Heart rate and blood pressure variability and baroreflex sensitivity in patients with anorexia nervosa

Heart Rate Variability in Psychiatric Disorders: A Systematic Review

Introduction

Heart rate variability (HRV) is a measure of the fluctuation in time interval between consecutive heart beats. Decreased heart rate variability has been shown to have associations with autonomic dysfunction in psychiatric conditions such as depression, substance abuse, anxiety, and schizophrenia, although its use as a prognostic tool remains highly debated. This study aims to review the current literature on heart rate variability as a diagnostic and prognostic tool in psychiatric populations.

Methods

A literature search was conducted using the MEDLINE, EMBASE, Cochrane, and PsycINFO libraries to identify full-text studies involving adult psychiatric populations that reported HRV measurements. From 1647 originally identified, 31 studies were narrowed down through an abstract and full-text screen. Studies were excluded if they enrolled adolescents or children, used animal models, enrolled patients with another primary diagnosis other than psychiatric as outlined by the diagnostic and statistical manual of mental disorders (DSM) V, or if they assessed HRV in the context of treatment rather than diagnosis. Study quality assessment was conducted using a modified Downs and Blacks quality assessment tool for observational rather than interventional studies. Data were reported in four tables: 1) summarizing study characteristics, 2) methods of HRV detection, 3) key findings and statistics, and 4) quality assessment.

Results

There is significant variability between studies in their methodology of recording as well as reporting HRV, which makes it difficult to meaningfully interpret data that is clinically applicable due to the presence of significant bias in existing studies. The presence of an association between HRV and the severity of various psychiatric disorders, however, remains promising.

Conclusion

Future studies should be done to further explore how HRV parameters may be used to enhance the diagnosis and prognosis of several psychiatric disorders.

Validity and Consistency of the Arabic Version of the Eating Disorder Examination Questionnaire (EDE-Q) among Saudi Adults

The prevalence of eating disorders (EDs) is growing, and early screening is important to prevent related health complications. The Eating Disorder Examination Questionnaire (EDE-Q) has been widely used as a diagnostic tool to identify cases of EDs; however, a validated Arabic version of the tool is needed to help in the screening process of EDs. The aim of this study was to validate the Arabic version of EDE-Q. A cross-sectional study included a sample of 549 adults, who were recruited mainly from the four major provinces in Saudi Arabia. A forward–backward translation method was conducted, and then the tool was validated using the confirmatory factor analysis (CFA). The dataset was split for further convergent analysis using exploratory factor analysis (EFA) and CFA. The results of CFA from the main dataset did not support the four-factor original EDE-Q. The results of EFA from the first data-split suggested a three-factor EDE-Q-14 Arabic version. This was supported by the results of CFA of the second data-split. A total of five items were allocated in each shape and weight concern, and restraint component, with correlations ranging from 0.969 and 0.462 and from 0.847 to 0.437, respectively. A total of four items were allocated in eating concern, with correlations ranging from 0.748 to 0.556. The internal consistency of the global and the three subscales were high, with Cronbach’s α ranging from 0.762 to 0.900. Findings of the current study suggest that the Arabic version of the EDE-Q-14 is a valid and reliable tool to screen for EDs among adults in Saudi Arabia.

Cardiac abnormalities determined by tissue Doppler imaging and arrhythmias in adolescents with anorexia nervosa

BACKGROUND

Anorexia nervosa has a prevalence of 0.5-3% in adolescents, placing this population at increased risk of cardiac anomalies including arrhythmias, pericardial effusion, and myocardial dysfunction. Our objective is to describe cardiovascular anomalies observed by tissue Doppler imaging in patients with anorexia nervosa.

METHODS

We retrospectively reviewed electrocardiogram, Holter, and echocardiography findings in 28 patients diagnosed with anorexia nervosa.

RESULTS

Electrocardiogram was abnormal in 71% of patients with sinus bradycardia observed in 57%. Holter confirmed sinus bradycardia without significant pauses. Prolonged QTc, low voltage, and ectopic beats were each seen in 14% of patients. Wenckebach atrioventricular block was observed in one patient. Supraventricular or ventricular tachycardia was not observed. Echocardiography showed structurally normal heart in all patients. Pericardial effusion was seen in 7.1% of patients and left ventricular mass was decreased in 10.7%. Mean ejection fraction was 0.73 and mean fractional shortening was 38.4%. Tissue Doppler imaging revealed systolic or diastolic dysfunction in four patients with e', a', and s' velocities in the lateral and septal basal segments more than two standard deviations below the mean. Two patients had decreased left ventricular mass but no significant difference in disease duration from the group. Basal segment velocities below one standard deviation were also observed in an additional seven patients.

