A. In this illustration showing lead I, identify with + or − signs which half of the

circle will be positive and which half will be negative.

B. In this illustration showing lead aVF, identify with + or − signs which half of

the circle will be positive and which half will be negative.

C. When the left ventricle is enlarged, the axis of the heart moves

a. leftward.

b. rightward.

c. upward.

d. lower.

D. The axis shifts because the sum of the electrical impulses in the enlarged ventricle is

a. equal on both sides of the heart.

b. greater on the left than the right.

c. lesser on the left than the right.

d. greater on the bottom than the top.