The normal heart rhythm is sinus rhythm with impulses from the sinus node, which is mainly seen in normal people. The electrocardiographic axis is the mean QRS electrocardiographic axis, which mainly indicates the mean electrical potential direction during ventricular depolarization. The normal electrocardiographic axis size is -30° to 90°. If the axis is -30° to 90°, it indicates a leftward bias of the axis, which can occur in short and fat people, as well as in elderly people, in patients with left ventricular hypertrophy, and in patients with left anterior bundle branch block. If there are no abnormal changes, no special treatment is needed. If there is excessive weight obesity, the direction of the electrical axis can be changed after reducing the weight.