Heart rate variability as a measure of cardiac autonomic function in anorexia nervosa: a review of the literature.

OBJECTIVE: Patients with anorexia nervosa (AN) exhibit a wide range of autonomic system disturbances; these patients have also high mortality risk due to cardio-vascular complications. Origin and pathogenesis of such changes are not absolutely clear.
METHODS: Relevant publications were drawn from PUBMED using the keywords 'anorexia nervosa' AND 'autonomic'. Fifty two abstracts were identified and screened for papers that measured the state of autonomic regulation by means of analysis of heart rate variability either during 24-hour electrocardiography (ECG) monitoring or during a short-term laboratory test. Studies selected were analysed for the number of patients included, the presence and quality of control groups, gender, age and body mass index (BMI) of patients, type of AN as well as methods used to determine heart rate variability (HRV).
RESULTS: Twenty papers on HRV in patients with anorexia were identified and analysed, revealing three distinct positions regarding changes of autonomic nervous system (ANS) functions in patients with AN. The majority of papers identified parasympathetic/sympathetic imbalance with parasympathetic dominance and decreased sympathetic modulation; others could not replicate these findings, but instead described sympathetic dominance; finally a group of papers could not identify any autonomic differences in comparison to control samples. We conclude that in its current state of analysis HRV may not be suitable for routine assessment of ANS function in AN patients but rather remains a research tool.