Pacing

effects of pacing

by Tracey_E - 2018-07-07 11:56:47

First let me say, the dangers of not being paced far outweigh the potential side effects that may come from pacing. Having the heart out of sync and having the heart rate too low are very hard on the body. So pacing is always the right choice.

If you have heart block, it's common to end up pacing 100%. Like many others with heart block, I've paced 100% since mine was turned on. 

When I asked my ep, he said as many as 10% of patients may eventually have reduced heart function due to pacing. However, the way they place leads has changed and is easier on the heart so that number may go down. He said that if we go 5 years with no change in EF (ejection fraction, how they measure function), then he rarely sees it happen after that.  And, the treatments for heart failure/reduced EF have come a long way so many continue to lead full lives between medication and 3 lead pacing (paces both ventricles and forces them to stay in sync). It's something to be aware of, but it's not something to fear, imo.  Eat a heart healthy diet, stay active, be diligent about check ups. Other than that, there isn't much we can do so it is what it is and worrying won't change it. Stress will shorten our lives, too. 

2-lead pacing

by AgentX86 - 2018-07-07 12:10:32

You don't give a lot of information so let me try to read through the lines and you can correct any false assumptions I've made.  From your description, I assume your pacemaker is DDD, that is the two leads are in the right atrium and right ventricle.  The pacemaker was implanted to correct a heart block, which has now become complete (100% loss through the AV node). In this case, your pacemaker is now replacing the AV node 100% of the time.   That is, it's detecting a normal beat from the SI node (right atrium lead) and transmitting that signal to the right ventricle.

Yes, this isn't optimum. It's certainly better than nothing but it does cause problems.  Picure the heart's four chambers.  In a normal heart the top half squeezes, pushing the blood into the bottom chambers.  Then the bottom chambers squeeze, pushing the blood out to the body.  In your heart, the signal is blocked from the top half to the bottom half, so the last half of the cycle doesn't happen (it does, but at some slower, random time but let's ignore that for now).

Enter your two-lead pacemaker...  Now, when the top two chambers as signled to squeeze, an external box seses this, delays a little (time for the blood to be pumped to the bottom chambers), and then squeezes the bottom right chamber.  What happens to the bottom left chamber?  It gets pushed sideways by the right sidepush blood up against it.  A few milliseconds later, the signal from the pacemaker gets to the bottom left chamber and it squeezes, and the reverse happens.  This causes the muscles to compensate which causes abnormal changes in the ventricles. 

CRT (Cardiac Rehibilitation Therapy) pacemakers use three leads, instead of the two leads, described above.  The third lead is inserted into the left ventricle.  In our mind game above, instead of triggering the bottom right chamber and waiting for the signal to propogate to the left side, the signal triggers both, so both ventricles compress together.  The pressure from the left side is there to support the right side as it's pressure increases, which is more natural.

Given that your pacemaker is only two years old, I'm really surprised it's not a CRT type.  I believe they've been common longer than that. These pacemakers are used to treat people with low left ventricular Ejection Fraction, the percentage of ventricular volume pumped out in each beat. These "CRT" type pacemakers are also pretty standard for anyone with ventricular pacing (so "therapy" isn't needed later). Low EF is the cause of CHF - the heart can't pump enough blood.

Do you happen to know your ejection fraction?  That's something I'd keep an eye on, in your situation.

CRT

by Tracey_E - 2018-07-07 21:55:29

It's not at all common to start with a CRT if EF is normal in a patient with heart block. A very few doctors are doing it, but not many. 

pacing

by The real Patch - 2018-07-07 22:37:52

the effect of your device pacing you 100% is far less damaging than dead long term

Not common?

by AgentX86 - 2018-07-07 23:08:01

"It's not at all common to start with a CRT if EF is normal in a patient with heart block. A very few doctors are doing it, but not many."

I started down the paced road (February) with a CRT-P, with an EF of 65%, because of an AV ablation (complete and intentional heart block).  I have only the two ventricular leads, however.  I'm in persistent flutter/fib so the atria aren't doing anything anyway.  I also have SSS (tachy-brady and long pauses).  Only my ventricles are paced and the atria don't matter.

My EP and cardiologist wanted the CRT so my EF didn't degrade, not because it had.

AgentX

by Tracey_E - 2018-07-08 13:34:58

CRT is 3% of our members, nowhere close to the percentage of members with heart block, so it's not common. That's all I was saying, that the standard treatment for heart block is two lead. For you, CRT was a good choice, but you have a lot more going on than heart block.

https://www.pacemakerclub.com/users/poll-results/26

Heart block

by AgentX86 - 2018-07-08 15:48:20

However,  the heart block is the (only) reason for the CRT. I had the choice of a single lead pacemaker but would have been zoned out on antiarrhythmics for the rest of my life. Perhaps CRTs aren't common but evidence says that perhaps they should be.