Systole (medicine)

The systole (Greek συστολή - contraction ) is a part of the cardiac cycle. Simply put, it is the tensing and thus blood - Ausströmungsphase of the heart, in contrast to the diastole, the Erschlaffungs and thus blood - Einströmungsphase. In systole, the blood is, from the right and left heart chamber ( ventricle) is forced out. The systole describes the pumping of the heart. It determines the pulse and the pulse amplitude.

The duration of the systole remains fairly constant even if the change of the heart rate, whereas the duration of the diastole varies considerably. The systole is about 300 milliseconds in adult humans.

The systole of the chamber is divided into a short mechanical heart muscle contraction phase and a prolonged blood - Ausströmungsphase. Immediately prior to the exertion stage of the chambers are filled with blood, sailing and pocket flaps are closed. The heart muscle to contract, so that the pressure rises. In the Ausströmungssphase the pressure exceeds the pressure in the chambers in the pulmonary trunk ( pulmonary artery ) and aorta, the semilunar valves open and blood flows into the large vessels.

The mechanical Ausströmungsphase begins

  • In the phonocardiogram or auscultation with the first heart sound
  • In echocardiography with the opening of the aortic valve
  • In the ECG R-wave

The mechanical Ausströmungsphase ends

  • In the phonocardiogram or auscultation with the second heart sound
  • In echocardiography at the closing of the aortic valve
  • The ECG T-wave

Before the systole, the chambers are stretched and filled with blood, the atria are contracted. During systole, the two chambers pull together simultaneously. The blood is thus pumped into the pulmonary artery and the aorta, from where it flows to the periphery of the body and lungs. At the same time the atria expand and fill with blood. This does not flow during systole, the blood from the chambers into the atria, whose access is sealed valve-like with the wing flaps. According to the systole the muscle relaxes (diastole ). The collected blood in the atria flows through the opening atrioventricular valves into the ventricles. The pocket flaps are now closed for the blood that was pumped through the systole in the aorta and pulmonary artery, can not flow back into the chambers.

The excitability of the heart muscle is abolished during systole ( absolute refractoriness ).

Note: The systole of the atria falls in late diastole of the heart chamber.

Diseases

  • Extrasystole, an extra heartbeat, with different causes
  • Anatomy of the heart
  • Cardiovascular physiology
Systolic geometry Heart valve Premature ventricular contraction
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