Cardiovascular complications and sudden death associated with eating disorders

摘要

Sudden death in eating disordered patients has been attributed to cardiac arrhythmias and susceptibility might be identified by using heart rate variability (HRV) as a marker of impaired cardiac autonomic regulation. The aim of the study was to examine this parameter in female eating disorder patients and the effect of a short rehabilitation programme. HRV was investigated by linear and nonlinear analysis of ECG recordings from hospitalised female patients with diverse eating disorders. Twenty minute ECG recordings were made at admission, one week and six weeks later. HRV was significantly lower and of reduced complexity across eating disorder groups compared to control. Autonomic dysregulation was shown and differences between the groups persisted after six weeks of specialised hospital treatment. Heart rate variability can be measured simply and has potential as a marker of cardiac risk and an indication for high level care across the spectrum of eating disorders. Work was carried out at the Northside Clinic Eating Disorders Program, Greenwich, Australia. Introduction Cardiovascular perturbations associated with eating disorders suggest that autonomic regulation of the heart is affected in these conditions. Sudden death has been reported in anorexia nervosa.(1) This could be a consequence of low body weight, weight losing behaviours, associated mood states or medications.(1-4) Heart rate variability (HRV), the moment to moment fluctuations in heart rate over time and frequency domains, reflects the underlying stability of autonomic function, the integration of sympathetic and parasympathetic modulation and susceptibility to potentially fatal cardiac arrhythmic events.(5) Previous results on heart rate variability (HRV) analysis in anorexia nervosa (AN) include some apparently conflicting data that is resolved if acute and chronic AN are considered separately. Acute AN is characterized by decreased heart rate (HR) and increased HRV. In chronic AN, HR is increased but HRV reduced.(6, 7) Reduced HRV has been demonstrated in AN using linear analysis methods but little has been published concerning HRV in other eating disorders.(3, 4, 8) These include the syndromes of bulimia nervosa, characterised by normal body weight, binge eating and weight losing behaviours of a specified frequency, and EDNOS. In EDNOS diagnostic criteria for anorexia nervosa (emaciation as defined by a body mass index of 17.5 or less) and bulimia nervosa have not been met despite similarly eating disordered behaviours and attitudes. A risk of premature death similar to that seen in anorexia nervosa has been reported in EDNOS.(9) Methods Participants in the study were females diagnosed with anorexia nervosa (N=17), eating disorders otherwise not specified (EDNOS) (N=9) and bulimia nervosa (N=3). All were participating in a specialised hospital treatment program. Subjects gave their informed consent and the study protocol was approved by the Charles Sturt University Committee on Human Research. Diagnosis was reached by clinical consensus based on DSMIV and ICD10 criteria(10, 11) and by use of a computerised diagnostic instrument (EEE-C).(12) All patients had been engaging in weight losing behaviours prior to hospital admission and the majority were anxious and/or depressed. The proportion of smokers in both patient and control groups was similar. All patients were ostensibly medically stable when first assessed and no major ECG or biochemical abnormalities were detected. HRV was analysed soon after admission, one week later and prior to discharge (mean interval 6 weeks). ECG recordings were made at least 30 minutes after main meals and smoking. During their hospital stay, patients were started on various regular medications including nutritional supplements, hormone replacement, antidepressants and novel antipsychotic agents, depending on clinical need. When weight gain was indicated, this was achieved at a mean rate of 0.7kg per week.Thirty five age-matched,