Electrocardiograms (ECGs) are an important diagnostic test that helps healthcare professionals to diagnose conditions related to the heart, including heart attacks, chronic illnesses, and more. Thus, reading an ECG correctly is a vital skill for providers. These diagrams are a representation of how a person’s heart muscle works – the electrical activity of it is demonstrated in the form of a wave rhythm with specific segments and intervals. While the ECG has many components, the three main elements are the P wave, the QRS complex, and the T wave.
First, the P wave is a part of the ECG that denotes atrial depolarization. It comes at the start of the sinus rhythm, as usually shown in the diagrams. When the atria are full of blood, the sinoatrial node sends a signal, which causes the atria muscles to contract. As a result of the pressure, the blood pumps into the lower chambers – ventricles (Hossain et al., 2021). Normal P waves go upwards and downwards, showing a reaction to the node’s signal. However, abnormalities may change the shape of this ECG element, which can be detected from an inverted form or a large or small amplitude of the wave (Hossain et al., 2021). In such cases, the problems may be connected to the heart’s location, enlargement of the atria, and the sinoatrial node’s malfunction.
The next vital component is the QRS complex – a combination of three waves (Q, R, and S). Some of these waves may not be present in a person’s ECG results, but the complex retains its name due to the actions of the heart muscles. After the atrial depolarization and contraction, the following steps are repeated in the ventricles. During the previous step, the left and right ventricles were filled with blood. As the size of the ventricles is much larger than that of the atria, the waves are bigger on the ECG and are interpreted in three parts (Hossain et al., 2021). Here, the contraction is regulated by the atrioventricular node, and it moves from this node to the next parts of the process, such as the Bundle of His (Hossain et al., 2021). As the outcome of this action, the blood exits the ventricles and gets into the aorta and the pulmonary artery. Problems with the QRS complect in ECGs imply blocks in branches and abnormal contraction of the ventricles.
Finally, the last vital component of the ECG is the T wave, which follows the blood’s exit from the ventricles. The relaxation of the ventricles is also termed ventricular repolarization. This process is marked by the T wave, and it is depicted as a slope in the diagram (Kashou et al., 2020). As the pressure in the ventricles falls, the muscle cells start to relax, the pulmonic and aortic valves close, and the systole ends (Hossain et al., 2021). Therefore, an ECG shows problems if the T wave is not gradually lowering but is going upward or is completely absent (Kashou et al., 2020). Some potential abnormalities may show ischemia or improper levels of potassium ions, which are responsible for the contraction and relaxation of the heart muscle.
In conclusion, the process of reading an ECG is broken down into small steps that correspond to the heart’s contraction and relaxation. The diagram has many components, but the three most important elements are the waves – the P wave, the QRS complex, and the T wave. Thy show how the blood moves during the heart’s contraction. Their interpretation may show many possible issues with the system, including the heart’s position and size, the nodes’ activity, and blockages in any of the branches.
References
Hossain, M. B., Bashar, S. K., Lazaro, J., Reljin, N., Noh, Y., & Chon, K. H. (2021). A robust ECG denoising technique using variable frequency complex demodulation. Computer methods and programs in biomedicine, 200, 105856. Web.
Kashou, A. H., Ko, W. Y., Attia, Z. I., Cohen, M. S., Friedman, P. A., & Noseworthy, P. A. (2020). A comprehensive artificial intelligence–enabled electrocardiogram interpretation program. Cardiovascular Digital Health Journal, 1(2), 62-70. Web.