Behavioral Neurocardiac Training in Hypertension

Abstract

Abstract-It is not established whether behavioral interventions add benefit to pharmacological therapy for hypertension.We hypothesized that behavioral neurocardiac training (BNT) with heart rate variability biofeedback would reduce blood pressure further by modifying vagal heart rate modulation during reactivity and recovery from standardized cognitive tasks ("mental stress"). This randomized, controlled trial enrolled 65 patients with uncomplicated hypertension to BNT or active control (autogenic relaxation), with six 1-hour sessions over 2 months with home practice. Outcomes were analyzed with linear mixed models that adjusted for antihypertensive drugs. BNT reduced daytime and 24-hour systolic blood pressures (Ϫ2.4Ϯ0.9 mm Hg, Pϭ0.009, and Ϫ2.1Ϯ0.9 mm Hg, Pϭ0.03, respectively) and pulse pressures (Ϫ1.7Ϯ0.6 mm Hg, Pϭ0.004, and Ϫ1.4Ϯ0.6 mm Hg, Pϭ0.02, respectively). No effect was observed for controls (PϾ0.10 for all indices). BNT also increased RR-high-frequency power (0.15 to 0.40 Hz; Pϭ0.01) and RR interval (PϽ0.001) during cognitive tasks. Among controls, high-frequency power was unchanged (Pϭ0.29), and RR interval decreased (Pϭ0.03). Neither intervention altered spontaneous baroreflex sensitivity (PϾ0.10). In contrast to relaxation therapy, BNT with heart rate variability biofeedback modestly lowers ambulatory blood pressure during wakefulness, and it augments tonic vagal heart rate modulation. It is unknown whether efficacy of this treatment can be improved with biofeedback of baroreflex gain. BNT, alone or as an adjunct to drug therapy, may represent a promising new intervention for hypertension. Key Words: hypertension Ⅲ heart rate variability Ⅲ baroreflex Ⅲ clinical trials Ⅲ biofeedback Ⅲ relaxation Ⅲ stress T he hypothesis that a behavioral intervention augments the hypotensive effect of pharmacological treatment of hypertension was tested in a randomized, controlled trial first by Patel and North. 1 Training in yoga-induced relaxation with electrodermal biofeedback significantly reduced systolic and diastolic blood pressures (BPs; SBP and DBP), whereas no change was observed with self-guided relaxation as the control intervention. The therapeutic model for this approach can be traced to early research by Smirk, who recognized that BP could be lowered to a basal level by an emotionally calm or "desensitized" state and that emotional and environmental factors contributed to the "supplemental" elevation that was observed during casual BP measurements. 2 It was subsequently asserted that repeated exposure to a "hypometabolic" state, popularly known as the relaxation response, could lower BP by reducing environmentally driven sympathetic overactivity. 1,3 Commentary at the time concerning a behavioral treatment for hypertension focused on 2 issues: the need for differentiation between the depressor effect of biofeedback-assisted relaxation and any placebo response 4 and whether active training with biofeedback augmented or interfered with the passive mental attitude that was considered necessary for ther...

Response to comment from Dr. Sloan: ‘Look what's going down’

“…This is partially correct and (surprisingly) it is more consistent with details of our 2005 trial [3]. In contrast, markers of vagal heart rate modulation in our 2010 trial [4] included not only HF power, but baroreflex sensitivity and RR interval as well. Indeed, a compelling feature of our secondary analysis of that trial is that we observed an inverse association between change in each of these markers of vagal heart rate modulation and change in hsCRP-as the resting baseline measures were compared before versus after an 8-week period of behavioural intervention.…”

Beyond Medications and Diet: Alternative Approaches to Lowering Blood Pressure

“…52 Training in behavioral neurocardiac training and in the control was supplemented by 20-minute audiotaped exercises for daily home practice. Behavioral neurocardiac training reduced daytime and 24-hour systolic BP levels (−2.4±0.9 mm Hg, P=0.009, and −2.1±0.9 mm Hg, P=0.03, respectively).…”

“…51,52 It is plausible that some techniques may be more effective than others 52 ; however, a paucity of data precludes making recommendations for implementing a specific methodology to treat high BP in clinical practice. On the other hand, no significant health risks were reported among the trials.…”

“…On the other hand, no significant health risks were reported among the trials. 47,52 The writing group conferred to biofeedback techniques in general a Class IIB, Level of Evidence B recommendation in regard to BP-lowering efficacy. Biofeedback may be considered in clinical practice to lower BP.…”

Short-term HRV Biofeedback: Perspectives in Environmental Physiology and Medicine

“…[12,13] It is shown that the application of HRVB helps to normalizing BP, increasing vagal reserve of autonomic regulation of cardiac activity. [13,14] Realization of the biofeedback effect is possible with the optimal functioning of the higher nervous activity mechanisms (motivation, memory, emotional and positive reinforcement) and cortical-visceral relations from the cardiovascular centers in the brain to the cardiac conduction system.…”