Syndrome Brugada - Causes, symptoms and treatment. MF.

Normally, the heart contracts at a frequency of 60 to 80 beats per minute. Abnormalities may indicate bradycardia( below the norm) or tachycardia( above the norm).Tachycardia develops as a response to stress, physical effort, or disease. In addition, the rapidity of the heart rhythm can arise as a result of organic damage to the heart, for example, inflammation of the cells of the heart muscle or their death( myocarditis or myocardial infarction).Such tachycardias, especially if they develop from the tissue of the ventricles rather than the atria, are very dangerous to human health, since in some cases they can cause heart failure.

In recent years, scientists have found that ventricular tachycardia occurs not only when the cardiac tissue is affected by inflammation, necrosis( death) or when it is replaced with scar tissue, but in the absence of a visible cause in the presence of a healthy heart in the patient. However, there is still a reason invisible to the naked eye. This is Brugada syndrome, which accounts for more than 50% of all sudden cardiac deaths at a young age( 30 to 40 years).

So, Brugada syndrome is a genetically determined violation of micronutrient metabolism in cardiac muscle cells( myocytes), leading to a sudden unprovoked paroxysm of ventricular tachycardia with or without loss of consciousness, with a high risk of sudden cardiac death. This syndrome refers to the list of causes that cause a paroxysmal ventricular tachycardia.

What happens in the syndrome of Brugada? As you know, all information about the human body is encoded in the genes that are the "bricks" of chromosomes. This information includes many parameters, from the color of the eyes to the formation of proteins in the cells responsible for the work of internal organs. The activity of myocytes is also influenced by the genes, since they synthesize proteins that carry sodium and potassium and calcium into and out of the cell. In turn, these substances play an important role in electrochemical processes, which contribute to the reduction and relaxation of cells. That is, the frequency of contraction of the heart muscle cells directly depends on the intake of sodium ions into the cell. With this syndrome, there is a genetic mutation leading to inactivation of sodium channels in myocytes, and anomalous electrical activity of the myocardium arises. The right ventricle is more susceptible to this, where the focus of excitation, which causes paroxysm of tachycardia, is formed most often.

Brugada syndrome is most often found in the South-Asian region( 1 - 60 people per 10 thousand population, according to different authors), among Europeans the prevalence is less. Men suffer more than women. Isolate syncopal( with loss of consciousness) and asymptomatic( asymptomatic) types of the syndrome.

Causes of the Brugada Syndrome

The reason is the mutation of genes responsible for the synthesis of proteins transporting sodium ions into the cell. The disease is inherited by the autosomal dominant way, that is, if the mutated gene is transmitted to the child or from the mother or from the father, then it necessarily manifests itself in the form of a disease, in contrast to the recessive type of inheritance, when two mutated genes, one from each parent,so that the disease manifests itself in the child. Syndrome Brugada may appear in offspring in a ratio of 1: 1, that is, half of all children born in marriage, where one parent carries the mutated gene, will suffer from this pathology.

The risk factors for the presence of the Brugada syndrome include:
- the presence of syncope in a patient without an established cause.
is an aggravated heredity for sudden cardiac death( especially if there have been deaths of men in the family aged 30 to 40 years without visible heart disease)
- the patient had cases of paroxysmal ventricular tachycardia.

Symptoms of the Brugada syndrome

Despite the fact that the syndrome is genetic, that is, a congenital disease, it manifests itself most often at the age of 30 - 40 years. However, single cases of sudden death caused by Brugada syndrome in children and adolescents are described.

The main manifestation of the syndrome is a paroxysm of ventricular tachycardia, in most cases accompanied by loss of consciousness( syncope).The patient at rest( in the evening or at night), and also after a load, drinking alcohol, or during a fever, feels a sudden malaise, tremors in the heart area followed by a distinctly palpitated heartbeat. All this can be accompanied by deafness, sweating, dizziness, flashing of flies before your eyes. The patient may lose consciousness, sometimes it is accompanied by cramps. After 20 - 30 seconds, consciousness is fully restored, but in 11% of cases, ventricular fibrillation and cardiac arrest may develop.

Sometimes the syndrome is manifested by paroxysm of tachycardia without loss of consciousness.

