_.png)
_.png)
_(1)_1.png)
_1.png)
_1.png)
_(1)_1.png)
Atrial Fibrillation
Overview
Atrial fibrillation (atrial fibrillation) is a violation of the rhythm of the heart, in which there is no mechanical atrial systole and there is a chaotic electrical activity of their myocardium, the condition is accompanied by irregular contractions of the ventricles and hemodynamic disorders.
Signs of atrial fibrillation on the ECG:
1. The absence of clearly defined p waves with their replacement by fibrillation waves with different amplitudes and frequencies from 350 to 600 per minute. Most clearly, changes are recorded in 1 chest lead (v1);
2. Irregular RR intervals.
The prevalence of atrial fibrillation in the general population is 1 to 2%.
In most cases, the development of fibrillation is associated with organic pathology of the organs of the cardiovascular system, which create a substrate for maintaining fibrillation, however, the appearance of this symptom complex does not always fit into any nosological category, in such a situation they speak of isolated atrial fibrillation.
Diseases that contribute to the occurrence of atrial fibrillation
• Hypertension;
• Damage and malformations of the valvular apparatus of the heart;8/
• Congenital heart defects;
• Chronic ischemic heart disease and acute myocardial infarction;
• Severe chronic cardiovascular insufficiency (stage 2, ii-iv fc);
• Various variants of cardiomyopathy and cardiomyodystrophy (including toxic and alcoholic);
• Hyper- and hypothyroidism;
• Violation of carbohydrate metabolism and diabetes mellitus type 1 and 2;
• Obesity;
• Pickwick's syndrome (sleep apnea);
• Chronic kidney disease.
Lifestyle factors contributing to atrial fibrillation
Certain medications, narcotic substances, tobacco smoking, neuropsychic overstrain, heart surgery, electric shock, and the presence of HIV infection can also provoke atrial fibrillation.
Why is atrial fibrillation dangerous?
Violation can lead to the development of chronic heart failure. Inconsistent contraction of the heart chambers can significantly affect hemodynamics. Lack of coordinated atrial contraction can reduce cardiac output by about 10%. This reduction is usually well tolerated, except in cases of increased ventricular rate, when the rhythm becomes too fast (eg, more than 140 beats/minute) or when patients initially have borderline or reduced cardiac output. Heart failure might result in such circumstances.
Development of acute cerebrovascular accident. The risk of ischemic stroke is 1.5% in people aged 50-59 and 23.5% in people aged 80-89. Particularly dangerous is paroxysmal atrial fibrillation with frequent disruptions of the sinus rhythm. The risk of developing cerebral thrombosis increases especially during the period of disruption and restoration of sinus rhythm. Allocate so-called. Atherothrombotic subtype of acute cerebrovascular accident by ischemic type.
Symptoms
In atrial fibrillation, there is no effective mechanical systole. In this case, the ventricles are filled mainly passively due to the pressure gradient between the cavities of the heart during diastole. In conditions of increased heart rate, there is not sufficient filling of the ventricles, which leads to hemodynamic disorders of varying severity.
Patients complain of palpitations, a feeling of interruption in the rhythm of the heart, decreased performance, increased fatigue, shortness of breath and palpitations with a previously habitual load. In addition, the symptoms of already existing diseases of the cardiovascular system may be aggravated.
The pathogenesis of atrial fibrillation:
Chronic diseases of the cardiovascular system, as well as conditions characterized by increased activity of the raas, cause structural remodeling of the walls of the atria and ventricles - the proliferation and differentiation of fibroblasts into myofibroblasts, the synthesis of connective tissue fibers and the development of fibrosis. The processes of remodeling of the chambers of the heart lead to heterogeneity in the conduction of the action potential and to the dissociation of the contraction of muscle bundles. In this case, the mechanical atrial systole is disturbed and conditions are created for the persistence of this pathological condition.
The ventricles produce non-rhythmic contractions, as a result, blood is retained in the atria, their volume increases. A decrease in ventricular filling, their frequent contraction, and the lack of effective atrial contraction can lead to a decrease in cardiac output and severe hemodynamic disorders.
Due to the fact that the blood flow in the atria slows down due to a violation of their mechanical systole, as well as due to turbulent mixing of blood, blood clots form, mainly in the left atrial appendage.
