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 do negative T waves mean here, for example? Only the attending physician will give a complete exhaustive answer specifically for your case. Indeed, in reading a cardiogram, not only certain knowledge is important, but also extensive work experience. In this material, we will present the reader with important basic indicators, their norm, and estimated deviation values.
What is this?
With this we will begin preparations for the ECG transcript. The T wave is the most important indicator on the electrocardiogram, which can help the doctor draw a conclusion about 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, taking improperly selected medications, etc.
Let's take a closer look at the interpretation of the ECG and the norm for this indicator.
Normal readings 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 heart cells. It is after this that the muscle fiber of the cells will be ready for the next contraction.
Now the ECG transcript. Norm in adults:
- The T contour will start after the S wave.
- The direction must visually coincide with the QRS. That is, to be positive where R predominates, negative in areas where S already dominates.
- Normal tooth shape - smooth. Its first part will be flatter.
- The amplitude reaches the 8th cell.
- Increases from 1 to 3 chest ECG leads.
- The prong is negative in V1 and aVL.
- Always negative T in aVR.
Norms for newborns and children
Features of ECG decoding (we presented the norm in adults above) for newborns:
- In this case, normal T-waves are low or even completely flat.
- Directions will be directly opposite to adults. What is it connected with? The baby's heart turns in the direction - it takes its constant physiological position only for 2-4 weeks of life.
Now we list the features of the pediatric ECG - older children:
- Normal negative T in V4 canlast up to 10 years, and in V2 and 3 - up to 15 years.
- Negative T in the first and second chest ECG leads are acceptable in both adolescents and older young people. By the way, this type is called juvenile.
- Height T will gradually increase from 1 to 5mm. For example, in schoolchildren it is approximately equal to 3-7 mm. And these are indicators comparable to adults.
What do the changes say?
Let's take a closer look at what causes a negative T wave on an ECG. In general, the electrocardiogram helps to diagnose the following diseases:
- Osteochondrosis.
- Impaired circulation in certain areas of the brain.
- Total potassium deficiency.
- Diseases of the endocrine nature.
- Neurocirculatory dystonia.
- Constant stress, severe nervous overload.
- Different types of intoxication of the body. Including nicotine, glycosides, chlorpromazine, antiarrhythmic drugs.
- Hypertrophy of the cardiac ventricles.
- Injuries, infections and tumors of various nature.
- Pericarditis.
- Thromboembolism.
- Myocarditis, etc.
Basic deviations
Negative T-waves are just one type of abnormal ECG reading. But all in all, there is a whole list of them - each name will speak about its violation.
The main ones will be:
- Negative T-waves
- Two-phase.
- Flat.
- Smoothed.
- Invert.
- Coronary.
- Depression.
- Decline.
- Tooth lifting.
- High performance.
Explanation of a number of deviations will be given in the following sections of the article.
Negative T
What does a negative T wave on an ECG say in the first place? It points to coronary heart disease. A heart attack can also cause a negative T wave - if the deviation is accompanied by changes in the QRS complex.
Changes that will show the ECG graph, allow us to judge the stage of necrosis of the damaged heart muscle:
- Acute stage. On the chart, abnormal QS, Q, ST segment will pass above the line. T is positive.
- Subacute stage. Characterized by negative T.
- Scarring. T wave slightly negative or positive.
Negative T waves in all ECG leads do not always indicate a serious pathology. Such indicators will be normal if the patient has frequent breathing, he is worried. In addition, negative T may also indicate that the subject recently dined heavily on a dish containing a large percentage of carbohydrates. Therefore, proper ECG preparation is important to avoid false suspicions.
Negative T can also demonstrate the individual peculiarity of the heart of perfectly he althy people.
Pathologies indicated by negative T
However, in most cases thisindicator indicates various pathological conditions. Negative T wave will be observed in the following diseases and disorders:
- Subarachnoid hemorrhage.
- Condition after frequent extrasystoles, paroxysmal tachycardia.
