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- (HE) 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 HE 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.