Electrocardiograph (ECG) is a device that allowsassess cardiac activity, and also diagnose the condition of this organ. During the examination, the doctor receives the data in the form of a curve. How to read the ECG curve? What kind of teeth are there? What changes are visible on the ECG? Why do doctors need this method of diagnosis? What does the ECG show? This is far from all the issues that interest people who are faced with electrocardiography. First you need to find out how the heart is arranged.
The human heart consists of two auricles and twoventricles. The left side of the heart is more developed than the right side, since it puts a heavy load on it. It is this ventricle that most often suffers. Despite the difference in size, both sides of the heart should work stably, cohesively.
How to read the ECG correctly?This is not so difficult as it might seem at first glance. First you should look at the cardiogram. It is printed on special paper with cells, and two types of cells are clearly visible: large and small.
Conclusion ECG is read by these cells. What do ECG-teeth show, cells? These are the basic parameters of the cardiogram. Let's try to learn how to read the ECG from scratch.
On paper for printing the result of the surveyThere are two types of cells: large and small. They all consist of vertical and horizontal guides. Vertical is the voltage, and the horizontal is the time.
Large squares consist of 25 small cells.Each small cell is 1 mm and corresponds to 0.04 seconds in the horizontal direction. The large squares are 5 mm and 0.2 seconds. In the vertical direction, the centimeter of the strip is equal to 1 mV of voltage.
To read the ECG conclusion, you need to know which teeth are there and what they mean.
There are five prongs in total. Each of them on the graph displays the work of the heart.
All ECG teeth have their own reading characteristics.
All the electrocardiogram teeth have a definite value for the correct diagnosis.
The very first tooth of the graph is called R.It denotes the time between the palpitations. To measure it, it is best to select the beginning and end of the tooth with vertical lines, and then count the number of small cells. Normally the tooth P should be between 0.12 and 2 seconds.
However, measurement of this indicator only on onesite will not give accurate results. To make sure that the heartbeat is smooth, it is necessary to determine the interval of the P wave in all parts of the electrocardiogram.
Knowing how to read an electrocardiogram in an easy way, you canto understand whether there is a pathology of the heart. The next important tooth of the graph is R. It's easy to find it - it's the highest peak on the chart. This will be a positive prong. Its highest part is marked on the cardiogram R, and its lower parts Q and S.
The QRS complex is called ventricular, or sinus. In a healthy person, the sinus rhythm on the ECG is narrow, high. The figure clearly shows the teeth of ECG R, they are the highest:
Between these peaks, the number of large squares indicates the heart rate (heart rate). This indicator is calculated by the following formula:
300 / number of large squares = heart rate.
For example, between the peaks are four full squares, then the calculation will look like this:
300/4 = 75 beats per minute.
Sometimes on the cardiogram the elongation of the QRS complex is noted to be more than 0.12 s, which indicates the blockade of the bundle of His.
PQ is the interval from the tooth P to Q.It corresponds to the time of excitation of the atria to the ventricular myocardium. The norm of the PQ interval at different ages is different. Usually it is 0.12-0.2 seconds.
With age, the interval increases. Thus, in children under 15 years of age, PQ can reach 0.16 s. At the age of 15 to 18 years, PQ increases to 0.18 s. In adults, this figure is equal to a fifth of a second (0.2).
When the interval is extended to 0.22 s, they speak of bradycardia.
To know how to read the ECG correctly, you need to understand the intervals. After the determination of the teeth, the calculation of the QT interval begins. Normally, it is 400-450 ms.
If this complex is longer, then we can assume IHD, myocarditis or rheumatism. With a shortened type, hypercalcemia can occur.
Normally, this indicator is located at the level of the midline, but can be higher than it by two cells. This segment shows the process of restoring the depolarization of the heart muscle.
In rare cases, the indicator may rise three cells above the midline.
Decoding of the cardiogram in the norm should look like this:
And how to read the ECG for various pathologies?One of the most frequent heart diseases is a sinus rhythm disturbance. It can be pathological and physiological. The latter type is usually diagnosed in people involved in sports, with neuroses.
With sinus arrhythmia, the cardiogram has the following form: sinus rhythms are preserved, fluctuations of R-R intervals are observed, but during the delay of breathing the graph is flat.
With pathological arrhythmia, the preservation of the sinus pulse is observed continuously, regardless of the delay in breathing, while wave-like changes are observed at all intervals of R-R.
When there is a myocardial infarction, changes on the ECG are clearly pronounced. The signs of pathology are:
With a heart attack, the main means of recognizing the necrosis of the heart muscle is a cardiogram. With its help you can determine the depth of the organ damage.
With a heart attack, the graph shows an increase in the ST segment, and the R wave is lowered down, giving the ST a shape resembling a cat's back. Sometimes, in pathology, there may be changes in the Q wave.
If you experience ischemia on the ECG, you can see in which part it is located.
ECG shows changes in the ventricles.Most often they appear in the left ventricle. This kind of cardiogram occurs in people with prolonged extra workload, for example, with obesity. With this pathology, the electric axis deviates to the left, against which the tooth S becomes higher than R.
And how to learn to read the ECG, if not alwaysit is clear, what teeth and how are located? In such cases, a continuous recording of the cardiogram using a mobile device is prescribed. He constantly writes ECG data to a special tape.
Such a survey method is necessary in those cases,if the classical ECG can not detect pathologies. During the diagnosis of Holter, a detailed diary is always kept, where the patient records all his actions: sleep, walks, sensations during activity, all activity, rest, symptoms of the disease.
Usually, data are recorded within 24 hours. However, there are cases when it is necessary to take readings for up to three days.
When decoding the cardiogram, it is recommended to follow a certain sequence.
The length of the R-R cycle isregularity and rate of heart rhythm. When evaluating the heart, not one R-R gap is assessed, but all. Normally, deviations within 10% of the norm are allowed. In other cases, the abnormal (pathological) rhythm is determined.
To establish the pathology, the QRS complex is taken anda certain time period. It calculates how many times the segment is repeated. Then the same time interval is taken, but further on the cardiogram, again counted. If on equal parts of time the amount of QRS is the same, then this is the norm. At different numbers - the pathology is assumed, while they focus on the teeth of P. They should be positive and stand in front of the QRS complex. Throughout the chart, the form P must be the same. This option speaks about the sinus rhythm of the heart.
Atrial rhythms, the tooth P is negative.Behind it is the QRS segment. In some people, the P tooth on the ECG may be absent, completely merging with QRS, which indicates the pathology of the atria and ventricles, which the impulse achieves simultaneously.
The ventricular rhythm is shown on the electrocardiogram by deformed and expanded QRS. In this connection, the relationship between P and QRS is not visible. Between the teeth R is large distances.
ECG is used to determine cardiac conduction.At the P wave, the atrial pulse is determined, normally this value should be 0.1 s. The P-QRS interval displays the overall rate of conduction in the atria. The rate of this indicator should be in the range of 0.12 to 0.2 s.
The QRS segment shows the conductivity of the ventricles, the norm is the limit of 0.08 to 0.09 s. As the intervals increase, the cardiac conduction slows down.
What the ECG shows, patients do not need to know.This must be understood by a specialist. Only a doctor can correctly decipher a cardiogram and put the correct diagnosis, given the degree of deformation of each individual tooth, segment.
It is not always possible to read the result of the electrocardiogram independently due to lack of experience and fuzzy teeth, segments, intervals, and also the peculiarities of the paper.