Changes of the corrected Q-T interval in the electrocardiogram of patients with anorexia nervosa

Electrocardiographic QTc as a Surrogate Measure of Cardiac Risk in Children, Adolescents, and Young Adults With Eating Disorders

The study goal was to investigate electrocardiographic findings, including corrected QT interval (QTc), in patients aged 8 to 23 with eating disorders (EDs) at presentation, compared with an age-and sex-matched control population. We retrospectively reviewed 200 ED patients, and 200 controls. Blinded electrocardiograms (ECGs) were interpreted by an expert reader, and QT intervals corrected using the Bazett formula. Eating disorder patients were 89.5% female, with mean age 16.4 years and median percent median body mass index (BMI)-for-age (%mBMI)a of 91.1%. In ED patients, QTc was significantly shorter than controls (399.6 vs 415.0msec, P < .001). After adjusting for height, %mBMI, sex, magnesium level, and bradycardia, mean QTc duration in patients with anorexia nervosa-restricting subtype (AN-R) was significantly shorter than other ED patients (P = .010). Higher %mBMI was associated with shorter QTc duration (P = .041) after adjusting for height, magnesium, bradycardia, and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis. Within the ED group, no significant association was identified between QTc and medications, electrolytes, or inpatient status.

Long-term cardiac arrhythmia and chronotropic evaluation in patients with severe anorexia nervosa (LACE-AN): A pilot study

BACKGROUND

Anorexia nervosa (AN) is associated with autonomic dysfunction and carries a high risk of sudden death, putatively attributed to ventricular tachyarrhythmias. To date, long-term cardiac monitoring has not been performed to confirm this speculation.

METHODS AND RESULTS

We assessed the safety and acceptability of an insertable cardiac monitor (ICM) in patients with severe AN with markedly reduced body mass index (BMI), and investigated heart rate (HR) and rhythm before and after weight restoration. Autonomic function was assessed as HR response to a standardized activity protocol at baseline and four additional visits over 360 days. The Florida Patient Acceptance Survey (FPAS) was used to measure ICM acceptability. During a mean follow-up of 10 months, no ICM-related complications occurred and ICM was well-accepted by the 11 study participants (nine women, aged 19-59 years, baseline BMI = 12.7 ± 1.6 kg/m² ). Both resting and peak HR increased with weight restoration and were directly associated with BMI (both P < .001). No ventricular tachyarrhythmias occurred during the study period, but two participants (18%) experienced eight sinus pauses (3.0-7.0 seconds) and three runs of supraventricular tachycardia.

CONCLUSIONS

Long-term cardiac rhythm monitoring with an ICM is feasible, safe, and acceptable in patients with severe AN. Autonomic dysfunction in AN results in not only profound resting bradycardia, but also some degree of chronotropic incompetence, both of which improve with weight restoration. Clinically significant bradyarrhythmias are more common than ventricular tachyarrhythmias in AN, and may represent a competing underlying mechanism for the high risk of sudden death in this population.

Cardiac evaluation in children with malnutrition

AIM

The main purpose of this study was to identify myocardial changes in malnourished children.

MATERIAL AND METHODS

This prospective study included 47 patients with malnutrition and 44 healthy controls. The subjects who had malnutrition were classified according to the method of Gomez and Waterlow. Electrocardiographic and echocardiographic examinations, 24-h Holter monitoring, and biochemical assessments were performed in all subjects.

