Three month appointment intervals

Hi friends, 

I have a Medtronic Azure, dual lead pacemaker.  It's been implanted for almost three years now.  I'm copying the notes from my last appointment a couple of weeks ago.  Some of you have fairly deep knowledge of what the notes below might indicate.  I'd appreciate your comments, particularly on what may be causing the 'noise'.  Many thanks.


Routine pacemaker follow-up intensified for RV lead watch. Device appears to be functioning appropriately. 43 ventricular high rates noted, EGMs reviewed appear to be likely noise on ventricular lead as noted previously. Ventricular senses appear slightly irreg. Able to recreate noise in clinic with myopotential muscle movements-pushing hands together. 2224 short v-v intervals noted. Remains UNI sensing. No programming changes made today. Next clinic assessment will be in 3 months. (Technician sign off, doctor to review)

Data reviewed, tracings do suggest "noise", no symptoms at present but will continue to need close follow up.  (Doctor's sign off)



by AgentX86 - 2023-02-01 22:58:59

Noise indicates a failing lead.  "Follow-up intensified for RV lead" means that they want to check it more often to make sure it's not getting worse.

"43 ventricular high rates noted, EGMs reviewed appear to be likely noise on ventricular lead as noted previously. "

Simply means that they detected some ventricular tachycardia but on inspection it was just the noise.


by BradyJohn - 2023-02-02 00:30:09

Thanks AgentX86.


by Tracey_E - 2023-02-02 12:34:59

I would say aging is a more accurate term than failing. Noise can come from ruptures to the insulation, growth of scar tissue, things like that. Average lead life is 15 years, some make it much longer than that, some don't make it quite that long. As they age, they develop noise.

Mine was a rupture to the insulation and we kept an eye on it for a full 5 years before replacing it. All they do is monitor if it's stable. I would add it to your list of questions for future check ups, is it still stable?

The first thing they will do when a lead shows a drop in function is try to program around it. Another question to ask is have they had to turn it up to get the signal through? If yes, know that will shorten battery life. Think running the air conditioner with the windows open. The house cools, but the power bill goes up. 

As long as it's stable, they will hold off and replace it when you get your next device. 


by BradyJohn - 2023-02-02 15:37:29

Thanks Tracey_E,

How big a deal is it to replace a lead?  I've seen some stuff online that suggests it can be somewhat risky.  And, aging would seem a bit odd, since I've only had it three years.

Many thanks,




Just a few thoughts

by Gemita - 2023-02-02 16:16:50

Hello BradyJohn, thank you for sharing your clinic notes with us.  That is how we all learn.  I agree 3 years is no age for your leads and I am wondering just what has caused this? 

I see that the notes from your last visit state that no programming changes were made on the day of your recent appointment, so I am assuming that unless changes were made earlier, the RV lead is stable at the moment and you are free from symptoms it appears which is also a good sign?  

Your notes seem to confirm your pacing/sensing polarity is Unipolar as opposed to Bipolar, if that is correct?   Could Unipolar pacing and sensing cause any noise I wonder.  Anyway, perhaps another question for your team?  I think many of us are pacing/sensing Bipolar.

I wouldn't worry about your leads at the moment.  Just keep an eye on any new, or worsening symptoms and report these, otherwise they are keeping a close eye on you.  In expert hands, lead replacement should not pose a significant risk to you, but you need to look for a surgeon with lots of experience.  I hope for the best for you BradyJohn


by BradyJohn - 2023-02-02 21:42:24

Thanks Gemita for your care full thoughts and advice. 



Bipolar vs. unipolar

by AgentX86 - 2023-02-03 16:16:01

Just some information...

Think of a lead as a headphone cable and connector.  At the business end there is a pointy thing ("tip") and a cylindrical "ring" around the tip. The tip is buried in the heart wall and the ring just outside.  When "bipolar" pacing is used, the tip is negative in relation to ring (positive). The term "bipolar" means that the lead has both the voltage and return in the same lead. Remember, for an electrical signal must be a complete circuit.

"Unipolar" then means that the lead only supplies only the pacing pulse.  The returm is the case of the pacemaker.

At one time, all pacing was done "unipolar".  There was only one wire in the lead.  Bipolar pacing is an improvement in that the bipolar lead now has both the pacing pulse and its return in the same lead. The result is thate the pacing is very localized to just the heart so the loop area of the circuit is small.  This greatly reduces any potential electro-magnetic interference.  Because of this, bipolar pacing is considered superior because of the reduced chance of EMI caused over-sensing.

Monopolar pacing just uses the probe tip (the leads are really the same but only one wire is used) as one electrode and the case of the pacer as the other. The pacing current then passes from the lead tip through the heart, lung, and back to the can. The loop area is quite large and makes a better antenna for EMI (not desired, of course).

In my case my RV lead is bipolar for all the reasons above.  My LV lead doesn't sense (just plays tag-along with my RV) so it's programmed unipolar. The advantage here is that, since the circuit includes the lung, the impedance of the loop gives some indication of the resistivity of the path and fluid buildup in the lung can be deduced from changes in the pacing impedance. It's some additional "free" information that the pacer can give.


by BradyJohn - 2023-02-03 22:22:48

Thanks AgentX86,

That is helpful information.  Do you know if my pacemaker can be programmed for either bi or unipolar? Or does it depend on the leads that were used? 

Also,  to Gemita's question earlier,  I am not experiencing any symptoms,  other than a huge improvement from my pre-paced life. 

Cheers,  and thanks again, 


Unipolar of bipolar

by AgentX86 - 2023-02-04 00:24:30

I believe all pacemakers can be programmed either way.  Not all have the fluid measurement feature (though impedance measurement is always there).

Leads, at least modern leads, are bipolar. A bipolar lead can be used for unipolar pacing just by disabling the positive lead and sensing through the case.

Understood. Gemita mentioned uni/bipolar so I thought I'd just explain the difference.


by Tracey_E - 2023-02-04 17:00:38

They tried that on mine when we were babying the lead. I couldn't stand the feeling and asked them to change it back. It was like I could feel the shock with every beat. Very disconcerting. 

Getting a new lead. As new as yours are, they may want to take it out and start fresh because the longer they are in, the harder they are to get out. Getting it out now should be easy. Years ago this was a high risk surgery but now it's routine when done by someone experienced. The lasers they use have come a long way, and it's much easier to find an experienced surgeon. 

Another option is add a new lead and cap off the bad one. I opted for this 10 years ago. My other original lead is still going strong. But that is not the common/preferred way to do it now. My leads are very old with nearly 30 years of scar tissue so removing them will be high risk. I chose to wait and gamble that technology would continue to improve so that by the time I have no choice but to extract, it will be lower risk. And that's what has happened. But that old lead just keeps chugging along, stable as can be! 

If you do a search for extraction, you can find a lot of info on the surgery itself. They go in through the groin with a laser and remove the old lead mm by mm. 

Thanks Tracey and AgentX86,

by BradyJohn - 2023-02-04 23:48:45

I really appreciate the shared experiences and information here. I'll be going to my next appointment much better informed. 

Take care, 



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