electrocardiogram (ECG) axis

Introduction

Normal QRS axis is -30 to +90.

If lead I & aVF are positive, then axis is normal.

If lead I is negative, then right axis deviation

If lead II is negative, then left axis deviation

axis	+110	+90	+60	+30	0	-30	-45
lead I	-	=	+	+	+	+	+
lead II	+	+	+	+	+	=	-
lead III	+	+	+	=	-	-	-

+ lead	axis
I	-90 to +90
II	-30 to +150
III	+30 to -150
aVF	0 to +180
aVL	-120 to +60
avR	+120 to -60

+ lead	axis
I	-90 to +90
II	-30 to +150
III	+30 to -150
aVF	0 to +180
aVL	-120 to +60
avR	+120 to -60

More general terms

• electrocardiogram feature

Additional terms

• left axis deviation
• right axis deviation