RESULTS

The malnutrition group included 20 (42.5%) males, and the control group included 19 (43.1%) males (p<0.05). There was no difference between the malnutrition and control groups with regard to mean age (69.4±57.3 months and 68.9±48.2 months, respectively, p=0.5). Although the left ventricular mass was lower in the patient group compared with the control group, the left ventricular mass index was not different (42.3±24.5 g, 53.4±23.9 g, p=0.049 and 60.7±13.3 g/m2, 61.9±12.1 g/m2, p=0.67, respectively). The left ventricular ejection fraction and fractional shortening were lower in the patient group compared with the control group (66.2±5.3%, 69.2±4.07%, p=0.04 and 35.4±4.2%, 37.9±3.4%, p=0.03, respectively). The myocardial performance index was higher in the patient group (0.45±0.09, 0.36±0.05, respectively, p=0.001). The deterioration of cardiac functions was associated with the severity and duration of malnutrition. Troponin concentrations were not elevated in any patients. The corrected QT dispersion was significantly higher in patients with malnutrition (47.9±16.8, 32.9±10.6, respectively, p=0.001). Complex ventricular arrhythmias were not noted in any patients.

CONCLUSION

The malnourished children in this study exhibited impairment in the functions of cardiac contraction including mainly systolic functions and in cardiac conduction system. Cardiac morbidity and mortality can be prevented by early detection and treatment of malnutrition in these patients.

QTc Interval and Risk of Cardiac Events in Adults With Anorexia Nervosa: A Long-Term Follow-Up Study

BACKGROUND

The literature contains several cases of anorexia nervosa (AN) patients with prolonged QTc interval. However, the risk of prolonged QTc interval is controversial and the risk of cardiac events in AN patients has yet to be investigated.

METHODS

We estimated the difference in mean QTc interval and relative risk of borderline prolonged QTc (>440 ms) and prolonged QTc (>460 ms) between 430 adult women AN patients and 123 healthy controls using 3 correction formulas. In a follow-up study, we estimated the risk of a primary end point (a composite of ventricular tachycardia, aborted cardiac arrest, and cardiac arrest) in AN patients compared with a population-based cohort derived from the Danish Civil Register.

RESULTS

Mean QTc for AN patients was 408 ms (Hodges), 402 ms (Fridericia), and 399 ms (Bazett). Hodges' found a slightly increased mean QTc (6.8 ms, 95% confidence interval, 1.6-12.0; P=0.01) and percentage with QTc >440 ms in AN patients (relative risk, 3.7, 95% confidence interval, 1.4-10.3; P=0.01), not observed with Fridericia's and Bazett's formulas. There was no difference in the risk of QTc >460 ms between AN patients and healthy controls. During a median follow-up of 10.1 years, AN patients had an increased risk of the primary end point compared with the population-based cohort (hazard ratio, 10.4, 95% confidence interval, 2.6-41.6; P=0.001). However, absolute numbers were small with cumulative incidences of 0.5% and 0.07%, respectively, after 10 years. No events occurred in any AN patient with QTc >440 ms. All-cause mortality was also significantly increased in AN patients compared with the population-based cohort (hazard ratio, 11.2, 95% confidence interval, 5.1-24.5; P<0.001).

CONCLUSIONS

Overall, there was no difference in mean QTc interval or risk of prolonged QTc between AN patients and healthy controls. However, AN patients had a notably increased all-cause mortality, as well as an increased risk of cardiac events, which was not related to the baseline QTc interval.

Risk for prolonged QT interval and associated outcomes in children with early restrictive eating patterns

Aim This study aimed to describe the frequency of QTc prolongation in children with restrictive eating disorders early in the course of disease admitted for inpatient therapy, to determine the frequency of associated ventricular arrhythmia, and to evaluate the relationship between QTc interval and concomitant electrolyte abnormalities and rate of weight loss.

METHODS

This was a retrospective cohort study of patients aged 11-25 years with early restrictive eating disorders.

RESULTS

In all, 82 patients met the inclusion criteria (84% female). In total, 9.8% had prolonged QTc interval during hospitalisation. Patients with prolonged QTc had significantly higher resting heart rates (p=0.006), but there was no association with hypokalaemia (p=0.31), hypomagnesaemia (p=0.43), hypophosphataemia (p=1), or rate of weight loss (p=1).