CONCLUSION

A trend for decreased tissue Doppler imaging velocities was seen in 25.0% of patients, while significant systolic and diastolic dysfunction was seen in 14.3% of patients, associated with a significant reduction in left ventricular mass and independent of disease duration.

Autonomic nervous system function in women with anorexia nervosa

PURPOSE

Abnormalities in autonomic function have been observed in people with anorexia nervosa. However, the majority of investigations have utilised heart rate variability as the sole assessment of autonomic activity. The current study utilised a variety of methodologies to assess autonomic nervous system function in women with a current diagnosis of anorexia, a past diagnosis of anorexia who were weight-restored, and healthy controls.

METHODS

The sample included 37 participants: 10 participants with anorexia, 17 weight-restored participants (minimum body mass index > 18.5 for minimum of 12 months) and 10 controls. Assessments of autonomic function included muscle sympathetic nerve activity (MSNA) using microneurography, heart rate variability, baroreflex sensitivity, blood pressure variability, head-up tilt table test, sudomotor function and assessment of plasma catecholamines.

RESULTS

MSNA (bursts/min) was significantly decreased in both anorexia (10.22 ± 6.24) and weight-restored (17.58 ± 1.68) groups, as compared to controls (23.62 ± 1.01, p < 0.001 and p = 0.033, respectively). Participants with anorexia had a significantly lower standard deviation in heart rate, lower blood pressure variability and decreased sudomotor function as compared to controls. Weight-restored participants demonstrated decreased baroreflex sensitivity in response to head-up tilt as compared to controls.

CONCLUSION

Women with a current or previous diagnosis of anorexia have significantly decreased sympathetic activity, which may reflect a physiological response to decreased energy intake. During the state of starvation, women with anorexia also displayed decreased sudomotor function. The consequences of a sustained decrease in MSNA are unknown, and future studies should investigate autonomic function in long-term weight-restored participants to determine whether activity returns to normal.

Effects of short-term hypercaloric nutrition on orthostatic tolerance in healthy individuals: a randomized controlled crossover study

Reduced-caloric intake lowers blood pressure through sympathetic inhibition, and worsens orthostatic tolerance within days. Conversely, hypercaloric nutrition augments sympathetic activity and blood pressure. Because dietary interventions could be applied in patients with syncope, we tested the hypothesis that short-term hypercaloric dieting improves orthostatic tolerance. In a randomized crossover trial, 20 healthy individuals (7 women, 26.7 ± 8 years, 22.6 ± 2 kg/m²) followed a 4-day hypercaloric (25% increase of energy intake by fat) or normocaloric nutritional plan, with a washout period of at least 23 days between interventions. We then performed head-up tilt table testing with incremental lower body negative pressure while recording beat-by-beat blood pressure and heart rate. The primary endpoint was orthostatic tolerance defined as time to presyncope. Time to presyncope during combined head-up tilt and lower body negative pressure did not differ between hypercaloric and normocaloric dieting (median 23.19 versus 23.04 min, ratio of median 1.01, 95% CI of ratio 0.5-1.9). Heart rate, blood pressure, heart rate variability, and blood pressure variability in the supine position and during orthostatic testing did not differ between interventions. We conclude that 4 days of moderate hypercaloric nutrition does not significantly improve orthostatic tolerance in healthy individuals. Nevertheless, given the important interaction between energy balance and cardiovascular autonomic control in the brain, caloric intake deserves more attention as a potential contributor and treatment target for orthostatic intolerance.

