Electrocardiography (ECG ) - Causes, Symptoms and Treatment .MF .
early as the 19th century, scientists studying the anatomical and physiological characteristics of the animals and the human heart, came to the conclusion that this body is a muscle that is capable to generate and conduct electrical impulses.The human heart consists of two atria and two ventricles.Proper conduct them good electrical signals causes the myocardial (heart muscle) and provides the right rhythm reductions.
Originally pulse occurs in the cells of the sinoatrial (atrial) node, located on the border of the right atrium and the superior vena cava.Then he spreads atria, reaching the atrioventricular node (located between the right atrium and ventricle), here there is a small delay pulse, then passes through the bundle of His in the thickness of the interventricular septum, and is distributed by Purkinje fibers in the walls of both ventricles.This is the path of the electrical signal on the cardiac conduction system is correct and provides a full heartbeat as on impulse there is a reduction in mu
conductive system of the heart A little later, the scientists were able to create a device that allows you to capture and read processes of electrical activity in the heart by applying electrodes to the chest.A huge role here belongs Willem Eythovenu, the Dutch scientist who constructed the first apparatus for electrocardiography and showed that in patients with various heart diseases vary parameters of cardiac electrophysiology in the ECG (1903).So, what is an electrocardiogram?
ECG - this instrumental method studies the electrophysiological activity of the heart based on the recording and graphic representation of the potential difference that occurs in the process of contraction of the heart muscle to diagnose heart disease.
ECG is performed by applying electrodes on the front wall of the chest in the projection of the heart and limbs, followed by a very EKG machine recorded electrical potentials of heart and displayed as a graphical curve on a computer monitor or thermal paper (using an ink recorder).The electrical impulses generated by the heart and spread throughout the body, so for ease of reading the diversion were developed - schemes which allow to record potential differences in different parts of the heart.There are three standard retraction - 1, 11, 111;three reinforced abduction - aVL, aVR, aVF;and six chest leads - V1 to V6.All twelve lead ECG displayed on the film and allow in each abduction to see the work of a particular area of the heart.
in modern electrocardiography method is very widespread because of its availability, ease of use, low cost and lack of invasiveness (violation of the integrity of body tissues).ECG allows to diagnose many diseases -. Acute coronary pathology (myocardial infarction), hypertension, cardiac arrhythmias and conduction, etc., as well as to evaluate the effectiveness of the medical or surgical treatment of heart disease.
are the following methods of ECG:
- Holter (daily) monitoring of ECG - patient set portable small device on the chest, which captures the slightest variations in cardiac activity during the day.The method is good because it allows you to observe the work of the heart in normal everyday activity of the patient and for a longer time than when removing a simple ECG.Helps in registration of cardiac arrhythmias, myocardial ischemia, is not identified with a single ECG.
- ECG load - drug use (using drugs farmakologichsekih) or exercise (treadmill - test, bicycle ergometry);and electrical stimulation of the heart during the introduction of the sensor through the esophagus (CHPEFI - Transesophageal electrophysiological study).It allows you to diagnose the early stages of coronary artery disease, when the patient complains of pain in the heart during exercise, and ECG at rest does not detect the changes.
- transesophageal ECG - usually held before CHPEFI, as well as in cases where the ECG through the anterior chest wall is uninformative and does not help the doctor to establish the true nature of cardiac arrhythmias.
Indications for ECG
Why conduct an electrocardiogram is necessary?Electrocardiography can diagnose many cardiac diseases.Indications for ECG are:
1. Routine examination of children, adolescents, pregnant women, military personnel, drivers, athletes, individuals older than 40 years, patients before surgery, patients with other diseases (diabetes, thyroid disease, lung disease, digestive diseasesystem, etc.);
2. Diagnosis of diseases:
- coronary heart disease (CHD), including acute, subacute myocardial infarction, myocardial infarction;
- endocrine, dysmetabolic, alcohol - toxic cardiomyopathy;
- chronic heart failure;
- heart disease;
- rhythm and conduction disturbances -VPV syndrome, atrial fibrillation, premature beats, tachycardia - bradycardia, sinoatrial and atrioventricular block, bundle branch block feet, etc.
3. Control after treatment of these diseases (medical or cardiac surgery)
Contraindications for ECG
contraindications for standard electrocardiography not.However, the procedure can be difficult in patients with complex injuries of the chest, with a high degree of obesity, with a strong body hair of the chest (the electrodes simply can not fit snugly to the skin).Also significantly distort the ECG data can be the presence of the pacemaker in the patient's heart.
There are contraindications for an electrocardiogram with a load: the acute phase of myocardial infarction, acute infectious disease, worsening of arterial hypertension, coronary heart disease, congestive heart failure, complex arrhythmias, suspected bundle aortic aneurysm, decompensation (current deterioration) of other organs diseasesand systems - digestive, respiratory, urinary.For transesophageal ECG is contraindication esophageal disease - tumors, strictures, diverticula, etc.