CONCLUSION

Mild QTc prolongation in patients with restrictive eating disorders is not related to electrolyte abnormalities or rate of weight loss in this population, suggesting that investigation about other potential risk factors of prolonged QTc interval may be warranted.

Cardiovascular complications of anorexia nervosa: A systematic review

OBJECTIVE

Anorexia nervosa portends the highest mortality among psychiatric diseases, despite primarily being a disease of adolescents and younger adults. Although some of this mortality risk is attributable to suicide, many deaths are likely cardiovascular in etiology. Recent studies suggest that adverse myocardial structural changes occur in this condition, which could underlie the increased mortality. Given limited prevalence of severe anorexia there is a paucity of clinical and autopsy data to discern an exact cause of death.

METHODS

Given this background we conducted a systematic review of the medical literature to provide a contemporary summary of the pathobiologic sequelae of severe anorexia nervosa on the cardiovascular system. We sought to elucidate the impact of anorexia nervosa in four cardiovascular domains: structural, repolarization/conduction, hemodynamic, and peripheral vascular.

RESULTS

A number of cardiac abnormalities associated with anorexia nervosa have been described in the literature, including pericardial and valvular pathology, changes in left ventricular mass and function, conduction abnormalities, bradycardia, hypotension, and dysregulation in peripheral vascular contractility. Despite the prevalent theory that malignant arrhythmias are implicated as a cause of sudden death in this disorder, data to support this causal relationship are lacking.

DISCUSSION

It is reasonable to obtain routine electrocardiography and measurements of orthostatic vital signs in patients presenting with anorexia nervosa. Echocardiography is generally not indicated unless prompted by clinical signs of disease. Admission to an inpatient unit with telemetry monitoring is recommended for patients with severe sinus bradycardia or junction rhythm, marked prolongation of the corrected QT interval, or syncope.

Characterization of Myocardial Repolarization Reserve in Adolescent Females With Anorexia Nervosa

BACKGROUND

Patients with anorexia nervosa exhibit abnormal myocardial repolarization and are susceptible to sudden cardiac death. Exercise testing is useful in unmasking QT prolongation in disorders associated with abnormal repolarization. We characterized QT adaptation during exercise in anorexia.

METHODS AND RESULTS

Sixty-one adolescent female patients with anorexia nervosa and 45 age- and sex-matched healthy volunteers performed symptom-limited cycle ergometry during 12-lead ECG monitoring. Changes in the QT interval during exercise were measured, and QT/RR-interval slopes were determined by using mixed-effects regression modeling. Patients had significantly lower body mass index than controls; however, resting heart rates and QT/QTc intervals were similar at baseline. Patients had shorter exercise times (13.7±4.5 versus 20.6±4.5 minutes; P<0.001) and lower peak heart rates (159±20 versus 184±9 beats/min; P<0.001). The mean QTc intervals were longer at peak exercise in patients (442±29 versus 422±19 ms; P<0.001). During submaximal exertion at comparable heart rates (114±6 versus 115±11 beats/min; P=0.54), the QTc interval had prolonged significantly more in patients than controls (37±28 versus 24±25 ms; P<0.016). The RR/QT slope, best described by a curvilinear relationship, was more gradual in patients than in controls (13.4; 95% confidence interval, 12.8-13.9 versus 15.8; 95% confidence interval, 15.3-16.4 ms QT change per 10% change in RR interval; P<0.001) and steepest in patients within the highest body mass index tertile versus the lowest (13.9; 95% confidence interval, 12.9-14.9 versus 12.3; 95% confidence interval, 11.3-13.3; P=0.026).

CONCLUSIONS

Despite the absence of manifest QT prolongation, adolescent anorexic females have impaired repolarization reserve in comparison with healthy controls. Further study may identify impaired QT dynamics as a risk factor for arrhythmias in anorexia nervosa.

Delirium and refeeding syndrome in anorexia nervosa

OBJECTIVE

To review the literature on delirium and refeeding syndrome in patients with anorexia nervosa (AN) and present case examples in an attempt to identify common clinical features and response to therapy.

