Spectral analysis of heart period variability in anorexia nervosa

Heart rate variability as a biomarker for anorexia nervosa: A review

OBJECTIVE

Anorexia nervosa (AN) typically begins in early adolescence and other than weight status has few reliable biomarkers. Early diagnosis is a critical prognostic factor, but this can be clinically challenging. Heart rate variability (HRV), the beat-by-beat variance in heart rate (HR), may provide a unique assessment for the presence of AN because it has clinical utility as a biomarker of cardiac autonomic control in various populations (e.g., athletes, the aged, those with cardiovascular diseases, etc.). We present a review of the literature examining HRV in those with AN.

METHOD

Relevant publications were selected from PubMed using the search terms 'anorexia nervosa AND (HR OR HRV)'. Twenty papers were selected and reviewed.

RESULTS

The majority of studies suggest that those with AN have markedly and consistently elevated HRV compared to controls, even greater than among young athletes. However, no studies have explored HRV as a biomarker for AN.

DISCUSSION

Future studies on HRV should elucidate its role as a diagnostic biomarker for AN as well as its responsiveness with serial measurement to track response rates and predict relapse.

Irreversibility of cardiac autonomic dysfunction in female adolescents diagnosed with anorexia nervosa after short- and long-term weight gain

Anorexia nervosa (AN) patients may present with cardiac autonomic system dysfunction. Power spectral analysis of heart rate variability (HRV) is a reliable noninvasive examination for the quantitative assessment of the central sympathovagal interaction that modulates cardiovascular autonomic function. In the present study, HRV parameters were assessed in female adolescent AN inpatients in the malnourished phase at admission, at discharge when achieving weight restoration, and 24-36 months after discharge, when considered remitted. Nineteen normal-weight female controls were similarly assessed. Spectral analysis of HRV was done with the fast Fourier transform algorithm. At admission and discharge, patients underwent routine laboratory examinations and responded to questionnaires assessing eating-related preoccupations, behaviors, and personality attributes, depression and anxiety. Compared with the controls, AN patients had significantly lower heart-rate and HRV, lower total power and low frequency components, elevated high frequency components, and decreased low to high frequency power ratio as assessed with the power spectral analysis at all three evaluation points. These disturbances were not correlated with the baseline laboratory and psychometric measures. Our preliminary findings suggest that female adolescent AN inpatients may have a cardiovascular autonomic dysfunction in the form of vagal abnormality present not only in malnourished patients, but also persisting following short-term and long-term weight restoration.