History

Erstbeschreiber and name givers of the syndrome were the brothers Josep and Pedro Brugada, which described 1992 eight patients, who had suffered all a heart stop and had successfully been revived. They all showed a special form of the right thigh block in the electrocardiogram (ELECTROCARDIOGRAM), pointed however otherwise no indications of an organic heart illness aufBrugada P, Brugada J: Right bundle branch block, persistent ST segment elevation and sudden cardiac death: A distinct clinical and electrocardiographic syndromes. A multi-center report. J at the Coll Cardiol (1992) 20 (6): 1391-6. PMID 1309182. The cause of the syndrome was at that time still unclear.

Epidemiology

The of the Brugada syndrome is not well-known, it seems in the East Asian population to be more frequent than in Europe and North America.

Pathogenesis and pathophysiology

Meanwhile the Brugada syndrome as well as some other rare genetically determined heart diseases becomes like the QT-syndrome, the family sine knot syndrome and the family Wolff Parkinson White syndrome the ion channel illnesses (English channelopathies) A, Brugada P.: Sudden cardiac death and inherited arrhythmia syndrome. J Cardiovasc Electrophysiol (2005) 16 Suppl 1: S8-20. PMID 16138889. A genetically caused change of the protein molecules (proteins) is common to them, which adjust ion transport by the cell walls of the heart muscle. They lead to an increased (gain OF function) or decreased (loss OF function) transport mainly of sodium and potassium ions and change thereby the electrical characteristics of the cells.

A responsible person gene defect could be identified so far only with a smaller part of the patients with Brugada syndrome: 15 to 25 per cent of them shows a mutation of the gene SCN5A, which is coded on the third Chromosom (Genlocus 3p21).

Symptoms and disease process

The syndrome to reason which is appropriate the repolarization disturbance of the heart muscle cells is not noticeable, so that a part of the patients does not notice any symptoms. The guiding symptoms sudden unconsciousness (Synkope) and heart stop arise only by heartbeat disturbances like polymorphe tachycardias or to ventricular fibrillations, which are favoured by the changed Repolaristion. Individual cases with a very early occurrence of symptoms with newborn children are already described, usually however arise the symptoms for the first time in the third or fourth life decade.

Diagnosis

The only diagnostic indication of a Brugada syndrome is the typical change ELECTROCARDIOGRAM with a right-thigh-block-similar picture and characteristic saddle-shaped or deszendierenden ST-elevations in the derivatives of the V1-3. These electrocardiogram changes can be changing pronouncedly and also only occasionally present. They can be strengthened or unmasked by the gift of antiarrhythmics of the class I such as Ajmalin or Flecainid.

Genotyp phenotype relation

With about a fifth of the patients with Brugada syndrome a defect of the SCN5A-Gens is provable, which knows remaining patient is so far genotypisch not assigned. Patients with SCN5A-Mutation differ by an extended PQ-time and an extended HV-interval of those without SCN5A-Mutation. A PQ-time of = 210 milliseconds (ms) and an HV-interval of = 60 ms in the ELECTROCARDIOGRAM refer to a SCN5A-Mutation. The gift of an class I antiarrhythmic led beyond that with carriers of the SCN5A-Mutation to a significantly longer PQ-time and QRS duration. Regarding demographic variables, anamnesis and family anamnesis however between the groups no differences were determined. Smits JP et al.: Genotype phenotype relationship in Brugada syndromes: electrocardiographic feature differentiate SCN5A-related patients from non-SCN5A-related patients. J at the Coll Cardiol (2002) 40 (2): 350-6. PMID 12106943.

Therapy

The only measure with proven effectiveness against sudden heart death is the implantation of an automatic Defibrillators (ICD). It is meaningful with all patients with serious rhythm disturbances or Synkopen already documented. It is unclear whether also so far asymptomatische patients should receive a ICD, as soon as the typical electrocardiogram changes were noticeable.

Beta blockers are probably contraindicated with most patients with Brugada syndrome, since with low heart frequency the danger is increased by ventricular fibrillations. Patients with rezidivierenden episodes of ventricular fibrillations can occasionally by means of sympatomimetischer medication (e.g. Orciprenalin Perfusor) temporarily to be at least successfully treated. With some patients can possibly be caused by the action potential-extending effect of Chinidin a decrease of the typical electrocardiogram changes and a reduction of the risk for ventricular fibrillations.

Literature

• Douglas P. Zipes et al. (Hrsg.): Braunwald's Heart Disease: A Textbook OF Cardiovascular Medicine. 7. Edition. W.B. Saunders company, Philadelphia 2004 ISBN 1-41-600014-3

Related links

• Youichi A et al.: Assessment OF of marker for Identifying Patients RK Risk for Life Threatening Arrhythmic Events in Brugada of syndromes. J Cardiovasc Electrophysiol (2005) 16 (1): 45-51

Sources

Articles in category "Brugada syndrome"

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