P3405Association between heart rate thresholds for cardiovascular risk defined by new ESC/ESH Guidelines and neuroadrenergic markers

Abstract

Abstract Background The ESC/ESH Guidelines for hypertension issued in 2018 identify resting heart rate (HR) values greater than 80 beats/minute as predictors of cardiovascular risk, with the undocumented evidence that this detection might represent the occurrence of a sympathetic cardiovascular overdrive. Purpose In the present study we tested this hypothesis throughout the use of direct and indirect markers of sympathetic neural function. Methods In 167 untreated and uncomplicated mild-to moderate essential hypertensives recruited for different investigations and aged 51.8±3.2 years (mean±SEM) without other cardiovascular or non-cardiovascular disease, we measured clinic and ambulatory blood pressure (BP), HR (EKG), venous plasma norepinephrine (NE, HPLC assay) and efferent postganglionic muscle sympathetic nerve traffic (MSNA, microneurography). We then subdivided the study population in 2 groups according to HR values ≤ or >80 beats/minute. Results Sixty-eight patients displayed resting HR >80 beats/minute while the remaining 99 below this threshold value, the 2 groups showing superimposable age values and gender distribution. Body mass index, clinic and ambulatory BP were similar in the 2 groups this being the case also for LVMI and metabolic variables. In contrast MSNA values were significantly greater (P<0.02) in the former than in the latter group both when expressed as bursts incidence over time (49.2±1.8 vs 39.5±1.4 bs/min) and when corrected for HR (60.7±3.0 vs 51.4±2.5 bs/100 hb). NE showed a tendency to be greater in the former group without achieving, however, statistical significance. In the whole population there was a significant direct relationship between MSNA and HR values (r=0.61, P<0.01) Conclusions Thus hypertensive patients displaying HR >80 beats/minute are characterized by a marked sympathetic overdrive, particularly when direct adrenergic markers are employed. This finding suggests that cardiac and peripheral sympathetic activation may participate at the increased cardiovascular risk detected in this group of patients.