Atrial fibrillation - Causes, symptoms and treatment. MF.

Causes of atrial fibrillation
Symptoms of
Diagnosis
Treatment and lifestyle
Possible complications and prediction of

The human heart is capable of generating and conducting electrical impulses, this ability is realized by the conduction system of the heart. In a normally functioning heart, pulses occur at the same frequency and frequency from 60 to 90 per minute, providing the right rhythm of heartbeats. In the presence of certain heart diseases, rhythm and conduction disorders occur, leading to an asynchronous contraction of the myocardium and causing unpleasant sensations. One of these disorders of rhythm is atrial fibrillation. Atrial fibrillation is a disease resulting from a chaotic contraction of individual atrial muscle fibers, characterized by the appearance of a regular( regular) or abnormal rhythm and leading to myocardial wear with the development of heart failure. With the development of this type of rhythm disturbance, each fiber is reduced individually, which prevents the full-fledged ejection of blood into the ventricles, and, accordingly, into the aorta and pulmonary arteries, followed by a violation of blood flow in other organs.

According to electrophysiological criteria, atrial fibrillation is divided into flicker( fibrillation) and atrial flutter. These two types differ in that at fibrillation the frequency of atrial contractions exceeds 400 beats per minute( usually 600-800 per minute), with the rhythm being incorrect, that is, the ventricles contract at different intervals. When fluttering, the frequency of atrial contractions is less than 400 per minute( 240-300), and the rhythm can remain correct, that is, the ventricles contract with the same periodicity in response to every second, third or fourth atrial contraction. In both types of atrial fibrillation, the frequency of contractions of the ventricles( respectively, HR) is less than the frequency of atrial contractions, since the atrioventricular node, by virtue of its physiological characteristics, can conduct pulses from the atria to the ventricles at a frequency of 200 to 220 per minute.

Often in the same patient, flicker and flutter occur sequentially, replacing each other, so from the standpoint of clinical terminology, the term atrial fibrillation is equated with the term atrial fibrillation, which is not entirely accurate.

Allocate paroxysmal( paroxysmal) and permanent forms of atrial fibrillation. Paroxysm is the appearance and arrest of an attack( independent or medicated) during the first seven days, then, in the absence of restoring the correct rhythm, atrial fibrillation is considered permanent. The difference between these forms lies in the tactics of patients' management - with a paroxysm of flickering or fluttering( first arising or repeated), the rhythm should be restored, while with a constant form the restoration of rhythm is fraught with the development of thromboembolic complications.

Depending on the heart rate, there are tachysitolic( heart rate more than 90 per minute), normosystolic( 60-90 per minute) and bradiscystolic( less than 60 per minute) types of atrial fibrillation.

Causes of atrial fibrillation

In the development of the disease, the main role is played by the processes that cause the repeated entry of electrical excitation into the same muscle fiber, which is manifested by the onset of fibrillation( literally - muscle twitching).Such repeated circulation waves arise if nearby fibers do not have the ability to carry out an impulse that, as it were, comes back.

The most common cause of these processes in the myocardium is acquired heart disease, since the overflow of atrial blood leads to stretching of their walls, increased atrial pressure and impaired muscle fiber supply, so they can no longer carry out impulses.

The presence of cardiosclerosis in the patient( replacement of the heart muscle with a scar tissue) also provokes the above-described mechanism of incorrect impulse transmission, because the scar tissue is unable to conduct electrical signals. The formation of cardiosclerosis can result in such diseases as coronary heart disease, myocardial infarction, myocarditis( inflammatory diseases of the heart muscle - viral or rheumatic).

Endocrine diseases should be singled out as a separate item, because some hormones have an influence on the heart muscle with a rapid increase in the rhythm, for example, thyroid hormones and adrenal glands( epinephrine, noradrenaline).With excess content in the blood of these hormones, constant stimulation of the heart muscle develops, which sooner or later will fail and lead to chaotic operation of the fibers of the atria. Such diseases include hyperthyroidism and pheochromocytoma.

In addition, violations in synchronous reduction can occur when the body is poisoned with toxic substances - alcohol, carbon monoxide, other poison gases.

Symptoms of atrial fibrillation

Sometimes the disease is asymptomatic and can only be detected by routine examination. But in most cases, patients are concerned about the following complaints:

- a feeling of rapid heartbeat, stopping and disruption of the heart;
- weakness, dizziness, sweating;
- pain in the region of the heart;
- shortness of breath, a feeling of shortness of breath.

With a constant form of atrial fibrillation, clinical signs are more blurred, as patients adapt to the disease and are accustomed to subjective feelings of rhythm disturbance. With a long-lasting permanent form( for many years), the heart muscle gradually wears out, resulting in chronic heart failure. This pathology is characterized by stagnation of blood in the lungs, liver and other organs and is manifested by shortness of breath( walking, climbing stairs, at rest), episodes of "cardiac" asthma or pulmonary edema( more often at night), lower limb edema, abdominal pain and painin the right hypochondrium( due to increased blood filling of the liver).

In the development of complications, the clinical picture is supplemented by characteristic symptoms - choking with bubbling breath, loss of consciousness, paralysis of the body part, a sharp decrease in blood pressure, collapse, stopping breathing and cardiac activity.

Diagnosis of atrial fibrillation

The diagnosis of atrial fibrillation can be suspected even on the basis of complaints. When examining a patient, a non-rhythmic rapid pulse is felt, usually less frequently than the heart rate( a lack of pulse arises from the fact that not every contraction of the ventricles can lead to a full cardiac outgrowth).When listening( auscultation) of the heart and lungs are determined by irregular heartbeats, with swelling of the lungs can be wet gurgling rales. Tonometry can show either increased, normal or even low blood pressure.

