RESTING HEART RATE AND MORTALITY RISK IN HYPERTENSIVE PATIENTS WITH NO ATRIAL FIBRILLATION

Abstract

Objective: The recent ESH Guidelines include elevated resting heart rate (RHR) as an independent risk factor among the established and suggested novel risk factors that influence cardiovascular risk in patients with hypertension, indicating sympathetic overdrive. Increased fitness affects both mortality and RHR. However, the association between RHR and mortality risk, adjusted for cardiorespiratory fitness, age, comorbidities and medication has not been fully explored. Design and method: We evaluated the association between RHR and mortality in 422,702 hypertensive patients (mean age 62.5 ± 8.6 years) with no evidence of atrial fibrillation during the entire follow-up. All completed a standardized exercise treadmill test (ETT), with no evidence of overt heart disease prior to and at the time of the ETT. To assess the risk in a wide and clinically relevant spectrum, we established 6 RHR categories per 10 heartbeat intervals ranging from <=60 to >100 beats. We used multivariable Cox regression to assess the RHR-mortality association. We adjusted the models for age, body mass index, cardiac risk factors, exercise capacity, and medications (including b-blockers). Results: During the median follow-up of 10.6 years, providing 4,551,327 person-years, there were 107,863 deaths with an average annual rate of 23.7 events per 1,000 person-years. We noted approximately 7% increase in risk for each 10 heart beats. Mortality risk was significantly elevated at a RHR of >80 beats/min (HR; 1.15, CI; 1.12 - 1.17; p <0.006) and increased progressively to 41% (HR; 1.41, CI; 1.36 - 1.45; p <0.001) for those with a RHR of >100 beats/min. Similar trends were noted for subjects aged <60; 60-69; and >=70 years and those treated with b blockers. In all assessments, mortality risk was consistently overestimated when fitness was not considered. Conclusions: We noted a progressive increase in mortality risk with increased RHR at >80 bpm in hypertensive patients with no AF. The association was independent of comorbidities, and medications.