Atrial fibrillation
The content of the article:
- Forms of the disease
- Causes of atrial fibrillation
- Atrial fibrillation symptoms
- Diagnostics
- Atrial fibrillation treatment
- Diet for atrial fibrillation
- Possible complications and consequences
- Forecast
- Prevention
Atrial fibrillation (atrial fibrillation, atrial fibrillation) is one of the types of cardiac arrhythmias, which is characterized by rapid irregular atrial contraction with a frequency of 350-700 per minute. If the paroxysm of atrial fibrillation lasts more than 48 hours, the risk of thrombosis and the development of severe ischemic stroke increases dramatically. The chronic form of atrial fibrillation contributes to the rapid progression of chronic cardiovascular failure.
Patients with atrial fibrillation are often encountered in the practice of a cardiologist. In the general structure of the incidence of various types of arrhythmia, atrial fibrillation accounts for about 30%. Its prevalence increases with age. So, up to 60 years old, this type of arrhythmia is observed in 1% of people, and after 60 years, the disease is detected already in 6%.
Atrial fibrillation is characterized by frequent agitation and contraction of the atria
Forms of the disease
The classification of forms of atrial fibrillation is carried out taking into account electrophysiological mechanisms, etiological factors and features of the clinical course.
According to the duration of the course of the pathological process, the following forms of atrial fibrillation are distinguished:
- paroxysmal (transient) - an attack in most cases lasts no more than a day, but can last up to a week;
- persistent - signs of atrial fibrillation persist for more than 7 days;
- chronic - its main distinguishing feature is the ineffectiveness of electrical cardioversion.
Persistent and transient forms of atrial fibrillation can have a recurrent course, i.e. attacks of atrial fibrillation can occur repeatedly.
Depending on the type of atrial rhythm disturbance, atrial fibrillation is divided into two types:
- Flicker (fibrillation) of the atria. There is no coordinated contraction of the atria, as there is an uncoordinated contraction of individual muscle fiber groups. Many electrical impulses accumulate in the atrioventricular junction. Some of them begins to spread to the myocardium of the ventricles, causing them to contract. Depending on the frequency of ventricular contractions, atrial fibrillation is divided into bradystolic (less than 60 beats per minute), normosystolic (60–90 beats per minute) and tachysystolic (over 90 beats per minute).
- Atrial flutter. The frequency of atrial contractions reaches 200-400 per minute. At the same time, their correct coordinated rhythm is preserved. With atrial flutter, there is almost no diastolic pause. They are in a constant state of systole, that is, they do not relax. This becomes the reason for the difficulty in filling them with blood and, as a result, insufficient supply of blood to the ventricles. If every second, third or fourth impulse arrives at the ventricles through the atrioventricular connections, this ensures the correct rhythm of their contractions, and this form of the disease is called correct atrial flutter. In cases where there is a chaotic contraction of the ventricles, due to violations of atrioventricular conduction, they talk about the development of abnormal atrial flutter.
Atrial flutter on an ECG
During paroxysm of atrial fibrillation, the atria are reduced ineffectively. In this case, the complete filling of the ventricles does not occur, and at the time of their contraction, there is periodically no release of blood into the aorta.
Causes of atrial fibrillation
Atrial fibrillation can be caused by both heart disease and a number of other pathologies. The most common occurrence of atrial fibrillation occurs against the background of severe heart failure, myocardial infarction, arterial hypertension, cardiosclerosis, cardiomyopathies, myocarditis, rheumatic heart defects.
Other causes of atrial fibrillation are:
- thyrotoxicosis (thyrotoxic heart);
- hypokalemia;
- intoxication with adrenergic agonists;
- overdose of cardiac glycosides;
- alcoholic cardiopathy;
- chronic obstructive pulmonary disease;
- pulmonary embolism (PE).
Atrial fibrillation is often observed with thyrotoxicosis (hyperthyroidism)
If the cause of atrial fibrillation cannot be established, an idiopathic form of the disease is diagnosed.
Atrial fibrillation symptoms
The clinical picture of atrial fibrillation depends on the state of the valvular apparatus of the heart and myocardium, the form of the disease (permanent, paroxysmal, tachysystolic or bradystolic), as well as the characteristics of the patient's psycho-emotional state.
Tachysystolic atrial fibrillation is the most severely tolerated by patients. Its symptoms are:
- cardiopalmus;
- interruptions and pain in the heart;
- shortness of breath, aggravated by exertion.
Initially, atrial fibrillation is paroxysmal. Further development of the disease with a change in the frequency and duration of paroxysms in each patient occurs in different ways. In some patients, seizures occur extremely rarely, and there is no tendency to progression. In others, on the contrary, after 2-3 episodes of atrial fibrillation, the disease becomes persistent or chronic.
