ECG (electrocardiogram) is a universal examination method that helps to identify a wide range of diseases of a different nature. However, the resulting graph is by and large a mystery to the patient. What does, for example, negative T waves mean here? The full comprehensive answer specifically for your case will be given only by the attending doctor. Indeed, in reading the cardiogram, not only certain knowledge is important, but also extensive experience. In this article, we will introduce the reader to important basic indicators, their norm, and estimated deviations.
What it is?
From this we will begin preparations for ECG decoding. The T wave is the most important indicator on the electrocardiogram, which can help the doctor conclude on the recovery process after the contraction of the heart ventricles. He is the most volatile in the schedule.
By its shape and location, one can judge the amplitude of heart contractions, the presence of such dangerous diseases, conditions and pathologies as myocardial damage, endocrine diseases, intoxication of the body, intake of improperly selected medications, etc.
Closer to the decoding of the ECG and the norm for this indicator.
Normal rates for adults
On the graph, this tooth coincides with the so-called repolarization phase, that is, with the reverse transition of potassium and magnesium ions through the membrane of cardiac cells. It is after this that the muscle fiber of the cells will be ready for the next contraction.
Now decoding the ECG. Norm in adults:
- On the isoline, T will begin after tooth S.
- The direction should visually coincide with the QRS. That is, to be positive where R predominates, negative in areas where S already dominates.
- The normal shape of the tooth is smooth. Its first part will be more gentle.
- The amplitude reaches the 8th cell.
- From 1 to 3 chest ECG leads increase.
- The prong is negative in V1 and aVL.
- Always negative T in aVR.
Norms for newborns and children
Features of decoding ECG (the norm in adults we presented above) for newborns:
- In this case, normal T waves are low or even completely flat.
- Directions will be directly opposite to adults. What is the reason for this? The baby’s heart turns in the direction - it occupies its constant physiological position only for 2-4 weeks of life.
Now we list the features of a children's ECG - older children:
- Normally, negative T in V4 can last up to 10 years, and in V2 and 3 - up to 15 years.
- Negative T in the first and second chest leads of an ECG is admissible in both adolescents and young people of an older age. By the way, this type is called juvenile.
- The height T will gradually increase from 1 to 5 mm. For example, in schoolchildren, it is approximately equal to 3-7 mm. And these are indicators comparable with adults.
What are the changes talking about?
Let's look in detail what are the causes of the negative T wave on the ECG. In general, an electrocardiogram helps diagnose the following diseases:
- Osteochondrosis.
- Circulatory disorders in certain areas of the brain.
- Total potassium deficiency.
- Diseases of the endocrine nature.
- Cardiopsychoneurosis.
- Constant stress, severe nervous overload.
- Various types of intoxication. Including nicotine, glycosides, chlorpromazine, antiarrhythmic drugs.
- Hypertrophy of the heart ventricles.
- Injuries, infections and tumors of various nature.
- Pericarditis.
- Thromboembolism.
- Myocarditis, etc.
Major deviations
Negative T waves are just one kind of deviation of such an electrocardiogram indicator from the norm. But all in all there is a whole list of them - each name will speak about its violation.
The main ones will be as follows:
- Negative T waves.
- Biphasic.
- Flat.
- Smoothed out.
- Inversion.
- Coronary.
- Depression.
- Decrease in indicators.
- Rise of a tooth.
- High rates.
An explanation of a number of deviations will be given in the following sections of the article.
Negative T
What does the negative T wave on the ECG mean in the first place? It indicates coronary heart disease. A cause of a negative T wave can also be a heart attack - if the deviation is accompanied by changes in the QRS complex.
Changes that the ECG graph will show allow us to judge the stage of necrosis of the damaged heart muscle:
- The acute stage. On the graph, the abnormal QS, Q, ST segment will go above the line. T is positive.
- Subacute stage. It is characterized by negative T.
- Scarring. T wave is slightly negative or positive.
Negative T waves in all leads of the electrocardiogram do not always indicate a serious pathology. Such indicators will be normal, if the patient has fixed breathing, he is worried. In addition, negative T can indicate that the subject recently had a solid dinner with a dish containing a large percentage of carbohydrates. Therefore, proper preparation for the ECG is important to avoid false suspicions.
Negative T can also demonstrate the individual feature of the heart function of perfectly healthy people.
