The end of systole


At the end of this phase the semilunar (aortic and pulmonary) valves close.

Pressures & Volume:

After the peak in ventricular and arterial pressures (red and green), blood flow out of the ventricles decreases and ventricular volume decreases more slowly (white).

When the pressure in the ventricles falls below the pressure in the arteries, blood in the arteries begins to flow back toward the ventricles and causes the semilunar valves to close. This marks the end of ventricular systole mechanically.


The T wave is due to ventricular repolarization. The end of the T wave marks the end of ventricular systole electrically.

Heart sounds:


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