The systole


The systole (Greek for contraction), is part of the heart's action. Put simply, the systole is the tension phase of the heart, and thus the phase in which blood is expelled from the heart through the body and pulmonary circulation. It is replaced by diastole, the relaxation phase of the heart.

This means that during systole, the blood is drawn from the right and left ventricles (Ventricle) pressed out. The systole describes the pumping capacity of the heart and determines the pulse. The duration of the systole remains almost the same even when the heart rate changes; it is approx. 300 milliseconds long in an adult.

Structure of the systole

In the systole, a distinction is made between a short mechanical myocardial tension phase and a longer-lasting blood outflow phase. The chambers (Ventricle) filled with blood. The sail and pocket flaps are tightly closed. The subsequent contraction of the heart muscle increases the pressure in the two chambers. If the pressure in the chambers exceeds the pressure in the large pulmonary artery and aorta, the outflow phase begins. The pocket flaps open and the blood flows into the large vessels and from there into the periphery of the pulmonary and body circulation. At the same time, the two atria fill with blood. So that the blood cannot flow back from the chambers into the atria during systole, the access is closed by the leaflet valves.

The beginning and end of the systole can be identified by various diagnostic means. In auscultation, the outflow phase begins with the 1st heart sound and ends with the 2nd heart sound. In echocardiography, the opening of the aortic valve can be seen at the beginning and the end of the valve at the end. In the EKG, the outflow phase begins with the R wave and ends with the T wave. During the entire systole, the excitability of the heart muscle is suspended so that no irregularities can arise. This is known as absolute refractory period.

Systole too high

The upper blood pressure value measured during systole corresponds to the maximum pressure that the heart can generate during the tension and ejection phases.
The systolic value is usually between 110-130 mmHg.

The following overview clarifies the classification of the measured blood pressure values:

  • Optimal: <120 - <80
  • Normal: 120-129 - 80-84
  • High normal: 130-139 - 85-59
  • High blood pressure grade 1: 140-159 - 90-99
  • Grade 2 high blood pressure: 160-179-100-109
  • High blood pressure grade 3:> 179 -> 110
  • Isolated systolic hypertension:> 139 - <90

(from the guidelines of the German Hypertension League)

The blood pressure fluctuates throughout the day: the systole is increased during physical or emotional exertion without high blood pressure being present. It is only when the systole is measured permanently (in at least three measurements on two different days) that the blood pressure is too high.

The causes of too high a systole are complex, for example obesity, increased alcohol consumption, smoking and increasing age play a role in the development of high blood pressure. But there are also organic causes such as kidney or hormone diseases that can cause high blood pressure. The isolated systolic hypertension with normal values ​​in the diastole and too high values ​​for the systole indicates either a disease of the aortic valve or severe calcification of the blood vessels.

A systole that is too high is usually asymptomatic, so many patients do not even know that their blood pressure is too high. Warning symptoms for too high a systole can be a headache in the early morning, especially at the back of the head, dizziness, ringing in the ears, nervousness and shortness of breath during exercise can also be an indication of high blood pressure. Often, however, too high a systole only becomes noticeable through complications. These include damage to the vessel walls (including in the eye), heart attack, stroke and kidney disease.

To avoid these complications, every patient with high blood pressure should receive medical attention. Therapy consists of lifestyle changes:

  • More movement
  • Reduction of obesity
  • healthier diet
  • Stop smoking.

If these measures cannot permanently reduce the excessively high systole, so-called ones are used Antihypertensive drugs back, which are supposed to lower blood pressure.
Here are:

  • Diuretics (dehydrating agents)
  • ACE inhibitors
  • Angiotensin receptor blockers
  • Calcium channel blockers
  • Beta blockers

used. The complications mentioned above can be significantly reduced by lowering the blood pressure.

Read more on the topic: Systole too high

Systole too low

Values ​​between 100mmHg and 130mmHg are considered normal systolic blood pressure values.

If the systolic blood pressure falls below 100mmHg, one speaks of low blood pressure, which is also known as hypotension. The consequence of low blood pressure is that the blood from the heart is pumped out of the heart with less pressure and this leads to reduced blood flow to some organs. The brain is particularly affected in this regard.

