What is Hysteresis mode?

I got my pacemaker in April 2001. I was constantly in bradycardia and had vaso-vagal Syncope and Orthostatic hypotension with dizziness, vertigo and lost of consciousness. Since then I feel much better, but unfortunately those symptoms did not disappear. My lower rate was set at 40, the ADL at 95 and the upper rate at 140. After 1 year the lower rate was changed to 60 and the upper rate to 120. Today I had a new checkup and the PM was switched to hysteresis mode on.
Can you tell me what is Hysteresis mode and how it works?

Greetings, Maguila


Switched on switched off

by Blueaustralia - 2007-06-28 08:06:36

My pm Sept 2004 was switched on to that mode for a while then they took it off. It was explained to me how it worked but was beyond me. When it was switched on I was 60/120 same as you. I would be sitting down and would have to get up and walk around because my pm kicked in so hard. They switched the H mode off and set my pm at 55/140 I rarely know I have a pm. It seems a case of getting the right settings for your own body. It takes time. I have an Ela dual lead pm.
All the best.

Hysteresis mode

by SMITTY - 2007-06-28 09:06:17

The hysteresis mode is used for controling a digital output based on a high and low limit.

Hysteresis control is when a controller changes output states only when a gvien input goes below the low limit, or goes above the high limit. This method of control is frequently used when the input is highly responsive to the output, or when the input may fluxuate rapidly above and below a single setpoint.

The best known use of hysteresis control is the common household thermostat. A furnace is turned on when the room temperature drops below a set point. It is turned off when the room temperature rises some fixed number of degrees above the set point.

On a pacemaker hysteresis control is when your PM starts assisting your heart beat when the natural heart beat drops below 60 beats per minute or when the PM takes itself out the picture when your heart beat exceeds 120 beats per minute.

I think you should kick that doctor on the shin next time you see him for using words to describe something that could have been explained so much easier.


Thanks for the Hysterese info

by Maguila - 2007-06-29 05:06:52

Hi to all and thanks a lot for the fast information about my doubt. It is fantastic to be able to count on you. And it seams that somebody always has the same problem or like that (you are the example Blueaustralia). This way I feel that it is possible to share it very easy. As you say, I hope they find the right settings for me and fast.... by the way my PM is a Medtronic (Kappa 701 DDD).

And thanks specially to you Smitty (college of Medtronic) who seem to be an expert in clarifying the questions. The comparison you made with the common household thermostat is completely elucidative. And don´t worry I will talk with my doctor next time :)
Actually I will "be checked" again in the next two weeks, because this up and down situation is not very nice and therefor he wants to know how I am feeling with this new change again.

All the best and take care,

You know you're wired when...

Jerry & The Pacemakers is your favorite band.

Member Quotes

The pacer systems are really very reliable. The main problem is the incompetent programming of them. If yours is working well for you, get on with life and enjoy it. You probably are more at risk of problems with a valve job than the pacer.