probably stupid question

But, my normal HR is 41 - 46, when I say normal that is what it runs at work and averages for 24 hour time frame. As I have posted before, (hate to be a PITA) but one more question. Not sure, but lets say they set the pacemaker to 60 BPM. How does it do that? Add 20 bpm? Override my natural pace and just take over? Will i feel the difference?
Again sorry to be a PITA, just starting to freak out...

Wally

13 Comments

Look at monitor

by Theknotguy - 2014-02-18 01:02:19

If you can get hooked up to a medical monitor, it will show how the PM kicks in and starts your heart. I'm not sure how the algorithm works, but the PM sits there and watches the heart. If the heart doesn't initiate a beat within the accepted number of miliseconds, the PM will step in and initiate the beat.

When you get a print out of your PM settings it will tell you what the wait time is, when it will initiate the beat, and a lot of other stuff. Mostly you just note the information. Obviously I'm not trained enough to get into a discussion with my EP guy as to why heart beats are initiated at so many milliseconds. I'm just glad it's beating at a regular pace.

Prior to them turning on Atrial Preference Pacing I'd get an atrial spike from the PM just before it initiated the beat. Post APP I get a spike on the atrial side and another spike on the ventrical side. Dual lead PM, dual spikes.

My heart, on its own, would initiate a beat. Then it might initiate another beat within the required number of miliseconds. Then it might wait for a while and maybe decide to initiate another beat. Then I might get three beats in quick succession. Plenty of head rushes, dizzy, SOB, etc. With the PM you see regular and timed spikes showing the heartbeats. A much more comforting pattern. Less head rushes, not so dizzy, not SOB.

Oh, in answer to your question, if they set the PM to 60 beats per minute, you can see on the monitor when your heart starts to drop below the rate and the PM kicks in. Kinda comforting to have something working for you.

Will you feel a difference? Depends upon you and what your body feels. You might notice a faster heart beat, you might not. I can tell when I'm in a-fib, my wife can't tell when she's in a-fib. So it depends upon you as to what you will feel.

As for stupid questions... Remember the old adage, "The road to wisdom is paved with stupid questions." Believe me, I've put quite a few bricks in that road.

Hang in there. Life gets better.

Theknotguy

Hope this answers your questions.

it just does?

by Tracey_E - 2014-02-18 01:02:37

That gets over my head! But it works out and we usually have a nice even rate. We're only talking fractions of a second so if it's 1 second, 1 second, 3/4 second, 1 second, 3/4 second, it's going to feel about the same.

I'm sorry I don't remember your details from your other posts, why are you getting it? All of the above is atrial pacing. If you have av block, that's ventricular pacing and totally different. The pacer will just make sure the ventricles beat when the atria does. That's what I have. My resting rate was in the 30's because that's how often my ventricles decided they were in the mood to beat. My atria was beating normally with a resting rate in the 70's, so that's what my pulse is now. My min is 60, but it's irrelevant for my type of pacing. Ventricular pacing the pm is playing follow the leader, not setting the pace.

Don't over think it

by Grateful Heart - 2014-02-18 02:02:09

That's what the pacemaker's computer is for. That's the beauty of it, the Doctor sets it and eventually, you forget it.

We've all been there, you'll be fine, try not to "freak out".

Grateful Heart

not thinking at all

by wjs1954 - 2014-02-18 06:02:29

Home from work, shoveled the driveway. Okay used the snowblower but anyway 3 beers later not really thinking about the up coming pacemaker. Okay you got me, thinking about it otherwise would not be posting.
Again thank you for your support, I know things will be fine.

pacing

by Tracey_E - 2014-02-18 11:02:14

You will probably feel energized. It may feel fast at first but you get used to it.

It's not set in beats per minute, rather per second. So if it's set to not let you go under 60, that is one beat per second so it won't let you go a second without a beat. If the heart beats, it just watches. If it goes a fraction of a second too long and doesn't beat, it kicks in and paces.

p.s.

by Tracey_E - 2014-02-18 12:02:14

there are no stupid questions! You can always use the search feature to see if your question has been asked before.

pacing?

by wjs1954 - 2014-02-18 12:02:18

So lets say it is midnight 12.00.so at my current HR my heart would not beat till 12.00.01.45. However the pace maker would cause it to beat at 12.00.01, So how would it keep a pace of 60 and have it be evenly paced. By evenly paced I mean for 60 bpm 1 beat per second.

one more time

by wjs1954 - 2014-02-19 01:02:38

so again if the PM 'says' to the heart lets go the SA does not send the signal? if Brady is the problem. when i run or the last time i ran 3 months ago i could get my HR up to the mid 140 without a problem.

Correct

by donr - 2014-02-19 08:02:49

If the PM decides that the SA Node is going to be late, it sends a pacing "Pulse" of electrical energy to the heart through the appropriate lead. This "Pulse " of energy forces the chambers to contract. It no longer does the SA Node any good to send its contraction signal. This, of course applies to the Atria; same is true if the Pm sends a Pace "Pulse " to the Ventricles.

