The indication - when the ECG is used
Since the normal ECG for dormant patients for this is risk-free, it is carried out in case of suspected heart disease as a routine examination. Can be recognized
- Circulatory disorders (diseases of the coronary arteries, myocardial infarction)
- Cardiac arrhythmia (too fast, too slow or irregular heartbeat, atrial fibrillation / flutter, ventricular fibrillation / flutter)
- Drug overdose
- Mineral deficiency or excess (eg potassium) and
- Inflammation of heart muscle or pericardium
It is also used to control the course and therapy of heart disease. Some lung diseases (eg embolism [link to "pulmonary embolism - a life-threatening graft"]) lead to changes in the ECG. Before and during surgery, it is an essential part of the diagnostics to check the heart function of the patient.
The execution - how the investigation is done
If the person is taking medication, he should inform the examiner beforehand. In particular, heart medications can alter the ECG and otherwise lead to misdiagnosis.
In order to obtain evaluable results, the electrodes are always fixed in a specific sequence at defined locations on the chest (chest wall leads V1-V6) and the wrists and ankles (limb leads). In order to increase their conductivity, in the case of suction electrodes, a gel can be used and the electrode paper moistened; with strong chest hair, a partial shaving may be necessary. The electrodes are connected to the ECG device by means of cables.
- With the resting ECG - the "basic form" - the patient lies calm and relaxed during the measurement.
- Some changes, such as circulatory or arrhythmic disorders, only manifest themselves under physical stress; In such cases, a stress ECG (ergometry) is displayed on the bike or treadmill. The load is controlled in several steps increased up to the "load" (highest load level, which depends inter alia on age and gender) or until complaints or serious ECG changes occur. In addition to the heart rate curve, blood pressure and heart rate are also measured. The ergometry is also used in cases of suspected high pressure, for therapy control and to clarify the resilience after a heart attack or after cardiac surgery. Since complications such as heartache or even an infarction can occur, the ergometry always takes place under medical supervision.
- If cardiac arrhythmia is suspected, a long-term ECG may be indicated. The person concerned carries a small recording device with him 24 hours and notes activities and complaints. Diseases of the coronary arteries and the control of a cardiac pacemaker are also areas of application of the long-term ECG.
- Special forms such as the intracardiac ECG (during a cardiac catheterization) or oesophageal ECG remain reserved for certain issues.