- The so-called "cor pulmonale".
- Violation of the nervous or hormonal regulation of the heart - diabetes mellitus, thyrotoxicosis, diseases affecting the adrenal glands or the pituitary gland.
- A number of cardiac pathologies - cardiomyopathy, heart attack, inflammatory process in the pericardium, myocardium, angina pectoris, mitral valve prolapse, endocarditis.
Two-phase T
Another name is a sign of a "roller coaster". The T wave first falls below the isoline, after which it crosses it, becoming positive.
Two-phase T-prong may indicate the following deviations:
- Blockade of the elements-legs of the Hiss bundle.
- Intoxication with glycoside drugs.
- Hypertrophy of the left heart ventricle.
- Increased percentage of calcium in the blood.
Smoothed prong
T will look somewhat flattened on the chart. The following reasons can lead to smoothing of the indicator:
- Abuse of alcoholic beverages, antidepressants, Cordarone.
- The patient is in a state of excitement or fear.
- Myocardial infarction in the scarring stage.
- Diabetes mellitus.
- Overdrinkingsugar, sugary foods and drinks before the examination.
- Dystonia neurocirculatory.
- 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 indicate?
There are several reasons for a reduced T-wave:
- Obesity, overweight.
- Cardiosclerosis.
- Hypothyroidism.
- Respectable age of the patient.
- Tonsillitis.
- Myocardial dystrophy.
- Anemia.
- Dishormonal cardiopathy.
The patient may also be taking corticosteroid medications as a reason for rejection.
Invert
Inversion - in other words, inversion of the T wave. How does it look on the electrocardiogram? The tooth changes its position relative to the isoline. That is, in leads with positive (normal) T, he suddenly reverses his own polarity.
Inversion will not always speak specifically about pathology. It is considered normal in the juvenile configuration (if observed only in the right leads), signs of early repolarization, which is typical for professional athletes.
T inversion at the same time will be a sign of a number of diseases and pathologies:
- Hemorrhage in the brain.
- Recent tachycardia.
- Cerebral or myocardial ischemia.
- Irregularities in the conduction of impulses along the bundle of Hiss legs.
- A state of severe stress.
High performance
High T-wave readings will not be considered the norm-exception. They testify to similar diseases:
- Anemia.
- Hypertrophy of the left heart ventricle.
- The first minutes of subendocardial ischemia.
- Hyperkalemia.
- Cardiomyopathy - alcoholic or menopausal.
- The predominant influence on the heart muscle of the parasympathetic nervous system.
Flat T
A flattened, slightly inverted T is a debatable indicator. In individual cases, it will be the norm. In some patients, he talks about dysfunctions of the heart muscle, ischemic, dystrophic processes.
May accompany the following serious diseases and dangerous conditions:
- Complete blockade in the ventricles of the pathways.
- Chronic or acute pancreatitis.
- Myocardial hypertrophy.
- Electrolyte or hormonal imbalance.
Also, a flat T wave may occur with systemic antiarrhythmic medications.
Coronary T
On the cardiogram, the T wave reflects the ability of the endocardium to hold an electrical negative potential. From this it follows that with coronary insufficiency, the tooth will change its direction. When violated, it is visualized in one of the following forms:
- Negative, negative.
- Isosceles.
- Pointed.
All of the above are the so-called ischemia teeth. Their other name iscoronary.
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 on the graph, the more myocardial damage manifested.
Tooth lift
Growth in amplitude may be the result of moderate physical overexertion of the patient, anemia, thyrotoxicosis, hyperkalemia, and various infections. It is also an individual norm for a number of he althy people.
T wave elevation may be one of the signs of vegetative-vascular pathologies with a predominance of vagal tone.
The T wave is an important indicator on the ECG. A specialist in his deviations judges the development of diseases in a patient, the presence of dysfunctions - not only cardiac, but also nervous, hormonal, infectious or inflammatory.
