Brugada Syndrome

Definition
Brugada syndrome is a rare, hereditary condition characterized by an abnormal electrocardiogram (ECG) and the occurrence of heart rhythm disturbances  called arrhythmias  arising from the ventricles (the pomp) that can result in syncope (loss of consciousness), dizzy spells  and the risk of sudden cardiac death. It generally occurs in young adults without detectable heart disease but can occur at any age with predominance in the male sex. The incidence in the general population of an abnormal ECG the Brugada type is less than 1 per 1000 ECG screened

Diagnosis 
The patient generally consults for symptoms such as syncope of dizzy spells occurring most often in the evening related to ventricular arrhythmias (Ref. to ventricular arrhythmia topic) that can be spontaneously terminated or  be prolonged and responsible for sudden death in a person  with apparently normal heart.
The Brugada syndrome diagnosis is made or at least suspected on the ECG.  The aspect is characteristic and easily recognized when typical   by the cardiologist. The ECG pattern may be variable from time to time as a number of factors may increase or decrease the pattern. For example, fever or some medications (as some antiarrhythmic medications) may increase the ECG abnormalities. The presence of a family history of sudden death reinforces the diagnosis. Familial screening of the siblings who have no symptoms is indicated and may discover subjects with the ECG pattern initially described by Drs Pedro and Josep Brugada in 1992. Some ECG patterns are more diagnostic than others.
An echocardiogram is done to rule out a structural anomaly of the heart. As said previously the heart is structurally normal. A blood test is performed in order to detect particularly an electrolyte anomaly (mainly to exclude a deficit of potassium in the blood that can also modify the ECG).

Genetic testing

As Brugada is a genetic syndrome transmitted according to the autosomal dominant mode which indicates that the patient with the syndrome has one of his/her parents affected and that he/she has also 50% chances to transmit the syndrome. Several anomalies of the chromosomes called mutations have been described in patients with the ECG pattern on the ECG and who experienced syncope or sudden cardiac death or/and a familial history of sudden death.


Treatment 

The only proven treatment is an implantable cardiac defibrillator capable of detecting malignant heart rhythm disturbances that may be cause sudden death and delivering a shock to restore normal rhythm in patients at high risk. The indication of such device should be done in highly specialized centers.

 

S. Lévy
F. de La Souchère

 

         

References:
Denjoy I et al. https://www.orpha.net/data/patho/Pro/fr/Brugada-FRfrPro8022.pdf
 
http://www.mayoclinic.org/diseases-conditions/brugada-syndrome/basics/symptoms/con-20034848 

Key words: Ventricular tachycardia; ventricular fibrillation; sudden cardiac death; syncope; hereditary syndromes


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