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Brugada Syndrome: Difference between revisions
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==Characteristics of the Brugada syndrome:== | ==Characteristics of the Brugada syndrome:== | ||
*Inheritable arrhythmia syndrome with [[w:Autosomal_dominant|autosomal dominant]] inheritance. If one of both parents | *Inheritable arrhythmia syndrome with [[w:Autosomal_dominant|autosomal dominant]] inheritance. If one of both parents is affected, their children (either males or females) have a 50% chance of inheriting the disease. | ||
*Males are more often symptomatic than females, probably by the influence of sex hormones on cardiac arrhythmias and/or ion channels, and a different distribution of ion channels across the heart in males versus females. | *Males are more often symptomatic than females, probably by the influence of sex hormones on cardiac arrhythmias and/or ion channels, and a different distribution of ion channels across the heart in males versus females. | ||
*The arrhythmias usually occur between 30 and 40 years of age. (range 1-77 yrs) and often during rest or while sleeping (high vagal tone). | *The arrhythmias usually occur between 30 and 40 years of age. (range 1-77 yrs) and often during rest or while sleeping (high vagal tone). | ||
*Only in about 30% of patients, genetic defects can be detected in the ([http://ghr.nlm.nih.gov/gene=scn5a SCN5A]) gene which encodes the cardiac sodium channel. In much smaller quantities mutations may be found in the GPD1L gene (which probably influences cardiac sodium channel function) or in cardiac calcium channel encoding genes (CACNxxx). In the other patients the disease is probably multi-genetic or caused by yet unknown genetic defects. | *Only in about 30% of patients, genetic defects can be detected in the ([http://ghr.nlm.nih.gov/gene=scn5a SCN5A]) gene which encodes the cardiac sodium channel (loss-of-function mutation). In much smaller quantities mutations may be found in the GPD1L gene (which probably influences cardiac sodium channel function) or in cardiac calcium channel encoding genes (CACNxxx). In the other patients, the disease is probably multi-genetic or caused by yet unknown genetic defects. | ||
*The right ventricle is most affected in Brugada syndrome, and particularly (but not specifically) the right ventricular outflow tract . | *The right ventricle is most affected in Brugada syndrome, and particularly (but not specifically) the right ventricular outflow tract . | ||
*The prevalence varies between 5-50:10.000, largely depending on geographic location. In some south-east Asian countries the disease is considered endemic and believed to be the second cause of death amongst young men (after car accidents). In these countries Brugada syndrome is believed to underly (in part) the 'Sudden Unexpected Death Syndrome' (SUDS). This relation has however not been thoroughly investigated and there are almost no epidemiological studies into Brugada syndrome ECGs (apart from Japan). In different Asian countries, different names have been given to SUDS: in the Phillipines it is called ''bangungut'' (to rise and moan in sleep) and in Thailand ''lai tai'' (death during sleep). | *The prevalence varies between 5-50:10.000, largely depending on geographic location. In some south-east Asian countries the disease is considered endemic and believed to be the second cause of death amongst young men (after car accidents). In these countries Brugada syndrome is believed to underly (in part) the 'Sudden Unexpected Death Syndrome' (SUDS). This relation has however not been thoroughly investigated and there are almost no epidemiological studies into Brugada syndrome ECGs (apart from Japan). In different Asian countries, different names have been given to SUDS: in the Phillipines it is called ''bangungut'' (to rise and moan in sleep) and in Thailand ''lai tai'' (death during sleep). | ||
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==Diagnosis and treatment== | ==Diagnosis and treatment== | ||
*Patients who are symptomatic (unexplained syncope, ventricular tachycardias or survivors of sudden cardiac death) have a mortality risk of up to 10% per year. In these patients an [[:w:nl:Internal_Cardiac_Defibrillator|ICD]] | *Patients who are symptomatic (unexplained syncope, ventricular tachycardias or survivors of sudden cardiac death) have a mortality risk of up to 10% per year. In these patients an [[:w:nl:Internal_Cardiac_Defibrillator|ICD]] is adviced to be implanted. | ||
*Some groups advice an electrophysiological investigation (inducibility of VF) for risk assessment in Brugada patients,<cite>brug2</cite><cite>brug3</cite> but others could not reproduce the | *Some groups advice an electrophysiological investigation (inducibility of VF) for risk assessment in Brugada patients,<cite>brug2</cite><cite>brug3</cite> but others could not reproduce the predictive value of these tests,<cite>priori</cite><cite>eckhardt</cite> so the value of inducibility is (very) controversial. | ||
*In large studies familial sudden death did not appear to be a risk factor for sudden death in siblings. | *In large studies familial sudden death did not appear to be a risk factor for sudden death in siblings. | ||
*In asymptomatic patients in whom the Brugada ECG characteristics are present (either spontaneously or provoked by fever or sodium channel blockers like ajmaline, procainimde or flecainide) life style advices are given, which include: | *In asymptomatic patients in whom the Brugada ECG characteristics are present (either spontaneously or provoked by fever or sodium channel blockers like ajmaline, procainimde or flecainide) life style advices are given, which include: | ||
**A number of medications should not be taken (amongst which beta-blockers, and sodium channel blockers such as certain anti-depressants and anti-arrhythmics) | **A number of medications should not be taken (amongst which beta-blockers, and sodium channel blockers such as certain anti-depressants and anti-arrhythmics) | ||
**Rigorous treatment of fever with paracetamol / Tylenol, as fever may elicited the Brugada ECG and arrhythmias in some patients | **Rigorous treatment of fever with paracetamol / Tylenol, as fever may elicited the Brugada ECG and arrhythmias in some patients. | ||
* Spontaneous Type I ECGs do however appear to be more prevalent in patients who experienced symptoms. | |||
For a full list of the diagnostic criteria, see <cite>Wilde</cite> | For a full list of the diagnostic criteria, see <cite>Wilde</cite> | ||
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Three ECG repolarization patterns in the right precordial leads are recognized in the diagnosis of Brugada syndrome. | Three ECG repolarization patterns in the right precordial leads are recognized in the diagnosis of Brugada syndrome. | ||
'''Type I''' is the only ECG criterion that is diagnostic of Brugada syndrome. The type I ECG is characterized by a | '''Type I''' is the only ECG criterion that is diagnostic of Brugada syndrome. The type I ECG is characterized by a J elevation >=2 mm (0.2 mV) a coved type ST segment followed by a negative T wave (see figure). Brugada syndrome is definitively diagnosed when a type 1 ST-segment is observed in >1 right precordial lead (V1 to V3) in the presence or absence of a sodium channel–blocking agent, and in conjunction with one of the following: | ||
*documented ventricular fibrillation (VF) | *documented ventricular fibrillation (VF) | ||
*polymorphic ventricular tachycardia (VT) | *polymorphic ventricular tachycardia (VT) | ||