Preliminary Studies Of Prevalence And Molecular Genetic Of Brugada Electrocardiogram Pattern In In-patients Without Evidence Of Structural Heart Disease

BackgroundBrugada syndrome is a kind of congenital "ion channelopathy" first described by Brugada in 1992, and is characterestic by polymorphous ventricular tachycardia(PVT), ventricular fibrillation(VF) and sudden death. The disease had draw world wide attention since it was frequently seen in young male adults (especially in Southeast Asian) and is associated with high incidence rate of sudden death. Brugada syndrome has been increasingly recognized in China, and there were increasing evidences of high incidence rate in Chinese population, but no data is available regarding the epidemiology of this disease. Thus, a preliminary study focusing on the prevalence of Brugada ECG pattern was performed by retrospectivly investigating 23,082 ECGs recorded from non-cardiac in-patients admitted to our clinic institute in recent years. Genetic defects of gene SCN5A, which encodes cardiac sodium channel protein a unit, is responsible for Brugada syndrome. Currently dozens of mutation had been identified in SCN5A, part of which had been proved can cause abnormal electrophysiological property of cardiac sodium channel.ObjectiveTo study the prevalence of Brugada ECG pattern in Chinese, ECGs from in-patients without evidence of structural heart disease were reviewed. Mutation screening of SCN5A was performed in patients who were diagnosed as Brugadasyndrome to find out whether genetic defect exist in these patients. MethodStrict criterions were established to exclude the structural heart diseases and influence of metabolic or neural disorders. ECG Criteria were also established ECG selection of the Brugada ECG pattern was in accordance with the morphology defined in the Consensus Report, and Brugada ECG pattern were classed into 3 types as described above. 23082 ECGs recorded from no-cardiac in-patients (13134 males, 9 948 females) of our hospital were included for analysis. Genomic DNA was extracted from peripheral blood of patients who diagnosed as Brugada syndrome and their family members by standard procedure. 41 pairs of PCR primers was designed to amplify all 28 exons of SCN5A gene, then SSCP electrophoresis was followed to determinate the abnormal conformer of PCR products. If aberrant conformer was seen in the patient but not in more than 200 healthy unrelated individuals, mutation was suspected and further confirmation by DNA sequencing and analysis would be followed. ResultTotally 23,082 electrocardiograms from non-cardiopathy inpatients duration from January 1999 to December 2002 were investigated. The result shows that 31 electrocardiograms ( 1.34 %o, 31 / 23,082) were positive of Brugada electrocardiographic pattern. The distribution status of 31 patients are showed as follows: 30 male patients (2.28%