Objective: To investigate the effects of renal denervation (RDN) on heart rate variability (HRV) in resistant hypertension (RHTN) with and without disturbance of glucose metabolism. Design and method: In a single-arm prospective interventional study with renal denervation (NCT02667912 and NCT01499810 on ClinicalTrial.gov) were included 87 patients with RHTN: 39 patients without disturbance of glucose metabolism (RHTN group) (mean age 51.2 ± 8.5years, 20 (51%) men, 24-hour (24 h) blood pressure (BP) (systolic/diastolic) 162.3 ± 19.4/99.6 ± 13.5 mmHg); 34 patients with type 2 diabetes mellitus (RHTN + DM group) (mean age 59.2 ± 7.8 years, 11 (32%) men, 24 h BP 157.8 ± 17.4/80.1 ± 12.4 mmHg, mean HbA1c 6.9 ± 1.4%) and 14 patients with impaired glucose tolerance (RHTN + IGT group) (mean age 54.0 ± 10.0 years, 3 (27%) men, 24 h BP 156.6 ± 14.3/89.5 ± 15.6 mmHg). All patients were underwent ABPM and 24-h Holter monitoring with analysis of time and frequency domain-based HRV. Follow-up after 12 months was completed by 38 patients of RHTN group, 22 patients of RHTN + DM group and 9 patients of RHTN + IGT group. Results: There was a significant decrease in 24 h BP in all groups at 12 months after RDN (p < 0,001). In the RHTN group, there were no significant changes in both high frequency (HF) and low frequency (LF) (for HF from 14.8 (8.6; 24) to 29.5 (19.0; 40), p > 0.05, and for LF (from 23.1 (15, 0; 61) to 61.0 (40.5; 70), p > 0.05). There were also no significant changes in both LF and HF in the RHTN + IGT group (for LF from 52 (38; 61) to 50 (42; 61), p > 0.05, for HF from 37 (30; 50) to 44 (29; 47), p > 0.05). On the contrary, in the RHTN + DM group, there was a significant decrease in LF (from 55 (39; 63) to 50 (42; 61), p = 0.004), which occurred independently from BP effects, and a non-significant increase in HF. Other measured HRV parameters (mean NN, SDNN, SDNN-I, SDANN-I, r-MSSD, pNN50) were unchanged in all groups (p > 0.05). Conclusions: RDN was associated with a reduction of LF, HRV parameters that mainly reflect sympathetic overactivity, only in patients with resistant hypertension and diabetes mellitus.

Objective: To evaluate the differences in heart rate variability (HRV) among patients with resistant hypertension (RHTH) with and without disturbance of glucose metabolism. Design and method: A total of 87 patients with RHTN were included in the study: 39 patients without disturbance of glucose metabolism (RHTN group) (mean age 51.2 ± 8.5years, 20 (51%) men, 24-hour (24 h) blood pressure (BP) (systolic/diastolic) 162.3 ± 19.4/99.6 ± 13.5 mmHg); 34 patients with type 2 diabetes mellitus (RHTN + DM group) (mean age 59.2 ± 7.8 years, 11 (32%) men, 24 h BP 157.8 ± 17.4/80.1 ± 12.4 mmHg, mean HbA1c 6.9 ± 1.4%) and 14 patients with impaired glucose tolerance (RHTN + IGT group) (mean age 54.0 ± 10.0 years, 3 (27%) men, 24 h BP 156.6 ± 14.3/89.5 ± 15.6 mmHg). ABPM and 24-h Holter monitoring with analysis of time and frequency domain-based HRV were performed in all patients. Results: Patients of three groups had a comparable systolic BP level and number of antihypertensive drugs. At the same time, patients of the RHTN + DM group was older and had significantly higher level of 24h- diastolic BP (DBP) than patients without disturbance of glucose metabolism (p = 0.001 for age, and p = 0.001 for DBP). Low frequency (LF), HRV parameters that mainly reflect sympathetic overactivity, was significantly higher in patient of the RHTN + DM group compared with the RHTN group (52 (38;61) vs 23.1 (15.0;61) respectively, p = 0.03). High frequency (HF), HRV parameters that mainly reflect parasympathetic overactivity, was significantly higher in patients with disturbance of glucose metabolism compared with patient without it (37 (30;50) for the RHTN + DM group and 31 (24;42) for the RHTN + IGT group vs 14,8 (8,6;24) for the RHTN group, p = 0,00/0,01, respectively). Other measured HRV parameters (mean NN, SDNN, SDNN-I, SDANN-I, r-MSSD, pNN50) were comparable in all groups (p > 0,05). Conclusions: The presence of diabetes mellitus in patients with RHTN is associated with greater autonomic imbalance in the form of an increase in both the sympathetic and parasympathetic tone of the autonomic nervous system, while IGT is characterized by a significant increase in the parasympathetic tonus only to the same extent as in diabetes mellitus.

ConclusionWhen the ablation time in both temperature settings is the same, RF exposure at low temperatures causes a lesser depth of damage.