An electrocardiogram, or ECG, is one of the most widely used tests, especially in emergencies and internal medicine. Its correct interpretation is crucial in many cases. While it is a general test, it is not as easy to interpret as it may seem at first glance.
The electrocardiogram registers the electrical signals of the heart. Each heartbeat emits an electrical signal that is recorded by an ECG. Thus, the test allows medical professionals to visualize cardiac activity and detect potential changes.
As such, the electrocardiogram is only a linear representation. It shows graphics that cardiologists need to interpret. To do that, they need to follow the steps we will now describe below.
What to keep in mind when analyzing an electrocardiogram (ECG)
1. Confirm reliability
The first step is to confirm that the electrocardiogram is working properly. The ECG must have a speed of 25 mm / s and an amplitude of 1 mV / 10 mm. If an error is suspected, the test should be repeated.
If all seems right, proceed to the next step, where the data and values found using this analytical tool are interpreted.
2. Calculate a person’s heart rate
Heart rate is one of the most important pieces of information when diagnosing health problems.
Heart rate is the most important information from the electrocardiogram. Some ECGs calculate it automatically. If not, there are also manual methods for doing so.
The heartbeat mainly tells you how many times the heart contracts as it pumps blood to the rest of the body. Knowing this can determine if a person suffers from tachycardia or bradycardia, the identification of which is important for possible abnormalities and problems.
3. Assessment of heart rate
Heart rate consists of systolic and diastolic pressure in the heart muscle. If the body is functioning normally, it should shrink about 70-75 times per minute. It appears on the electrocardiogram in QRS complications.
This is one of the easiest data to observe. It helps your doctor determine if your heart rate is regular or irregular.
4. Location of the electrical axis of the heart
By observing the electrical axis of the heart, diseases such as cardiac arrhythmia can be detected.
This is one of the most difficult steps in interpreting an electrocardiogram.
The electrical axis of the heart corresponds to the direction followed by the electrical stimulus as it passes through the chambers. This information provides additional information about a possible intraventricular error.
5. Electrocardiogram (ECG): ST segment evaluation
QRS complexes are the sum of the electrical charge of all the cells in the chambers. The T-wave then describes the electrical recovery or repolarization of the chambers. The distance between the QRS complex and the T-wave is called the ST segment.
Sometimes the ST segment goes up or down, but if these values are not significant, it is most likely normal. In contrast, when values exceed the minimum range, the risk of ischemic heart disease is very likely.
6. Evaluation of electrocardiogram waves and intervals
Intervals between waves are very relevant for the diagnosis of all cardiovascular diseases.
It is also important to analyze all waves and intervals that have not been estimated.
Of particular importance are the PR interval and the QT interval. So when the PR interval is short, it means an accelerated atrium chamber. When it is long, it means that the space has slowed down.
The QT interval describes the duration of ventricular electrical systole. In addition, it includes a QRS interval, an ST segment, and a T-wave. It is also closely related to heart rate. For this reason, the intervals decrease when it is fast, and vice versa.
7. Schematic synthesis
In summary, these are the steps that should be followed when a physician interprets a electrocardiogram schematically:
- First, determine a person’s heart rate.
- Then set the heart rate.
- Define the axis.
- Identify the sinus rhythm (occurrence of a Q wave before each QRS complex).
- Then evaluate the PR interval.
- Also evaluate the QT interval.
- Evaluate QRS complexes.
- Analyze the ST segment.
- Evaluate T-waves.
When doctors complete all of these steps, they can identify most problems. They can then create an action plan that they follow, as well as decide what the person should do about the treatment.