Pacing during stress echo

I don't understand what my pacemaker does. Yesterday during my stress echocardiogram the pacemaker was pacing during it and I was told that that makes the results difficult to interpret because they make the heart look like it is working harder and that there could be a blockage. I thought my pacemaker should only pace if my heart goes below or above a certain rate, not while I am exerting myself in general?

7 Comments

What a PM does

by donr - 2013-03-06 01:03:00

Greetings: I just went back & looked at several posts you have made.

Here's the explanation: Your PM just worries about the rate at which your heart is beating. ACTUALLY - it essentially only worries about two things:

1) The elapsed time following the beginning of a SINGLE heart beat for pacing the ventricles...

2) Or the total elapsed time following the beginning of a single beat till the next beat starts for pacing the Atria.

Your PM is like the gas pedal in your car - it can ONLY make it go faster. There is no equivalent to the brake pedal. It cannot slow your heart down.

Your PM is a very powerful little digital computer that monitors what your heart does; it uses elapsed times for its decision making. If it does not sense a ventricle beat w/in the appropriate programmed time following the initiation of an atrium beat, it generates a signal that makes the ventricles beat.

If it does not sense the beginning of another atrium beat w/in the programmed elapsed time following an atrium beat, it generates a signal that makes the atria beat & start the process all over again.

Anything else falls under the category of "Bells & whistles." They are absolutely necessary for proper heart functioning, but they are really ancillary to the basic functioning.

The PM cannot measure workload of the heart, just its electrical signals & whether or not the various parts function at the correct TIME, based on its internal program.

Dunno what kind of stress echo you had, but I've never been told that before, during or after any test I've had.

The echo is to evaluate how muscles & valves function, not the electrical functioning. Your normal heart functioning now includes pacing for rhythm 24/7. I'd suspect that they would want to see how the physical heart functions under its normal mode of operation - paced.

You don't say WHY you have the PM - but there are two kinds of blockages - electrical & physical. They are NOT related.

The electrical blockage concerns signals getting down the heart from the SA Node to the AV node - between the Atria & ventricles. That's one of the malfunctions a PM can fix.

A physical blockage is a constriction in the coronary arteries & can lead to heart attacks. The PM can do nothing about that blockage.

There are three kinds of tests for heart functioning:

1) EKG (or ECG) that determines how the heart is functioning electrically. Granted, that having a heart attack - a physical event - can & does affect the results of the ECG test. The ECG is the basis for determining PM needs & programming.

2) Echo cardiograms - they determine valve & muscle functioning, & ...

3) Stress tests or catheterizations - they determine how the coronary arteries are functioning - are they clogged or open. They also can examine blood flow through the heart.

Hope this clears things up for you a bit.

Don

how do you pace?

by Tracey_E - 2013-03-06 01:03:09

Ditto what Smitty said and I'll add that if you pace ventricle (av block), then the pacing follows an atrial beat. It doesn't matter what your hr is at the time, if the atria beats and the ventricle doesn't, it will pace. I pace all of the time so every echo I've had for 20 years has been during pacing.

Was it a chemical stress test or were you on a treadmill?

Thanks!

by wantok - 2013-03-06 01:03:15

I know I have RR turned on, and I was on a treadmill. If I am understanding correctly, why couldn't they turn off the RR and do the stress echo? Would there still be the interference?

RR

by Tracey_E - 2013-03-06 04:03:22

If you were on the pm computer at the same time you were on the treadmill, then yes they could have turned off the RR. But! The main reason for doing a stress echo is to see what your heart does at higher rates. If it doesn't do high rates without the pm, then you won't see what you need to see on the echo.

I don't know if turning RR off would take care of the interference or not, maybe one of the others will know more. This is the first I've heard pacing interferes, and I've had a lot of echos in the 20 yrs I've been paced!

HR Increasing During Stress EKG

by SMITTY - 2013-03-06 12:03:15

Hello Wantok,

Pacemakers have a feature called rate response. This will increase your heat rate when it detects the load on the heart has increased. Depending on the make and model of your PM there are several things that can make the rate response increase your heart rate.

For some (but not all) a quick and easy way to see if their RR is activated is to sit quietly for about 15 minutes and then count your heart rate. This should give you a resting heart rate. Then close your fist and tap on your chest at the bottom of the rib cage, not top on the PM. Tap hard enough to jar your chest, but not hard enough to be uncomfortable. Do this for 20 to 30 seconds and then count your pulse. If the RR is activated your heart rate will increase from the vibrations it sees from the tapping on your chest.

If the RR is activated it could be affecting the heart rate during the stress EKG and your dr can tell you why. Mine is activated because my heart rate doesn't increase when I increase the load on my heart.

Good luck,

Smitty

Not for Long

by ebfox - 2013-03-07 06:03:59

If they turn off his Rate Response and put him on that treadmill, he probably won't last long. If you exert yourself and your heart rate doesn't increase, it feels very bad. I can attest to this from first hand experience; following my mini-maze surgery and resulting sinus node dysfunction, I went running (with RR turned off). I was wearing a chest strap monitor and at the beginning of the run my rate was 85. Three minutes later, about 1/8 mile down the road, I was gasping for air and my pulse was 85. Not a good feeling at all. Probably the shortest run of my life.

I am interested in the blockage comment. Are they scheduling a heart cath to look at that?

E. B.

Angioplasty

by wantok - 2013-03-07 07:03:25

The angioplasty is not yet scheduled. I haven't had a thorough check-in with the cardiologist (I just moved).

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