Which of the following describes the action of the heart's muscle working effectively to pump blood?

The term that most accurately describes the action of the heart's muscle working effectively to pump blood is referred to as cardiac output. Cardiac output signifies the volume of blood the heart pumps per minute, which is a crucial measure of the heart's effectiveness as a pump. It is calculated by multiplying the heart rate by the stroke volume—the amount of blood ejected from the heart with each beat. A well-functioning heart is essential for maintaining adequate blood flow to the body’s organs and tissues, which is fundamentally represented by cardiac output.

While hemodynamics involves the dynamics of blood flow within the circulatory system and myocardial function specifically relates to the heart muscle’s ability to contract and relax, these concepts are broader or more specific than the overall effectiveness of pumping blood represented by cardiac output. Cardiac efficiency, on the other hand, refers to the ratio of useful work performed by the heart to the energy expended, which is again a different aspect compared to the actual volume of blood being pumped.