pacemaker settings

I had a Medtroniic Azure PM implanted 4 weeks ago after a 7 day Holter Monitor which showed an average heart rate of 53 bpm.  I have bradycardia due to sick sinus node with periodic very low heart rate.   The cardiologist set the base rate of the PM at 40bpm and his tests showed it was pacing 80% of the time while i was in hospital overnight.  Since then I have been checking my heart rate and it is frequently at 40bpm.   It seems that my bpm is now consistently much lower than pre the PM.  I have not yet resumed my normal exercisee routine but find I am short of breath on relatively nonstress walks around the neighbourhood.  Prior to the PM my base heart rate was 50-52bpm.  Is there any explantion why my heart rate would now be consistently below my prior resting rate?


Welcome Ozzie

by Gemita - 2023-05-08 05:45:54

Ozzie, I have family in Queensland (near Brisbane).

You ask:  “Is there any explanation why my heart rate would now be consistently below my prior resting rate”?  

I would answer, electrical disturbances, like bradycardia, tachycardia, heart blocks can change at any time, and even be volatile, especially while we are healing from our pacemaker implant procedure and getting used to being paced.  I certainly had a worsening of my rhythm disturbances for up to 3 months following my implant, after which my disturbances settled and improved.

Looking at your settings, 40 bpm seems far too low a setting, particularly for any daily activities, although at night, or when you are at rest, it might be an acceptable rate.  I would let your doctors know that you are relatively short of breath on non stress walks and ask whether the 40 bpm lower rate might be too low for you?  Clearly your own heart is still able to work on its own approx 20% of the time, so if you increase your lower base rate setting to say 50-60 bpm, this percentage pacing figure will likely increase too, but if extra pacing support is needed, then it is needed? 

I hope you feel better very soon

Heart rate

by piglet22 - 2023-05-08 08:10:12

How do you check it?

Methods can give very different results.

Radial pulse for me is a lot different to that reported by an oximeter. The oximeter regularly over-estimates BPM. How you feel, low blood pressure, dizziness is more truthfully related to your actual pulse at your wrist.

Blood pressure monitors, especially those with arrhythmia detection are also better than oximeters.

As Gemita says 40 BPM is low enough to trigger concern for most people of average fitness.

I have a similar condition to you but with nearly 100% pacing. I was initially set to 60 BPM in 2005 and this was raised to 70 BPM this year.

I think that my pacemaker struggle s to cope with unusual electrical activity, but that's another story.

heart rate

by OZZIE - 2023-05-08 10:30:39

Thanks for the responses.  I generally use an oximeter but at times cross check it with a blood pressure monitor and there is good correlation.  I place the blood pressure monitor on my left arm and the oximeter on my right index finger.  

I was surprised that that my cardiologist set the base rate at 40bpm but although I am 78 years old, I exercise a lot and as noted usually had a resting bpm of 50 - 52, which I have had for the last 20+ years,  and this may have predisposed the setting of a low base rate for my PM.

Hopefully, my heart rate wil settle down and return to its previous base level and my current low rate is not the new normal.  I note that Gemita returned to a more stable level after three months.  Here's hoping.

new meds

by Tracey_E - 2023-05-08 11:48:45

Are you on meds that would drop your rate?

Do you have a history of pvc/pac? Those will throw off the count, little beats between the strong beats. 

I would ask to have that lower limit raised! Most set it at a min of 60, a very few will do 50. 40 is unusual. 

Agreed ...Setting too low ?

by IAN MC - 2023-05-08 12:38:23

A heart-rate of 40 bpm is, by definition, considered to be bradycardia so this may be causing your symptoms   ( a "normal" resting  heart-rate is usually between 60 and 100 bpm )

Your current base setting will stop you from fainting every time your sick sinus  causes your HR  to plummet but it may be too low a setting for you.

I was originally given a base-rate of 50 and felt MUCH better when they raised it to 55.     Hope you get it sorted.



by piglet22 - 2023-05-08 13:18:44

The reason I'm suspicious about some methods of measuring heart rate is that the physiologists I see always say the PM is fine and I think the ectopic beats I get, a recent development, are throwing the PM and maybe fooling it into counting the PVCs or PACs into calculating maybe 70 BPM.

It might be that my oximeter is not good at reporting the true BPM, the one that matters in my opinion, the pulse you actually feel. The optical method is quite sensitive and might pick up the weak pulses, whereas your finger or the blood pressure monitor does not.

The oximeter might report 70 BPM, but counting at my wrist returns nearer 35 BPM, and the blood pressure monitor which of course is reading the stronger pulses, is nearer the truth.

Part of the problem is that my reduced heart rate kicks in during the evening and at night when I'm relaxed and after exercise. On the few occasions that I get to go to a clinic, I'm usually not relaxed so the stock answer is "PM working fine".

As some of the others will know, I'm looking to record these relaxed ectopic episodes so that the medics can see what's going on in real life. Whether or not they take any notice is another matter.

Telephone or Message

by Penguin - 2023-05-08 15:22:52

Were you asked how you felt in hospital whilst this 40 bpm base rate was in place?  Sometimes we can report no symptoms because we're in bed or asleep for most of the time in hospital.  It changes when we leave hospital! 

40 bpm may be manageable for some people at night but 80% a.pacing suggests that your heart rate is also falling below 40 bpm during the day and the pacemaker is having to jump in.  Clearly you are struggling with this if you are feeling breathless. 

We can all guess as to why your base rate is set to 40 bpm, but as it's unusual for it to be set this low, it would be best (IMHO) to ask someone to explain the rationale to you. 

This alone is good reason to ring the pacing clinic and to ask why the base rate is set to 40 bpm and to ask whether it could be increased to relieve your symptoms.  





Have you had your first check-up yet?

by LondonAndy - 2023-05-08 18:48:25

I'm not sure if this is standard practice, but my understanding is that here in the UK a device is implanted without some key settings activated, such as "rate response", and that these are dealt with at the first check-up, a few weeks later. Indeed, I wonder if part of the reasoning for 40bpm is to see how your heart responds to it, providing a safety net but not much more, pending this first review.

But I agree with others: a 40bpm setting seems too low (I am 57yo and mine has been 60bpm base rate for the 9 years I have had it), and I would certainly ask for it to be increased given the issues you describe.

Day and night time settings

by BradyJohn - 2023-05-09 22:54:52

I agree 40 bpm is too low.  As I read the comments, Piglet22 and I might be 'symptom twins'.  My Medtronic Azure is set for 60 during the day and 50 overnight.  I too have some 'noise' and electrical issues, but don't notice them.  All the best Ozzie!

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