What is the heartbeat?
The heartbeat marks the rhythmic contraction of the heart muscle (systole), which is followed by a short relaxation phase (diastole). It is triggered by electrical impulses of the excitation conduction system, which originate in the sinus node. The sinus node is a collection of specialized cardiac muscle cells in the wall of the right atrium at the junction of the superior vena cava and acts automatically. From here, impulses are transmitted to the ventricles.
The heartbeat can be heard with a stethoscope. An electrocardiogram (ECG) can be used to record the electrical impulses that trigger it.
The normal resting heart rate for an adult is 60 to 80 beats per minute; for newborns, it is about 120 beats per minute. Well-trained endurance athletes get by on 40 to 50 beats per minute. During stress and physical work, the heartbeat rate increases to 160 to 180 beats per minute.
What is the purpose of the heartbeat?
With each heartbeat, blood is pumped through the circulatory system. It supplies all regions of the body with oxygen and nutrients via the vascular network.
How does the heartbeat work?
Conduction system
You can read more detailed information about the electrical conduction of the heart in the article Conduction System.
Sinus node
You can read everything important about the primary pacemaker of the heart in the article Sinus node.
AV node
You can read more about the secondary pacemaker of the heart in the article AV node.
What disturbances are there in the heartbeat?
Cardiac arrhythmias are an expression of irritation or damage to the conduction system. The cause is often organic heart disease such as coronary heart disease (CHD), heart muscle disease (cardiomyopathy) or inflammation of the heart muscle (myocarditis). Psychogenic causes are also possible. In addition, poisoning (intoxications) and thyroid dysfunction can be the trigger for cardiac arrhythmias. Depending on the heart rate, arrhythmias are divided into bradycardias and tachycardias: In bradycardia, the heartbeat is slower than normal; in tachycardia, it is faster.