Autonomic Nervous System Function in Anorexia Nervosa: A Systematic Review

Background: Autonomic nervous system (ANS) dysfunction has been suggested to contribute to the high prevalence of cardiovascular complications in individuals with anorexia nervosa (AN), yet has not been thoroughly investigated. The current review aimed to synthesize the evidence of basal ANS function in individuals with a current diagnosis of AN and those with a previous diagnosis who had achieved weight restoration, as compared to controls. Methods: A systematic review of nine databases was conducted and studies that were published in a peer-review journal, in English, that included at least one assessment of ANS function in individuals with a current or previous diagnosis of AN were selected. Forty-six studies were included with a total of 811 participants with a current diagnosis of AN and 123 participants with a previous diagnosis of AN. Results: ANS function was assessed through heart rate variability (n = 27), orthostatic challenge, blood pressure variability or baroreflex sensitivity (n = 11), adrenergic activity (n = 14), skin conductance level (n = 4), and pupillometry (n = 1). Individuals with AN demonstrated increased parasympathetic activity and decreased sympathetic activity, suggestive of autonomic dysregulation. Following weight restoration, autonomic function trended toward, or was equivalent to, control levels. Discussion: Autonomic dysregulation is indicated through a range of assessments in individuals with AN. Future investigations should utilize a variety of assessments together in order to conclusively establish the nature of autonomic dysfunction in AN, and following extended weight restoration. Moreover, investigation into the co-occurrence of ANS function and cardiovascular risk is required.

Heart rate variability as a biobehavioral marker of diverse psychopathologies: A review and argument for an "ideal range"

Heart rate variability (HRV), a measure of the variability in intervals between subsequent heart beats, is now widely considered an index of emotion regulatory capacity and the ability to adapt flexibly to changing environmental demands. Abnormalities in HRV are implicated in a host of psychopathologies, making it a potentially powerful transdiagnostic biobehavioral change mechanism in treatment interventions. While most mental illnesses are associated with low HRV, eating disorders have been linked to elevated HRV. We examined 62 research articles on HRV in psychopathology to test the hypothesis that there is an "ideal range" of HRV that predicts optimal functioning. Relationships between symptom severity and parameters that quantify HRV were examined graphically. More extreme time-domain HRV measures, both high and low, were associated with psychopathology, whereas healthy controls displayed mid-range values. Findings preliminarily support the hypothesis that there is an "ideal range" of HRV that could be targeted in biofeedback interventions.

Role of Neuroendocrine, Immune, and Autonomic Nervous System in Anorexia Nervosa-Linked Cardiovascular Diseases

Anorexia nervosa represents a severe mental disorder associated with food avoidance and malnutrition. In patients suffering from anorexia nervosa, cardiovascular complications are the main reason leading to morbidity and mortality. However, the origin and pathological mechanisms leading to higher cardiovascular risk in anorexia nervosa are still unclear. In this aspect, the issue of exact pathological mechanisms as well as sensitive biomarkers for detection of anorexia nervosa-linked cardiovascular risk are discussed. Therefore, this review synthesised recent evidence of dysfunction in multiple neuroendocrine axes and alterations in the immune system that may represent anorexia nervosa-linked pathological mechanisms contributing to complex cardiovascular dysregulation. Further, this review is focused on identification of non-invasive biomarkers for the assessment of increased cardiovascular risk in anorexia nervosa that can be linked to a clinical application. Complex non-invasive assessment of cardiovascular autonomic regulation—cardiac vagal control (heart rate variability), sympathetic vascular activity (blood pressure variability), and cardiovascular reflex control (baroreflex sensitivity)—could represent a promising tool for early diagnosis, personalized therapy, and monitoring of therapeutic interventions in anorexia nervosa particularly at a vulnerable adolescent age.

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.

Autonomic Nervous System Response during Light Physical Activity in Adolescents with Anorexia Nervosa Measured by Wearable Devices

Anorexia nervosa (AN) is associated with a wide range of disturbances of the autonomic nervous system. The aim of the present study was to monitor the heart rate (HR) and the heart rate variability (HRV) during light physical activity in a group of adolescent girls with AN and in age-matched controls using a wearable, minimally obtrusive device. For the study, we enrolled a sample of 23 adolescents with AN and 17 controls. After performing a 12-lead electrocardiogram and echocardiography, we used a wearable device to record a one-lead electrocardiogram for 5 min at baseline for 5 min during light physical exercise (Task) and for 5 min during recovery. From the recording, we extracted HR and HRV indices. Among subjects with AN, the HR increased at task and decreased at recovery, whereas among controls it did not change between the test phases. HRV features showed a different trend between the two groups, with an increased low-to-high frequency ratio (LF/HF) in the AN group due to increased LF and decreased HF, differently from controls that, otherwise, slightly increased their standard deviation of NN intervals (SDNN) and the root mean square of successive differences (RMSSD). The response in the AN group during the task as compared to that of healthy adolescents suggests a possible sympathetic activation or parasympathetic withdrawal, differently from controls. This result could be related to the low energy availability associated to the excessive loss of fat and lean mass in subjects with AN, that could drive to autonomic imbalance even during light physical activity.