METHOD

A comprehensive literature review was completed. In addition to the cases identified in the literature, we present two additional cases of our own.

RESULTS

We identified a total of 10 cases (all female; mean age 19 years old, range 12-29 years); 2/3 of the cases had similar clinical features predating the delirium and during refeeding.

DISCUSSION

Delirium, albeit rare, can be associated with the refeeding syndrome in low weight patients with AN. During the initial refeeding phase, close monitoring of medical, metabolic, and psychological parameters are important in establishing factors that may elevate risk. Early detection and treatment of delirium using nonpharmacologic and pharmacologic means are also important to help minimize the effects of this potentially deadly condition.

Factors influencing QT prolongation in patients hospitalized with severe anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) carries the highest mortality of any psychiatric disorder largely attributable to sudden cardiac death and suicide. Controversy exists regarding the underlying mechanism of cardiac risk, whether QT prolongation is a consistent feature of the disorder and whether repolarization varies by disease severity. Some of the uncertainty may relate to a lack of standardized electrocardiography (ECG). To date, studies have not utilized centrally adjudicated digital ECG, and most have relied on the Bazett formula for rate-correction, which is suboptimal at the extremes of heart rate often observed in AN.

METHODS

We evaluated a hospitalized cohort of medically compromised, very-low-body mass index (BMI) AN patients. The QT interval was measured with high-precision calipers by a single, blinded electrophysiologist and rate corrected (QTc) using the Fridericia formula. Anatomically corrected left ventricular (LV) mass and resting energy expenditure (REE) were calculated as proxies for disease severity. Proportions exceeding categorical thresholds for QTc prolongation and correlations between admission QTc and disease severity were performed.

RESULTS

Among 19 patients, mean BMI was 12.3 kg/m(2), and 95% were female. The majority (68%) of patients were receiving QT-prolonging drugs. Four patients (21%) had QTc prolongation. Two of these patients (10.5%) exceeded the 500 ms threshold for marked QTc-prolongation, though each had concomitant factors contributing to delayed repolarization. The QTc interval was not significantly correlated with LV mass, LV mass index, BMI or REE.

CONCLUSIONS

Although delayed cardiac repolarization was observed among a medically compromised cohort of patients with anorexia nervosa, the QTc interval was not a reliable correlate of disease severity despite digital ECG adjudication and optimal rate correction.

Heart failure in anorexia nervosa: case report and review of the literature

OBJECTIVE

To report the presentation and causes of heart failure complicating anorexia nervosa (AN).

METHOD

Report of a case of heart failure occurring in a patient with AN and a review of the literature.

RESULTS

A 56 year old woman with a 25 year history of AN binge-purge subtype experienced increasing shortness of breath on exertion, orthopnea, and swelling of the ankles. Investigations revealed a reduced left ventricular ejection fraction. A diagnosis of heart failure caused by severe prolonged protein-calorie malnutrition was made. She was treated with a diuretic, a beta adrenergic blocker and an angiotension enzyme inhibitor. Her cardiac function returned to normal after a year of refeeding. Protein-calorie malnutrition, ipecac toxicity, and deficiencies of thiamine, phosphorus, magnesium, and selenium have been reported to cause heart failure in patients with AN.

DISCUSSION

If shortness of breath occurs in AN it may be a symptom of heart failure. The diagnosis is further suggested by increased jugular venous pressure, increasing shortness of breath on exertion, and pulmonary crepitations at the bases of the lungs on physical examination. The chest x-ray usually shows pulmonary venous redistribution, the electrocardiogram may be normal, and the echocardiogram should document a reduced left ventricular ejection fraction. Standard medical therapy for heart failure should be started. In addition, a history of ipecac use should be taken, deficiencies should be corrected, and weight restoration can reverse cardiac abnormalities.