I checked your past Posts & Comments - 3 months ago was Pre-PM implant. What this tells me is that your heart has no problems at its higher HR's. When you get out of the base rate region, where you sense the problems of Brady, The heart is responding to a different set of controls - a part of the Autonomic nervous system. When greater output is required from the heart, the information comes to it via this system, telling it to pump harder & faster. A simultaneous signal goes to the Diaphragm, telling it to breathe faster. The SA responds to this signal & increases its rate. IF this system does NOT function correctly, it falls into a broad category of rate problems called "Chronotropic Incompetence." When you have this problem, you need an RR function to get your HR up. You obviously do NOT have this problem! Ever have a car that would not run smoothly at Idle RPM, But would run like a scared rabbit at pedal to the metal? Same problem. Back in the days of carburetors, there were at least three gas metering jets in the carburetor - Idle, Mid Range & High Speed. They worked independently of one another, Similar analog exists in the heart.

Don

You asked for it - here it is !

by donr - 2014-02-19 10:02:15

WARNING!!! I changed this on 25 Feb 2014 - I found a small, but highly significant error in the way it was originally. Either no one caught it or they did & were too polite to tell me. The letters designating squiggles in ECG's start w/ P, not Q. It has been corrected.

Don
To understand % Pacing, you need to know how a PM works & how the heart works.

First, I have to become an iconoclast & shatter some myths widely held by all people:
1) There is NO Santa Claus'
2) There is NO Easter Bunny.
3) Father Christmas does Not exist, nor does Kris Kringle.
4) Nope, no Tooth Fairy, either.
5) No Jack Frost.
6) Sorry to disappoint, but no Mermaids
7) There is NO SUCH THING as a Heart Rate!

The heart rate (HR) is a fiction of historical origin. Man has known for a long time how to determine a HR - the Dr. takes out his pocket watch w/ the second hand , gropes around to find the pulse at the patient's wrist, starts counting & timing at the same time. Counts for 15 seconds & multiplies by 4 - gets a HR. At the time this capability was discovered eons ago, no one knew how the heart worked. They all thought there was some master timer that ran the heart at whatever rate was needed - sorta like a sine wave of a fixed frequency or a square wave that created the rate. But at least some nice, periodic wave of some shape that ran everything. Then along about 1900, came a Dutchman who took his finger out of the dike long enough to discover that the heart had electrical activity & he could actually measure it. He stuck someone's feet in freezing buckets of salt water, likewise the hands, & started measuring voltages w a crude meter. Thus was born electrocardiography! But Hans in his wooden shoes did not / could not discover that there was no background timing wave that made things happen w/ regularity. Nor did he find out what the squiggles on a strip of paper looked like because he had not gotten that far in development. Sometime later, In Germany, I believe, someone came up w/ a recording device that traced the wave form out on a strip of paper & we started seeing what we get in the Cardio's office out of the ECG machine.

It took a while of study, but Cardios realized that something was wrong w/ the HR concept - there was no trace of a nice, regular, precise wave in the background. All they got was a flat base line w/ squiggles on it rising & falling as the heart beat. I cannot recall who it was who named those squiggles, but he chose to start w/ the letter P - mainly because A,B,C,D, etc were used to death, & starting w/ P made his work unique. Then Cardios started noticing that the timing of the various squiggles for one w/ a healthy heart was very, very accurate (meaning repeatable). Also, that when there was a beat that was funny (or arrhythmic) & slightly out of time, that the heart went BACK to its regular timing w/o necessarily following a regular, repeating wave - in other words, the heart reset itself & appeared to time events individually & based on a previous event in every case.

Conceptually, here's what happens:

They discovered that the START of a beat is run by the Sinus Node (SA) that somehow times individual events in cooperation w/ the A-T Node. That makes the SA Node the "Master Timer" for the heart.I do not think anyone knows if it is a digital timer or an analog timer, but it is a timer that takes cues from events. Your PM times things the same way, using the same reference events as the nodes - but we know the PM is a digital timer (Whoopee!).

This sorta gets to the question "Which came first, the chicken or the egg?" We do not know how the heart starts, but we know what it counts FROM. All learned by pure observation of hearts beating & squiggles on a line.

Look at a cy of your ECG. The first reference point is that little pimple called the P Wave -that's the Atria contracting & is started by the SA node by it giving a signal. The SA node starts a count. Meanwhile, the signal is traveling down the heart to the Atrio-Ventricular Node (AV), but is purposely delayed so the Ventricles can fill w/blood. After the delay, which is counted out by the AV, the Ventricles contract.That's the BIG squiggle called the QRS Complex. Meanwhile the AV is still counting, just in case the ventricles don't contract - this is so that it can act as a fail-safe & take over from the SA. (You'll read about people talking about an "Escape Rhythm." that's this). The QRS completes its course & there are two more critical events to take place. The stretch after the QRS has a purpose in the recharging of all the electrical tissues, leading up to the little speed bump, the T Wave, where the tissues do their work getting ready for the next beat. So what's the SA doing all this time? Still counting. The nature of the heart is that the SA cannot start the next beat till AFTER the functions of the T wave are complete. A so-called Refractory period keeps it from doing so. If the SA gives the signal for the Atria to contract while the T wave exists, confusion can result, leading to V-Fib - not a good result. So the SA timer can vary a bit from beat to beat.

