EKG question

I have read that if a woman has large breasts it can cause  EKG's to be inaccurate, is this correct?

[kenkeith]

There is a work around for large breasts for 12-lead electrode EKG.  For a woman with large breasts, place V3 (electrode) on the breast and V4 through V6 below the breast. If a problem, the voltage (amplitude) of the EKG is affected.

[islandgirl1947]

What do you mean by if a problem, the voltage (amplitude) of the EKG is affected?
Can you explain if a problem, then how the voltage of the EKG is affected? I just want to understand this clearly.
Thanks

[kenkeith]

Voltage is a measurement of the ability of the impulse (current) to pass through resistance.  For example, resistance of interest to EKG is damaged heart tissue (more resistance) or distance (thickened heart wall...more residstance) also referred to as conductivity.  Mathematically the calculation for a volt is current (amp) times resistance.  With amp being held constant, an increase in resistance increases volts.  The EKG trace, on the graphic output, will show an increase of voltage heigth (referred to as amplitude) on the verticle plane when there is more resistance (poor conductivity).  There is a gel (as one will remember) that is placed on the electrode (lead) that helps conductivity.  
If the electrode is misplaced or a bad connection the current (impulse) will not pass or poorly pass and there will be an incorrect reading.

[islandgirl1947]

Thank you, now I understand.