HR dropping below set pm rate

Hi all 

I was admitted to hospital today in the ambulance and in the ER ECG Showed my HR going as low as 40bpm my pacemaker is set at 60 showed pm capturing it but not increasing the rate like it should... i only have single lead turned on atm ... no one here could explain why.. my cardiologist is at different hospital...

Thought someone may have had this ,who could fill me in. 



Rate dropping

by AgentX86 - 2020-05-24 08:38:33

With only a single lead operating, I'd guess that you have a heart block (second degree Mobitz-II) going on. If so, it's time for the ventricle lead.


by Beattie - 2020-05-24 08:43:27

Ithanks heaps AgentX86  will text my cardio tomorrow.. 

They also took pulse manually and got same result .  


Rate drop

by AgentX86 - 2020-05-24 12:26:24

Is your heart beat regular or are you feeling two beats, then one dropped?  Since your heart rate is 2/3s of what it should be, it sounds like 3:2 conduction which would give the stutter feeling to the heart beat.

1 lead

by Tracey_E - 2020-05-24 12:37:11

If you have one lead and heart block, it's a ventricular lead. With av block the pacer makes sure the ventricles beat when the atria does, so it's playing follow the leader rather than setting the pace. If your atrial rate drops, there's not much the pacer can do without having the second lead to bring it up. You'll also want to be sure the lead is working properly. But for sure you need to be seen asap if your rate is getting to 40. Something is not right.

1 Lead

by AgentX86 - 2020-05-24 14:51:54

Tracy, how does one ventricular lead work with heart block?  How does the PM sense the P-wave without an atrial lead? Wouldn't a single ventricular lead mean it has to be VVI(R) (and the associated AV dyssynchrony)?

My assumption was that he had a single atrial lead for SSS (or some such) and that now has developed some sort of heart block (sounds like a 2:1 Mobitz-II but could be otherwise).

Atrial Lead

by Beattie - 2020-05-24 18:06:47

Thanks all, 

I have just an atrial lead that is set at 60... 

Yesterday i was feeling unwell after a stomach bug, i didnt think to check my pulse b4 the ambulance came, but i had several small blackouts about 6 or so.. and bloods at hospital have showed Acute Kidney failure as well... 

Last night i was getting the skipped beat feeling.. and now my BP is very low for some reason(?) I always normally have high BP so they have stopped all anti hypertensives..


by AgentX86 - 2020-05-24 21:24:47

Sorry to hear about the kidney problems.  That's not good.  Hope they can clear it up quickly!

I'm confused by your bio.  In it you state that you had a PM implanted because of a Mobitz type-2 heart block but above you say it only has one atrial lead.  That doesn't make any sense.  It would seem that your symptoms are exactly because of this odd combination.  For any heart block the PM has to have both an atrial and ventricular lead to maintain AV synchrony (atria and ventricles in sync).  I don't understand why they would have done this.

I have only two ventricular leads because the AV dyssynchrony is a "feature" (to stop flutter run amok) but it's unusua.


by Tracey_E - 2020-05-24 22:23:01

They do one atrial lead for SSS, one ventricular lead for av block. Agent, I have no idea how it senses!  But that's how they do it for av block.  Sounds like a lot more is going on than just pacing.

Or! Beattie, do you have bundle of HIS pacing? 


by AgentX86 - 2020-05-24 23:05:09

Yes, I understand the 1 vs. 2 leads and SSS vs. HB but he has a PM with a single atrial lead operating, no ventricular lead ("I have just an atrial lead that is set at 60..."), for a Mobitz-II heart block (implanted in 2017).  That makes no sense to me.  Something's wrong. Did a doctor somewhere along the line decide he didn't have HB?  Wow!  That's going out on a ledge.

Not sure

by Beattie - 2020-05-24 23:23:10

I am not sure myself why they are only using one lead atm. My diagnosis was Mobitz II.. + IST by the Electrophysiologist that put it in. He told me this plus its also on my discharge papers.. 

Have contacted my cardiologist this morning who wants to see me as soon as i get out. So hopefully can get some answers fast! 

Thanks all will keep you posted. 

Rate dropping

by Dave H - 2020-05-25 17:20:05

Hey Beattie: Lots of good advice caviate, though..................the PM club - as well as other sites, i.e. Stop AFib -  has its own "troll" who doesn't give much more than sarcastic answers to anyone posting.  In time, you'll figure out who it is. Ignore him.

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