Analysis Of Arrhythmia In Dialated Cardiomyopathy And Single Nucleotide Polymorphism Of Sodium Channel Gene-SCN5A Study

Objective: The purpose of this work is to analyze the types of arrhythmia and the relationship with the cardiac structure in patients with idiopathic dilated cardiomyopathy (DCM). Background: DCM has a close relationship with arrhythmia. Arrhythmia in patients with DCM is still an open issue in large sample. Method: The data of electrocardiogram, Holter, and Ultrasonic Cardiogram (UCG) of 649 patients with DCM was studied. Results: The types of arrhythmia accompany with DCM include: 54 (8.3%) patients sufferring from I°atria-ventricular block(AVB) , 21(3.2%) cases with severe AVB, 124(19.1%) cases with left branch block(LBBB), 48(7.4%) with right branch block(RBBB), 11(1.6%) with intraventricular block, 188(28.9%) with atrial fibrillation(Af), 28(4.3%) with untypical atrial flutter, and 36(5.5%)with paroxysm atrial tarchycardia(AT) or sinus tarchycardia, 7(1%) with sick sinus node syndrome, 419(64.5%) with preventricular contracts (PVc) and ventricular tarchycardia(VT), 4(0.6%) with W-P-W syndrome. The left atria diameter of the group with Af (28.9%) is 44.1±10.6mm, and is different from the group without Af (P<0.05). Left ventricular end diastolic diameter (LVED) of the cases with severe AVB, LBBB, RBBB, and intraventricular block is 70.3±14.3mm, and is different obviously from the LVED in the opposie group (65.8±10.2mm, P<0.05). Conclusions: In groups of patients with DCM, occurrence of major arrhythmic events is very often, especially ventricular arrhythmia. The ventricular arrhythmia might improve the risk of sudden arrest in these patients. Occurrence of Af and myocyte conduct block is related with the structure of the heart. Abjective: The mutation of SCN5A gene which encodes I_Na might lead to Dialated Cardiomyopathy (DCM) according to some studies, but the relationship of SCN5A single nucleotide polymorphism (SNP) and DCM has not been reported. As the difference of SNP exists in different population, the association of five SCN5A polymorphisms and DCM in Adult Chinese Han population will be studied and analyze the association between SNPs discovered and DCM. Methods: A case-control design was applied in this study. A total of 362 unrelated hospitalized patients (Male:276 cases, Female: 86 cases) diagnosed DCM were enrolled from Fuwai Hospital between Oct 2003 and Dec 2004. At the same time, control subjects of total 634 cases (Male: 510 cases, Female: 124) were recruited from individuals participating in a community-based survey. First, five SNPs of SCN5A gene H558R, P1090L, 4299+53T>C, C 5457T (D1819D) and V1950L were genotyped by restriction fragment length polymorphism (RFLP) in all subjects. Multivariate analysis was performed to investigate the independent effect or interaction between the polymorphisms and DCM. Statistical analysis was conducted using the SSPS 11.5 version for Windows. Result: 1) Minor allele frequencies of H558R, P1090L, 4299+53T>C, C5457T (D1819D) and V1950L were 11.1%, 5.2%, 28.2%, 31.8% and 0.4%. V1950L was not considered as polymorphism because of frequency less than 1%. 2) The frequency of the allele P1090L (P=0.008) and the polymorphism of 4299+53T>C between the DCM group and the control one is different obviously (P=0.0373). Conclusion: The study suggested the allele of P1090L and 4299+53T>C polymorphisms of SCN5A gene might be related to DCM.