The strength of heart muscle contractions is known as?

• A. Cardiac Output
• B. Myocardial Contractile Force
• C. Stroke Volume
• D. End-Systolic Pressure

Answer: (B)

The strength of heart muscle contractions is described by contractility, or myocardial contractile force. This intrinsic ability of the myocardium to generate force during systole determines how forcefully the ventricles squeeze blood.

Cardiac output, the total volume pumped per minute, depends on both how forcefully the heart contracts and how fast it beats, so it’s not a measure of contraction strength alone. Stroke volume is the amount ejected with each beat and is influenced by preload, afterload, and contractility, but it is a volume per beat, not the force of contraction itself. End-systolic pressure is the ventricular pressure at the end of systole and relates to afterload and overall ventricular function rather than the intrinsic contraction strength.

So the term that best fits the concept of how forcefully the heart muscle contracts is myocardial contractile force.