Heart rate variability is associated with polymorphic variation in the choline transporter gene.

OBJECTIVE The objective of this study was to determine whether interindividual variation in parasympathetic (cholinergic) and sympathetic (adrenergic) regulation of heart rate (as estimated by frequency components of heart rate variability [HRV]) may be accounted for, in part, by genetic variation in the choline transporter, a component of acetylcholine neurotransmission. METHODS Resting HRV estimates of high- (HF) and low-frequency (LF) power and LF/HF ratio were determined from electrocardiogram recordings collected continuously over 5 minutes in 413 white individuals of European ancestry (49% men; aged 30-54 years [mean, 44 years]). Subjects were genotyped for a single nucleotide polymorphism (SNP) located in the 3' untranslated region of the choline transporter gene (CHT1). Frequencies of the alternate CHT1 alleles, labeled G and T, were 76% and 24%. RESULTS Compared with GG homozygotes, participants having any T allele had greater HF power (p <.02), lower LF power (p <.02), and lower LF/HF ratios (p <.005). Relative to men, women had lower LF power (p <.001) and lower LF/HF ratios (p <.005). CONCLUSIONS These findings show that polymorphic variation in the CHT1 gene is associated significantly with interindividual variability in HRV indices related to parasympathetic (cholinergic) activity.