Background: Although biofeedback treatment is reported to be useful for patients with mild hypertension as an adjunct to medication, it is not certain whether the presence of organ damage affects its efficacy. The aim of this study is to clarify the clinical effects of biofeedback on mild hypertension in the absence and presence of organ damage.

Methods: Eleven mildly hypertensive outpatients without damage to the heart, brain, retina or kidney (4 men and 7 women), aged 40-65 years, and 11 mildly hypertensive outpatients with target organ damage and matching variables for age, sex and medication were included in this study. They underwent biofeedback treatment once a week for a total of four sessions.

Results: As a result of these sessions, mean blood pressures (MBP) in the organ-damage-negative (-) group and in the organ-damage-positive (+) group were significantly reduced by 12 +/- 11 and 12 +/- 8, respectively. The decrease was still significant 3 months after the treatment in the organ-damage (-) group, whereas no significant change was found 1 or 3 months after the treatment in the organ-damage (+) group. Throughout these sessions, the ratio of low frequency to high frequency of heart rate variance as well as systolic and MBP gradually decreased in each group (p < 0.01); this ratio of heart rate variance was smaller, and the alpha-wave amplitude on the electroencephalogram was larger in the organ-damage (-) group (p < 0.05).

Conclusion: These results suggested that biofeedback intervention may be effective in mild hypertension, especially when the patient is organ damage (-). Sympathetic activity seems to play an important role in the differentiated response.