Definition, function and process
The electrocardiogram (or electrocardiography) is one of the standard medical procedures for the diagnosis of internal medicine and cardiology. With the help of electrodes, the electrical activity of the heart muscle is recorded. Benefits of the ECG: It is completely painless, safe for the patient, quick to perform and comparatively inexpensive.
Based on the record of cardiac activity, statements can be made on heart rate, heart rhythm, arousal, excitation conduction, and arousal. Thus, the method is suitable both for the detection of heart muscle disease (including myocardial infarction), as well as for cardiac arrhythmias (for example, extrasystoles, ventricular fibrillation, atrial fibrillation).
How does an ECG work?
The transmission of stimuli in the human organism is based on electrical excitation transmission, in which measurable voltage changes occur in the body. In order to be able to measure these, several electrodes are attached to the chest of the patient.
Starting from the sinus node in the right atrium, which acts as a natural pacemaker, the electrical excitement passes through the atrioventricular node (AV node) to the ventricles and triggers contraction. This is followed by the regeneration of the arousal (excitation feedback) and the process begins again with the electrical impulse of the sinus node. Between the heart contraction (systole) and the relaxation of the heart muscle (diastole) is only about a second.
The electrodes derive arousal, conduction of excitation, and arousal from voltage changes of the heart over the skin. As a result, a characteristic wave and jagged pattern is obtained in healthy patients (see picture), which will not be discussed in detail here.
Different types of ECGs:
Exercise ECGThe patient increases the physical load under the direction of the physician either on a bicycle ergometer or a treadmill. The exercise ECG can detect cardiac arrhythmia, which only occurs when there is increased physical activity.
Holter: The patient will bring home a portable ECG that is usually worn for at least 24 hours. The recording device fits easily into your pocket. Long-term ECGs are usually induced when cardiac arrhythmias are to be examined, which only occur temporarily.
Resting ECG: The resting ECG is performed lying down. The examination usually lasts less than five minutes and is particularly suitable for rapid diagnoses, such as suspected heart attack or for general examination of heart activity.