QT dispersion in acute rheumatic fever

BACKGROUND

Disturbances of conduction are well known in the setting of acute rheumatic fever. The aim of this study is to investigate the QT dispersion as seen in the surface electrocardiogram of children with acute rheumatic fever.

METHODS

QT dispersion was quantitatively evaluated in 88 children with acute rheumatic fever. Patients were divided into two groups based on the absence or presence of carditis. As a control group, we studied 36 healthy children free of any disease, and matched for age with both groups. Repeat echocardiographic examinations were routinely scheduled in all patients at 3 months after the initial attack to study the evolution of valvar lesions.

RESULTS

The mean QT dispersion was significantly higher in children with rheumatic carditis. But there was no statistical difference between children without carditis and normal children. Among the children with carditis, the mean dispersion was higher in those with significant valvar regurgitation. Dispersion of greater than 55 milliseconds had a sensitivity of 85%, and specificity of 70%, in predicting rheumatic carditis, while a value of 65 milliseconds or greater had sensitivity of 81% specificity of 85% in predicting severe valvar lesions in acute rheumatic carditis. At follow-up examination, a clear reduction on the QT dispersion was the main finding, reflecting an electrophysiological improvement.

CONCLUSIONS

These observations suggest that QT dispersion is increased in association with cardiac involvement in children with acute rheumatic fever.

Acquired QT prolongation associated with esophagitis and acute weight loss: how to evaluate a prolonged QT interval

When the physician is confronted with a patient having significant QT prolongation, it is critical to determine whether the patient harbors a genetic defect and a transmissible form of long QT syndrome (LQTS) or whether the QT prolongation has an acquired cause. The distinction has profound ramifications for the type of care provided to the patient and family. We report the case of a previously healthy 14-year-old boy who presented with a 10-day history of painful swallowing, a 10-lb weight loss, and chest pain. A 12-lead electrocardiogram (ECG) showed marked QT prolongation. Endoscopy and culture identified a Herpes simplex esophageal ulcer. After treatment with acyclovir, the patient recovered completely. Three weeks after the resolution of his symptoms and recovery from his acute weight loss, a follow-up ECG showed complete normalization of the QT interval. This case illustrates yet another potential mechanism for acquired QT prolongation. We also provide a diagnostic algorithm for the careful evaluation of a prolonged QT interval.

QT interval dispersion and resting metabolic rate in chronic anorexia nervosa

OBJECTIVE

During the starvation phase of anorexia nervosa (AN), cardiac and skeletal muscle mass decreases, whereas electrocardiographic QT dispersion, a marker of arrhythmia risk, increases. QT dispersion during the chronic phase of AN and its relationship to resting metabolic rate (RMR) have not been described previously and is the subject of the current investigation.

METHOD

Six AN patients were compared with 10 age-matched control subjects. Serum electrolyte levels, electrocardiography, anthropomorphic data, and indirect calorimetry were obtained for all participants.

RESULTS

Corrected QT interval (QTc) did not differ between groups, but QT dispersion was significantly greater in AN patients. QT dispersion correlated negatively with resting oxygen consumption and RMR. The relationship between QT dispersion and RMR did not persist after correcting for lean body mass.

CONCLUSIONS

AN patients with a low RMR may be at risk for increased QT dispersion. QT dispersion is a widely available and inexpensive measure, which may reflect both metabolic status and arrhythmia potential.

Circadian variation of QTc dispersion in children with vasovagal syncope

AIMS

To assess the validity of QTc dispersion to cardiac autonomic nervous function status.

METHOD AND RESULTS

Prospective comparisons of QTc dispersion measurements in 77 neurally mediated cardiac syncope (NMCS) patients (29 boys, 48 girls, mean age 13.4+/-0.78) were evaluated. Head-up tilt test (HUT) was positive in 38 patients and negative in 39 patients. QTc dispersion was significantly higher early morning and late night in HUT-positive group compared with HUT-negative group (p<0.001). Although there was a circadian rhythm in HUT-positive group, there was no change on the QTc dispersion within a day in the HUT-negative group. QTc dispersion in the HUT-positive group was high in accordance with their high sympathetic nervous stimulation. Moreover, QTc dispersion was higher during late night and early morning than the rest of the day.

