AbstractResting heart rate (RHR) is associated with increased risk of cardiovascular
morbidity and mortality. Thyroid hormones exert several effects on the
cardiovascular system, but the relation between thyroid function and RHR remains
to be further established. We evaluated whether measures of thyroid hormone
status are associated with RHR in patients referred to coronary angiography.
Thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxin
(FT4), and RHR were determined in 2795 participants of the Ludwigshafen Risk and
Cardiovascular Health (LURIC) Study. Median (25th to 75th percentile) serum
concentrations were 1.25 (0.76–1.92) mU/l for TSH, 4.8
(4.2–5.3) pmol/l for FT3 and 17.1
(15.4-19.0) pmol/l for FT4, and mean (±standard
deviation) RHR was 68.8 (±11.7) beats/min. Comparing the highest
versus the lowest quartile, RHR (beats/min) was significantly higher in
the fourth FT4 quartile [3.48, 95% confidence interval (CI):
2.23–4.73; p <0.001] and in the fourth FT3 quartile (2.30,
95% CI: 1.06–3.55; p <0.001), but there was no
significant difference for TSH quartiles. In multiple linear regression analyses
adjusting for various potential confounders, FT3 and FT4 were significant
predictors of RHR (p <0.001 for both). In subgroups restricted to TSH,
FT3, and FT4 values within the reference range, both FT3 and FT4 remained
significant predictors of RHR (p <0.001 for all). In conclusion, in
patients referred to coronary angiography, FT3 and FT4 but not TSH were
positively associated with RHR. The relationship between free thyroid hormones
and RHR warrants further investigations regarding its diagnostic and therapeutic
implications.
Age- and gender-specific differences in the prognostic value of resting heart rate for cardiovascular events in patients referred for coronary angiography