Predictive value of ambulatory heart rate in the Japanese general population: the Ohasama study

Background Resting heart rate can predict cardiovascular disease mortality or all-cause mortality. Because of the effect of the alert reaction, heart rates measured out-of-office should have better predictive power than those obtained at clinics. However, only a few studies have described the relationship between heart rate measured by ambulatory blood pressure monitoring devices and cardiovascular disease prediction. Methods We studied 1444 individuals from the Japanese general population who did not have a history of cardiovascular diseases including arrhythmia. We used multiple adjusted Cox proportional hazards to calculate the mortality risk of daytime heart rate, night-time heart rate, and the day - night heart rate dip ratio [ day - night heart rate dip ratio=(daytime heart rate-night-time heart rate)/daytime heart rate x 100]. Results After 12 years of follow-up, 101, 195, and 296 participants died due to cardiovascular diseases, noncardiovascular diseases, and all causes, respectively. As shown by others, neither daytime nor night-time heart rate predicted cardiovascular disease mortality, whereas both predicted noncardiovascular disease mortality. The day night heart rate dip ratio was significantly related to all-cause mortality. When night-time heart rate and day-night heart rate dip ratio were simultaneously included into the same Cox model, only night-time heart rate significantly and independently predicted all-cause mortality ( relative hazard per 10 bpm increase = 1.29, 95% confidence interval, 1.07 - 1.54). Conclusion Night-time heart rate value seems to have the most important predictor of all-cause mortality among ambulatory heart rate parameters in this population.