CONCLUSION

These results may explain why the HUT-positive patients usually have their syncope attacks early in the morning. Additionally, we can use QTc dispersion measurement as a new noninvasive electrocardiographic test to evaluate cardiac sympathetic nervous system in NMCS.

Prolonged cardiac repolarisation during spontaneous nocturnal hypoglycaemia in children and adolescents with type 1 diabetes

AIMS/HYPOTHESIS

It has been postulated that hypoglycaemia-related cardiac dysrhythmia and, in particular, prolonged cardiac repolarisation, may contribute to increased mortality rates in children and adolescents with type 1 diabetes.

METHODS

We examined the prevalence of prolonged QT interval on ECG during spontaneous hypoglycaemia in 44 type 1 diabetic subjects (aged 7-18 years), and explored the relationships between serial overnight measurements of QT interval corrected for heart rate (QTc) and serum glucose, potassium and epinephrine levels. Each subject underwent two overnight profiles; blood was sampled every 15 min for glucose measurements and hourly for potassium and epinephrine. Serial ECGs recorded half-hourly between 23.00 and 07.00 hours were available on 74 nights: 29 with spontaneous hypoglycaemia (defined as blood glucose <3.5 mmol/l) and 45 without hypoglycaemia.

RESULTS

Mean overnight QTc was longer in females than in males (412 vs 400 ms, p=0.02), but was not related to age, diabetes duration or HbA(1)c. Prolonged QTc (>440 ms) occurred on 20 out of 74 (27%) nights, with no significant differences between male and female subjects, and was more prevalent on nights with hypoglycaemia (13/29, 44%) than on nights without (7/45, 15%, p=0.0008). Potassium levels were lower on nights when hypoglycaemia occurred (minimum potassium 3.4 vs 3.7 mmol/l, p=0.0003) and were inversely correlated with maximum QTc (r=-0.40, p=0.03). In contrast, epinephrine levels were not higher on nights with hypoglycaemia and were not related to QTc.

CONCLUSIONS/INTERPRETATION

In young type 1 diabetic subjects, prolonged QTc occurred frequently with spontaneous overnight hypoglycaemia and may be related to insulin-induced hypokalaemia.

QT interval and QT dispersion in eating disorders

BACKGROUND

Eating disorders are thought to be risk factors for cardiac sudden death secondary to arrhythmia. Results in previous studies on QT interval and QT dispersion, markers of fatal arrhythmia, have been inconsistent.

METHODS

We prospectively examined 179 female eating disorder patients, being over 18 years old and diagnosed according to the DSM-IV criteria between January 1995 and December 2002, and 52 healthy women. Patients with abnormal plasma electrolytes or taking medications that might influence the electrocardiogram (ECG) were excluded from the study. QT intervals were corrected for heart rate using Bazett's formula and the nomogram method, which is more reliable at extremely low heart rates than Bazett's formula. QT dispersion was measured as the difference between the longest and shortest QT intervals. QT intervals and QT dispersion in each patient group were compared with those in the control group.

RESULTS

The 164 eligible patients consisted of 43 patients with anorexia nervosa restricting type, 35 with anorexia nervosa binge eating/purging type, 63 with bulimia nervosa purging type, and 23 with bulimia nervosa non-purging type. There was no significant difference in age between eating disorder patients and controls. QT interval and QT dispersion were significantly longer in all eating disorder subtypes than in the control group. QT interval and QT dispersion were significantly correlated with the rate of body weight loss in bulimia nervosa.

CONCLUSIONS

QT interval and QT dispersion were prolonged in both anorexia nervosa and bulimia nervosa. Examination of ECG in eating disorder patients without extremely low body weight also appears to be clinically important.

