APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -The final phase is the atrial contraction, also known as the atrial kick, when contraction of cardiac muscle in the atrium increases pressure, causing additional blood to flow across the mitral valve. In this last phase, 20% to 30% of the total diastolic volume crosses the mitral valve.

Detailed explanation-2: -70% of the atrial blood flows into the ventricles before atrial systole.

Detailed explanation-3: -The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as the cardiac cycle. The period of contraction that the heart undergoes while it pumps blood into circulation is called systole.

Detailed explanation-4: -You are listening to a typical example of a fourth heart sound, or S4. The late stage of diastole is marked by atrial contraction, or kick, where the final 20% of the atrial output is delivered to the ventricles.