Rapid heartbeat, shortness of breath, heart pain - the main symptoms of atrial fibrillation
Patients also feel differently atrial fibrillation attacks. For some, an attack is not accompanied by any unpleasant symptoms, and such patients learn about their arrhythmias only when they undergo a medical examination. But most often the symptoms of atrial fibrillation are intensely pronounced. These include:
- a feeling of chaotic heartbeats;
- muscle tremors;
- severe general weakness;
- fear of death;
- polyuria;
- excessive sweating.
In severe cases, severe dizziness, fainting occurs, attacks of Morgagni - Adams - Stokes develop.
After the restoration of a normal heart rate, all signs of atrial fibrillation cease. With a constant form of the disease, patients eventually cease to notice manifestations of arrhythmia.
With atrial fibrillation, during auscultation of the heart, irregular tones are heard with varying volume. The pulse is arrhythmic, pulse waves have different amplitudes. Another symptom of atrial fibrillation is pulse deficit - the number of pulse waves is less than the number of heartbeats. The development of pulse deficit is due to the fact that not every contraction of the ventricles is accompanied by the release of blood into the aorta.
With atrial flutter, patients complain of pulsation of the cervical veins, discomfort in the heart, shortness of breath, palpitations.
Diagnostics
The diagnosis of atrial fibrillation is usually not difficult, and the diagnosis is made already during the physical examination of the patient. Palpation of the peripheral artery determines the disordered rhythm of the pulsation of its walls, while the tension and filling of each pulse wave is different. During auscultation of the heart, significant fluctuations in volume and irregularity of heart tones are heard. The change in the volume of the I tone following the diastolic pause is explained by the different values of the diastolic filling of the ventricles with blood.
To confirm the diagnosis, an electrocardiogram is recorded. Atrial fibrillation is characterized by the following changes:
- chaotic arrangement of the QRS of the ventricular complexes;
- absence of P waves or definition of atrial waves in their place.
If necessary, daily ECG monitoring is carried out, which makes it possible to clarify the form of atrial fibrillation, the duration of the attack, and its relationship with physical activity. To select antiarrhythmic drugs and identify symptoms of myocardial ischemia, exercise tests (treadmill test, veloergometry) are performed.
Daily ECG monitoring allows you to clarify the picture of atrial fibrillation
Echocardiography (EchoCG) makes it possible to assess the size of the cardiac cavities, to reveal the presence of intracardiac thrombi, signs of possible damage to the pericardium and valve apparatus, cardiomyopathy, to assess the contractile function of the left ventricle. Echocardiography results help in the selection of drugs for antiarrhythmic and antithrombotic therapy.
For the purpose of detailed visualization of the structures of the heart, multispiral or magnetic resonance imaging of the heart is performed.
The method of transesophageal electrophysiological research helps to determine the mechanism of formation of atrial fibrillation. This study is performed for all patients with atrial fibrillation who are planning to have an artificial pacemaker (pacemaker) implantation or catheter ablation.
Atrial fibrillation treatment
Treatment of atrial fibrillation is aimed at restoring and maintaining the correct heart rate, preventing recurrent paroxysms, preventing the formation of blood clots and the development of thromboembolic complications.
To interrupt the attack of atrial fibrillation, antiarrhythmic drugs are administered intravenously to the patient under the control of ECG and blood pressure. In some cases, cardiac glycosides or slow calcium channel blockers are used, which help to improve the patient's well-being (reduction of weakness, shortness of breath, palpitations) by reducing the heart rate.
If conservative therapy is ineffective, the treatment of atrial fibrillation is carried out by applying an electric pulse discharge to the heart area (electrical cardioversion). This method allows you to restore the heart rate in 90% of cases.
You can relieve an attack of atrial fibrillation by applying an electrical impulse discharge to the heart area
If atrial fibrillation lasts more than 48 hours, the risk of thrombosis and the development of thromboembolic complications increases sharply. For their prevention, anticoagulant drugs are prescribed.
After the heart rhythm is restored, long-term use of antiarrhythmic drugs is indicated in order to prevent repeated episodes of atrial fibrillation.
In the chronic form of atrial fibrillation, treatment consists in the constant intake of anticoagulants, calcium antagonists, cardiac glycosides and adrenergic blockers. Active therapy of the underlying disease that caused the development of atrial fibrillation is being carried out.
