Blood pressure biofeedback treatment of white-coat hypertension

Exploring the effect of virtual reality relaxation environment on white coat hypertension in blood pressure measurement

A phenomenon called White Coat Hypertension (WCH) often occurs when measuring blood pressure (BP) in a real medical environment. Utilizing virtual reality (VR) technology to present appropriate relaxation scenes can isolate the real medical environments and may provide a new method to avoid WCH and improve the accuracy of BP measurement. In this study, we designed four immersive VR relaxation scenes and conducted an experiment to explore the role of VR scenes in eliminating/detecting WCH in BP measurement. Results from the current sample showed that both systolic BP and diastolic BP measured in the simulated medical environment were significantly higher than the baseline level and the VR scene condition, while there were no significant differences between the BPs measured in VR scenes and the baseline level. It can be concluded that VR provides an effective approach to avoid WCH in BP measurement by visually and aurally isolating the real environment and assisting relaxation and provides a new approach to detect the occurrence of WCH by the comparison of BPs measured in the VR scene condition and real medical environments.

Biofeedback-assisted cardiovascular control in hypertensives exposed to emotional stress: a pilot study

The study was aimed at examining the effect of a short Heart Rate-Biofeedback (HR-BF) protocol on systolic (SBP) and diastolic (DBP) blood pressure levels and BP emotional reactivity. Twenty-four unmedicated outpatients with pre- and stage 1 hypertension, were randomly assigned to active treatment (BF-Training) or control (BP-Monitoring) group. Subjects in BF-Training Group underwent four BF sessions. Guided imagery of stressful events was introduced during sessions 3 and 4. Control participants self-monitored their BP at home for 4 weeks. Subjects in both groups performed an emotional Speech Test before and after the training (or monitoring) period. SBP and mean arterial pressure responses to the emotional Speech Test were significantly smaller after the BF-training than the BP-monitoring. Moreover, clinic SBP and DBP were significantly reduced by about 10 mmHg in BF-Training Group, whereas they remained unchanged in control group. Self-monitored BP decreased significantly in the active treatment group and not in control group. A short BF-training, including guided imagery of stressful events, was effective in reducing BP reactions to a psychosocial stressor. BP measured in the clinic, and self-monitored at home were also significantly reduced in the BF-Training Group. HR-BF appears to be a suitable intervention for hypertensive patients, mostly when BP increase is associated with emotional activation.

Effect of slow abdominal breathing combined with biofeedback on blood pressure and heart rate variability in prehypertension

OBJECTIVE

Prehypertension is a new category designated by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) in 2003. Managing prehypertension with nonpharmacological intervention is possibly beneficial to the prevention of hypertension. In this study, we observed the effect of slow abdominal breathing combined with electromyographic (EMG) biofeedback training on blood pressure (BP) in prehypertensives and assessed the changes of heart rate variability (HRV) in order to find an optional intervention to prevent hypertension and acquire some experimental data to clarify the underlying neural mechanism.

METHODS

Twenty-two (22) postmenopausal women with prehypertension were randomly assigned to either the experiment group or the control group. The experiment group performed 10 sessions of slow abdominal breathing (six cycles/min) combined with frontal electromyographic (EMG) biofeedback training and daily home practice, while the control group only performed slow abdominal breathing and daily home practice. BP and HRV (including R-R interval and standard deviation of the normal-normal intervals [SDNN]) were measured.

RESULTS

Participants with prehypertension could lower their systolic blood pressure (SBP) 8.4 mm Hg (p < 0.001) and diastolic blood pressure (DBP) 3.9 mm Hg (p < 0.05) using slow abdominal breathing combined with EMG biofeedback. The slow abdominal breathing also significantly decreased the SBP 4.3 mm Hg (p < 0.05), while it had no effect on the DBP (p > 0.05). Repeated-measures analyses showed that the biofeedback group + abdominal respiratory group (AB+BF) training was more effective in lowering the BP than the slow breathing (p < 0.05). Compared with the control group, the R-R interval increased significantly during the training in the AB+BF group (p < 0.05). The SDNN increased remarkably in both groups during the training (p < 0.05).

CONCLUSIONS

Slow abdominal breathing combined with EMG biofeedback is an effective intervention to manage prehypertension. The possible mechanism is that slow abdominal breathing combined with EMG biofeedback could reduce sympathetic activity and meanwhile could enhance vagal activity.

Integrative approaches for cardiovascular disease

In the United States, $2.5 trillion is spent on healthcare annually. Seven chronic diseases account for half of all this expense. Of these 7, cardiovascular disease, hypertension, stroke, and diabetes mellitus are largely preventable. Integrative cardiology programs that focus on risk-factor modification through lifestyle change combined with early detection and advanced lipid management offer a new paradigm to the prevention of cardiovascular disease.

Relaxation therapies for the management of primary hypertension in adults

BACKGROUND

Lifestyle interventions are often recommended as initial treatment for mild hypertension, but the efficacy of relaxation therapies is unclear.

