0 to + 90
0 to -90
-90 to -180
+ 90 to +180
Right atrial enlargement
Left atrial enlargement
Deviated to right side.
Normal axis without any deviation.
Deviated to left side.
Deviated to extreme left/ right side.
A - NORMAL AXIS, B - RAD , C - LAD
A- RAD , B-LAD, C - NORMAL AXIS
A - LAD , B RAD , C - NORMAL AXIS
BOTH A & B ARE VARIANT OF NORMAL AXIS WHILE C IS EXTREME AXIS DEVIATION
A normal T wave has an asymmetrical shape.
As the heart rate increases , QT interval increases and as the heart rate decreases, QT interval decreases. Therefore,rate corrected QT or QTc is preferred in clinical practice.
The QT interval is measured from the beginning of the QRS complex to the end of the T wave.
It represents the return of stimulated ventricles to their resting state (ventricular repolarization).