RCIS Practice Test 2026 – All-in-One Exam Prep

Cardiac output is fundamentally defined as the product of heart rate and stroke volume. Stroke volume specifically refers to the amount of blood ejected by the heart's left ventricle with each contraction. By measuring stroke volume, which reflects the efficient functioning of the heart itself including aspects like preload, afterload, and contractility, clinicians can determine the volume of blood the heart pumps in a given time frame, usually expressed in liters per minute.

While heart rate does play a significant role in cardiac output, it is the stroke volume that is directly related to the volume of blood being circulated with each beat. Therefore, understanding and measuring stroke volume is vital in determining cardiac output accurately, making it the primary parameter for this measurement. Other options, such as pulmonary systolic pressure and SVC pressure, do not directly reflect cardiac output, as they pertain to different physiological or anatomical aspects of the cardiovascular system. Thus, recognizing stroke volume as a crucial measure in calculating cardiac output reinforces its importance in cardiovascular assessments.