Welch Allyn Cardioperfect Workstation, PEDMEANS ECG Interpretation Module - Physicians - User Manual - Manual (Page 15)

CardioPerfect Workstation
PEDMEANS ECG Interpretation Module Physicians Manual
DIR 80015051 Rev. C 15 / 55
2.7 Axis deviation
Axis deviations are distinguished in right, marked right, and extreme right inferior on the one hand, and
left, marked left, and extreme left superior on the other hand.
Say: “right axis deviation”
if: ULN < QRS axis

ULN + 20

Say:
“marked right axis deviation”
if: ULN + 20

< QRS axis

ULN + 60

Say:
“extreme right inferior axis deviation”
if: ULN + 60

< QRS axis

180

Say:
“left axis deviation”
if: LLN – 45  
QRS axis < LLN
Say:
“marked left axis deviation”
if: LLN – 120  
QRS axis < LLN – 45 
Say:
“extreme left superior axis deviation”
if: –180  
QRS axis < LLN – 120
2.8 Low QRS voltage
Say: “low voltage in extremity leads”
if: positive QRS amplitude + negative QRS amplitude

500 µV in all extremity leads
Say:
“low voltage in precordial leads”
if: positive QRS amplitude + negative QRS amplitude

1000 µV in all precordial leads
Say:
“low voltage”
if: both previous tests passed
2.9 QT abnormalities
The QT interval is measured from the overall onset of the QRS complex to the end of the T wave. In
case of intraventricular conduction delay, the QRS duration in excess of ULN is subtracted from the
measured QT. A correction is made for the heart rate, using Bazett's formula: corrected QT (QTc)
interval = QT interval *

(heart rate/60). The QTc interval renders the QT interval for a standard heart
rate of 60 beats per minute.
Say: “short QTc interval”
if: corrected QT interval < LLN – 20 ms
Say:
“long QTc interval”
if: corrected QT interval > ULN + 20 ms
Say:
“high voltage”
if: 330

corrected QT interval < 470 ms
and positive T amplitude > ULN in V4, V6, V7