Preparations for the study
The special preparation of the patient does not need to conduct an ECG...There are no restrictions in the normal household activity, acceptance of food or water.We do not recommend the use of the procedure of coffee, alcohol, or large amounts of cigarettes, as it will affect the work of the heart at the time of the survey, and the results can be misinterpreted.
How is electrocardiography?
ECG can be performed in a hospital or clinic.The hospital conducted a study in patients delivered brigade ambulance with cardiac symptoms, or patients already hospitalized in the hospital of any type (therapeutic, surgical, neurological, etc.).The clinic is held in the ECG as a routine examination, and patients whose state of health requires urgent hospitalization.
patient arrives at the appointed time in the ECG diagnostic study, lies on the couch on her back;nurse rubs his chest, wrists and ankles with a sponge dampened with water (for better conductivity) and imposes electrodes - one "clothespin" on the wrists and feet and six "suckers" on the chest at the heart projection.Next, turn on the device, the reading of the electrical activity of the heart, and the result is recorded in the form of a graphical curve via ink Thermal Film recorder or directly stored in a computer doctor.All study lasts about 5 - 10 minutes, without causing any discomfort to the patient.
Next, an analysis of ECG doctor of functional diagnostics, then the conclusion is handed to the patient or transferred directly to the doctor's office.If the ECG is not revealed major changes that require follow-up in the hospital, the patient can go home.
Explanation Now a closer look at the analysis of the electrocardiogram.Each complex consists of a normal electrocardiogram prongs P, Q, R, S, T and segments - PQ and ST.The teeth may be positive (upwards) and negative (directed downwards) and segments above and below the contour.
patient sees in the minutes of ECG following indicators:
1. Excitation source.During normal operation of the heart the source is in the sinus node, ie sinus rhythm.Signs of it are the presence of positive P waves in the 11 abduction before each ventricular complex of the same shape.Nesinusovy rhythm characterized by a negative P wave and appears with the sinoatrial blockade, arrhythmia, atrial fibrillation, atrial flutter, ventricular flutter and blink.
2. The validity (regularity) rate.It determines the distance between the R wave of several different complexes no more than 10%.If the abnormal rhythm, also indicate the presence of arrhythmias.Sinus, but an abnormal rhythm occurs with sinus (respiratory) arrhythmia and sinus rhythm at the right sinus tachycardia and bradi-.
3. HR - heart rate.Normally 60 - 80 beats per minute.The state with the heart rate is below this value is called bradycardia (slow heart rate), and the above - tachycardia (increased heart rate).
4. Determination of EOS (electrical heart axis of rotation).EOS is a vector summation of electrical activity of the heart, which coincides with the direction of its anatomical axis.Normally, the EOS range from semi-erect to polugorizontalnogo position.In obese people the heart is placed horizontally, and lean more upright.EOS Deviations may indicate myocardial hypertrophy (overgrowth of the heart muscle, such as hypertension, heart diseases, cardiomyopathies) or conduction disorders (blockade of legs and His bundle branches).
5. Analysis of P wave P wave reflects the pulse occurrence in the sinoatrial node and holding it in the atria.Normally, the P wave is positive (except for a diversion aVR), its width to 0.1 seconds and a height of 1.5 to 2.5 mm.Deformation of the P wave is characteristic of the pathology of the mitral valve (P mitrale) or bronchopulmonary disease with the development of circulatory failure (P pulmonale).
6. Analysis of the segment PQ.It reflects implementation and physiological delay pulse through the atrioventricular node and is 0.02 - 0.09 sec.Changing the duration characteristic of the conduction abnormalities - syndrome shortened PQ, atrioventricular block.
7. Analysis of the QRS complex.It reflects the conduction of impulses along the interventricular septum and ventricular myocardium.The normal duration of 0.1 seconds.Change its duration, as well as the deformation of the complex characteristic of myocardial infarction, bundle branch blockades legs, ventricular arrhythmia, paroxysmal ventricular tachycardia.
8. Analysis of the ST segment.It reflects the process of full coverage of the ventricular excitation.Normally located on the contour lines may be offset up or down by 0.5 mm.Depression (reduction) or ST rise indicates the presence of myocardial ischemia or myocardial infarction.
9. Analysis of the tooth T. reflects the process of ventricular excitation decay.Normally, yes.Negative T also indicates a melkoochagovogo ischemia or myocardial infarction.
patient must be remembered that an independent analysis of the ECG report is not acceptable.Deciphering ECG parameters should be carried out only by the doctor of functional diagnostics, cardiologist, therapist or doctor ambulance as a doctor in the internal survey can compare the data obtained with the clinical symptoms and the risk of conditions requiring treatment, including hospitalization.Otherwise underestimation ECG conclusion can be harmful to health and human life.
whether complications are possible during ECG?The procedure for ECG quite harmless and safe, so no complications arise.When conducting an electrocardiogram with loading can occur increase in blood pressure, the occurrence of arrhythmias and conduction in the heart, but rather, it can be attributed not to the complications, and disease, and to clarify which appointed provocative tests.
therapists Sazykina OJ