Twenty-four-hour ambulatory heart rate and organ damage in primary hypertension

BACKGROUND: The relationship between basal heart rate (HR) and the occurrence of myocardial ischemia, sudden death, cardiovascular mortality have been described. Therefore, further studies are warranted to evaluate the behaviour of heart rate in different scenarios. We sought to determine whether ambulatory heart rate is associated with the presence of target organ damage (TOD) in hypertensive patients. PATIENTS AND METHODS: Crossectional study of essential hypertensive patients in whom a twenty-four hour ambulatory blood pressure monitoring (ABPM) was performed. The relationship between TOD and 24 hour ambulatory heart rate (HR) was analyzed. RESULTS: Five hundred and sixty-six patients with arterial hypertension were included (55.8% male, mean age 59.9 +/- 14.2 years). 15% were smokers, 62.2% had dyslipidemia, 18.4% diabetes mellitus. Heart rate values were higher during activity as compared to the resting period (72.8 vs 63.3 bpm, p < 0.001). Heart rate, in both periods, was not associated with the presence of TOD. Nevertheless, the patients with nocturnal HR > or = 65 bpm have high risk and a high prevalence of TOD. This relationship was also present in multivariate analysis (HR 2.41; CI 95% 1.41-4.11; p=0.001). CONCLUSION: An elevated nocturnal HR, > or = 65 bpm, obtained with ABPM registry, is associated with the presence of TOD in hypertensive patients. ABPM is a powerful tool for hypertensive patients not only to monitor BP control but also to obtain information on HR which may provide additional information about current and future cardiovascular risk.