Alteration of the QT Rate Dependence in Anorexia Nervosa

Myocardial repolarization has been evaluated in patients with anorexia nervosa (AN) with conflicting results. The authors postulated that dynamic alterations in QT interval adaptation could characterize these patients. This study compared QT dynamicity along RR intervals from 24-hour ECG data of patients with and without AN. Twenty-five patients (23 women) fulfilling the Diagnostic and Statistical Manual (DSM IV) criteria for AN were included in the study. All underwent 24-hour ECG Holter recordings, allowing QT and RR measurements, and heart rate variability (HRV) analysis in free-living conditions. A group of 25 sex- and age-matched healthy subjects served as controls. Compared with controls, AN patients presented with relative bradycardia, more particularly during night periods but neither mean QT nor corrected mean QT length (calculated using Bazett formula) over the 24 hours of monitoring differed. However, QT/RR slope was found significantly enhanced compared with normals (-2.00 +/- 0.53 vs - 1.42 +/- 0.40) (P = 0.006): QT length related to heart rate was found longer for a heart rate <55 beats/min in AN. Mean 24-hours QT length appears unaltered in AN in the absence of electrolytic disorders. However, the QT/RR relationship was enhanced reflecting the specific autonomic imbalance encountered in this population. The clinical implications of such findings need to be discussed since an equivalent enhancement of QT/RR slope has been described after myocardial infarction in patients presenting life-threatening ventricular arrhythmias.

Reversibility of cardiac abnormalities in adolescents with anorexia nervosa after weight recovery

OBJECTIVE

Anorexia nervosa is a life-threatening condition, with significant risk for death due to cardiac complications. The objective of this study was to analyze the cardiac involvement in anorexia nervosa and to study the reversibility of cardiac abnormalities.

METHOD

Thirty-one consecutive adolescents (aged 12 to 17 years) with a diagnosis of anorexia nervosa were evaluated from January 1998 to January 1999 at the Hospital Clínic (University of Barcelona, Catalonia, Spain). An electrocardiogram, an echocardiogram, a 24-hour Holter recording with heart rate variability, an exercise test, and a tilt test were performed at initial examination and after refeeding (3 to 18 months later).

RESULTS

The basal body mass index was 15.2 +/- 2 kg/m2. Sinus bradycardia was found in 35% of patients, 93% showed a decreased left ventricular mass, and 70% had a diminished thickness of cardiac walls. The Holter recordings showed nocturnal bradycardia in 60% with an increased heart rate variability. After refeeding, a significant decrease in QT interval (p <.05) and QT dispersion (p <.01) was observed. Echocardiograms showed an increase in cardiac diameters (p <.01), left ventricular mass (p <.001), and cardiac output (p <.001). There was also an improvement in the exercise capacity (p <.05) and a normalization of the heart rate and heart rate variability (p <.05).

CONCLUSION

Cardiac structural and functional abnormalities provoked by anorexia nervosa are reversible in young adolescents after refeeding.

Anorexia nervosa medical issues

Anorexia nervosa is an increasingly common chronic psychiatric disorder with a multitude of medical complications. Most of these complications are reversible if there is timely restoration of body weight. A few of them, particularly osteoporosis, refeeding complications, and cardiac arrhythmia, are potentially much more serious. In the end, a multidisciplinary team approach with input from a primary care provider who is familiar with these medical sequelae, together with psychiatric and dietary expertise, can effectuate a successful outcome.