Symptoms of persistently low blood pressure can include tiredness, dizziness, general weakness, paleness and cool skin, and palpitations. If the pressure falls to values ​​below 70mmHg, the person usually passes out.

Which systolic values ​​are considered dangerous?

The blood pressure value 120/80 mmHg is regarded as the ideal blood pressure. However, slightly lower or higher values ​​are not bad and in no way dangerous. However, if the systolic blood pressure is above 140mmHg or below 100mmHg, this should be monitored regularly and if necessary, a doctor should be consulted. However, blood pressure can fluctuate differently depending on the day and physical activity. If the blood pressure should rise or fall briefly, this is not a cause for concern, but only an absolutely normal compensation of the body.

If the systolic blood pressure falls below a value of 100mmHg, reduced bleeding of the body, and especially of the brain, can occur. Many, especially young women, live with constant values ​​around 100mmHg and have no complaints whatsoever. However, if the systolic value falls below 90mmHg, this should be observed and, if necessary, examined by a doctor.

If the systolic blood pressure rises permanently above 140mmHg regardless of external or physical influences, this should be observed, as the vessels in the body have to withstand this increased pressure and this can lead to small cracks in the vessels or to thickening and hardening over a longer period of time. High blood pressure is therefore considered to be a decisive risk factor for arteriosclerosis.

What influence does systole have on blood pressure?

Blood pressure is the pressure that prevails in the large arteries of the body's circulation. The blood pressure can be divided into a systolic and a diastolic blood pressure value. The systolic blood pressure is the higher value, while the diastolic value is the lower value. The blood pressure depends on the cardiac output as well as the tension and elasticity of the vessel walls.

The systolic value represents the contraction phase of the heart and is representative of the ejection capacity of the heart. The stronger the heart's ejection capacity, the higher the maximum pressure with which blood is pumped into the body's arteries. At rest, the heart pumps between four and five liters per minute from the heart chambers into the body and lungs during systole. The maximum pressure reached with which the blood is pumped into the arteries is the systolic pressure and is subject to fluctuations that are dependent on various causes, such as physical activity.

What is systolic heart failure?

Systolic heart failure is a type of heart failure in which the amount of blood that is expelled from the heart chambers into the blood vessels is greatly reduced.

Normally, between 60 and 70 percent of the amount of blood is pumped into the aorta per heartbeat. About 70 milliliters enter the body's circulation per heartbeat. In the case of systolic heart failure, the amount of blood pumped out can drop to values ​​below 25% and thus below 25 milliliters.

The cause of systolic heart failure is a reduced contraction force of the heart muscle cells. Another cause can be an increased afterload. Afterload is determined by two factors - arterial blood pressure and the stiffness of the arteries. These two factors counteract the expulsion of blood from the ventricles in the body's arteries. The lower the contraction force and the higher the afterload, the lower the cardiac output.

The reduced ejection capacity of the heart leads to reduced blood flow in parts of the body. For this reason, action must be taken as quickly as possible in order to avoid permanent damage. This is usually done through drug treatment, such as diuretics, beta blockers or aldosterone antagonists.

What is the diastole?

The activity of the heart can be divided into a systole and a diastole. The systole represents the contraction of the atria and ventricles, while the diastole represents the relaxation phase. During diastole, the heart is filled with blood from the body and pulmonary circulation. The blood from the inferior and superior vena cava is pumped into the right atrium and the blood from the pulmonary veins is pumped into the left atrium.

The diastole can be divided into an atrial diastole and a ventricular diastole. Between the atrium and the chamber there are so-called leaflet valves, which are closed during the relaxation phase and open during the subsequent filling phase. During the atrial diastole, the atria initially relax - but the valves are still closed. As a result of the higher pressure in the supplying veins compared to the atrium, the atria are filled. During the ventricular diastole, the blood from the atria continues to flow into the heart chambers. The so-called pocket valves, which connect the heart chambers with the lungs and body circulation, are closed and are only opened during systole, i.e. the contraction of the heart muscles.

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