ecg_6lead003.html

Frontal Plane QRS Axis = +50 degrees-KH

Frank G. Yanowitz, M.D.

1) lead aVL is the smallest QRS and closest to being the isoelectric lead; 2) perpendiculars to aVL are +60 and -120 degrees; 3) lead I is positive; 4) therefore, the axis is closest to being +60 degrees. Because aVL is actually slightly positive, the axis is only about +50 degrees (i.e., slightly to the left of +60).