The main diagnostic method is the electrocardiogram .Atrial fibrillation on the ECG reveals the absence of a P wave( which means that the rhythm of cardiac contractions is not specified from the sinus node, as in the norm, but from the muscle fibers themselves or the atrioventricular node) and the different distance between the ventricular complexes( irregular rhythm, with heart rate,reach 200-220 beats per minute, which is due to the "throughput" ability of the atrioventricular node).Instead of isoline small fibrillation waves( f) are noted. Atrial flutter also indicates the absence of the P wave, large waves of flutter( F) and the same periodicity of contraction of the ventricles.

Signs of myocardial ischemia can be identified, as the heart muscle contracts at a rapid pace, requires more oxygen, and coronary vessels can not cope with this.

This is the atrial fibrillation on the

ECG. The day-to-day monitoring of the Holter ECG reveals short runs of fibrillation or flutter that can pass on their own, if no rhythm disturbances were detected on the standard ECG, and the patient makes characteristic complaints. In addition, the connection of rhythm disturbances with the load is estimated, for which the patient should keep a diary during the day, in which the psychoemotional and physical loads indicate in detail.

The esophageal ECG can be indicated if the standard electrocardiogram is uninformative.

When echocardiography is determined myocardial contractility, ejection fraction, stroke volume. Clots in the heart cavity can also be detected( most often formed in the left atrial appendage).

Radiography of the chest is prescribed to detect stagnant processes in the lung tissue, pulmonary edema, signs of pulmonary embolism, changes in the configuration of the heart due to the expansion of its parts.

In some cases, MRI( magnetic resonance imaging) and MSCT( multispiral computed tomography) of the heart can be prescribed for better visualization.

Treatment of atrial fibrillation

The tactics of treating paroxysmal and permanent forms differ.

The aim of the therapy for the paroxysmal form of is to restore sinus rhythm. If more than two days have passed since the onset of paroxysmal development, this issue is resolved strictly individually after three to four weeks of a continuous intake of warfarin or its analogues( blood thinning drugs), since the risk of developing thromboembolic complications is high. All medical measures in this form require in-patient monitoring. To restore the rhythm, the following methods are used:

- drug treatment - cordarone, novocaineamide, strophantine, korglikon, polarizing mixture( potassium chloride, glucose and insulin, diabetes mellitus - potassium chloride and saline solution) are intravenously administered. Inside is taken cordarone according to the scheme established by the doctor.
- in addition to drugs that restore the rhythm, funds are prescribed for continuous reception for heart failure( beta-adrenoblockers - carvedilol, bisoprolol, nebilet, calcium channel antagonists - verapamil, diltiazem, etc.), antiarrhythmics( propanorm, alapinin), antiplatelet agentsthe formation of blood clots in blood vessels and the heart - aspirin Cardio, cardiomagnet, thromboass, etc.).
- cardioversion is used in the ineffectiveness of drug therapy and is performed in the department of cardiac recovery with intravenous anesthesia. The essence of the method is that the electrical discharge of a certain power "restart" the heart and make it contract properly.

In case of frequent attacks of , the question is solved either about transferring the paroxysmal into a permanent form( that is, the doctors do not restore the rhythm, but treat atrial fibrillation as a permanent one) or about cardiosurgical treatment.

With a permanent form of treatment, the goal is to reduce the irregular heart rate and maintain it at the level most comfortable for the patient. For this purpose, digoxin, beta-blockers, antiaggregants and anticoagulants( warfarin under regular control of blood clotting parameters, in particular, INR) are constantly taken.

Cardiac Surgery Treatment of Atrial Fibrillation

This type of treatment is performed with ineffectiveness of drugs and cardioversion, as well as in severe clinical manifestationsdisease. There are two types of operations:

1) radiofrequency ablation of pulmonary veins consists in conducting a catheter through the peripheral artery to the left atrium and "cauterizing" the pathological foci of excitation, as a result of which the patient has the right rhythm of contractions of the heart.

The figure depicts the RFA of the pulmonary veins

2) the radiofrequency catheter ablation of the atrioventricular connection with the pacemaker installation consists in the complete rupture of the connection between the atria and ventricles, with the atrium contracting in its rhythm and the ventricle in the rhythm defined by the stimulator.

Lifestyle at atrial fibrillation

Patients with atrial fibrillation should regularly take prescribed medications not only to improve quality of life, but also to prevent complications. It is necessary to regulate the mode of work and rest, observe the principles of healthy eating, completely eliminate alcohol, since often this factor provokes "breakdowns" of the rhythm. Also, significant physical exertion should be eliminated, and, if possible, limiting the occurrence of stressful situations.

Pregnancy with atrial fibrillation is not contraindicated, but the possibility of bearing a child is determined by the underlying disease that led to the development of arrhythmia.

Complications of atrial fibrillation

The most common complications are thromboembolic - increased formation of blood clots in the heart and their movement with blood flow into the vessels of the brain with the development of ischemic stroke, in the vessels of the heart with the development of myocardial infarction, in the vessels of the liver, extremities, intestines. Increased thrombus formation is due to the fact that the blood in the "twinkling" or "fluttering" atria is whipped, as in a mixer, as a result of which the injured blood cells adhere to each other, forming a thrombus. Preventive maintenance of complications is a constant reception of antiaggregants and anticoagulants.

Other complications include acute heart failure, pulmonary edema, arrhythmogenic shock.

Forecast of the disease

With all the recommendations of the doctor, the prognosis of uncomplicated atrial fibrillation is favorable. But it must be remembered that the prognosis will depend on the underlying disease that caused the atrial fibrillation, and with the development of stroke, heart failure and other complications and their severity, among other things.

Doctor therapist Sazykina O.Yu.