Final answer:
Increased End Diastolic Volume stretches the cardiac muscle fibers, leading to a stronger contraction and is imperative for proper cardiac function. An elevated aortic pressure requires the heart to exert more force, potentially reducing stroke volume.
Step-by-step explanation:
End Diastolic Volume (EDV) is crucial for the regulation of cardiac contractility because it represents the amount of blood in the ventricles at the end of filling, or preload, which stretches the ventricles prior to contraction. According to the Frank-Starling law of the heart, the strength of ventricular contraction is proportionate to the initial length of cardiac muscle fibers (preload), therefore an increase in EDV leads to increased contractility and stroke volume (SV). In the situation where pressure in the aorta increases, the heart must work harder to overcome this increased afterload, which can lead to decreased SV and potential cardiac complications if not properly compensated.