Brugada Syndrome

Transcript of the video: Brugada Syndrome was described by Brugada brothers in 1992 as right bundle branch block pattern in anterior leads with ST segment elevation and syncope or sudden cardiac death and it was later in 1998, that the genetic basis of the disease was identified, with mutations in sodium channel. Later on, several other mutations have been attributed to cause the ECG pattern in Brugada syndrome.

I am always happy to see this ECG of Brugada syndrome sent to me by Professor Josep Brugada, in 2001, for the inaugural issue of the Indian Pacing and Electrophysiology Journal, which I started in 2001. And, this review article by Brugada brothers, in the very first issue of Indian Pacing and Electrophysiology Journal, gave a boos to the journal, so that, in 2007, it was included in PubMed Central, the full text archive of US National Library of Medicine, and earned a position for the journal, as the first online only Indian Journal to be included in PubMed Central, which was mentioned in the Limca Book of Indian Records in 2007. This ECG shows the classical findings of Brugada syndrome, the coved ST elevation seen in the anterior chest leads. Coved ST elevation in anterior chest leads. In V3, it is a saddle shaped ST elevation. You can see the saddle shaped ST elevation. And later on, this was described as the type 2 pattern of Brugada syndrome, while this was described as type 1 pattern and saddle shaped ST with ST elevation was described as type 3. Still later, it is found that only the classical pattern is diagnostic of Brugada syndrome. If you have other patterns alone, not when all the three are, all the two are present, but when only the saddle shaped ST elevation is present, you have to have additional tests like challenge test using Flecainide or Ajmaline, which are sodium channel blocking drugs, to see whether the typical pattern occurs. And, this pattern can occur with or without symptoms and sometimes with a family history of sudden cardiac death. So this is a typical Brugada syndrome ECG, which can be easily mistaken for an acute myocardial infarction with ST elevation in anterior leads may be taken as STEMI if the person presents with chest pain for some other reason.

Mutations in the sodium channel gene SCN5A, was the first one to be described in Brugada syndrome, and is still considered as the most important one, and there are several types of mutations possible in the same gene. Brugada syndrome has been classified into several genotypes, Brugada syndrome 1 to 8 or 9, and the number is increasing and you can check the Online Mendelian Inheritance in Man, OMIM database for the current status. It is always changing, because new genes are being discovered. An interesting fact is that many of the persons experience arrhythmias in Brugada syndrome with fever. So there is some relation between fever and precipitation of arrhythmias in Brugada syndrome. Another important factor which has been noted is, it is having autosomal dominant type of inheritance pattern, and somehow, it is much more common in men, almost as eight times as common in women. More than eight times of men are affected than women. Brugada syndrom typically manifests in adulthood, with probably the average age around 45 years, even though, in younger age also, it has been described. It has been sometimes mentioned as a cause for sudden infant death syndrome. And, even though Brugada syndrome, worldwide in occurrence, has been a little more common in the South Eastern region. Though sodium channel blockers can precipitate the Brugada pattern on ECG, quinidine, which is also a sodium channel blocker, has been noted to have some influence in decreasing the arrhythmias in Brugada syndrome. Medical therapy by and large is not that effective in Brugada syndrome, and the most recommended therapy if you have a definite diagnosis of Brugada syndrome, is implantation of an implantable cardioverter defibrillator for saving from sudden death which can occur due to life threatening ventricular arrhythmias in Brugada syndrome.

Even though Brugada syndrome is well known for its ventricular arrhythmias, the arrhythmogenic substrate in Brugada syndrome may not be restricted to the ventricles and atrial arrhythmias are being increasingly reported, with varying levels of spontaneous arrhythmias. Of course, the commonest sustained arrhythmia in general population is atrial fibrillation. It is also the most common arrhythmia, atrial arrhythmia found in Brugada syndrome. It is supposed due to enhanced duration of action potential and increased intra atrial conduction time may contribute to arrhythmias in Brugada syndrome. The importance is that, it is an important cause of inappropriate discharge of defibrillators. That is, defibrillators are meant as life saving devices to treat ventricular arrhythmias to prevent a sudden cardia death. When there is an atrial arrhythmia and a fast ventricular rate, especially if it is a single chamber defibrillator which has been implanted, they can have inappropriate shocks, which are painful and often cause psychological disturbances to persons with Brugada syndrome. So what is needed is implant a dual chamber defibrillator which has an atrial lead. The atrial lead will sense atrial electrical activity and tell the defibrillator that it is an atrial arrhythmia and not ventricular arrhythmia which has caused the fast rate. Dual chamber ICDs are naturally more costly and will have more problems because of two leads. So another possibililty is careful programming of single chamber devices to prevent these inappropriate shocks due to atrial fibrillation. Atrial fibrillation can occur with sodium and calcium channel mutations in Brugada syndrome.