What is defined as afterload in cardiac physiology?

Afterload refers to the resistance that the heart must overcome to eject blood during systole. It is a critical concept in cardiac physiology because it directly affects the stroke volume and overall efficiency of the heart's pumping action. When the afterload increases, the heart must work harder to push blood out of the ventricles into the circulation. Factors such as vascular resistance and blood pressure can influence the afterload. A higher afterload can lead to increased cardiac workload, which may ultimately affect heart function over time. Understanding afterload is essential for assessing cardiac health and managing conditions that involve heart function.