OBJECTIVES

To evaluate the effects of relaxation therapies on cardiovascular outcomes and blood pressure in people with elevated blood pressure.

SEARCH STRATEGY

We searched the Cochrane Library, MEDLINE, EMBASE, Science Citation Index, ISI Proceedings, ClinicalTrials.gov, Current Controlled Trials and reference lists of systematic reviews, meta-analyses and randomised controlled trials (RCTs) included in the review.

INCLUSION CRITERIA

RCTs of a parallel design comparing relaxation therapies with no active treatment, or sham therapy; follow-up >/=8 weeks; participants over 18 years, with raised systolic blood pressure (SBP) >/=140 mmHg or diastolic blood pressure (DBP) >/=85 mmHg); SBP and DBP reported at end of follow-up.

EXCLUSION CRITERIA

participants were pregnant; participants received antihypertensive medication which changed during the trial.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial quality. Disagreements were resolved by discussion or a third reviewer. Random effects meta-analyses and sensitivity analyses were conducted.

MAIN RESULTS

29 RCTs, with eight weeks to five years follow-up, met our inclusion criteria; four were excluded from the primary meta-analysis because of inadequate outcome data. The remaining 25 trials assessed 1,198 participants, but adequate randomisation was confirmed in only seven trials and concealment of allocation in only one. Only one trial reported deaths, heart attacks and strokes (one of each). Meta-analysis indicated that relaxation resulted in small, statistically significant reductions in SBP (mean difference: -5.5 mmHg, 95% CI: -8.2 to -2.8, I2 =72%) and DBP (mean difference: -3.5 mmHg, 95% CI: -5.3 to -1.6, I2 =75%) compared to control. The substantial heterogeneity between trials was not explained by duration of follow-up, type of control, type of relaxation therapy or baseline blood pressure. The nine trials that reported blinding of outcome assessors found a non-significant net reduction in blood pressure (SBP mean difference: -3.2 mmHg, 95% CI: -7.7 to 1.4, I(2) =69%) associated with relaxation. The 15 trials comparing relaxation with sham therapy likewise found a non-significant reduction in blood pressure (SBP mean difference: -3.5 mmHg, 95% CI: -7.1 to 0.2, I(2) =63%).

AUTHORS' CONCLUSIONS

In view of the poor quality of included trials and unexplained variation between trials, the evidence in favour of causal association between relaxation and blood pressure reduction is weak. Some of the apparent benefit of relaxation was probably due to aspects of treatment unrelated to relaxation.

Blood Pressure Biofeedback Exerts Intermediate-Term Effects on Blood Pressure and Pressure Reactivity in Individuals with Mild Hypertension: A Randomized Controlled Study

OBJECTIVE

This randomized controlled study examined whether a 4-week blood pressure (BP) biofeedback program can reduce BP and BP reactivity to stress in participants with mild hypertension.

METHODS

Participants in the active biofeedback group (n=20) were trained in 4 weekly laboratory sessions to self-regulate their BP with continuous BP feedback signals, whereas participants in the sham biofeedback group (n=18) were told to manipulate their BP without feedback signals. BP, skin temperature, skin conductance, BP reactivity to stress, body weight, and state anxiety were assessed before training and repeated at the eighth week after the training.

RESULTS

The decreases in systolic (12.6 +/- 8.8 versus 4.1 +/- 5.7) and mean BP (8.2 +/- 6.9 versus 3.3 +/- 4.9) from baseline at week 12 follow-up were significantly greater in the active biofeedback group compared with the sham biofeedback group (p=0.001 and 0.017, respectively). Results from analysis of covariance with the follow-up systolic blood pressure (SBP) (or mean arterial pressure [MAP]) as the dependent variable, baseline SBP (or MAP) as the covariate, and group as the independent variable showed that biofeedback training effectively lowered SBP and MAP (p=0.013 and 0.026, respectively). The pre-to-post differences in skin conductance and SBP reactivity were statistically significant for the biofeedback group (p=0.005 and 0.01, respectively), but not for the control group. For the sample as a whole and for the biofeedback group, the state anxiety score and body weight remained unchanged.

CONCLUSIONS

BP biofeedback exerts a specific treatment effect in reducing BP in individuals with mild hypertension, possibly through reducing pressor reactivity to stress.