Classification and stages of development of atrial fibrillation:
Clinically, there are several forms of atrial fibrillation, depending on which the patient management tactics is determined:
1. Newly diagnosed atrial fibrillation: Any new episode of fibrillation, regardless of its cause and duration.
2. Paroxysmal form: Recurrent episodes of atrial fibrillation lasting up to 7 days with spontaneous termination.
3. Persistent form: Episodes lasting more than 7 days without spontaneous termination.
4. Long-term persistent form: Episodes of atrial fibrillation last more than 1 year.
5. Permanent form: Always present
Depending on the presence of an artificial valve and lesions of the valvular apparatus, valvular and non-valvular forms of atrial fibrillation are distinguished.
Complications of atrial fibrillation:
• The development of chronic heart failure . Inconsistent contraction of the chambers of the heart affects the movement of blood in the vascular bed. Lack of coordinated atrial contraction can reduce cardiac output by about 10%. This reduction is usually well tolerated, except in cases of increased ventricular rate, when the rhythm becomes too fast (eg, more than 140 beats/minute) or when patients initially have borderline or reduced cardiac output. In such cases, a serious complication of atrial fibrillation can develop - heart failure.
• The development of acute cerebrovascular accident. The risk of ischemic stroke is 1.5% in people aged 50-59 years and 23.5% in people 80-89 years old. Particularly dangerous is paroxysmal atrial fibrillation with frequent disruptions of the sinus rhythm. The risk of developing cerebral thrombosis increases especially during the period of disruption and restoration of sinus rhythm.
Thus, there is a close relationship between atrial fibrillation and stroke and heart failure.
Prevention
Paroxysmal and persistent forms of atrial fibrillation may be a reason for exemption from work with the issuance of a certificate of incapacity for work. The approximate period for release from work in order to stop an attack is 7-10 days; selection of anti-relapse therapy requires an average of 7 to 18 days. The criteria for closing a temporary disability certificate are:
• Normalization of sinus rhythm or achievement of the target heart rate of 80 or 110 per minute in the case of choosing a strategy for heart rate control (depending on the presence of symptoms);
• Achievement of the target level of inr during treatment with a vitamin k antagonist (2-3, optimally 2.5);
• No cardiac decompensation;
• Absence of thromboembolic complications;
Treatment
Emergency care for patients with an acute attack of atrial fibrillation
With the first episode of atrial fibrillation, each patient is shown hospitalization in a round-the-clock hospital. Hospitalization is also indicated for patients with an attack lasting more than 24 hours.
In the event of shortness of breath, dizziness, loss of consciousness, pressing pain behind the sternum against the background of an attack, the patient himself or the accompanying person must definitely call an emergency team.
The goals of treating atrial fibrillation are:
1. Prevention of thrombovascular complications;
2. Improved clinical prognosis;
3. Reducing the symptoms of the disease and improving the quality of life of the patient;
4. Reduction in the frequency of hospitalizations.
Tests Required for Diagnosis
General clinical biochemical blood test;
• Determination of total cholesterol and LDL;
• Carrying out the wasserman reaction;
• Determination of APTT, PT and coagulography to assess the readiness of whole blood for thrombosis;
• Determination of the antigen to the hepatitis b virus (HBSAG) in the blood;
• Determination of antibodies of classes m, g (igm, igg) to viral hepatitis in the blood;
• Determination of antibodies of classes m, g (Igm, igg) to the human immunodeficiency virus hiv-1 and 2;
• INR during warfarin therapy;
• Determination of blood group and Rh factor;
• ECG;
• Holter ECG monitoring, especially if paroxysmal atrial fibrillation is suspected;
• Echo-CS to assess the functional and anatomical state of the heart;
• Radiography of the lungs;
• Scheduled consultation with a cardiologist.
Additional examination methods may be used:
• Transesophageal echo-ks;
• Stress echocardiography with dobutamine stimulation;
• Coronary angiography;
• Duplex ultrasonography of the neck vessels;
• Ultrasound duplex scanning of the arteries and veins of the lower extremities;
• Intracardiac electrophysiological study;
• Determination of t4 free and TSH;
• CT and MRI examination of the chest, etc., depending on the clinical situation.
