During long-term ECG, the heart rhythm is recorded over 24 hours. This allows statements to be made about cardiac function in relation to events during the course of the day or night. These must be carefully documented by the patient, including the time of day, and can thus be correlated with the results of the ECG. The method is also called Holter ECG in the Anglo-Saxon world after its inventor Norman J. Holter. During the ECG, heart rate, heart rhythm and position type (electrical cardiac axis) are determined. Furthermore, the electrical activity of the atria (lat. atrium) and ventricles (lat. ventricles) can be read. The long-term ECG is primarily used to diagnose cardiac arrhythmias (extra beats or skipped heartbeats). For example, “pauses” or bradycardias (= < 60 beats per minute; e.g., due to passager sinus bradycardia in sick sinus syndrome, bradycardic atrial fibrillation, AV blockages) or malignant (malignant) arrhythmias (e.g., ventricular volleys or ventricular tachycardias) may occur.
Indications (areas of application)
- Cardiac arrhythmias occurring only occasionally
- Detection of silent ischemia (reduced blood flow) of the myocardium.
- Pacemaker dysfunction
- Cardiomyopathy – heart muscle disease leading to impaired heart function.
- Control of antiarrhythmic therapy – (usually drug) therapy of cardiac arrhythmias.
- Phases of palpitations (tachycardia).
- Severe chronic heart failure (cardiac insufficiency).
- Syncope (momentary loss of consciousness)/pre-syncope.
- Unexplained dyspnea (shortness of breath) or thoracic pain (chest pain)
- Vertigo (dizziness)
- Condition after myocardial infarction (heart attack).
Before the examination
Long-term ECG is a non-invasive diagnostic method that does not require any preparation from the patient.
The procedure
Through the long-term ECG, the electrical activity of the heart muscle fibers can be derived and displayed as curves. There is a special stimulation system in the heart where the electrical excitation is formed, which is then propagated through the conduction system. The excitation is generated in the sinus node, which is located in the right atrium of the heart. The sinus node is also called the pacemaker because it drives the heart at a certain frequency. It is controlled by the sympathetic and parasympathetic nervous systems (vagus nerve), which thus significantly influence the heart rhythm. From the sinus node, the electrical impulse travels via fiber bundles to the AV node (atrioventricular node). This is located at the junction with the ventricles (heart chambers) and regulates the transmission of impulses to the heart chambers. The period of excitation conduction is called the atrioventricular conduction time (AV time). This corresponds to the duration of the PQ time in the ECG. If the sinus node fails, the AV node can take over the function as the primary rhythm generator. The heart rate is then 40-60 beats per minute.If there is a strong time delay in the transmission of stimuli by the AV node or it fails, the clinical picture of the so-called AV block occurs. The long-term ECG is a portable recording device worn on a belt or around the neck. The electrical impulses are derived with the help of electrodes (suction electrodes; adhesive electrodes). The electrodes are placed on the chest for this purpose. In the two-lead ECG, 5 electrodes are positioned, and in the three-lead ECG, 7 electrodes are positioned. The duration of the examination is usually more than 24 hours for the long-term ECG or up to 7 days for the R-test.In the R-test, the electrocardiogram is recorded using an event recorder. This is a pure rhythm monitoring with only two chest wall electrodes. Although the analysis is continuous, the recorder only stores events that are not normal or episodes that are marked by pressing a button on the recorder. At the end of the recording, the ECG data are analyzed by computer. Cardiac arrhythmias are divided into conduction disorders (excitation formation disorders) and conduction disorders (excitation conduction disorders), which in turn can be divided into several subgroups.Stimulation disorders (excitation formation disorders) include:
- Sinus arrhythmia – irregular heartbeat that is physiologically due to respiration; may also, in rare cases, be an expression of damage to the sinus node
- Sinus bradycardia (< 60 beats per minute).
- Sinus tachycardia (> 100 beats per minute)
- Sick sinus syndrome (sinus node syndrome; cardiac arrhythmia due to impaired function of the sinus node caused by various disease states).
- Supraventricular arrhythmias, i.e., the origin of the arrhythmia is above the ventricles – they include atrial flutter and atrial fibrillation
- Ventricular arrhythmias, ie the origin of the arrhythmia is in the ventricles – they include ventricular tachycardia, ventricular flutter and ventricular fibrillation.
- Extrasystoles, i.e. heartbeat outside the normal heart rhythm – ventricular extrasystoles (VES) or supraventricular extrasystoles (SVES).
Conduction disorders (conduction disorders) include:
- Sinuatrial block (SA block).
- Atrioventricular block (AV block)
- Intraventricular block
- Atrioventricular reentry tachycardia with/without preexcitation (short-term tachycardia due to conduction of excitation through short-circuit pathways)
Benefit
Through the long-term ECG, an existing heart disease can often be detected so that your doctor can act accordingly.The long-term ECG thus serves your health: a healthy heart is an important prerequisite for your well-being and performance.
