EnRhythm batteries?

I asked the tech today how much of my battery life was left (I had my Medtronic pacemaker implanted 1 1/2 ago). She said that some EnRhythms had been going into some other mode (sort of failing unexpectedly early) and she couldn't tell me how much of my battery was left?!?! What is up with this?

Wantok

8 Comments

EnRhythms Battery Life

by SMITTY - 2012-05-10 11:05:28

Hi Wantok,

My first comment is you need to get another tech to do your PM checkups. I have no patience with those that throw out bits of information that can disturb the patient but are unable to not follow through and give any details.

Below is a letter, dated 2-10-10, Medtronic sent to doctors addressing a problem with the EnRhythm battery life. Read this letter and if you feel there is a problem with the battery life of your PM then contract Medtronic, given them the Drs name, date of PM implant, and the model and serial number of your PM. I'm sure Medtronic will answer your questions.

My guess, for what that may be worth, is you have nothing to worry about.

Good luck,

Smitty


EnRhythm® Pacemakers
February 2010
Dear Doctor,
We are informing you of two specific battery issues with EnRhythm® pacemakers that will be addressed by a Medtronic software update available mid-2010. EnRhythm devices were commercially released in 2005, and these devices have been implanted for less than 5 years.

First Issue
Medtronic has received 62 reports (out of approximately 110,000 devices worldwide) indicating that the battery voltage at device interrogation was lower than the battery voltage that is tracked by the device to provide data for the elective replacement indicator (ERI) notification. The lower voltage measurement has caused confusion and occasionally has resulted in unnecessary explants.

Medtronic’s investigation has shown that none of these reports has resulted in loss of therapy. Importantly, the ERI notification, which uses the nightly battery measurement, is unaffected and accurate. Medtronic has identified the root cause as higher than expected battery resistance.

Interrogated Battery Voltage Medtronic’s internal testing has shown that there is no current risk for compromised therapy delivery. If the software update referenced above is not implemented, there will be a potential risk of loss of device functionality in a small percent (less than 0.08% six years post implant) of devices. The software update will eliminate this risk.

Medtronic recommends physicians continue to use the ERI notification to determine time for device replacement. At this time, no other action, reprogramming or change in the frequency of follow-up is recommended.

Second Issue
Through internal accelerated testing, Medtronic has identified a second issue that projects battery voltage could decrease sooner than expected due to a slightly increased rate of lithium depletion. This issue has not been clinically observed and is not expected to occur for another 4 years (approximately 9 years post-implant). If the software update referenced above is not implemented, there may be a potential risk for loss of therapy at or near ERI in a small number of devices. The software will eliminate this issue by changing ERI criteria.

Summary
The software update will eliminate any potential future risk of the two battery issues described above by changing the ERI criteria. This update will reduce longevity of these devices by approximately 10-15%, but the expected average longevity will still be 8.5 to 10.5 years depending on device settings.1 At this time, no other action, reprogramming or change in the frequency of patient follow-up is recommended. Your Medtronic representative will notify you when the software update is available, following regulatory approval.

We regret any difficulties this may cause you and your patients. If you have any questions, or if we can be of assistance, please contact your local Medtronic Representative or Medtronic Technical Services at 800-505- 4636.
Sincerely,

Tim Samsel
Vice President, Quality and Regulatory

Medtronic Cardiac Rhythm Disease Management
Medtronic encourages health care professionals and consumers to report any serious adverse affects with the use of any our products by calling Medtronic Technical Services at 800-505-4636 and FDA’s MedWatch Adverse Reporting program online or at 1-800-332-1088.

Thanks Smitty

by ElectricFrank - 2012-05-11 01:05:24

Being in the electronic field I can understand the problem Medtronics is having. Battery condition monitoring is one of the most difficult things to do. The same thing happens in notebook computer, cell phones, etc. There is really no way to accurately determine remaining life of a battery. The only measurements available from outside the cells is voltage, impedance (resistance), and temperature. To use these the software needs to have electrochemical data supplied by the battery manufacturer. Any of the manufacturers could have the same problem.

frank

Thank you as well

by Pookie - 2012-05-11 01:05:27

I have copied this letter because when I am due to have a new battery - probably in less than 3 yrs, I'm gonna make sure that if I end up with this brand at least I will be informed of what "bugs" it has...because I would bet my last penny that my hospital wouldn't be forthcoming with this information.

Thanks Smitty:)
Pookie

Confused?

by wantok - 2012-05-11 07:05:39

So no pacemakers have the capability of knowing how much of the battery has been used up?

If so, how is it determined you need a replacement? (I really misunderstood when I got mine and they told me to get it checked every six months--I thought in order to determine how much of the battery had been used.)

Wantok

Thanks!

by wantok - 2012-05-11 12:05:08

Thanks, Smitty. That was very helpful. As my pacemaker was implanted 12/10 I am probably okay, but I will call Medtronic to doublecheck. Yes, I know the tech(s) at my EPs office are not very good, but he is a big shot in town, and the alternatives I sought out wouldn't entertain me switching from him. Anyway, I am moving to Santa Cruz, California in two months so I will be changing EPs and techs.

Second update

by wantok - 2012-05-13 11:05:19

I talked to Medtronic and they told me that the tech can tell how much battery life is left, but they may not have sufficient training and need to call Medtronic when the patient is there. The politics of asking the tech to call Medtronic seem insurmountable to me. I am not timid with medical professionals, but there is no way to ask for this without engendering hostility/defensiveness, unless someone out there has got some clever ideas on this.

Wantok

The answer is relative

by ElectricFrank - 2012-05-15 12:05:02

What can be determined is an approximate remaining life. For instance my Medtronics for my checkup on 4/09/12 shows Estimated remaining longevity 4.5yrs 3.5-5 years.so at this point there is a 1.5yr uncertainty in the life. Also notice that the report calls it APPROXIMATE remaining life. Since the battery drain is affected by settings and myr hearts use of the the pacer, and there is no way to predict what will happen in the next few years, the reading is a best guess.

What is the most important is remaining life reported in the last year. As the end of battery life approaches the estimate becomes better. Look at it like the weather. Forecasts for 2 weeks later aren't near as accurate as the forecast for tomorrow.

frank

THE ANSWER

by SUPERSALE - 2012-05-31 12:05:47


.

SOMETHING YOU MIGHT BE ABLE TO GET YOUR REPORT ONLINE THROUGH YOUR DOCTOR YOU MIGHT GET IT THAT WAY

SOMETHING THEY MIGHT CHARGE YOU TO MAKE A COPY OF THE REPORT

SOMETHING SOME DOCTOR LET YOU HAVE A COPY OF THE REPORT OF PM FOR FREE

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