I have a couple of questions concerning a lead going bad. I have a medtronic dual lead pacer and the lead going to my upper chamber gave high readings during my last interrogation in July and will need replacement sometime in the future. My pacemaker works 40% of the time in the upper chamber (the lead that’s going bad) and in the high 90% in the lower chamber.
Questions????
How long can it take for lead to go completely bad?
If this lead quits working will my pacer still maintain its 60 BPM minimum??
Will I know when it quits working?

Thanks for any info

Tom

 

 

Hey Tom,

Since a "bad" lead can continue to function well enough for the pacemaker to assist your heart as needed, just having a "bad" lead does not necessarily mean its replacement is imminent.

How long it will take for a lead to go bad is a difficult question. As I understand it the condition of a lead is primality determined by its impedance. The lead may work fine for years, but depending on how high the impedance is it can shorten the life of the battery considerably. So when it is decided a lead must be replaced several things are taken into consideration. One, is lead impedance? Two, is the impedance going higher and how fast? Three, what is the estimated remaining battery life? Four how fast is this number decreasing? And it goes on from there.

Also a lead is a two-way street. The pacemaker uses one side, or one part, if you wish, to check to see if the heart's natural pacemaker is making the heart beat as needed. If the monitoring portion of the lead is defective, then the pacemaker may be doing little or nothing for the chamber of the heart that it is checking. Or, the defective portion of the lead could be giving faulty readings of the heart's natural pacemaker and the pacemaker will be sending an impulse when it is not needed. Or, lets look at the other side of the lead that carries the impulse from the pacemaker to the heart and if is defective and the impulse from the pacemaker will be weaker than necessary. This could cause the pacemaker to use more battery power than it should.

As for your question about will your pacemaker be able to keep your heart rate at 60 BPM if the lead quits working, I'll base this my answer on my experience. I was being paced 90%+ in the upper chamber and about 3% in the lower chamber. After 9 years, the battery on my Medtronic dual lead reached some predetermined point and my pacemaker shifted into something called VVI mode. This is a mode to extend the remaining battery life and meant it quit pacing the upper chamber and went to pacing only the lower chamber 100% of the time at a rate of 67 BPM. So yes, if your Medtronic is like mine it could maintain 60 BPM heart rate by pacing only the lower chamber. In my case this was uncomfortable to the point of being painful at times.

Will you know when it quit working, well just let me say I definitely knew when mine went to pacing only the lower chamber. However, keep in mind that in my case the change in pacing was brought on by a weak battery and not a defective lead.

As you continue to get PM checkups they will be looking at lead impedance and estimated remaining battery life and I would guess time of lead replacement will be determined by those readings.

Good luck,

Smitty

 

If there was ANY risk of it quitting working suddenly, you'd be getting it replaced today. They don't take chances. Either they work or they don't, so as long as it's working it'll keep you from going below your minimum.

How long it lasts depends on how the lead is going bad. I had one that got a kink in it and it ruptured through the first layer of insulation. The readings went up and that battery only lasted about 4 yrs. Think window open with the air conditioning running... the house will cool but you'll have an enormous power bill. We just kept an eye on it until the battery died. I was given the choice at that time whether or not to replace it and I decided to keep it. Replacements are really easy so I'd rather live with short battery life than mess with my leads before it was absolutely necessary. This was 6 or 7 years ago. Last year it ruptured through another layer of insulation and my battery life plummeted, only got 2 yrs out of it and this time replacing it wasn't optional. We did wait until the battery died and do it all at once, it was still working right up until it was turned off and I got the new one in January. I pace 100%.

 

Tom,

I disagree with Tracey’s statement that if there was any risk of your lead quitting working suddenly you’d be getting it replaced today.

That statement applies to people who are 100% dependent on their pacemaker, as she is. In your case you are not pacemaker dependant so if your lead were to quit suddenly you would just go back to the way you were before you got your pacemaker until the lead could be replaced. That is the reason your doctor can take the more casual approach of wait and see with your defective lead and not be replacing a lead before it is necessary.

I jut didn’t want you to become concerned about what may happen if your lead did suddenly fail. I think Smitty gave you a more realistic view of your future with a lead that may fail at some point.

J.B.