Principles of ECG examination

Everyone has an electric current in the heart, which is produced by the heart muscle and is called the bioelectric current of the heart. Although this current is extremely weak, it can be conducted to the surface of the body. The electric current is drawn out with electric wires, and through a special precision instrument, namely "electrocardiogram machine", the current is amplified and converted into a curve, and the graph that is continuously traced on paper is the electrocardiogram. If it is directly displayed on the oscilloscope screen, it is called ECG oscilloscope.

The value of an electrocardiogram

Electrocardiogram examination is the most commonly used method in the examination of cardiovascular diseases. It can help doctors to diagnose diseases and facilitate further treatment. The application value of electrocardiogram examination is mainly reflected in the following aspects:

1. ECG is one of the most reliable methods for diagnosing arrhythmia. Although some arrhythmias can be diagnosed according to other clinical examinations, the accuracy rate is low, while the electrocardiogram can accurately diagnose various arrhythmias.

2. Electrocardiogram is an important basis for judging myocardial infarction. General clinical data such as symptoms and signs, blood routine, and blood biochemical tests lack specificity in the diagnosis of myocardial infarction. In most cases, electrocardiogram is needed to judge the location and degree of myocardial infarction. and evolution process.

3. Electrocardiogram is a unique way to find myocardial damage. Mild to moderate myocardial damage or ischemia may not necessarily cause changes in x-rays or signs, and sometimes even severe myocardial damage may not necessarily have positive findings. Only through the electrocardiogram can assist in the diagnosis of myocarditis, cardiomyopathy, myocardial insufficiency and other diseases.

4. Electrocardiogram is of certain value in the diagnosis of atrial and ventricular hypertrophy. Electrocardiogram can reflect atrial and ventricular hypertrophy from an electrical point of view. Although it is prone to false positives or false negatives, its accuracy is not as good as that of X-rays in some aspects, but the combination of the two can improve the accuracy of diagnosis, especially for central hypertrophy. certain diagnostic value.

5.The electrocardiogram can also be used to understand the effects of certain drugs such as digitalis quinidine and procainamide, as well as the effects of electrolyte disorders and certain endocrine diseases on the myocardium.