Battery running down quickly

I had dual chamber pacemaker December 08. I've had a problem with one of my leads for a long time.
To cut a very long story short, when I had my pacemaker checked at the beginning of June it was decided the lead had come to the end of its useful life. I was referred back to my specialist centre for a new lead. At that time the technician said I had over 4 years on my battery.
I had my pacemaker checked again on Monday and my battery life is now around a year. I'm still waiting to have my lead replaced and this will be done in the next few weeks.
I am currently only pacing around 1% of the time due to the settings.
My question is, if I'm only pacing 1% of the time, how can my battery loss 3 years of life in 10 weeks?

Vicki

6 Comments

Well-explained, Don

by polrbear - 2012-08-23 04:08:00

Don's analogy is quite good. While it wouldn't be as big of a deal in the ten week period, do remember that the device also uses a small amount of current all the time to observe your rhythm/rate, record certain information (rhythm abnormalities, for example), and keep track of time.

Next, was this a human estimate or computer estimate? I know Medtronic, for example, only displays the amperage or voltage remaining and the experienced techs can give a reasonable estimate of time remaining. At least one brand does have computerized estimates that are usually better, but only if nothing changes. As Don pointed out, in your case, you might have experienced a major change. The time estimated to consume the total energy is based on how much energy remains and how quickly it is being consumed. A bad lead requires more energy. The four year estimate might have been accurate with a lead functioning adequately (even if not perfectly). If the lead is giving more resistance or the frequency of intervention (pacing or defibrillating, depending on the device) increases, that estimate can change rapidly. In your example, it may be requiring about four times the energy to pace you that 1% of the time. Consider that 1% of the time is still almost 15 minutes a day--not bad, but it adds up.

Dustin

THis can happen easily

by donr - 2012-08-23 07:08:11

Vicki: If the lead developed a current leakage somewhere, it could be very easy to happen. The PM is working to make your heart function. It takes a certain voltage at the heart implant site for that to happen. When your PM does its daily capture test to find out what voltage is actually existing at the heart wall, It may well be finding that the voltage is low & it needs to increase the current flow to increase that voltage. The more current it puts out to keep your heart functioning, the shorter the battery life.

To put it terms you can see - consider a water hose on your flower bed. You want a certain spray out of the end, but there are a bunch of leaks in the hose that you can see, causing the spray at the end to be less than you want. So what do you do? Turn up the flow of water at the valve. That's exactly what your PM is doing, but it only has a finite amount of power stored in the battery, so its predicted life goes down.

Good luck on your replacement.

Don

Thank you

by vicki2806 - 2012-08-24 05:08:03

Thank you both for those explanations.

This is a Medtronic pacemaker. The lead has been an issue for about 3 years, but as I had a very traumatic time having it placed initially and not being pacemaker dependant we've nursed the lead for a long time.

The lead moved at some point, but it now also might be fractured? Possibly?

Is there any possibility that damage can be caused to the heart when a high voltage is used for a period of time?

I'm waiting for a call this morning with a date to go in.

Thanks again.

Vicki

fracture changes a lot

by polrbear - 2012-08-24 09:08:00

Fracture can require significantly more energy to pace, even if electrical contact is made. The smaller the wire, the more resistance it has. A fracture might barely be touching, occasionally not at all, and be a tiny portion of the effective diameter it should be.

I've not heard definitely either way on damage to the heart, but there's a question about whether pacing at increasing current makes the heart more tolerant to pacing. Don't quote me on this, as it's merely something a pacemaker nurse tried to explain to me, However, the lead fracture likely is absorbing this electrical energy and turning it into a small amount of heat that dissipates safely into your body (not likely enough to cause a burn).

Dustin

Separarted Fracture

by donr - 2012-08-24 11:08:13

Vicki: I had a separated fracture w/ a visible separation between the two ends. The separation was INSIDE the vein.

Now blood is an excellent conductor of electricity - has lots of ions of potassium, sodium, etc. Blood is a water based solution, so you put those ions in the blood & it does very well, thank you, at conducting the pacing current the PM generates.

Looking back on it, my guess is that so many good folks had a tough time figuring it out because the PM thought it was actually pacing me when the current in actuality was being conducted between the two wires in the lead by the blood at the end of the exposed end. NOTHING got to the heart at all. That was almost a direct short circuit across the end of the lead, so it ate up energy from the battery very fast. Since it could sense NOTHING, it always thought my chamber needed pacing & sent out a pulse. Kinda explains why I felt so crappy all the time!

If it is truly fractured, no voltage ever gets to the heart wall.

Don

lead fracture

by papaknight - 2012-09-17 06:09:37

Thereis no way a fractured lead belongs in your body, especially if it is on an ICD. See your EP..Do not believe anything your REP tells you....best of luck. Papa Knight

You know you're wired when...

Your favorite poem is “Ode to a Cardiac Node”.

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