The orthogonal leads X, Y and Z used in vectorcardiography can be calculated in adults from the 12-lead ECG using the inverted matrix technique. This method is also called the "inverse Dower" technique.
V1
V2
V3
V4
V5
V6
I
II
X
-0.172
-0.074
0.122
0.231
0.239
0.194
0.156
-0.010
Y
0.057
-0.019
-0.106
-0.022
0.041
0.048
-0.227
0.887
Z
0.229
0.310
0.246
0.063
-0.055
-0.108
-0.022
-0.102
X in mV =
= (-0.172 * V1) - (0.074 * V2)+(0.122 * V3) + (0.231* V4) + (0.239 * V5) + (0.194 * V6)+ (0.156 * I) - (0.010 * II)
Y in mV =
= (0.057 * V1) - (0.019 * V2) - (0.106 * V3) - (0.022 * V4) + (0.041 * V5) + (0.048 * V6) - (0.227 * I) + (0.887 * II)
Z in mV =
= (0.229 * V1) + (0.310 * V2) + (0.246 * V3) + (0.063 * V4) - (0.055 * V5) - (0.108 * V6) - (0.022 * I) - (0.102 * II))
where:
• Each of the 12-lead leads is in mV.
• 1 mm = 0.1 mV
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