Heart Rate Acceleration and Deceleration Capacities Associated With 24-Hour Circadian Blood Pressure Variation of Hypertension Patients

Abstract OBJECTIVE To observe the relationship between 24-hour ambulatory blood pressure circadian rhythm and heart rate acceleration (AC), deceleration capacities (DC) in patients with hypertension. METHODS A total of 198 patients with essential hypertension were included and were monitored by 24-hour ambulatory blood pressure. Based on the nocturnal decline rate of systolic blood pressure, patients were divided into 2 groups: dippers (decline rate 10%–20%, n = 58) and non-dippers (decline rate <10%, n = 140). DC and AC values were calculated based on dynamic electrocardiogram data and compared between 2 groups. Pearson correlation analysis was used to analyze the correlation between DC, AC, and blood pressure and circadian blood pressure variation. Multivariate logistic regression analysis was used to analyze the influencing factors of non-dippers. RESULTS Compared with dippers, AC increased, while DC, standard deviation of normal R–R intervals (SDNN), percentage of heart beats with difference between adjacent normal RR intervals >50 ms in the total number of NN intervals (PNN50%) decreased in non-dippers (P < 0.05). Pearson analysis showed that AC was positively correlated to nighttime systolic blood pressure (r = 0.297), slowest heart rate (r = 0.221) and negatively correlated to SDNN (r = −0.233) and PNN50 (r = −0.238), while DC was negatively correlated to nighttime systolic blood pressure (r = −0.300), 24-hour average heart rate (r = −0.144), slowest heart rate (r = −0.213), and positively correlated to SDNN (r = 0.230), PNN50 (r = 0.267) (all P < 0.05). Multivariate logistic regression analysis showed that in the model included AC, AC (odds ratio [OR] = 1.320, 95% confidence interval [CI] 1.102–1.580, P = 0.003), age (OR = 1.029, 95% CI 1.001–1.057, P = 0.039), and 24-hour average heart rate (OR = 1.062, 95% CI 1.010–1.116, P = 0.02) were independent risk factors for non-dippers, while in the model included DC, DC (OR = 0.824, 95% CI 0.709–0.956, P = 0.011), age (OR = 1.027, 95% CI 1.001–1.055, P = 0.046), and 24-hour average heart rate (OR = 1.058, 95% CI 1.007–1.113, P = 0.025) were independent risk factors for non-dippers. CONCLUSIONS AC increases and DC decreases in patients with non-dipper hypertension. Nighttime systolic blood pressure positively correlates with AC and negatively correlates with DC. AC and DC are independent risk factors for abnormal circadian rhythm of blood pressure in hypertensives.