So your heart has all these beats, each one being an individually timed, independent beat.

You asked HOW the PM "Adds 20 BPM to your HR." Very simple: The cardio enters a desired HR for the lower limit - say 60 BPM for simplicity. If your heart is suffering Brady & beating a) too slow & b) beating irregularly, the PM takes that HR the Cardiio enters & converts it into an ELAPSED TIME PER BEAT (That's 1 second) & sticks THAT number in its digital memory. He/she also enters a desired AV delay time into memory. THEN, the PM monitors EVERY beat for elapsed times & if one of them is going to be late according to the stored elapsed time, it sends a signal to cause the beat - for whichever chamber is going to be late. For Brady sufferers, it will be the Atria - the master timer.

Your PM follows all this activity, keeping track of times between actual events & comparing them to the times stored in its memory. Simplified, the PM stores a time equal to that from P Wave to P Wave that corresponds to the "Heart Rate" given for your lower limit. It also has a stored time for the P-QRS DESIRED elapsed time (called the AV Delay). Now the stored times are a bit longer than what the heart would really do, so the PM can allow the heart to do its thing naturally. The PM sits there, sensing what the heart is doing through it's two leads, counting along w/ the nodes. If the natural signals come w/i the correct interval, the PM does nothing. If the signal is NOT there before the PM counts to its stored time, it gives the old high sign & fires off a pacing pulse.

So how does it figure % pacing? It's a great counter; that's its main purpose - to count things. So it counts every beat of your heart. It counts the number of times it paces you. % Paced is a simple ratio: Number of paces (P) divided by total number of beats (T). % Paced = P/T. To complete the data, we need one other number - % unpaced (They call it S, for sensed, meaning that the PM did nothing) %Sensed = T-P/T Add the two up & they equal 1 as well they should!

Now your PM really gives you more than that; it gives you FOUR %ages. Called Atrial sensed, Ventricle sensed (AsVs); Atria sensed Ventricle paced (AsVp); Atria Paced-Ventricle sensed (ApVs): & Atria Paced-Ventricle Paced (ApVp). That tells you everything you need to know about how much you are paced.

When the PM calculates these percentages, it cares NOT what the HR is - it calculates them for the beats COUNTED w/o reference to the rates.

Hope this helps

Don

i think i got it

by wjs1954 - 2014-02-19 11:02:53

so what you are saying is from when the pacemaker is put in anytime my heart did not beat on it's own at 1 second. (if set at 60 BPM) the pacemaker "pace" as long as the heart said "hey i got this one" the pacemaker would just sit and watch till the heart did not beat at 1 second. meaning if i was out for a run the pacemaker would be just taking a "break", yet if i was sitting at work on this forum the Heart would be taking the "break"

Yes!

by Tracey_E - 2014-02-19 12:02:02

Yes, the pm only watches for the heart to go a second without beating.

The heart is always working, though. When the pm paces, think of it as giving the heart a nudge. The pm can only send the electrical signal that the heart should be doing on its own. The heart muscle responds by contracting (beating). It's the ultimate personal trainer.

If your rate goes up on its own during exercise, then no you probably won't pace when you run. If your rate doesn't go up enough on exertion, the pm can be programmed to help with that, too. It can be set to sense movement and raise the rate when the heart doesn't go up like it should, that's called Rate Response. Not everyone needs it but it's there.

Well, kinda, sorta , almost...

by donr - 2014-02-19 12:02:26

... a good description of what happens. That was "Heart Functioning 101." What happens as the heart increases Rate is in "Heart Functioning 102." Here's a preview of that lecture series: Face it, as the HR increases, for whatever reason, the overall elapsed time between the beginnings of each beat decreases (that's the P-P Wave time). AT 120 BPM, exactly twice the resting rate of 60 BPM, the total elapsed time would be exactly 1/2 that at rest - or 1/2 second. To keep you functioning, the PM can adapt to that - either through an Algorithm driving the RR function or the ability to sense what is going on & adapting its stored times to an appropriate value commensurate w/ HR.

So - in a word, NO, the PM does NOT take a break UNLESS the heart is functioning correctly, but it probably is not, so the PM keeps doing its job, regardless of rate.

Lemme give you an example. ME! My heart has bad Brady/SSS. I am paced in the Atria close to 100% of the time. Well I sure as Heck don't spend nearly 100% of my life at base rate. MOF, I'm up in the 80's & 90's most of the time, so the PM has to be adapting to the situation to keep me going or I'd be in perpetual SOB & feeling like crap.

Next series will be "Heart Functioning 201."

Keep asking - I'll either give you answers, or make them up.

Don

You know you're wired when...

Your signature looks like an EKG.

Member Quotes

My cardiologist is brilliant and after lots of trial and error got me running. I finished this years London Marathon in 3hrs 38 minutes.