Lead Size

OK, I goofed, Now I'll make an attempt to correct my goof. I put in a comment - "An implantable cardiac stimulation lead system for use with an implantable stimulation device includes at least a pair of conductors, braided together and extending between proximal and distal ends and co-extruded with flexible resilient insulation material. Each conductor may be a multi-strand cable composed of MP35N or DFT and have its outer peripheral surfaces coated with insulative material. An electrical connector is coupled to the proximal end of the lead system for connection with a stimulation device and includes terminals electrically connected to the conductors. The proximal connector is thereby electrically coupled to a distal tip electrode and to at least one electrode proximally spaced from the distal tip electrode. The lead system may include an elongated tubular lead body of flexible resilient insulative material having a longitudinally extending lumen for receiving a stylet for aid in implanting the lead system. Alternatively, an introducer sheath may be employed for implantation."

Now let me say I’m sorry for ever throwing out that description of a pacemaker lead system. I have no idea who wrote that – it certainly was not me - but on further analysis I would guess it was someone trying to impress their engineering professor. They have taken a simple description of a PM lead system and turned it into one of the most convoluted descriptions I ever hope to see.

Now, with that said, I’ll try give my interpretation of what is actually said:

Pacemaker leads for use with a pacemaker include at least two of wires capable of conducting the electrical impulse from a pacemaker to the heart. These leads are braided or twisted together (I’m not in total agreement with that statement, but that is another story) and sent through an extruding machine where they are coated with an insulating material. This lead wire is connected to the PM (proximal) and extends (distal) wall to the heart. These leads are MP35N or DFT* (wire made of as silver alloy and a very tough or strong insulator) that is further coated with additional insulating material. A sheath may be used to help insert the lead(s) into the vein and on into the heart chambers.

My short interpretation of the above is that doctors use a wire made of a silver alloy and thread it through a vein into the heart. After that it is connected to the pacemaker. This wire transfers the electrical impulse from our pacemaker/defribillator to our heart.

Nowhere do they say what the size of the leads. I have seen where the wire (MP35N - DFT) they speak of comes in sizes ranging from 0.004" to 0.015" but they do not say if those sizes do or do not include the insulation The price of the wire ranges from $39.85/100’ to $356.00/100’. Size and silver content determines the price.



oh well

by CathrynB - 2007-12-07 01:12:48

I guess this means I don't get to win the "Stump Smitty" game (referring to my last response to the previous posting re leads). I'll keep trying. Thanks for the explanation Smitty. That helps! Now if we can just get auntiesamm (sharon) or someone else with medical background to tell us more about that SVC we'll all be SOOO smart!
Take care, Cathryn


by SMITTY - 2007-12-07 03:12:32

Hi Cathryn,

See if this helps.

According to Mosby's Medical Dictionary the Superior Vena Cava (SVC) is the second largest vein in the body. It is about 3/4" (2 cm) in dia. and about 2.75" (7 cm) in length. It located just below the clavicle, contains no valves and is for returning deoxygenated blood form the upper body to the atrium. It's size and the fact it has no valves makes it a favorite to use for placement of pacemaker leads into the heart.




by pacergirl - 2007-12-07 07:12:23

All this is making me dizzy,... I have no idea what you guys are talking about... please do not try to explain... way too detailed for me!

You know you're wired when...

You trust technology more than your heart.

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