Diagnosis of the Brugada syndrome

For diagnostics, in addition to the examination of the patient, the following apply:
1. ECG.Signs on the ECG:
- full or incomplete blockage of the right bundle branch of the bundle
- elevation of the j-point( the transition point of the QRS complex to the ST segment, reflects depolarization of the ventricles).
- ST segment elevation as a "vault" or "saddle".According to the type of the vault corresponds to the syncopal form of the syndrome, the saddle type is asymptomatic.
These signs are recorded in the right breast leads( V1 - V3).ECG - signs of the syndrome can be registered after 5 years of age.

The figure shows the symptoms of the syndrome according to the type of "arch"( type 1) and "saddle"( types 2, 3).

2. ECG with high chest leads are assigned with transient changes in the usual ECG.To record high chest leads electrodes are superimposed on one or two intercostals higher than usual.
3. Daily ECG monitoring is indicated for recording short runs of ventricular arrhythmias at night and throughout the day.
4. An electrophysiological study( transesophageal or invasive) is prescribed to more accurately record a cardiogram after electrical stimulation of the heart.
5. The test with the introduction of sodium channel blockers( aymalin, novocainamide) is used only in a hospital or intensive care setting and consists of administering drugs intravenously followed by ECG recording. A positive test is considered in the development of paroxysm of ventricular tachycardia and / or signs of Brugada syndrome.
6. Genetic studies are designed to find a mutated gene to confirm a disease or to examine the relatives of a patient with an already established syndrome, especially when it comes to planning children in patients. However, the accuracy of the method is only 20 - 30%, so the negative result of the analysis does not allow to reject the diagnosis of the syndrome.
7. Consultation of a neurologist, neurosonography, MRI of the brain. Are shown to exclude the neurogenic nature of syncope.

Treatment of Brugada

Syndrome Currently, there is no drug treatment that allows to completely eliminate the disease. Studies are under way to learn how to eliminate the genetic defects that caused the syndrome. Drugs are used to prevent paroxysms of ventricular arrhythmias and reduce the risk of sudden cardiac death.

Antiarrhythmic drugs of class 1A-quinidine, disopyramide( rhythmodan) are used. Amiodarone( cordarone) may be prescribed. Antiarrhythmics of other classes are contraindicated, since they are capable of causing ventricular arrhythmias. Especially it concerns novokainamida, ajmalina, propafenona and other preparations blocking sodium channels. Out of beta-blockers propranolol is prescribed.

The surgical method of treatment is the most effective in the treatment of the syndrome and consists in the installation of a cardioverter-defibrillator. This type of artificial pacemaker, whose functions are reduced to two nuances - the determination of the heart rate and the development of ventricular arrhythmia defibrillation of the heart through electrodes located intracardiac. Defibrillation helps to restart the heart, restoring the correct rhythm of contractions.

Lifestyle with the Brugada Syndrome

Some preventive measures that can prevent the development of an attack have not been developed. However, adherence to the principles of rational nutrition, limiting the use of extreme sports, exclusion of stress, has a beneficial effect on the cardiovascular system as a whole.
Patients with an established diagnosis should be observed for life at the arrhythmologist, take prescribed medications and be examined on time. With the cardioverter-defibrillator installed, a cardiosurgeon should be visited annually, and the pacemaker should be replaced according to the term of his work, usually no later than 4 to 6 years, depending on the model of the device.

A married couple in whom one of the spouses is ill, when planning a child, it is necessary to visit the medical and genetic consultation and undergo a survey to assess the risk of having a child with the Brugada syndrome, as well as to determine the tactics of pregnancy and childbirth.

Complications of

Complications of the Brugada syndrome are life-threatening conditions - fatal rhythm disturbances( persistent ventricular tachycardia, resulting in fibrillation of the ventricles), asystole and clinical death.

Forecast

The prognosis is unfavorable, as according to the authors who described this syndrome for the first time, 30% of patients die in the first three years from the onset of clinical manifestations. Subsequent studies of a larger group of patients have shown that this figure remains within 11%, but nevertheless, nevertheless, the death rate is high, especially if we consider that the syndrome manifests in young people.

Doctor therapist Sazykina O.Yu.