Arterial stiffness and haemodynamic regulation in adolescent anorexia nervosa versus obesity

Cardiovascular complications contribute to higher morbidity and mortality in patients with anorexia nervosa. We aimed to study biomarkers of cardiovascular risk in anorexic, normal-weight, and obese adolescents with focus on complex cardiovascular autonomic regulation and early arteriosclerotic damage. We examined 20 adolescent girls with anorexia nervosa, 20 obese girls, and 20 healthy normal-weight controls. Collected data: body composition analysis, 5 min recordings of R-R intervals and beat-to-beat blood pressure (BP), and arterial stiffness evaluated using cardio-ankle vascular index (CAVI). Evaluated parameters: beat-to-beat heart rate and BP variability, haemodynamic parameters (total peripheral resistance (TPR) cardiac output), CAVI, and anthropometric indices, including novel body roundness index (BRI). Adolescents with anorexia nervosa had increased CAVI associated with lower arterial constriction indexed by low-frequency band of BP variability compared with normal-weight peers (p = 0.03, p = 0.04, respectively) and obese adolescents (p < 0.01, p = 0.01, respectively). After normalization of CAVI and TPR by BRI, the relationship between CAVI and TPR was significant for all groups with the highest slope in the anorexia nervosa group (R² = 0.724, p < 0.01). This is the first study revealing early arteriosclerotic damage in anorexic girls with increased CAVI. Complex analysis of cardiovascular autonomic regulation, and early arteriosclerotic, hemodynamic, and anthropometric changes in spectrum anorexia nervosa, normal weight, and obesity could help to understand the mechanisms of increased cardiovascular risk in malnutrition. Novelty Girls with anorexia nervosa showed signs of early arteriosclerotic damage indexed by CAVI. Insufficient sympathetic cardiovascular control was found already in adolescents with anorexia nervosa. The effect of body composition on CAVI was best predicted by novel body roundness index.

Hypothesis: Clues From Mammalian Hibernation for Treating Patients With Anorexia Nervosa

This hypothesis is that anorexia nervosa (AN) is a biologically driven disorder, and mammalian hibernation may offer clues to its pathogenesis. Using this approach, this hypothesis offers suggestions for employing heart rate variability as an early diagnostic test for AN; employing the ketogenic diet for refeeding patients, attending to omega 3:6 ratio of polyunsaturated fatty acids (PUFAs) in the refeeding diet; and exploring clinical trials of the endocannabinoid-like agent, palmitoylethanolamde for patients with AN. This hypothesis also explores the role of lipids and autoimmune phenomena in AN, and suggest a lipodomics study to search for antibodies in the serum on patients with AN.

Depression and cardiac dysautonomia in eating disorders

PURPOSE

Individuals with eating disorder (ED) are at an increased risk of cardiac arrhythmias due to cardiac dysautonomia, which may be exacerbated if depression is also present. The aim of the study was to use heart rate analysis as a marker for cardiac dysautonomia in patients with eating disorders and depression as a comorbidity.

METHODS

Clinical data, including presence of depression, was obtained from all participants. A three-lead ECG was used to determine interbeat intervals, and these were analyzed using time domain, frequency domain, and nonlinear heart rate variability measures.

RESULTS

Thirty ED patients and 44 healthy controls participated in the research. The presence of depression was associated with additional decreased time domain (RMSSD 36.8 ± 26 vs. 22.9 ± 12.3; p < 0.05), frequency domain (HF power 788 ± 1075 vs. 279 ± 261; p < 0.05), and nonlinear domain (DFAα₂ 0.82 ± 0.1 vs. 0.97 ± 0.1; p < 0.01) which results in the ED group compared to patients with no depression.

CONCLUSIONS

The presence of depression in ED patients decreased HRV even further compared to the non-depressed patient group and controls, suggesting that higher vigilance and a holistic treatment approach may be required for these patients to avoid cardiac arrhythmia complications.