In order to radically eliminate atrial fibrillation, radiofrequency isolation of the pulmonary veins is performed. In the course of this minimally invasive procedure, the focus of ectopic excitation located in the mouth of the pulmonary veins is isolated. The efficiency of radiofrequency isolation of the pulmonary veins reaches 60%.
With a constant form of atrial fibrillation or frequently recurring paroxysms, there are indications for radiofrequency ablation (RFA) of the heart. Its essence lies in cauterization of the atrioventricular node using a special electrode, which leads to complete AV blockade with the further installation of a permanent pacemaker.
Diet for atrial fibrillation
In the complex therapy of atrial fibrillation, an important role is played by proper nutrition. The basis of the diet should be low-fat protein and plant foods. Food should be taken frequently in small portions. Dinner should be no later than 2.5-3 hours before bedtime. This approach prevents overstimulation of the vagus nerve receptors, which affects the functions of the sinus node.
Patients with atrial fibrillation should refuse strong tea, coffee, alcoholic beverages, as they can provoke an attack.
With atrial fibrillation, the diet should include a large number of foods rich in potassium and magnesium. These products include:
- soya beans;
- nuts (cashews, almonds, peanuts);
- wheat germ;
- wheat bran;
- Brown rice;
- beans;
- spinach;
- oat flakes;
- oranges;
- bananas;
- baked potato;
- tomatoes.
With atrial fibrillation, you need to enrich the diet with foods containing magnesium and potassium
To preserve the maximum amount of trace elements and vitamins in dishes, it is best to steam or bake them. It is useful to include vegetable, fruit or berry smoothies in the menu.
Possible complications and consequences
The most common complications of atrial fibrillation are progressive heart failure and thromboembolism. In patients with mitral stenosis, atrial fibrillation often causes the formation of an intra-atrial thrombus that can block the atrioventricular opening. This leads to sudden death.
The resulting intracardiac thrombi with arterial blood flow are carried throughout the body and lead to thromboembolism of various organs. In about 65% of cases, blood clots enter the blood vessels of the brain, causing the development of ischemic stroke. According to medical statistics, every sixth ischemic stroke is diagnosed in patients with atrial fibrillation. Factors that increase the risk of developing this complication are:
- advanced age (over 65);
- previously transferred thromboembolism of any localization;
- the presence of concomitant pathology (arterial hypertension, diabetes mellitus, congestive heart failure).
The development of atrial fibrillation against the background of a violation of the contractile function of the ventricles and heart defects leads to the formation of heart failure. With hypertrophic cardiomyopathy and mitral stenosis, developing heart failure occurs as cardiac asthma or pulmonary edema. Acute left ventricular failure always develops as a result of impaired blood outflow from the left heart, which leads to a significant increase in pressure in the pulmonary veins and capillaries.
The most severe manifestation of heart failure associated with atrial fibrillation is arrhythmogenic shock due to low cardiac output.
Atrial fibrillation can turn into ventricular fibrillation, which is fatal.
Most often, atrial fibrillation is complicated by the formation of chronic heart failure, which progresses at one rate or another and leads to the development of dilated arrhythmic cardiomyopathy.
Forecast
The prognosis for atrial fibrillation is determined by the cause that caused the development of cardiac arrhythmias, and the presence of complications. Atrial fibrillation, which occurs against the background of heart defects and severe myocardial damage (dilated cardiomyopathy, diffuse or general cardiosclerosis, large-focal myocardial infarction), quickly leads to the development of heart failure.
The presence of atrial fibrillation increases mortality in cardiac diseases by more than 1.5 times.
The prognosis is also unfavorable for atrial fibrillation complicated by thromboembolism.
A more favorable prognosis in patients with a satisfactory condition of the ventricles and myocardium. However, if paroxysms of atrial fibrillation occur frequently, the quality of life of patients significantly deteriorates.
The idiopathic form of atrial fibrillation usually does not cause a deterioration in well-being, patients feel healthy and lead an almost normal life.
Prevention
In order to prevent atrial fibrillation, it is necessary to timely identify and actively treat diseases of the cardiovascular and respiratory systems.
Secondary prevention of atrial fibrillation is aimed at preventing the occurrence of new episodes of cardiac arrhythmias and includes:
- long-term drug therapy with antiarrhythmic drugs;
- performing cardiac surgery if indicated;
- refusal to use alcoholic beverages;
- limitation of mental and physical overload.
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Elena Minkina Doctor anesthesiologist-resuscitator About the author
Education: graduated from the Tashkent State Medical Institute, specializing in general medicine in 1991. Repeatedly passed refresher courses.
Work experience: anesthesiologist-resuscitator of the city maternity complex, resuscitator of the hemodialysis department.
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