Relationship between brachial-ankle pulse wave velocity and heart rate variability in young Japanese men

This study examined the relationship between arterial stiffness and autonomic nervous function in a young population. A cross-sectional study was conducted on 382 Japanese males, aged 24 to 39 years, who worked at the same information service company. Brachial-ankle pulse wave velocity (baPWV) was measured using an automatic waveform analyzer, and the spectral power of heart rate variability in the low frequency (LF: 0.04-0.15 Hz) and the high frequency (HF: 0.15-0.40 Hz) band was evaluated by the maximum entropy method. LF/HF and HF were used as the indicators of sympathetic and parasympathetic nervous activity, respectively. Psycho-hormonal responses were examined by the Profile of Mood State (tension-anxiety and anger-hostility scales) and Hamilton's Depression Scale with serum cortisol and catecholamine levels. In a univariate analysis, baPWV was positively associated with the following variables (all p <0.05): LF/HF, age, body mass index, systolic and diastolic blood pressures, heart rate, serum total cholesterol and triglycerides, blood glucose, and plasma cortisol and noradrenaline. Multiple regression analysis indicated that LF/HF was an independent predictor of baPWV (p <0.05), after controlling for significant effects of age, systolic blood pressure, and plasma noradrenaline levels. There was no significant effect of HF on baPWV in this multivariate analysis. Neither mood state nor health-related lifestyle factors such as smoking were significant. It was suggested that baPWV is closely associated with sympathetic nervous activity in young men.

Biofeedback Applications in the Treatment of Cardiovascular Diseases

Cardiovascular diseases impair the lives of millions of Americans each year. Researchers have studied a variety of nonpharmacologic interventions in an attempt to discover their use as therapies for these diseases. Various methods of biofeedback have shown promise in the treatment or management of several cardiovascular disorders. The literature relating to the use of biofeedback therapies for hypertension, cardiac arrhythmias, angina pectoris, cardiac ischemia, myocardial infarction, and Raynaud's phenomenon is reviewed. The number and types of studies in each of these areas vary widely, but research to date suggests that biofeedback could be a useful alternative or adjunct to more conventional forms of treatment. Further research to clarify the appropriate uses of biofeedback in the management of these disorders is recommended.

Blood pressure-lowering effects of biofeedback treatment in hypertension: a meta-analysis of randomized controlled trials

To examine the blood pressure-lowering effects of biofeedback treatment in patients with essential hypertension, a meta-analysis was conducted on studies published between 1966 and 2001. A total of 22 randomized controlled studies with 905 essential hypertensive patients were selected for review. Compared with clinical visits or self-monitoring of blood pressure (non-intervention controls), biofeedback intervention resulted in systolic and diastolic blood pressure reductions that were greater by 7.3 mmHg (for systole; 95% confidence interval: 2.6 to 12.0) and 5.8 mmHg (for diastole; 95% confidence interval: 2.9 to 8.6). Compared with sham or non-specific behavioral intervention controls, the net reductions in systolic and diastolic blood pressures by biofeedback intervention were 3.9 (95% confidence interval: -0.3 to 8.2) and 3.5 (-0.1 to 7.0) mmHg, respectively. The results of multiple regression analysis also indicated that biofeedback intervention decreased systolic and diastolic blood pressures more than non-intervention controls (p < 0.001), but not more than sham or non-specific behavioral intervention controls (p > 0.05), when controlling for the effects of initial blood pressures. When biofeedback intervention types were classified into two types, simple biofeedback and relaxation-assisted biofeedback, only the relaxation-assisted biofeedback significantly decreased both systolic and diastolic blood pressures (p < 0.05) compared with those in sham or non-specific behavioral intervention controls. The results suggested that biofeedback was more effective in reducing blood pressure in patients with essential hypertension than no intervention. However, the treatment was only found to be superior to sham or non-specific behavioral intervention when combined with other relaxation techniques. Further studies will be needed to determine whether biofeedback itself has an antihypertensive effect beyond the general relaxation response.

Nondrug interventions in hypertension prevention and control

This review was undertaken to address the relation of various factors to HBP and their potential for preventing and controlling this widespread problem. With respect to salt intake and BP, the 1999 Workshop on Sodium and Blood Pressure of the (US) National Heart, Lung, and Blood Institute [5] will serve the reader well as a point of departure. The body of the present review provides more detailed discussion especially of recent epidemiologic research, including the DASH-Sodium trial, published more recently than the proceedings of that workshop. The DASH-Sodium trial demonstrates significant increases in SBP and DBP, with sodium intake greater than 65 mmol/d (= 3.7 g NaCl--see equivalencies in Appendix A) and with the usual American diet (versus the DASH diet). These results provide substantial evidence against current dietary practices in many populations where daily intakes of salt are much higher than recommended. We also have addressed alcohol consumption, micronutrients/macronutrients, physical activity and inactivity, obesity, cigarette smoking, and alternative approaches to treatment such as stress reduction/biofeedback, yoga/meditation, and acupuncture. Evidence for the efficacy of certain nonpharmacologic approaches to preventing and controlling HBP is strong. This evidence offers a basis for public health policies and clinical approaches that can greatly affect the incidence and consequences of HBP in the population at large. What is needed now is implementation of the policies and practices addressed here. Unless such action is taken on a large scale, we will have made poor use of the knowledge accrued over decades of research. The clinician is referred to the National Heart, Lung and Blood Institute Web site at www.nhlbi.gov/health/prof/heart/index.htm for resource and guideline information for hypertension. Patients and the general public are referred to the sister web page at www.nhlbi.gov\health\public\heart\index.htm for educational fact sheets and general information on hypertension.