The effects of body weight status on orthostatic intolerance and predisposition to noncardiac syncope

Orthostatic intolerance (OI) is frequently the mechanism underlying the occurrence of noncardiac syncope (NCS) and is associated with substantial risk for injury. Body weight status appears to be a modifier of orthostatic responses and possibly influences the propensity to NCS. The majority of cross-sectional studies have found that the lower the body mass index (BMI) the greater the predisposition to OI is, accompanied with both down-regulation of sympathetic nervous system activity and up-regulation of parasympathetic nervous system activity. These changes appear to occur across the whole spectrum of BMI values from underweight to obesity, while they may be associated more strongly with central body fat than total body fat. Weight loss following bariatric surgery has been consistently found to increase OI, attributed first to the effects of weight loss per se, second to the specific type of surgical procedure and third to the potential postoperative autonomic neuropathy due to vitamin deficiency. The increased OI following bariatric surgery renders this intervention not easily tolerable for the affected individuals, mandating increased fluid and salt intake, pharmacological measures or surgical adjustments to attenuate OI. All future studies investigating orthostatic responses and NCS should implement a matching of the population arms for BMI and ideally for body fat.

Prospective associations between problematic eating attitudes in midchildhood and the future onset of adolescent obesity and high blood pressure

BACKGROUND

Clinically diagnosed eating disorders may have adverse cardiometabolic consequences, including overweight or obesity and high blood pressure. However, the link between problematic eating attitudes in early adolescence, which can lead to disordered eating behaviors, and future cardiometabolic health is, to our knowledge, unknown.

OBJECTIVE

We assessed whether variations in midchildhood eating attitudes influence the future development of overweight or obesity and high blood pressure.

DESIGN

Of 17,046 children who participated in the Promotion of Breastfeeding Intervention Trial (PROBIT), we included 13,557 participants (79.5% response rate) who completed the Children's Eating Attitudes Test (ChEAT) at age 11.5 y and in whom we measured adiposity and blood pressure at ages 6.5, 11.5, and 16 y. We assessed whether ChEAT scores ≥85th percentile (indicative of problematic eating attitudes) compared with scores <85th percentile at age 11.5 y were associated with new-onset overweight, obesity, high systolic blood pressure, or high diastolic blood pressure between midchildhood and early adolescence.

RESULTS

After controlling for baseline sociodemographic confounders, we observed positive associations of problematic eating attitudes at age 11.5 y with new-onset obesity (OR: 2.18; 95% CI: 1.58, 3.02), new-onset high systolic blood pressure (OR: 1.34; 95% CI: 1.05, 1.70), and new-onset high diastolic blood pressure (OR: 1.25; 95% CI: 0.99, 1.58) at age 16 y. After further controlling for body mass index at age 6.5 y, problematic eating attitudes remained positively associated with new-onset obesity (OR: 1.80; 95% CI: 1.28, 2.53); however, associations with new-onset high blood pressure were attenuated (OR: 1.14; 95% CI: 0.89, 1.45 and OR: 1.09; 95% CI: 0.86, 1.39 for new-onset systolic and diastolic blood pressure, respectively).

CONCLUSIONS

Problematic eating attitudes in midchildhood seem to be related to the development of obesity in adolescence, a relatively novel observation with potentially important public health implications for obesity control. PROBIT was registered at clinicaltrials.gov as NCT01561612 and isrctn.com as ISRCTN37687716.

The role of wearable sensors and wireless technologies for the assessment of heart rate variability in anorexia nervosa

PURPOSE

Bradycardia and abnormal cardiac autonomic function are related to increased mortality in anorexia nervosa (AN). The aim of this study was to assess heart rate (HR) and HR variability of young adolescents with AN as compared to controls by means of wearable sensors and wireless technologies.

METHOD

The ECG signal was recorded in 27 AN girls and 15 healthy girls at rest using a wearable chest strap. The tachogram, the mean intervals between R peaks (meanRR), the root mean square of successive differences (RMSSD), the power of low-frequency (LF) and high-frequency (HF) bands and the LF/HF ratio were assessed.

RESULTS

All AN girls showed a reduced HR and an increased meanRR and RMSSD. An HF increase, a LF decrease, and a LF/HF reduction indicated a prevalence of the parasympathetic on sympathetic activity.

CONCLUSIONS

The instruments used in this pilot study were feasible, unobtrusive and extremely suitable in AN subjects who are burdened by high incidence of cardiovascular mortality; their application could open to new approaches of vital signs monitoring in hospitals as well as in home settings.

