THE ROLE OF BETA-1 RECEPTOR GENE POLYMORPHISM IN BETA-BLOCKER THERAPY FOR VASOVAGAL SYNCOPE

Abstract

Background: Vasovagal syncope (VVS) is a common clinical condition involving genetic background. The role of beta-blockers in the treatment is controversial. Objective: The aim of this study was to investigate the effect of beta-1 gene polymorphism on beta-blocker therapy in patients with VVS. Methods: We included 123 patients who were diagnosed with VVS after the tilt-table test. We searched for the polymorphism Arg389Gly (rs1801253) in the beta-1 adrenoceptor gene. Results: Overall, 64 patients (52%) had Arg389Arg genotype and 59 patients (48%) had Arg389Gly genotype. The syncopal episodes of patients with Arg389Arg genotype were more frequent compared with patients having Arg389Gly genotype (total syncopal episodes [TSE], 7.9 +/- 3.7 vs. 6.4 +/- 3.0; p = 0.012). TSE in patients with Arg389Arg genotype decreased significantly after 18 months of beta-blocker treatment (7.9 +/- 3.7 vs. 3.0 +/- 1.4, p < 0.001). After 18 months of beta-blocker treatment, patients with Arg389Arg genotype had significantly fewer syncopal episodes than patients with Arg389Gly genotype (3.0 +/- 1.4 vs. 6.8 +/- 3.2, p < 0.001). Conclusions: Results of beta-blocker therapy in patients with Arg389Arg genotype suggest that VVS pathophysiology is a multifactorial condition, with genetic, psychological, and environmental components, and therefore, treatment selection can be based on gene polymorphism.