ARDMS Adult Echo Practice Exam 2026 - Free Adult Echo Practice Questions and Study Guide

Stroke Volume and Cardiac Output are fundamental concepts in cardiovascular physiology, reflecting the amount of blood ejected by the heart per beat and the total amount of blood pumped by the heart per minute, respectively. Preload and Afterload are key determinants of Stroke Volume.

Preload refers to the degree of stretch of the cardiac muscle fibers at the end of diastole, which is influenced by the volume of blood returning to the heart. A greater preload typically leads to an increased Stroke Volume due to the Frank-Starling mechanism, where increased stretching of the heart muscle results in a more forceful contraction.

Afterload, on the other hand, is the resistance the heart must overcome to eject blood. It represents the pressure in the aorta during systole and, if increased, can decrease Stroke Volume. Therefore, both preload and afterload directly affect how much blood is being pumped out with each heartbeat.

While myocardial contractility and heart rate also play roles in cardiac function, the combination of preload and afterload provides a more comprehensive understanding of how Stroke Volume and Cardiac Output are derived. Understanding these interrelationships is crucial for evaluating cardiac performance and assessing various cardiovascular conditions.