Autonomic dysfunction responses to head-up tilt in anorexia nervosa

PURPOSE

Autonomic dysfunction of the cardiovascular system in anorexia nervosa (AN) was reported not only in the rest position, but also in the standing position in some previous studies, which might contribute to cardiac complications such as lethal arrhythmia. However, there has not been sufficient literature in this issue. Therefore, we performed a head-up tilt test, and compared the changes after tilting in indices of autonomic function between AN patients and healthy subjects by heart rate variability (HRV) and blood pressure variability (BPV).

METHODS

The subjects were 21 females with AN and 30 age-matched healthy women. A head-up tilt test was performed following the protocol recommended by the American Heart Association. Blood pressure and heart rate data were collected for 10 min before and after tilting. In the frequency analysis, the powers of low-frequency (LF) and high-frequency (HF) components were calculated by a fast Fourier transformation.

RESULTS

Regarding interactions between groups and head-up tilting, the head-up tilting-induced reduction of the HF component of HRV was significantly greater in the AN group. In addition, increases in the LF/HF of HRV and the LF component of BPV after head-up tilting were significantly smaller in the AN group.

CONCLUSIONS

Regardless of the posture, changes in HF and LF/HF of HRV and LF of BPV in AN patients suggested the presence of autonomic insufficiency.

Insular dysfunction and descending pain inhibition in anorexia nervosa

OBJECTIVE

Reduced perception of pain is a well-established phenomenon in patients with anorexia nervosa (AN). We tested the hypothesis that altered processing of pain within the insula might account for reduced perception of pain.

METHOD

Heat pain thresholds were obtained in nineteen patients with AN and matched controls. Thereafter, a thermode was used to deliver thermal painful stimuli to the right arm during functional magnetic resonance imaging (fMRI) measurements. Stimuli were initiated for 10 s from a baseline resting temperature (32°C) to three different levels (37, 42, 45°C).

RESULTS

Significantly increased heat pain thresholds were observed in patients. A stronger activation during heat pain perception was found in the left posterior insula in controls. In contrast, higher levels of activity were shown in the ipsilateral pons in patients when compared to controls. In patients, we found a significant interrelation between the depression score (Beck depression inventory) and heat pain activations.

CONCLUSION

We suggest that reduced activity in the left posterior insula might contribute to increased pain thresholds in patients, while increased activations in the right anterior insula and pons mirror augmented sympathetic modulation putatively related to amplification of adrenergic descending pain inhibition. In addition, pain thresholds and brain activations were influenced by disease-inherent depressed mood.

[The processing of pain in psychiatric diseases]

The perception and processing of pain is disturbed in many psychiatric diseases. Some diseases are known to show decreased perception of pain (e.g. borderline personality disorder), while others are associated with augmented pain perception (e.g. alcohol and drug dependence). The close relationship between psychiatric diseases and pain is most probably caused by aberrant processing of pain in brain structures, known to be involved in psychiatric disorders as well. Aberrant perception and processing of pain in patients with anorexia nervosa (AN) will be used to demonstrate this close relationship. Dysfunction within the insula has been suggested to account for many features of AN and might contribute to reduced pain perception. Moreover, it might lead to increased adrenergic descending inhibition associated with increased sympathetic modulation. Thus, pain research might be able to alter our view on autonomic regulation, which is putatively associated with increased cardiac mortality of the disease.

Anorexia nervosa: a case report of a teenager presenting with bradycardia, general fatigue, and weakness

BACKGROUND

Anorexia nervosa is a disease with high prevalence in adolescents and carries the highest mortality of any psychiatric disorder.

CASE

We present a case of a 17-year-old female presenting to the emergency department with bradycardia that was subsequently diagnosed with anorexia nervosa. We also review the clinical features, diagnosis, complications, and emergency department management of this disease.

CONCLUSIONS

Patients with anorexia may present with multiple medical complaints, and it is imperative that the emergency physician be familiar with the syndrome so as to correctly identify and treat patients with this disease.

Heart rate variability in anorexia nervosa and the irritable bowel syndrome

BACKGROUND

Many studies have reported disturbances of heart rate variability (HRV) in patients with psychosomatic disorders such as anorexia nervosa (AN) and the irritable bowel syndrome (IBS). However, both have never been directly compared.

