👉 Presystolic is a medical term that describes the upper part of the heart, where blood pressure is low. It occurs when the heart's valves are closed and the atria (upper chambers) are contracting to pump blood up into the right ventricle, or "right atrium". This process occurs before the diaphragm is fully relaxed, which helps to prevent a decrease in blood pressure during exercise. Presystolic conditions can occur for various reasons, such as heart disease, high blood
