What Is Brugada Syndrome?
Brugada syndrome is a very rare hereditary cardiovascular disorder that produces alterations in the electrical system of the heart. According to the National Organization for Rare Diseases, up to 20% of sudden deaths in people with a structurally healthy heart may be due to this condition. It’s more common in males and is almost always detected or manifested during adulthood.
This condition was first described in 1992 by Josep and Pedro Brugada. Since then, the understanding of it has increased, both in the description of the symptoms and in its diagnosis and treatment. In the following paragraphs, we show you what the experts know about this rare cardiac disorder and the options available for dealing with it.
The symptoms of Brugada syndrome
The heart is made up of four chambers. The two upper chambers are called the atria and the two lower chambers are called the ventricles.
This organ beats due to the mediation of electrical impulses. In the specific case of Brugada syndrome, the electrical impulses in the lower chambers (ventricles) lose coordination and beat faster; something known as ventricular fibrillation. As a consequence, a decrease in blood flow is generated.
The symptoms of this disorder usually manifest themselves around the age of 40, and until then, those who suffer from it haven’t experienced any indication of an underlying heart condition. The characteristic signs of the syndrome are the following:
- Irregular heartbeat (very slow or very fast)
- Difficulty breathing
These clinical manifestations are more common when the person is at rest, after a large meal, or during sleep. Therefore, they manifest more regularly during the night or late in the afternoon.
As can be seen, the signs are very vague, so that in many cases, the person chooses to ignore them or isn’t even aware of them.
Under certain conditions, the symptoms tend to get worse. Fever and the intake of certain medications are among the most important. Regarding the latter, antiarrhythmic, psychotropic, anesthetic, and analgesic drugs stand out. Recreational drugs can also encourage exacerbation of symptoms.
Note that the worldwide prevalence of the disorder is relatively low. Recent estimates indicate that only 0.05% of the population develops the syndrome.
Of course, there are regional variables; so the actual percentage may be slightly higher. We point this out to avoid associating the symptoms with the syndrome, because, as we have pointed out, these are general and can be triggered by other underlying conditions.
The causes of Brugada syndrome
Initially, researchers associated Brugada syndrome with a mutation in the alpha subunit of the SCN5A cardiac sodium channel gene. However, to date, more than 250 genes that mediate the development of the condition have been cataloged.
As we’ve already indicated, the disorder is hereditary, and although women inherit the defective gene with the same probability, the evidence indicates that the phenotypic manifestation is 8 to 10 times more common in men.
There are many variables that affect when the disorder appears, among which we can name cocaine use, high levels of calcium in the blood, the intake of heart medications, abnormal levels of potassium in the blood, and even ambient temperature. We also know that the syndrome is more common in the population of Southeast Asia and Japan.
The diagnosis of Brugada syndrome
Recurrent syncope, ventricular fibrillation, self-terminating polymorphic ventricular tachycardia, and a family history of sudden cardiac death are red flags for the possible diagnosis of this disorder.
As specialists point out, more than 75% of diagnoses are made based on these signs and the results of an electrocardiogram.
During the electrocardiogram, doctors will look for an elevation of the J wave ≥ 2 millimeters with a negative T wave and a concave and gradually descending ST segment. All this with or without the administration of sodium channel blockers.
Together with the above signs, these are the basis for ruling out or confirming the presence of the syndrome. Genetic testing isn’t a sure test, as the gene is found in only 30% of patients.
During diagnosis, complementary tests will be considered, with the purpose of assessing the health of the heart and identifying possible differential diagnoses.
For example, Romano-Ward syndrome, arrhythmogenic cardiomyopathy, Duchenne muscular dystrophy, acute pulmonary thromboembolism, acute myocarditis, hypercalcemia, hyperkalemia, and others should be ruled out as causes of symptoms.
There’s no cure for Brugada syndrome, but it’s a condition that can be treated. Treatment is chosen based on symptoms.
If the patient doesn’t develop symptoms, it’s likely that they won’t require treatment, although some considerations to take into account will be suggested. For example, progressively treating episodes of fever, avoiding playing very competitive sports, and avoiding taking psychotropic drugs and drugs that cause changes in heart rate.
On the contrary, those who do show symptoms (mild, moderate, or severe) are usually controlled with an antiarrhythmic medication. There are many options, although the most used are quinidine and isoproterenol.
In those at high risk of ventricular fibrillation, an implantable cardioverter-defibrillator (ICD) is recommended. This is a small device that delivers electrical shocks to control irregular heartbeats.
These are the preferred methods of coping with the disorder. When they don’t have the desired effects, radiofrequency catheter ablation may be chosen.
The function of the catheter is to deliver high energy that scars or destroys the heart tissue that causes the irregular heart rhythm. Limiting the consumption of coffee and alcohol, avoiding episodes of acute stress, and following the basic criteria of a healthy life are also part of the treatment.
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- Brugada, R., & Campuzano, O. Brugada Syndrome Synonym: Sudden Unexpected Nocturnal Death Syndrome. Gene. 2016; 1(2): 3.
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- El Sayed, M., Goyal, A., & Callahan, A. L. Brugada syndrome. In StatPearls [Internet]. StatPearls Publishing. 2021.