METHODS

We compared HRV in AN (n = 21) and in IBS (n = 21) (all females) with 42 healthy female control subjects who were matched for age and in IBS to body mass index (BMI). Recovery periods between different cardiac load tests were compared with baseline recordings and tilt test to estimate time [mean successive difference (MSD)] and frequency domain (Goldberger dimension, frequency of HF peak location and HF power, log HF power) values and to assess general reactivity of the autonomic nervous system (ANS).

KEY RESULTS

Significantly longer inter-beat intervals (IBIs) in AN patients and lower values of MSD in IBS patients were found in comparison with respective controls; both were independent from experimental conditions and are found in baseline recordings only. Both effects were independent of age and BMI. We also demonstrate a significant relationship between age, BMI and some HRV parameters.

CONCLUSIONS & INFERENCES

Opposite autonomic patterns were found in AN and IBS: stronger vagal withdrawal in IBS and weaker vagal inhibition in AN patients. Records made at rest and without any autonomic load may be representative for assessment of ANS function. Age and BMI should be taken into consideration during assessment of HRV data.

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.

Hedonic reactivity to visual and olfactory cues: rapid facial electromyographic reactions are altered in anorexia nervosa

Though it has been suggested that hedonic processing is altered in anorexia nervosa (AN), few studies have used objective measures to assess affective processes in this eating disorder. Accordingly, we investigated facial electromyographic, autonomic and subjective reactivity to the smell and sight of food and non-food stimuli, and assessed more particularly rapid facial reactions reflecting automatic processing of pleasantness. AN and healthy control (HC) women were exposed, before and after a standardized lunch, to pictures and odorants of foods differing in energy density, as well as to non-food sensory cues. Whereas the temporal profile of zygomatic activity in AN patients was typified by a fast drop to sensory cues within the 1000 ms following stimulus onset, HC showed a larger EMG reactivity to pictures in a 800-1000 ms time window. In contrast, pleasantness ratings discriminated the two groups only for high energy density food cues suggesting a partial dissociation between objective and subjective measures of hedonic processes in AN patients. The findings suggest that the automatic processing of pleasantness might be altered in AN, with the sensitivity to reward being modulated by controlled processes.

Increased QT variability in patients with anorexia nervosa--an indicator for increased cardiac mortality?

OBJECTIVE

Increased mortality in anorexia nervosa is associated with autonomic dysfunction and prolongation of the QT interval. In this study, we examined the relative importance of repolarization abnormalities and vagal modulation of heart rate. In particular, we hypothesized that patients with anorexia nervosa show increased QT interval variability, particularly since this measure has been shown to correlate with serious cardiac arrhythmias.

METHOD

We assessed linear and nonlinear heart rate variability (HRV) parameters as well as measures of QT variability in 20 female patients with anorexia nervosa and 20 controls. In patients, parameters were correlated with serum electrolytes.

RESULTS

QT variability was significantly increased in the patient group and correlated negatively with serum potassium concentrations. HRV measures showed a shift of autonomic balance towards vagal predominance.

DISCUSSION

The increase in QT variability might at least in part account for the higher risk of cardiac arrhythmias in patients with anorexia nervosa. Once validated in a prospective study design, parameters of QT variability might serve as surrogate markers for arrhythmia risk stratification in anorexia nervosa. Supplementation with potassium might normalize QT variability abnormalities.

Sympathetic nervous system overactivity and its role in the development of cardiovascular disease

This review examines how the sympathetic nervous system plays a major role in the regulation of cardiovascular function over multiple time scales. This is achieved through differential regulation of sympathetic outflow to a variety of organs. This differential control is a product of the topographical organization of the central nervous system and a myriad of afferent inputs. Together this organization produces sympathetic responses tailored to match stimuli. The long-term control of sympathetic nerve activity (SNA) is an area of considerable interest and involves a variety of mediators acting in a quite distinct fashion. These mediators include arterial baroreflexes, angiotensin II, blood volume and osmolarity, and a host of humoral factors. A key feature of many cardiovascular diseases is increased SNA. However, rather than there being a generalized increase in SNA, it is organ specific, in particular to the heart and kidneys. These increases in regional SNA are associated with increased mortality. Understanding the regulation of organ-specific SNA is likely to offer new targets for drug therapy. There is a need for the research community to develop better animal models and technologies that reflect the disease progression seen in humans. A particular focus is required on models in which SNA is chronically elevated.