What does the term afterload refer to in cardiac function?

The term afterload specifically refers to the resistance that the ventricles must overcome to eject blood during systole (ventricular contraction). It is essentially the tension in the ventricular walls that must be achieved to push blood into the aorta and pulmonary artery. Afterload is influenced by factors such as vascular resistance and arterial pressure, which means that the higher the afterload, the more work the heart has to do to pump blood, affecting cardiac output.

Understanding afterload is crucial in cardiac physiology and perfusion, as it directly impacts the performance of the heart and the overall hemodynamics of the patient. When the afterload increases, it can lead to diminished cardiac output if the heart is unable to compensate adequately, which is often a consideration in managing patients during and after cardiac procedures.