single Lead VS double lead

I have my PM (single lead VDD) 6 weeks ago because of 3rd degree heart block . I had no problem running for 1hr before it.
Since I received it I am having problem with fast walking or stairs. I talked to PM clinic last week, she turned the switch mode (or something like that) off to see if that helps, but didnt. They told me that my upper part of heart is fine, and lower part needs to be paced.
When I was in the PM clinic, she told me if I had a dual leads PM she could do a better adjustment. Do you think that dual lead PM works better than single one? she said next time she will change the volt from 5 to lower(I guess 2.5v) , do you think that may help? Does anyone can help me? It also seems that there is a delay when I start running, my heart cannot catch up especially at the beginning.



Single Lead VS Double Lead

by SMITTY - 2007-05-18 12:05:11

Hello Rob,

I doubt that I can help your solve your problem but I have looked for some answers and ended up with more questions.

My first question is what were your symptoms that resulted in the pacemaker? You obviously are in pretty good physical condition if you could run for an hour before the pacemaker. Most of the time you distance runners have a very low heart rate anyway so again what prompted the implanting of the pacemaker? Is it possible you didn’t need a pacemaker to start with? That is not a totally crazy question as I have read of more than one case where people got a PM they really didn’t need.

In fact, you might ask the question of what would happen if they turned the thing off for a while. I was having many problems that my doctor couldn’t solve and I had mine turned off. Of course, I knew I was not pacemaker dependent, which is something you will have to know before considering that step.

A dual lead PM may be of more benefit. I was surprised to see that you got a single lead unit because from I have been reading for several months are that single lead units are seldom implanted anymore.

Lowering the voltage may help, but I doubt it as 2.4 V. is enough current to cause the heart chamber to contract. In fact both of my leads get 2.5 V. I have to say it certainly will not hurt.

They tell you the upper part of your heart is fine, and it is the lower part that needs pacing. Where did they put the single lead, upper or lower chamber?

The following may shed a little light on the subject for you.
What is third-degree or complete heart block? Complete heart block (complete AV block) means that the heart's electrical signal doesn't pass from the upper to the lower chambers. When this occurs, an independent pacemaker in the lower chambers takes over. The ventricles can contract and pump blood, but at a slower rate than that of the atrial pacemaker.
I hope you can have a heart to heart discussion with your doctor. From what you tell us there seems to be more questions than answers right now.
I wish you the best in getting your problem solved.


some answers

by Robshahamat - 2007-05-30 11:05:52

Starting about a month before pm, I noticed that my hear rate wont go up even when I was running, also I got dizziness, and kind of electric shock for about 5 sec. When I went to the ER they said that I have the 2nd /3rd degree of hear block. They said that the upper chamber seems to be fine but the signal cannot reach the lower ones. So my lower chamber needs to be paced. My heart rate was about 35-40. they put the lead in lower chamber.

opps! sorry

by jimkirschvink - 2007-06-11 02:06:15

Sorry I forgot to answer your question, Robshahamat -

You want the two leader because the top lead will send a signal to the computer telling it when to zap the bottom half. If your sinus node (the top one) is ok, and your av node is bad (like me) the top lead will tell the bottom one when to pace you.

Only 2.4v? - Smittly

by jimkirschvink - 2007-06-11 02:06:41

huh? I thought my voltage was only 1.5 V, and it only shocked for 1/1000 of a second or so to kick the heart in. I'm surprised your voltage is so high, or is mine just low?

Voltage outputs

by complex - 2007-06-30 06:06:01

Hey guys, the voltages you are referring to are derived from testing. Each time you go for a check the tech does a test called a threshold test. Depending on the test results the tech up or lowers the outputs to allow for a two to one window or double what you need to allow for subsequent changes. Some devices also have circuits that do this automatically . They self test and adjust to the self check. One name for this is auto capture. It has nothing to do with how you respond to exercise. It does help to prolong battery life.

Max tracking rate

by Pacemaker_pal - 2007-07-30 05:07:02

As your top chamber is fine it dictates what your heart rate should be. With complete heart block this dictation of the heart rate does not reach the lower chamber. Thus your lower chamber will go slower.

What the pacemaker does is restore the connection between the upper and lower. So when your top chamber says go faster your bottom one will.

You say you have a VDD pacemaker. If it really is a VDD pacemaker it means that although it is only one lead the part that passes through the upper chamber (the atrium) has an electrode. In this way your pacemaker is still getting some of the information from the upper chamber.

If you look at the code VDD the first letter means the chamber it is paces in..the ventricle or lower chamber. The second letter means where is senses (see's electrical activity) and this is a D for dual which means is senses in the atrium and the ventricle (upper and lower ). And the 3rd letter I won't go into cause its not part of my point.

There fore if you have a VDD lead even though it is single it works like 2. Its not as great as 2 but its OK.

Check that the lead is sensing and tracking the atrial signal OK.If it can't see what the atrial (upper) chamber is dictating then the pacemaker can't make the lower chamber follow.

What is more important is the upper tracking rate. The pacemaker can only go as fast as it is programmed to go. If its upper rate is 100bpm then thats the fastest you can go. If your young and fit and active 160bpm is what a normal fit person of 30-40yrs should be doing.

The calculation is 220 - your age in years = 100% predicted HR. Our rule is to go to 85% unless a patient has under lying heart disease where a faster Heart rate would be detrimental.

Sorry if its a bit long...

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