Pathologies as evidenced by negative T
However, in most cases, this indicator indicates various pathological conditions. A negative T wave will be observed with the following diseases and disorders:
- Subarachnoid hemorrhage.
- Condition after frequent extrasystoles, paroxysmal tachycardia.
- The so-called "pulmonary heart".
- Violation of the nervous or hormonal regulation of the heart - diabetes, thyrotoxicosis, diseases affecting the adrenal glands or pituitary gland.
- A number of cardiac pathologies - cardiomyopathy, heart attack, inflammation in the pericardium, myocardium, angina pectoris, mitral valve prolapse, endocarditis.
Two Phase T
Another name is a sign of "roller coaster." The tooth T first falls below the contour, and then crosses it, becoming positive.
A two-phase T-wave may indicate the following deviations:
- Blockade of the elements of the legs of the bundle of Giss.
- Intoxication with glycoside preparations.
- Hypertrophy of the left heart ventricle.
- An increased percentage of calcium in the blood.
Smooth tooth
On the graph, T will look somewhat flattened. The following reasons can lead to smoothing of an indicator:
- Abuse of alcoholic beverages, antidepressant drugs, "Cordaron".
- The patient is in a state of excitement or fear.
- Myocardial infarction, which is undergoing scarring.
- Diabetes.
- Excessive consumption of sugar, sweet foods and drinks before the examination.
- Neurocirculatory dystonia.
- Hypokalemia.
Reduced rate
This refers to the amplitude of the T wave - it will be less than 10% of the QRS complex. What does this deviation from the norm mean?
There are several reasons for the reduced T-wave index:
- Obesity, overweight.
- Cardiosclerosis
- Hypothyroidism
- The venerable age of the patient.
- Tonsillitis.
- Myocardial dystrophy.
- Anemia.
- Cardiopathy is dishormonal.
Also, the patient may be treated with corticosteroid drugs.
Inversion
Inversion - in other words, the turning of the T wave. How does it look on the electrocardiogram? The tooth changes its position relative to the contour. That is, in leads with positive (normal) T he suddenly flips his own polarity.
Inversion will not always speak specifically about pathology. It is considered the norm with a juvenile configuration (if observed only in the right leads), signs of early repolarization, which is typical for professional athletes.
Inversion of T at the same time will be a sign of a number of diseases and pathologies:
- Cerebral hemorrhage.
- A recent attack of tachycardia.
- Ischemia of the brain or myocardium.
- Violations in the conduction of impulses along a bundle of Giss legs.
- State of severe stress.
High rates
High values on the T wave will not be considered an exception. They indicate similar diseases:
- Anemia.
- Hypertrophy of the left heart ventricle.
- The first minutes of subendocardial ischemia.
- Hyperkalemia
- Cardiomyopathy - alcoholic or menopausal.
- The predominant effect on the heart muscle of the parasympathetic nervous system.
Flat t
A flattened, slightly inverted T is a controversial indicator. In individual cases, it will be the norm. In some patients, he speaks of dysfunctions of the heart muscle, ischemic, dystrophic processes.
May accompany the following serious diseases and dangerous conditions:
- Complete blockage in the ventricles of the pathways.
- Chronic or acute pancreatitis.
- Myocardial hypertrophy.
- Violation of electrolyte or hormonal balance.
In addition, a flat T wave can be observed with systemic administration of antiarrhythmic drugs.
Coronary T
On the cardiogram, the T wave reflects the ability of the endocardium to hold electrical negative potential. From this it follows that with coronary insufficiency, the tooth will change its direction. If violated, it is visualized in one of the following forms:
- Negative, negative.
- Isosceles.
- Pointed.
All of the above are the so-called teeth of ischemia. Their other name is coronary.
An important feature - the teeth will be maximally manifested on the cardiogram in those areas where the greatest damage is observed. In the mirror leads, the indicator will be sharp, isosceles. The more pronounced T is on the graph, the more pronounced myocardial damage is.
Tooth rise
The increase in amplitude may be the result of moderate physical overstrain of the patient, anemia, thyrotoxicosis, hyperkalemia, various infections. It is also an individual norm for a number of healthy people.
The rise of the T wave can be one of the signs of vegetative-vascular pathologies with a predominance of vagus nerve tone.
T wave - an important indicator on an ECG. The specialist in his deviations judges the development of diseases in the patient, the presence of dysfunctions - not only cardiac, but also nervous, hormonal, infectious or inflammatory.