Alterations in QT dispersion in the surface electrocardiogram of female adolescent inpatients diagnosed with bulimia nervosa

T-wave morphology descriptors in patients with bulimia nervosa

PURPOSE

Bulimia nervosa (BN) is associated with increased risk of cardiovascular disease and arrhythmias. Some reports found abnormal electrocardiographic markers of arrhythmias in BN, while others did not. This study investigated novel parameters of T-wave morphology that were reported to be associated with adverse cardiovascular outcomes in other patient groups, among patients with BN under medical care.

METHOD

Thirty-five BN patients and 76 healthy controls were included. Total cosine R to T (TCRT) and T-wave Morphology Dispersion (TMD) parameters were computed according to accepted standards for an average beat and a random beat. Patients were followed for 11.1 ± 0.1 years for the emergence of arrhythmias or events of sudden death.

RESULTS

Twenty-five (71.4%) BN patients were hospitalized when enrolled, for a mean duration of 1.1 ± 0.2 months. The rest were ambulatory patients. The BN group had lower blood pressure, more smokers, and used antidepressants, neuroleptic drugs and benzodiazepines more than controls did. Other demographic parameters were comparable between groups. TCRT and TMD parameters were statistically similar and within the normal ranges reported by other research groups. None of the BN patients had prolonged QTc interval or electrolyte abnormalities on inclusion. During the follow-up period, no clinical symptoms suggestive of arrhythmias were reported, and no cardiovascular-related hospitalizations or deaths occurred in either group.

CONCLUSION

Medically treated BN patients have normal T-wave morphology parameters and hence, low risk for repolarization-associated malignant ventricular arrhythmias. The prognostic importance of these novel repolarization parameters remains to be explored among untreated patients, those who ingest emetic substances and patients with electrolyte imbalance.

LEVEL OF EVIDENCE

Level III.

Changes to the electrocardiogram during exercise in anorexia nervosa

BACKGROUND

Anorexia Nervosa (AN) is an eating disorder characterized by low body weight, distorted body image, and an intense fear of gaining weight. Electrocardiogram (ECG) changes, particularly in the QT interval, have been implicated in AN-associated sudden death but not well defined.

OBJECTIVES

To characterize QT interval changes during exercise in anorexia nervosa.

METHODS

The QT interval was evaluated in a prospective cohort undergoing structured exercise. Patients from the St. Paul's Hospital Provincial Adult Tertiary Eating Disorders Program underwent a 6-minute modified exercise test protocol. A single lead ECG patch recording device was used to record a Lead I equivalent, due to challenges applying standard ECG monitoring in subjects with low body mass. Heart rate (HR) and QT interval were assessed.

RESULTS

Eighteen eating disorder patients (16 female) completed testing (age 31 ± 12 years, BMI 16.5 ± 3.8 kg/m²). Patients were compared to age- and sex-matched healthy controls. HR was similar between patients and controls (baseline: 65 (55-70)bpm vs. 69 (53-73)bpm, p = 0.83; maximum: 110 (94-139) bpm vs. 108 (93-141) bpm, p = 0.96; end recovery: 62 (54-68) bpm vs. 66 (55-75) bpm, p = 0.39). QTc intervals were similar between groups at baseline (381 ± 17 ms vs. 381 ± 46 ms, p = 0.93) and end recovery (397 ± 42 ms vs 398 ± 42 ms, p = 0.91). However, AN patients demonstrated QTc prolongation while controls showed QTc shortening at maximum HR (426 ± 70 ms vs. 345 ± 59 ms, p = 0.001).

CONCLUSION

Low level exercise HR increases are similar between AN patients and controls, but the QTc interval fails to shorten, which may explain the increased arrhythmic risk in AN.

Medical Complications of Eating Disorders in Youth

Eating disorders affect a significant number of individuals across the life span and are found among all demographic groups (including all genders, socioeconomic statuses, and ethnicities). They can cause malnutrition, which can have significant effects on every organ system in the body. Cardiovascular complications are particularly dangerous and cause eating disorders to have the highest mortality rate of all mental illnesses. This article outlines the medical assessment and treatment of malnutrition due to disordered eating.

Medical Complications of Anorexia Nervosa and Bulimia Nervosa

Anorexia nervosa and bulimia nervosa are mental illnesses with associated complications affecting all body systems with arguably the highest mortality of all mental health disorders. A comprehensive medical evaluation is an essential first step in the treatment of anorexia nervosa and bulimia nervosa. Weight restoration and cessation of purging behaviors are often essential components in the management of medical complications of these illnesses.

The QTc interval and risk of cardiac events in bulimia nervosa: A long-term follow-up study

OBJECTIVE

An association between bulimia nervosa (BN) and prolonged corrected QT interval (QTc) in the electrocardiogram has been suggested, but results of previous studies are conflicting, and the risk of cardiac events in patients with BN has yet to be investigated.

