The strength of contraction of left ventricular muscle increases when

A. True  As seen in the Frank–Starling left ventricular function curve.

B. False  High K levels decrease cardiac contractility.

C. False  Calcium channel blockers decrease cardiac contractility.

D. True  Due to increased sympathetic drive to the ventricles and increased venous return.

E. True  Initially by increased ventricular filling: later by ventricular hypertrophy.