What Is a Breathing Cycle?

The cardiac cycle refers to the process that the cardiovascular system undergoes from the beginning of one heartbeat to the beginning of the next heartbeat. ^[1]

Cardiac cycle

The cardiac cycle refers to the process that the cardiovascular system undergoes from the beginning of one heartbeat to the beginning of the next heartbeat. ^[1]

Systole and

The periodicity of the heart pumping blood causes the following various periodic phenomena: such as the intracardiac pressure and intravascular pressure, the volume of the atrium and ventricle, the opening and closing of intracardiac valves, and blood flow velocity. These changes drive blood in a certain direction within the blood vessel

It can be seen that ventricular contraction produces strong intraventricular pressure, which is the main driving force for the heart to eject blood from the artery. Decreased ventricular blood pressure during early diastole is the main cause of ventricular blood filling. If ventricular arrest or fibrillation occurs, the blood circulation will stop and the body will die; while if fibrillation occurs in the atrium, although the atrium cannot contract normally, the filling of the ventricle will not be seriously affected. When the heart rate increases to more than 180 times per minute, because

Changes in the central sound of the cardiac cycle During the cardiac cycle, the closing of the valve and the heart wall vibrations produced by the myocardial contraction can produce heart sounds, which can be heard by placing a stethoscope on a certain part of the chest wall, or using electronic instruments to convert the heart sound vibrations into electrical currents. Recorded after magnification

Heart murmurs occur during valvular disease. Multi-channel physiographs are used to simultaneously record the ECG, heart sounds, and carotid pulse curves, and the relevant time limit of the systolic interval is measured, which can be used as an index for evaluating ventricular function.

Cardiac cycle time elapsed (in seconds)

Ventricular systole

Isovolumic systole

0.06 0.08

Rapid ejection phase

0.11

3. Slow down the ejection period

0.14

Ventricular diastole

4. Isovolumic diastole

0.06 0.08

5. Fast filling period

0.11

6. Slow down the filling period

0.19

7. Atrial systole

0.1

The contraction and relaxation of the heart is to maintain blood circulation, that is, the ventricle shoots blood from the ventricle into the blood vessels, and at the same time draws blood from the blood vessels back to the ventricles (ventricular filling). During the contraction, the ejection period occurs. Because the ejection speed is fast first and then slow, it is divided into a rapid ejection period and a slow ejection period. In the same way, a filling period occurs during ventricular diastole. Because the filling rate is fast first and then slow, it is divided into a fast filling period and a slow filling period. At this time, the atrial contraction (atrial systole) also occurs. There is an excessive period in the process of ventricular ejection and filling conversion. At this stage, the ventricle is neither ejecting nor filling, that is, the amount of blood in the ventricle is unchanged, that is, the volume of the ventricle is basically unchanged. The diastolic states are different, and they are named as isovolumetric diastole and isovolumetric systole respectively.