Final answer:
Increasing contractility shifts the force-velocity curve to the right and increases the maximum velocity of contraction (Vmax), indicating enhanced cardiac muscle performance.
Step-by-step explanation:
Increasing contractility in the heart leads to a change in the force-velocity curve, which represents the relationship between the force generated by cardiac muscle and the velocity of fiber shortening. An increase in contractility, which can be brought about by positive inotropic agents, enhances the ability of the heart to contract powerfully. As a result, for any given level of afterload (the force the heart must work against to eject blood), the heart can contract more rapidly.
Therefore, the correct answer to how increasing contractility changes the force-velocity curve is A) Shifts it to the right and increases Vmax. This represents both an increase in the force generated at any given velocity and the maximum velocity of contraction (Vmax) at zero afterload.