How is stroke volume defined?

Stroke volume is defined as the amount of blood pumped out of each ventricle during a single heartbeat. This measurement is crucial because it reflects the efficiency of the heart in contributing to the overall cardiac output, which is a key indicator of cardiovascular health. Stroke volume is influenced by factors such as myocardial contractility, preload (the degree of stretch of the cardiac muscle fibers before contraction), and afterload (the resistance the heart must overcome to eject blood).

Understanding stroke volume is essential for cardiac sonographers as it aids in diagnosing and managing various cardiac conditions. In contrast, the other choices focus on different hemodynamic aspects:

• The volume of blood in each chamber of the heart does not specifically refer to the amount of blood ejected during each heartbeat but rather the static state of blood in those chambers at any one time.

• The total volume of blood in circulation encompasses all blood within the cardiovascular system, which is larger in scope than stroke volume.

• The volume of blood returned to the heart is related to venous return and preload but does not equate to the stroke volume itself.

Thus, option B provides the most accurate definition of stroke volume as it pertains to the function of the heart during a cardiac cycle.