METHOD

We estimated mean QTc interval and relative risk of borderline (QTc >440 ms) and prolonged QTc (QTc >460 ms) between adult women with BN (N = 531) and healthy controls (N = 123). In follow-up analyses, we investigated the risk of a primary endpoint (syncope, ventricular tachycardia, and cardiac arrest) and all-cause mortality in patients with BN (N = 702) compared with a population-based cohort derived from the Danish Civil Register (N = 7,020).

RESULTS

Mean QTc did not differ between patients with BN and controls. Relative risk of borderline prolonged QTc was 2.3 (p = 0.28). The number of patients and controls with prolonged QTc was small, and the risk did not differ between patients with BN and controls. Median follow-up was 10.6 years. Although there appeared to be increased risks after 5 years of follow-up, long-term risks of the primary endpoint (Hazard ratio [HR] = 1.4, p = 0.37) and all-cause mortality (HR = 1.7, p = .28), respectively, were not increased in patients with BN compared to a population-based cohort.

DISCUSSION

Mean QTc did not differ between patients with BN and healthy controls, and the risk of prolonged QTc was not increased in patients with BN. There was no difference in the long-term risk of cardiac events, and long-term all-cause mortality did not differ significantly between patients with BN and a population-based cohort.

Eating disorders in children and adolescents: state of the art review

Despite their high prevalence, associated morbidity and mortality, and available treatment options, eating disorders (EDs) continue to be underdiagnosed by pediatric professionals. Many adolescents go untreated, do not recover, or reach only partial recovery. Higher rates of EDs are seen now in younger children, boys, and minority groups; EDs are increasingly recognized in patients with previous histories of obesity. Medical complications are common in both full and subthreshold EDs and affect every organ system. No single cause of EDs has emerged, although neurobiological and genetic predispositions are emerging as important. Recent treatment paradigms acknowledge that they are not caused by families or chosen by patients. EDs present differently in pediatric populations, and providers should have a high index of suspicion using new Diagnostic and Statistical Manual, 5th edition diagnostic criteria because early intervention can affect prognosis. Outpatient family-based treatment focused on weight restoration, reducing blame, and empowering caregivers has emerged as particularly effective; cognitive behavioral therapy, individual therapy, and higher levels of care may also be appropriate. Pharmacotherapy is useful in specific contexts. Full weight restoration is critical, often involves high-calorie diets, and must allow for continued growth and development; weight maintenance is typically inappropriate in pediatric populations. Physical, nutritional, behavioral, and psychological health are all metrics of a full recovery, and pediatric EDs have a good prognosis with appropriate care. ED prevention efforts should work toward aligning with families and understanding the impact of antiobesity efforts. Primary care providers can be key players in treatment success.

Normal late ventricular potentials in hospitalized patients with eating disorders

OBJECTIVE

Eating disorders, in particular anorexia nervosa (AN), are associated with cardiovascular complications and risk of arrhythmias. In a recent published study, it was found that patients with eating disorders, especially those affected by bulimia nervosa (BN) and a history of AN have abnormal late ventricular potentials (LPs). LPs are electrocardiographic markers used in detecting abnormal depolarization and increased risk of arrhythmias. Given the paucity of knowledge regarding the affects of eating disorders on cardiac depolarization, our aim was to further explore LPs in patients with eating disorders.

METHOD

The study group included 30 hospitalized patients with eating disorders (14 with AN, 10 with BN with no history of AN, and 6 with BN and history of AN). Signal averaged electrocardiography was conducted on all patients using the Frank corrected orthogonal lead system.

RESULTS

No patient with either eating disorder tested positive for LPs.

DISCUSSION

Hospitalized patients with eating disorders, medically monitored and treated for several weeks, had normal serum electrolytes, started to normalize their weight, and did not appear to be prone to arrhythmias associated with abnormal depolarization. The prognostic significance of LPs in risk stratification of patients with eating disorders should be further evaluated by large cohort studies and longer follow-up studies.

Prolonged QT interval in bulimia nervosa

A 39-year-old woman with an unremarkable history presented to the emergency department with three episodes of collapse. Each episode was witnessed by her son who described a loss of consciousness followed by rapid and complete recovery. The patient appeared well and examination was unremarkable. Her ECG showed a marked QTc prolongation of 642 ms (normal <470 ms) and low serum potassium at 1.8 mmol/l (3.5-5.3 mmol/l). The patient was moved to the coronary care unit and started on potassium replacement. On the ward a thorough history was taken and the patient confessed to being very conscious about his body shape and weight and admitted to episodes of binge eating and self induced vomiting. Her history suggested bulimia nervosa which is known to cause electrolyte disturbances and cardiac arrhythmia. Over the following 2 days the patient's potassium increased and the QTc interval normalised; the patient was discharged with an outpatient referral for a psychiatric opinion.