The pathology of the cardiovascular system is one of the most common problems that affects people of all ages. Timely treatment and diagnosis of the circulatory system can significantly reduce the risk of developing dangerous diseases.
To date, the most effective and easily accessible method of examining the heart is an electrocardiogram.
Basic rules In the study the results of the patient survey, doctors pay attention to such components of the ECG as:
- teeth;
- Intervals;
- Segments.
There are strict standard parameters for each line on the ECG tape, the slightest deviation from which may indicate violations of in the heart.
The analysis of the cardiogram
The whole set of ECG lines is examined and measured mathematically, after which the doctor can determine some parameters of the heart muscle and its conducting system: heart rate, heart rate, pacemaker, conductivity, electrical axis of the heart.
To date, all these indicators are exploring high-precision electrocardiographs.
Sinus rhythm of the heart
This is a parameter that reflects the rhythm of the heartbeats that occur under the influence of the sinus node( normal).It shows the coordination of the work of all parts of the heart, the sequence of the processes of tension and relaxation of the heart muscle.
Rhythm very is easy to determine by the highest teeth R : if the distance between them is the same throughout the entire record or deviates by no more than 10%, then the patient does not suffer from arrhythmia.
Heart rate
The number of beats per minute can be determined not only by counting the pulse, but also by ECG.To do this, you need to know the speed with which the ECG was recorded( usually 25, 50 or 100mm / s), as well as the distance between the highest teeth( from one vertex to the other).
Multiplying the recording time of one mm by the length of the segment R-R , you can get the heart rate. Normally, its values range from 60 to 80 beats per minute.
Excitation source
The autonomic nervous system of the heart is arranged in such a way that the process of contraction depends on the accumulation of nerve cells in one of the heart zones. In norm it is a sinus node, the impulses from which diverge throughout the nervous system of the heart.
In some cases, the role of the pacemaker can assume other nodes( atrial, ventricular, atrioventricular).You can determine this by examining the P-prism, which is slightly above the isoline.
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Conductivity
This is a criterion showing the process of impulse transmission. Normally, the impulses are transmitted sequentially from one pacemaker to another, without changing the order.
Electric axis
Indicator based on the process of excitation of the ventricles. Mathematical analysis of the Q, R, S teeth in the I and III leads allows to calculate a certain vector of their excitation. This is necessary to establish the functioning of the branches of the bundle.
The received angle of inclination of the axis of the heart is estimated by the value: 50-70 ° norm, 70-90 ° deviation to the right, 50-0 ° deviation to the left.
Teeth, segments and intervals
Teeth are areas of the ECG lying above the contour, their meaning is as follows:
- P - reflects the processes of atrial contraction and relaxation.
- Q, S - reflect the processes of excitation of the interventricular septum.
- R - the process of excitation of the ventricles.
- T - the process of relaxing the ventricles.
Intervals are ECG regions lying on the contour line.
- PQ - reflects the propagation time of the pulse from the atria to the ventricles.
Segments - ECG sections, including the interval and the tooth.
- QRST - duration of ventricular contraction.
- ST - time of full excitation of ventricles.
- TP is the time of electric heart diastole.
Rate in males and females
The interpretation of the cardiac ECG and the norm of the indices in adults is presented in this table:
Healthy child results
The decoding of the ECG measurement results in children and their norm in this table:
Dangerous diagnoses
What dangerous conditions can be determined by ECG readingswhen decrypting?
Extrasystolia
This phenomenon of is characterized by cardiac rhythm failure .A person feels a temporary increase in the frequency of contractions followed by a pause. It is associated with the activation of other rhythm drivers, sending an additional volley of impulses along with the sinus node, which leads to an extraordinary reduction.
Arrhythmia
The is characterized by a change in the sinus rhythm frequency , when pulses come in at different frequencies. Only 30% of such arrhythmias require treatment;can provoke more serious diseases.
In other cases this may be a manifestation of physical activity, a change in the hormonal background, the result of the transferred fever, and does not threaten health.
Bradycardia
Occurs when a sinus node weakens, unable to generate pulses at the proper frequency, and the heart rate also slows down, up to 30-45 beats per minute .
Tachycardia
The opposite phenomenon, characterized by an increase in heart rate more than 90 beats per minute. In some cases, temporary tachycardia occurs under the influence of strong physical exertion and emotional stress, as well as during illness associated with fever.
Conductivity disorder
In addition to the sinus node, there are other lower-order drivers of the second and third order rhythms. Normally they carry out impulses from the driver of the rhythm of the first order. But if their functions are weakened, a person can feel weakness, dizziness , caused by oppression of the heart.
It is also possible to lower blood pressure, t.ventricles will contract less often or arrhythmically.
Why there may be differences in the indicators of
In some cases, when performing repeated ECG analysis, deviations from previously obtained results are revealed. With what it can be connected?
- Other time of day .It is usually recommended to do an ECG in the morning or in the daytime, when the body has not yet been influenced by stress factors.
- Loads of .It is very important that the patient be calm when recording the ECG.The release of hormones can increase heart rate and distort the indicators. In addition, before the examination, it is also not recommended to engage in heavy physical labor.
- Food intake .Digestion processes affect blood circulation, and alcoholic beverages, tobacco and caffeine can affect the heart rate and pressure.
- Electrodes .Incorrect imposition or random displacement can seriously change the performance. Therefore, it is important not to move during the recording and to degrease the skin in the area of application of electrodes( the use of creams and other means for the skin before the examination is highly undesirable).
- Background of the .Sometimes foreign instruments can interfere with the operation of the electrocardiograph.
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Additional survey techniques
Holter
The method of long-term study of the heart , possible due to a portable compact tape recorder that is able to record the results on a magnetic film. The method is especially good when it is necessary to investigate periodically arising pathologies, their frequency and time of occurrence.
Treadmill
Unlike conventional ECG recording at rest, this method is based on the analysis of the results of after physical exertion of .Most often this is used to assess the risk of possible pathologies that are not detected on a standard ECG, or when assigning a course of rehabilitation to patients who have had a heart attack.
Phonocardiography
Allows the to analyze heart tones and sounds. Their duration, periodicity and time of occurrence correlate with phases of cardiac activity, which makes it possible to evaluate the operation of valves, the risks of endo- and rheumatic carditis.
The standard ECG is a graphical representation of the work of all parts of the heart. Its accuracy can be affected by many factors, so the should be followed by the recommendations of the doctor .
The examination reveals most of the pathologies of the cardiovascular system, but additional tests may be required for an accurate diagnosis.
Finally, we offer a video-course on decoding "ECG under everyone's power":
