atria.  How do you know?  You feel your ventricals contracting (or the results of it) but not your atria.

For some time after implant, all sorts of things happen as the heart gets used to being bossed around.  This could be one of them but it never hurts to ask.  This is a case where it might hurt not to.


Thanks Gemita and Agentx86

by Jerry10 - 2021-11-06 15:52:59

Thanks to both of you, this was very helpful. 

I'm definitely chronotropically incompetent - prior to implant my resting pulse was 35-40 and I had to work out like mad to get it over 100 or so. My new PM will take me as far as 140 BPM (max setting at the moment) if I really bounce it around for several minutes, which is great. (Mode is set to DDDR, so motion detection only.)  Indeed, I'm starting to wonder what working out really means if I can get a cardio workout by tapping my chest for a minute or two. :)

I realized recently that whatever my nightly tachycardia issue is, it's not entirely new. I've had this since I was a kid, but it was very rare, often going years with no "events". Indeed one reason I gave up caffeine about 10 years ago was to reduce incidence of these events. Now it's 8-10 times a night and for much longer stretches - one was 90 minutes!

Gemita, I will certainly be patient for a few months and hope this will settle down.

That said, I do want to thoroughly understand what this is, i.e. get a proper diagnosis. To do this I need an EKG when it's happening. I know the Dr.'s office can wire me up for an overnight, but I just discovered that you can buy a 6-lead EKG machine for home for about $125 US. It's much more sophisticated than my Apple Watch, which only does a 1-lead recording. The reviews say it works very well, gives the same results as a professional machine. One of the reviews is even from a cardiologist who uses it regularly.

So first I'm going to try to capture the culprit in the act. Hopefully my doctor can learn something from the recording.

Agentx86: "When you say it feels like your ventricles are taking off without your atria.  How do you know?  You feel your ventricals contracting (or the results of it) but not your atria."

Well I can't really tell what's happening, or distinguish atrial from ventrical contraction, but what I definitely feel is that during these episodes not only does my pulse go up, which itself wouldn't worry me so much, but that my heart beats much more strongly, likely pumping as hard as it can. I suspect Gemita might have experienced the same thing. Given the strength, it's a bit alarming, and definitely wakes me up. I'm trying to sleep and my heart is running a 100-yard dash. I also have a sense that there's a lot of other uncoordinated activity, so I'm just guessing that my PM is pacing my atrium, and my ventricle is doing it's own thing independently.  One way or another this must have some health consequences.

If I find out anything interesting I'll try to update here ... thanks for the info and support!



The Kardia Mobile ?

by Gemita - 2021-11-06 18:46:40

Hello Jerry,

Yes the Kardia Mobile 6 lead might well be worth investing in and my EP also initially suggested I buy one.  Eventually they implanted a gem of a monitor, the Reveal Linq, which stayed in for three+ years and gave my doctors all the detail they needed.  It actually detected many different arrhythmias from multiple sites which were often missed with short term monitoring.  In fact it was fundamental to my being offered a pacemaker and getting a proper diagnosis (tachycardia/bradycardia syndrome, with pausing and evidence of syncope).  

I am now 100% atrial paced because of sick sinus syndrome.  I also pace in the ventricles about 4% of the time although this figure fluctuates.  My pacemaker has a feature set up called "Mode Switch" which prevents the “tracking” of any atrial tachyarrhythmia, thereby preventing a rapid ventricular paced rate in response to the rapid atrial rate.   See link below for detailed "Medtronic" explanation of Mode Switch.  This is performed by placing the device in DDIR mode until the episode is over.  On cessation of the atrial tachyarrhythmia, my pacemaker switches back to AAIR Mode where I feel more comfortable until the next tachyarrhythmia and switch occur. It is a good protective feature but I can certainly feel the switching, especially if my atrial tachyarrhythmias occur multiple times in a 24 hour period.

Yes I am afraid arrhythmias can causes a lot of uncoordinated activity, which can make us feel truly awful and interrupt the normal flow of blood in the body.  I can tell instantly when my heart loses rhythm or when normal sinus is restored. I can usually tell from my symptoms too what arrhythmia I am in and whether it is irregular or regular and how high or low my heart rate is.  I still believe your present increase in symptoms is likely due to trauma of implant and will settle, but yes if you have started getting regular arrhythmias, these need assessing/treating.

Nocturnal Arrhythmias

by Selwyn - 2021-11-07 08:13:44

To be aware of the problem is half the battle. The other half is to know what is causing the fast heart beats - some of this could be dangerous arrhythmias.

I would advise proper monitoring ( eg. a 48 hour ECG or similar). See your doctor.

My pacemaker was implanted because of such problems at night. During the day I had some palpitations, at night, asystole. Who knows what is happening when you are asleep?

It is good to wake up in the morning.


My 2 cents

by TLee - 2021-11-08 12:03:00

I asked my cardiologist why my arrhythmia seemed worse at night & he had a simple (maybe too simple) explanation: Because when you are at rest it is more noticeable. I wore a monitor for 4 weeks, and they could see that things were actually happening a pretty good percentage of the time, but maybe I was blaming other things whie I was awake & active. I think more detailed monitoring is a good idea. Good luck!

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