Heritability of ambulatory heart rate variability.
BACKGROUND
Reduced heart rate variability (HRV) is a prognostic factor for cardiac disease and cardiac mortality. Understanding the sources of individual differences in HRV may increase its diagnostic use and provide new angles for preventive therapy. To date, the contribution of genetic and environmental factors to the variance in HRV has not been investigated during prolonged periods of ambulatory monitoring in a naturalistic setting.


RESULTS
In 772 healthy twins and singleton siblings, ambulatory ECG was recorded during 24 hours. Two time domain measures of HRV were used: the standard deviations of all normal-to-normal intervals across 5-minute segments (SDNN index) and the root mean square of successive differences between adjacent normal RR intervals (RMSSD). Multivariate genetic analyses across 4 periods of day (morning, afternoon, evening, night) yielded significant estimates for genetic contribution to the mean ambulatory SDNN index (ranging from 35% to 47%) and the mean ambulatory RMSSD (ranging from 40% to 48%).


CONCLUSIONS
Ambulatory HRV measures are highly heritable traits that can be used to support genetic association and linkage studies in their search for genetic variation influencing cardiovascular disease risk.
Kupper
Nina H M
NH
Vrije Universiteit, Amsterdam, The Netherlands. hm.kupper@psy.vu.nl
Willemsen
Gonneke
G
van den Berg
Mireille
M
de Boer
Dolf
D
Posthuma
Daniëlle
D
Boomsma
Dorret I
DI
de Geus
Eco J C
EJ
D000328:Adult; D002940:Circadian Rhythm; D015716:Electrocardiography, Ambulatory; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006339:Heart Rate / Q000235:genetics*; D006801:Humans; D008297:Male; D035781:Siblings; D014429:Twins, Dizygotic / Q000235:genetics / Q000502:physiology; D014430:Twins, Monozygotic / Q000235:genetics / Q000502:physiology