Heart rate variability biofeedback in patients with alcohol dependence: a randomized controlled study

Abstract

Background and objective: In patients with alcohol dependence, ethyl-toxic damage of vasomotor and cardiac autonomic nerve fibers leads to autonomic imbalance with neurovascular and cardiac dysfunction, the latter resulting in reduced heart rate variability (HRV). Autonomic imbalance is linked to increased craving and cardiovascular mortality. In this study, we sought to assess the effects of HRV biofeedback training on HRV, vasomotor function, craving, and anxiety.

Methods: We conducted a randomized controlled study in 48 patients (14 females, ages 25-59 years) undergoing inpatient rehabilitation treatment. In the treatment group, patients (n=24) attended six sessions of HRV biofeedback over 2 weeks in addition to standard rehabilitative care, whereas, in the control group, subjects received standard care only. Psychometric testing for craving (Obsessive Compulsive Drinking Scale), anxiety (Symptom Checklist-90-Revised), HRV assessment using coefficient of variation of R-R intervals (CVNN) analysis, and vasomotor function assessment using laser Doppler flowmetry were performed at baseline, immediately after completion of treatment or control period, and 3 and 6 weeks afterward (follow-ups 1 and 2).

Results: Psychometric testing showed decreased craving in the biofeedback group immediately postintervention (OCDS scores: 8.6±7.9 post-biofeedback versus 13.7±11.0 baseline [mean ± standard deviation], P<0.05), whereas craving was unchanged at this time point in the control group. Anxiety was reduced at follow-ups 1 and 2 post-biofeedback, but was unchanged in the control group (P<0.05). Following biofeedback, CVNN tended to be increased (10.3%±2.8% post-biofeedback, 10.1%±3.5% follow-up 1, 10.1%±2.9% follow-up 2 versus 9.7%±3.6% baseline; P=not significant). There was no such trend in the control group. Vasomotor function assessed using the mean duration to 50% vasoconstriction of cutaneous vessels after deep inspiration was improved following biofeedback immediately postintervention and was unchanged in the control group (P<0.05).

Conclusion: Our data indicate that HRV biofeedback might be useful to decrease anxiety, increase HRV, and improve vasomotor function in patients with alcohol dependence when complementing standard rehabilitative inpatient care.

Keywords: CVNN; HRV; alcohol addiction; craving; laser Doppler flowmetry; rehabilitation.

Figure 1

CVNN under resting conditions. Notes: The bar graph illustrates a trend toward increased CVNN in HRV biofeedback-treated patients, indicating possible improved function of cardiac autonomic nerve fibers. Data are presented as mean±standard deviation. P=ns compared to baseline and control. HRV biofeedback: n=24; control: n=24. In the control group, the term “postintervention” refers to the post-control period. Abbreviations: CVNN, coefficient of variation of R-R intervals; HRV, heart rate variability; ns, not significant.

Figure 2

CVNN under paced breathing conditions. Notes: The bar graph illustrates a trend toward increased CVNN in HRV biofeedback-treated patients, indicating possible improved function of cardiac autonomic nerve fibers. Data are presented as mean±standard deviation. P=ns compared to baseline and control. HRV biofeedback: n=24; control: n=24. In the control group, the term “postintervention” refers to the post-control period. Abbreviations: CVNN, coefficient of variation of R-R intervals; HRV, heart rate variability.

Figure 3

Vasomotor function: Δt50%down. Notes: After HRV biofeedback (but not in the control group), Δt50%down was increased, indicating possible improved function of vasomotor autonomic nerve fibers. Data are presented as mean±standard deviation. ^*P<0.05 versus baseline. HRV biofeedback: n=24; control: n=24. In the control group, the term “postintervention” refers to the post-control period. Abbreviations: Δt50%down, mean duration to 50% vasoconstriction; HRV, heart rate variability; ns, not significant.

Figure 4

Vasomotor function: Δt50%up. Notes: Δt50%up was unchanged in both the HRV biofeedback group and in the control group. Data are presented as mean±standard deviation. P=ns compared to baseline and control. HRV biofeedback: n=24; control: n=24. In the control group, the term “postintervention” refers to the post-control period. Abbreviations: Δt50%up, duration to 50% redilation of cutaneous vessels; HRV, heart rate variability; ns, not significant.