HEART RATE DIPPING AS AN INDEPENDANT RESIDUAL CARDIOVASCULAR RISK FACTOR IN CONTROLLED HYPERNTESIVE PATIENTS

Objective: To evaluate the independent cardiovascular residual risk value of heart rate (HR) non-dipping in controlled hypertension.Design and method: A sequential cohort of controlled hypertension patients, referred to 24 h ambulatory blood pressure monitoring (ABPM), were analyzed through SPSS Statistics. The primary endpoint utilized was the 3-point major adverse cardiovascular events, and a secondary endpoint of global mortality was also utilized. HR dipping was defined as a fall in nighttime HR 10% as compared to daytime HR. Results: A descriptive sample analysis was performed, yielding in 55.8% female (n=72), with a mean age of 61.8 years (range of 31 to 80 years old). This sample showed a relatively low prevalence of cardiovascular risk factors with 25.6% (n=33) obese (mean BMI of 28.3 with a range of 20.8 to 45.2 kg/m2), 24.0% dyslipidemic (n=31) and 19.4% diabetic (n=25). Heart rate values from office and 24 h ambulatory blood pressure monitoring was analyzed, with a mean office HR of 76 bpm, a mean daytime HR of 74 bpm, and mean nighttime HR of 65 bpm. The mean HR dipping was 12.3 bpm and 53.5% (n=69) had a dipping pattern 10%. Independant sample T-testing showed a statistically significant inverse relation between HR dipping and major adverse cardiovascular events. A non-significant inverse relation was also observed between HR dipping ang global mortality. A survival curve analysis was performed utilizing the Kaplan-Meier method, with HR non-dippers showing statistically significant lower survival, with a log rank 4.614 (p=0.032) (Figure 1). Likewise, a non-significant trend was observed between HR non-dippers and global mortality, likely due to the low sample size and low incidence of events (n=5). The independent prognostic value of HR non-dipping status was evaluated in a multivariate analysis through the Cox Regression method, stratified to sex and the modifiable cardiovascular risk factors, maintaining its statistical significance (HR 9.0, p= 0.046). Conclusions: In this population of controlled hypertension patients, heart rate non-dipping was an independent predictor of major adverse cardiovascular events, highlighting its potential value as a residual cardiovascular risk factor. It could serve as an important risk stratification tool in this population.