BACKGROUNDImbalance of the sympathetic nervous system was involved in the pathogenesis of idiopathic ventricular outflow-tract tachycardia (IVOT). We aimed to investigate whether the major genetic variants in β(1)- and β(2)-adrenoceptors and GNB3 C825T were associated with IVOT and verapamil sensitive idiopathic left ventricular tachycardia (ILVT).

METHODSPatients with IVOT and ILVT from December 2005 to December 2007 were consecutively enrolled into this study. Controls were randomly selected from the community-based inhabitants. Five genetic variants, Ser49Gly and Gly389Arg in the β(1)-adrenoceptor, Arg16Gly and Gln27Glu in the β(2)-adrenoceptor and GNB3 C825T, were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis.

RESULTSA total of 227 patients with IVOT and 110 patients with ILVT were included. Genotyping revealed that the 16Gly allele of Arg16Gly variant of β(2)-adrenoceptor was associated with a higher risk of IVOT (OR: 1.40, 95%CI: 1.12 - 1.75, P = 0.003 in the addictive model and OR: 1.62, 95%CI: 1.14 - 2.31, P = 0.007 in the dominant model). Patients with Gly16Gln27 haplotype also had a higher risk of IVOT (OR: 1.38, 95%CI: 1.11 - 1.73, P = 0.012). Other four variants, including Ser49Gly and Arg389Gly in β(1)-adrenoceptor, Gln27Glu in β(2)-adrenoceptor and GNB3 C825T, did not differ between patients with IVOT and controls. In patients with ILVT, no significant difference was found in these five variants compared with controls.

CONCLUSIONSArg16Gly in β(2)-adrenoceptor is significantly associated with IVOT in Chinese Han population. Major genetic variants in β(1)- and β(2)-adrenoceptor and GNB3 C825T may not be associated with ILVT. These data suggest a different arrhythmogenic mechanism in IVOT and ILVT.