1. The safety and efficacy of using the same intervention for treating resistant hypertensives in the community setting,
2. Compliance and self-monitored home BP using devices with automatic data storage combined with a PC-based data collection system on the Web that assures objective and quantitative monitoring of both. Home BP is particularly valuable, being free of placebo and white coat effects.
Study population. Patients were recruited from two family clinics and one hospital outpatient clinics. Inclusion criteria were age 40 to 80 years, with resistance to drug therapy (i.e., having office systolic BP in the range 140 to 160mm Hg or diastolic BP in the range 90 to 100mm Hg in spite of taking three or more antihypertensive drugs at maximal dosage and without changing of medication three weeks before the study).
Obese, diabetics, patients with severe chronic conditions, concomitant drug therapy causing hypertension, or secondary forms of hypertension were excluded. All participants were required to sign a consent form before their participation in the study.
Treatment. Patients were asked to perform daily a 15-minute session of device- guided breathing exercise during each afternoon or evening for eight weeks. The device (RESPeRATE, InterCure Ltd. Lod,) includes a belt type respiration sensor worn on the clothing around the torso connected to a computerized box that generates musical patterns listened through earphones. The device guides the user interactively to slow breathing with a relatively prolonged expiration by creating the following loop:
1. The monitored breathing pattern is continuously analyzed
2. Its parameters, including inspiration time and expiration time, are averaged over the last four breaths and used for synthesizing in real-time musical patterns with differentiated "inspiration" and "expiration" sounds. The duration of the expiration sound is slightly longer than the monitored expiration time.
3. The user synchronizes voluntarily inhaling and exhaling with their guiding musical sounds, which closes the loop. The guiding continues as long as the user can follow conveniently. The inspiration and expiration times are stored automatically once every minute of use together with date and hour and other performance variables. The device shuts off automatically after 15 minutes of use. Patients were instructed in its use before treatment at visit 2. The device was collected at the end of treatment.
Discussion. Resistant hypertensives responded favorably to nonpharmacologic treatment by slow breathing exercises guided interactively by a device and have demonstrated good compliance with both treatment and BP monitoring in the home setting. These findings generalize previous results obtained with the same treatment protocol in uncontrolled hypertensives, but not specifically in these hard-to-treat patients. The good compliance observed, in spite of the fact the present protocol requires much more time and attention than pharmacologic therapy, with these patients are frequently noncompliant with, reflects perhaps a change in patient’s attitude toward this treatment modality. The potential contribution of the white coat effect is excluded for the tested population, as mean home and office baselines BP levels were remarkably similar. The increase of home BP reductions for greater baseline value, which has been observed in previous studies, has clinical implications in the practice, as patients at higher risk appear to benefit more. This result is unlikely to be a statistical artifact (i.e., "regression to the mean") due to the repeated baseline measurements involved in home BP monitoring, or reflecting a placebo effect, to which home BP measurements are known to be insensitive. The successful use of PC-based data collection system in the study for both treatment and diagnostic devices used at the home setting is in line with the future view of telemedicine. The patient is proactive in treatment and follow-up, all related variables are objective, reliable, cannot be manipulated and can be reviewed by the physician.
This may enhance compliance and responsibility sharing between the patient and the physician. Results may have a physiologic rationale. Evidence suggests that slow breathing has some modulating effect on the cardiovascular system, which may be beneficial in hypertension, as in increasing baroreflex sensitivity, heart rate variability, venous return, and reducing peripheral resistance. These effects are mediated by both mechanical and neural pathways, which may differ from those affected by drugs.
The main limitation of the present study are its small sample size and the lack of control for placebo effect. Consistency of the results, generalizing previous randomized controlled studies, are encouraging.
In summary, the present study has demonstrated that device-guided slow breathing exercises may be a beneficial nonpharmacologic adjunct in treating resistant hypertensives. The lack of side effects, the demonstrated efficacy and compliance show there is a potential benefit for using this therapy in clinical practice, especially when pharmacologic therapy has failed to achieve BP control.