Brugada syndrome is a genetic disease that is characterized by raised ST segment in the right precordial leads, complete or incomplete right bundle branch block and susceptibility to ventricular tachyarrhythmias and sudden cardiac death.
The patients suffering from Brugada syndrome may present to a doctor with various complaints, however, most frequently, these complaints are related to cardiovascular system and/or alterations in electrocardiographic (ECG) patterns.
Syncope is one of the most common manifestations of Brugada syndrome.
Cardiac arrest is another common presentation in these patients.
The patients of Brugada syndrome sometimes complain of nightmares.
Atrial fibrillation is the presentation in about 20% of the cases of Brugada syndrome .
Sometimes fever is reported and it also triggers the cardiac events in patients of Brugada syndrome.
Heart murmurs are also present in Brugada syndrome.
Brugada syndrome requires complete work-up and laboratory investigations for proper diagnosis. The investigations relevant to Brugada syndrome are listed below:
The best option for the treatment of syncope and cardiac arrest in the patients of Brugada syndrome is the placement of an automatic implantable cardiac defibrillator (ICD). As mentioned earlier, the patients suffering from Brugada syndrome usually die of ventricular fibrillation. If a defibrillating device is in place, episodes of ventricular fibrillation will be promptly reversed and the patient’s life will be saved.
Recent studies have shown that quinidine decreases the episodes of ventricular defibrillation . It may also be used for the treatment of Brugada syndrome in selected cases.
Regular exercise should be stopped as it increases the vagal tone, thereby increasing the risk of ventricular fibrillation.
Long term follow up is necessary for all the patients suffering from Brugada syndrome.
Prognosis depends largely upon the long term proper follow-up. Prognosis is good with proper treatment and management.
Without treatment, sudden cardiac death occurs in men under 40 years of age. With proper placement of implanted cardiac defibrillator, life expectancy and quality of life are improved.
The mean age of sudden death in patients suffering from Brugada syndrome is 41+/- 15 years .
Brugada syndrome is primarily caused by mutations in SCN5A gene, although mutations in other genes are also seen in some cases . Variants of Brugada syndrome can be caused by the mutations in the genes that code subunits of the L-type calcium channel (CACNA1C and CACNB2).
Some cases of Brugada syndrome also carry mutations in GPD1-L and SCN1B genes. Besides, some conditions and diseases can exaggerate or unmask electrocardiographic changes of Brugada syndrome. Some of them are listed below.
Brugada syndrome is predominantly a disease of Asian people. It is much less common in the Western world. It is also much more prevalent in men as compared to women .
Several different mutations can result in Brugada syndrome. The underlying pathophysiology therefore varies with different genes. The voltage gated sodium channels of the heart are encoded by the SCN5A gene. Therefore, when the mutation is in the SCN5A gene - the most common mutation in Brugada syndrome - the cardiac voltage gated sodium channels do not function normally.
Abnormal voltage-gated sodium channels directly affect the cardiac action potential by reducing the sodium current available during the phases 0 (upstroke) and 1 (early repolarization). This reduction in sodium current then affects the endocardium of the right ventricle and leads to the clinical manifestations as well as the electrocardiographic variations that characterize Brugada syndrome.
The T wave remains upright and causes a saddleback electrocardiographic pattern when the usual time duration of repolarization is not changed.
Mutations in Glycerol-3-phosphate dehydrogenase 1-like (GPD1L) gene are also seen in some patients of Brugada syndrome. This gene acts as ion channel modulator in the heart muscle.
There are no guidelines for prevention of Brugada syndrome.
Brugada syndrome is a clinic-pathological entity that is characterized by an increased risk of sudden cardiac death as well as certain electrocardiographic (ECG) changes in the heart; most commonly the elevation of the ST segment in the precordial leads.
Brugada syndrome is a genetically pre-determined condition. The pattern of inheritance is autosomal dominant in as many as 50% of the familial cases. Brugada syndrome is the major cause of sudden unexplained death syndrome (SUDS) .
It is known to be one of the major causes of sudden death in young men without any previously diagnosed cardiac disorders .
Brugada syndrome is a genetic disease that affects the heart at a cellular level. In some patients, it produces no symptoms and remains undetected. In others, it causes symptoms related to the heart.
The patients who receive proper treatment and follow-up have a good prognosis. If untreated, it can cause sudden death in young patients (below 40 years of age) even in the absence of other heart diseases.