Heart rate measurement and outcome.

Previous studies on the predictive value of heart rate and heart rate variability for the risk of cardiovascular disease remains controversial. Since heart rate is known to be variable with several physical and mental stresses, the inconclusive nature of previous studies might reflect the difference in accuracy and reproducibility of the heart rate measurement. In the Ohasama study, which has been conducted since 1985 in the northern part of Japan, home measurements and ambulatory monitoring of heart rate as well as blood pressure were examined with special reference to cardiovascular mortality. Heart rate measured at home and averaged for 21 days was shown to be linearly associated with cardiovascular mortality, while heart rate variability (standard deviation of daytime ambulatory heart rate measured every 30 min) inversely correlated with cardiovascular mortality. In conclusion, heart rate and heart rate variability must not be overlooked when evaluating hypertension.