Transcranial direct current stimulation modulates autonomic nervous system and reduces ambulatory blood pressure in hypertensives.

Purpose: Transcranial direct current stimulation (tDCS) seems to positively modulate the autonomic nervous system in different clinical conditions and healthy subjects; however, its effects on hypertensive (HTN) patients are not completely known. This study aimed to evaluate the effects of a tDCS or SHAM session (20 min) on blood pressure (BP) and autonomic variables of HTN patients.Materials and Methods: Subjects (n = 13) were randomly submitted to SHAM and tDCS sessions (1 week of washout). Hemodynamic and autonomic variables were measured at baseline, during, and immediately after tDCS or SHAM stimulation (Finometer®, Beatscope). Ambulatory BP measurement (ABPM) was evaluated after the experimental period.Results: Hemodynamic variables were not changed by tDCS, except for the fall in peripheral vascular resistance (Δ = -1696.51 ± 204.65 dyn.s/cm5). After the tDCS, sympathetic modulation was decreased (-61.47%), and vagal modulation was increased (+38.09%). Such acute autonomic changes may have evoked positive results observed in 24 hs-systolic blood pressure (Δ = -8.4 ± 6.2; P = .0022) and 24hs-diastolic blood pressure (Δ = -5.4 ± 4.2; P = .0010) in tDCS subjects compared with that in SHAM.Conclusion: These findings suggest that the tDCS could promote positive acute adjustments on cardiac autonomic control and reduced values on 24-hs BP of HTN patients. More than a proof-of-concept, these results may point out to the future, where brain stimulation (tDCS) can be used to HTN syndromes, such as refractory HTN.

Acute and Short-Term Autonomic and Hemodynamic Responses to Transcranial Direct Current Stimulation in Patients With Resistant Hypertension.

Previously, we demonstrated that acute transcranial direct current stimulation (tDCS) reduced blood pressure (BP) and improved autonomic modulation in hypertensives. We hypothesized that acute and short-term tDCS intervention can promote similar benefits in resistant hypertensive patients (RHT). We assessed the impact of one (acute intervention) and ten (short-term intervention) tDCS or SHAM (20 min, each) sessions on BP, pulse interval (PI) and systolic blood pressure variabilities, humoral mechanisms associated with BP regulation, and cytokines levels. True RHT subjects (n = 13) were randomly submitted to one and ten SHAM and tDCS crossing sessions (1 week of "washout"). Hemodynamic (Finometer®, Beatscope), office BP, and autonomic variables (accessed through spectral analysis of the pulse-to-pulse BP signal, in the time and frequency domain - Fast Fourrier Transform) were measured at baseline and after the short-term intervention. 24 h-ambulatory BP monitoring was measured after acute and short-term protocols. Acute intervention: tDCS reduced BP, cardiac output, and increase high-frequency band of PI (vagal modulation to the heart). Short-term protocol: tDCS did not change BP and cardiac output parameters. In contrast, central systolic BP (-12%), augmentation index (-31%), and pulse wave velocity (34%) were decreased by the short-term tDCS when compared to SHAM. These positive results were accompanied by a reduction in the low-frequency band (-37%) and an increase of the high-frequency band of PI (+62%) compared to SHAM. These findings collectively indicate that short-term tDCS concomitantly improves resting cardiac autonomic control and pulse wave behavior and reduces central BP in RHT patients, https://ensaiosclinicos.gov.br/rg/RBR-8n7c9p.

ACUTE TRANSCRANIAL DIRECT CURRENT STIMULATION (tDCS) IMPROVES VENTILATORY VARIABILITY AND AUTONOMIC MODULATION IN RESISTANT HYPERTENSIVE PATIENTS.

Here, we assessed the impact of one session of transcranial direct current stimulation (tDCS) or SHAM (20 min, each) on ventilatory responses to cardiopulmonary exercise test, central and peripheral blood pressure (BP), and autonomic modulation in resistant hypertensive (RHT) patients. RHT subjects (n = 13) were randomly submitted to SHAM and tDCS crossing sessions (1 week of "washout"). Patients and a technician who set the tDCS/Sham room up were both blind. After brain stimulation, patients were submitted to a cardiopulmonary exercise test to evaluate ventilatory and cardiovascular response to exercise. Hemodynamic (Finometer®, Beatscope), and autonomic variables were measured at baseline (before tDCS/Sham) and after incremental exercise. RESULTS: Our study shows that tDCS condition improved heart rate recovery, VO2 peak, and vagal modulation (after cardiopulmonary exercise test); attenuated the ventilatory variability response, central and peripheral blood pressure well as sympathetic modulation (after cardiopulmonary exercise test) in comparison with SHAM. These data suggest that acute tDCS sessions prevented oscillatory ventilation behavior during the cardiopulmonary exercise test and mitigated the increase of systolic blood pressure in RHT patients. After the exercise test, tDCS promotes better vagal reentry and improved autonomic modulation, possibly reducing central blood pressure and aortic augmentation index compared to SHAM. Brazilian Registry of Clinical Trials (ReBEC): https://ensaiosclinicos.gov.br/rg/RBR-8n7c9p.