Drug and Alcohol Dependence, 17 (1986) 365-368 Elsevier Scientific Publishers Ireland Ltd.

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HEART RATE VARIABILITY IN CHRONIC ALCOHOLICS: A FOLLOW-UP STUDY

FRANK WEISEa, DIETHARD MtiLLERb, DIETER KRELLb, VOLKER KIELSTEINb and ROLF D. KOCHb

aDepartment ofPathological Biochemistry and bhJeurofogy, Medical Academy of Magdeburg, 3090 Magdeburg (G.D.R.)

(Received October 22nd, 1985)

SUMMARY

Heart rate variability (HRV) was studied in 11 chronic alcoholic subjects, l-30 days after the beginning of abstinence and again 5,12 and 24 weeks later. Two patients could be re-examined after 19 and 22 months, respective- ly. In the follow-up study, the total patient group showed a statistically significant increase in HRV with prolonged abstinence of at least 6 months. No recovery of efferent vagal function was found in 4 patients. It is suggest- ed that the vagal neuropathy may improve in chronic alcoholics, but perhaps only in patients with a short to moderately long duration of drinking history or a functional rather than an organic vagal damage,

Key words: Alcoholics - Heart rate variability - Follow-up study

INTRODUCTION

Autonomic neuropathy is generally considered to be irreversible [ 11. On the other hand, Said et al observed a degeneration of unmyelinated and small myelinated axons with subsequent axonal sprouting in nerve biopsies of diabetics, even if the regeneration was still insufficient to com- pensate the loss [2]. They suggested that only an efficient long-term control of blood glucose levels may allow a functionally satisfying improve- ment of the neuropathy. Recently it was demonstrated that the transplant- ation of pancreatic islets in rats with chronic streptozotocin diabetes resulted in a wide resolution of the autonomic neuropathy within 3 months [ 31.

The present follow-up study was therefore undertaken to examine the vagal function of the heart in chronic alcoholic patients with prolonged abstinence.

0376~8716/86/$03.50 o Elsevier Scientific Publishers Ireland Ltd. Printed and Published in Ireland

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MATERIALS AND METHODS

Eleven consecutively admitted patients (M = 9; F = 2; mean age ? SD. = 40.5 + 4.5 years, range 31-45 years) were examined. All fulfilled the alcohol addiction criteria of the Munich alcoholism test [ 41.

Duration of drinking ranged from 5 to 20 years and the average daily intake was estimated to be 150-350 g of ethanol/day.

The patients were examined l-30 days after the beginning of abstinence and again 5, 12 and 24 weeks later. Two patients could be re-examined after 19 and 22 months, respectively.

The HRV was calculated as the mean difference between successive instantaneous heart rate scores, called mean momentary arrhythmia (MMA) as reported in an earlier study [ 51. The variability of the results of each patient was related to values of normal subjects. Therefore, the MMA of healthy volunteers (M = 5; F = 2; mean age + S.D. = 25.6 * 3.2 years) was measured on 5 days in succession from 0700 to 1900 at intervals of 3 h. Wilcoxon’s signed rank test, Fisher’s exact probability test, and Pearson’s variability coefficient (VC) were used for statistical analysis.

RESULTS

In the follow-up study, the total patient group showed a statistically significant increase in HRV with prolonged abstinence of at least 6 months (2p = 0.01; Fig. 1). No significant changes in heart rate were observed. Four patients were found to have reduced HRV up to pathological values in all investigations; this was judged to be cardiac autonomic neuropathy (for age-dependent normal data see [5]). Two out of these 4 patients were reinvestigated after 19 and 22 months, respectively. Both showed an in- creased HRV, but the lower limits of age dependent normal data were not reached. The VCs in these 2 patients were 29 and 38% respectively. In 3 patients with HRV within normal limits the VCs ran to 25, 35 and 53%, respectively. In comparison, the VCs in healthy subjects during the period of observation varied between 3 and 20%.

The VCs were significantly higher in the alcoholics as compared to the control subjects (2P < 0.005).

DISCUSSION

In the total patient group an increase in sinus arrhythmia with prolonged abstinence was found. Within 6 months of abstinence no recovery of efferent vagal function, as measured by MMA, occurred in patients with possibly an organic damage of the vagus nerve. However, an increased HRV was demon- strated in 2 patients with evidence of cardiac neuropathy after more than 1% years. The age dependent normal data were not reached, but the higher VCs, related to those of normal subjects, may indicate the beginning of

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investigation

Fig. 1. MMA in alcoholic patients on first and follow-up examinations. Arrows indicate subjects investigated within t.he fist 5 days after cessation of drinking; these values were not included in the calculation of the variability coefficients - see Ref. 6.

organic restitution. High VCs were also seen in 3 patients with normal HRV. It appears that in these alcoholics some few months were sufficient for a functional recovery of the vagus nerve, the HRVs of normal subjects were not obtained in the same follow-up regimen as for alcoholics. But we believe that the VCs in normal subjects give a good insight into the possible variation of the parameter, also valid for the time interval investigated for alcoholics.

Moreover, the greater variation in some alcoholics as compared to normal subjects is always due to a higher HRV with continued abstinence in spite of advancing age. The VCs calculated from age dependent mean values in normal subjects are permanently below 2096, even for a period of 8 years [ 51. Recently, Tan et al. reported about a follow-up investigation in chronic alcoholics after 4-27 months of continued abstinence [ 71. They were able to demonstrate a significant improvement in heart rate responses to standing. Valsalva’s manoeuvre and atropine. It was surprising that the deep breathing test, a test with a relatively well known physiological background and sensitive for cardiac vagal function, showed no significant change. Possibly, this behavior is due to the fact that the discrimination of the HRV between patients and healthy subjects is really difficult with advancing years, especially after the age of 50-55 years. We are in agreement with Tan et al. that the vagal neuropathy may improve in chronic alcoholics, but perhaps

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only in patients with a short to moderately long duration of drinking history or a functional rather than organic damage.

REFERENCES

1 N. Canal and G. Comi, in: L. Battistin et al. (Eds.), Clinical and biological aspects of peripheral nerve diseases, Alan R. Liss, Inc., 1983, p. 149.

2 G. Said et al., Brain, 106 (1983) 791. 3 R.E. Schmidt et al., Diabetes, 32 (1983) 532. 4 W. Feuerlein et al., Munch. Med. Wschr., 119 (1977) 1275. 5 F. Weise et al., Clin. Neurol. Neurosurg., 87 (1985) 95. 6 F. Weise et al., Drug Alcohol Depend., 16 (1986) 85. 7 E.T.H. Tan et al., J. Neurol. Neurosurg. Psychiatry, 47 (1984) 1335.