A study on the position of chest electrodes for the Frank lead system Part I. A study using a human torso model

The effect of horizontal displacement of chest electrodes C, A and I for the Frank lead system on transfer impedance was studied in a human torso model. The results obtained were as follows: 1) With electrode C displaced 2 cm to the right of its original position, the magnitude of transfer impedance of lead Z increased by 6.3% and the azimuthal angle of transfer impedance of lead X deviated by 3.7%. A displacement of 2 cm to the left caused a decrease in the magnitude of the transfer impedance of lead Z of 5.6%. On the other hand, backward deviation changed the azimuthal angle of the transfer impedance of lead Z by 2.8°. 2) By moving electrodes A and I forward simultaneously by 2 cm the magnitude of the transfer impedance of lead X increased by approximately 5% while 2 cm backward-displacement of the electrodes decreased the magnitude of the transfer impedance of lead X by 5.7%. 3) With the center of the heart approaching the precordial wall, changes observed in 1) and 2) became conspicuous when the electrodes were on the left but obscure when the electrodes were located backwards or to the right.