Welch Allyn Cardioperfect Workstation, PEDMEANS ECG Interpretation Module - Physicians - User Manual - Manual (Page 16)

CardioPerfect Workstation
PEDMEANS ECG Interpretation Module Physicians Manual
DIR 80015051 Rev. C 16 / 55
2.10 Left ventricular hypertrophy (LVH)
In LVH, the voltage of the QRS complex in the leads that reflect the left ventricle (LV) is increased. In
the frontal plane the LV lies to the left and inferiorly, in the horizontal plane to the left and posteriorly.
Therefore, an increase in voltage of the R wave is found in I, II, aVF, V6, and V7, while the S
amplitude is increased in V3R, V1, and V2. However, due to cancellation of opposing electromotive
forces only changes in the RS ratio may be observed. A decrease in RS ratio in V3R, V1, and V2,
suggests LVH. The most reliable sign of LVH is an asymmetric T-
wave inversion or “strain” pattern in
I, II, aVL, aVF, V6, and V7. If LVH characteristics are found both in left and right precordial leads
(mirror image), the certainty of LVH increases.
In the program logic, two types of parameters are used: voltage and repolarization. For the voltage
parameter, points are accumulated according to the degree of voltage abnormality of the positive QRS
amplitude in I, II, aVF, V6, and V7, and the negative QRS amplitude in V3R, V1, and V2. Three
degrees of abnormality are distinguished:
“minor”: ULN < QRS amplitude < ULN + 150 µV
“moderate”:
ULN + 150 µV < QRS amplitude < ULN + 300 µV
“major”: QRS amplitude > ULN + 300 µV
For each lead, the “minor”, “moderate”, and “major” degrees increase the voltage parameter by 1, 2,
and 3 points, respectively.
For the repolarization parameter, the program tests for the presence and degree of ST depression and
T negativity in leads I, II, aVL, aVF, V6, and V7. Strain scores are determined using the J- and T-wave
amplitudes.
No definite LVH statements are made below one month.
Say: “LVH”
if: voltage parameter

8
or strain
and voltage parameter

3
or moderate strain
and voltage parameter

4
or moderate strain in 1 of V6, V7
and voltage parameter

2
or positive QRS amplitude > ULN in V6
and negative QRS amplitude > ULN in V1
Say:
“probable LVH”
if: voltage parameter

6
or strain
and voltage parameter

2
or moderate strain
and voltage parameter

3
or moderate strain in 1 of V6, V7
and voltage parameter

1
or positive QRS amplitude > ULN in 1 of V6, V7
and negative QRS amplitude > ULN in 1 of V3R, V1, V2