The electrocardiogram, or ECG, is a medical device used to measure and record the various electrical activities of the heart muscle.
What is an electrocardiogram (ECG)?
Electrocardiogram (ECG) is the recording of the electrical impulses of the heart muscle fibers. Every movement of the heart is preceded by electrical excitation. This can be measured and displayed graphically or digitally with the ECG. Here is a stress ECG on the ergometer. The ECG is mostly used in cardiological diagnostics as well as in emergency medicine and intensive care. The contractions of the heart muscle are preceded by weak electrical impulses. These are generated by the sinus node and transmitted to the AV node via the various cells. This results in a continuous electrical activity of the heart. Through the ECG, these electrical voltage changes can be recorded at a precisely defined rate. For the measurement, electrodes are applied to different parts of the body. With the help of the ECG device, the weak impulses of the heart are amplified so that they can be recorded. Because the images are curved, they are also called cardiac waveforms. The accurate recording of the sum of all the heart activities allows a very high and accurate information value.
Function, effect, and goals
The ECG is mainly used in the cardiological field. It is an essential component of cardiological diagnostics, but also in the intensive medical monitoring of critical patients. For example, during surgery, patients are monitored by ECG. In emergency medicine, the ECG is one of the most important tools, especially for severely injured patients and patients with acute heart problems. Resuscitations are also performed here using an ECG. In addition to heart rate and heart rhythm, an ECG can also be used to determine the position type of the heart. The basic principle of an ECG is always the same. However, there are different methods and types of recording. The choice of the appropriate method depends on the aim of the examination. An ECG can be done at rest, under stress, or long-term. In addition to these mostly ambulatory examinations, there is the so-called monitoring, i.e. the constant monitoring of critical patients or in the form of telemetry. Here, the data are sent to a receiver by radio. In addition, an ECG can be performed in various measurement forms, the leads. Here, depending on the number of leads, different numbers of electrodes are attached. However, at least three electrodes are required; a standard ECG usually comprises twelve (12-lead ECG). The more leads recorded, the more meaningful the ECG, since the leads are measured in different directions. This provides a comprehensive picture, which forms the basis for further diagnostic or therapeutic measures. However, the ECG is not only used for diagnostic purposes. Rather, it is an indispensable method for detecting acute dangers such as a heart attack. The various measurement options also make it possible to determine the location of the infarction, since there is no longer any electrical activity in the area of the infarction. This is important for operations or minimally invasive procedures such as cardiac catheterization. Diseases of the heart muscle or pericardium can be detected with the aid of an ECG, as can the overdose of some medications or a mineral deficiency or excess, since they affect conduction. An ECG can also provide information about the extra workload on one side of the heart.
Risks and dangers
The most difficult thing about an ECG is the evaluation. This should always be done by a specialist. Although modern devices now show initial diagnostic options, they are no substitute for the analytical and experienced eye of a specialist. Since the devices are subject to strict quality controls, errors or failures rarely occur. In the worst case, a patient can end up on the operating table without any reason for this. Of course, this is very rare, but the risk is not only from equipment failures, but especially from interpretation errors. These represent the greatest risk. Another risk exists with the stress ECG. Here, for example, in the case of severely constricted vessels, the stress can lead to an acute infarction in the worst case.However, as this test is always carried out under the supervision of specialist personnel, appropriate emergency measures are initiated immediately in the event of such complications. The resting ECG, on the other hand, is not dangerous. Despite possible risks, the ECG is one of the most reliable methods for early detection of heart disease. Thus, serious consequences such as a heart attack can often be avoided.