The 12-lead electrocardiogram in anorexia nervosa: A report of 2 cases followed by a retrospective study

Anorexia nervosa (AN) has been associated with various cardiac disorders and several electrocardiographic abnormalities, the most prominent being sudden death and prolonged QT duration and dispersion. We report 2 cases of AN with marked repolarization abnormalities, the first clearly related to electrolyte imbalance, the second without a good explanation from metabolic, electrolytic or pharmacological sources. A retrospective analysis of 47 other consecutive patients with AN showed that sinus bradycardia was the most common ECG finding, but that QT or QTc interval prolongation was not a typical feature, being present in only 1 patient. The sole variable slightly correlated with QTc duration was the serum potassium concentration. Consequently, marked repolarization changes (QT interval and/or T wave morphology) in AN should not be taken as a feature of the disease, but should call for the search of potential causes such as metabolic and electrolytic disturbances, drug effects, or a possible genetic component.

Prolonged QT interval in acute psychotic patients

Some recent clinical studies indicate that hypokalemia is characteristic for acute psychotic patients at the time of emergency admission. As hypokalemia is one of the major causes for prolonged QT interval, it was hypothesized that acute psychotic patients could show prolonged QT interval. Sixty-seven drug-free, acute psychotic patients were evaluated for corrected QT (QTc) interval, as well as demographic and clinical characteristics at the time of emergency admission. The mean QTc interval of psychiatric emergency patients was prolonged, and the mean QTc interval of psychiatric emergency patients was longer than that of psychiatric outpatients (t=5.20, P<0.0001). Age- or gender-related difference, circadian fluctuation of QT interval, medication, concomitant disease, obesity, and serum electrolytes except potassium were not major causes. There was a significant negative correlation as evidenced by a coefficient of correlation of -0.28 (P<0.05). As psychiatric emergency patients often receive parenteral antipsychotics, which may have adverse effects on prolonged QT interval, paying attention to QT interval might have some clinical significance on emergency admission.

Electrocardiographic findings in adolescents with eating disorders

OBJECTIVES

We sought to determine the prevalence and clinical correlates of electrocardiographic findings in adolescents with eating disorders.

STUDY DESIGN

We undertook matched case-control study of electrocardiographic findings at initial assessment in 62 adolescents with anorexia nervosa, 9 with bulimia nervosa, and 26 with eating disorder not otherwise specified presenting from March 1995 to September 1996.

RESULTS

Mean (+/- 1 standard deviation) age was 15.0 +/- 1.4 years (95% were female). Patients with anorexia nervosa had significantly lower heart rates (mean case-control difference: -20 +/- 17 beats per minute), lower R in V(6) (-2.6 +/- 5.5 mm), longer QRS interval (+.004 +/-.010 seconds), shorter mean QTc (-.0136 +/-.033 seconds) and lesser QTc dispersion (-.010 +/-. 031 seconds). The bulimia nervosa group had slightly longer mean QTc (.019 +/-.020 seconds), with no significant case-control differences in the eating disorder not otherwise specified group.

CONCLUSION

Electrocardiographic findings are abnormal in adolescents with anorexia nervosa but not in adolescents with bulimia nervosa or eating disorder not otherwise specified.

Dispersion of QT and QTc interval in healthy children, and effects of sinus arrhythmia on QT dispersion

OBJECTIVE

To determine the normal values of QT and QTc dispersion and the effects of sinus arrhythmia on QT dispersion in healthy children.

PATIENTS AND SETTING

The study was carried out in a university hospital on 372 local schoolchildren (200 male, 172 female), aged seven to 18 years.

METHODS

The QT and preceding RR intervals of at least one sinus beat were measured manually in a range of nine to 12 leads on standard 12 lead surface ECGs. The corrected QT interval was computed by the method of Bazett. Dispersion of QT and QTc were defined as (1) the difference between the maximum and minimum QT and QTc intervals occurring in any of the 12 leads (QTD and QTcD), (2) the standard deviation of the QT and QTc interval in the measurable leads (QT-SD and QTc-SD).

RESULTS

There was no significant difference in QT, QTc, and RR dispersion between girls and boys. Overall 53% of children had sinus arrhythmia. Although QTD and QT-SD were not affected by sinus arrhythmia, both QTcD and QTc-SD were significantly greater in children with sinus arrhythmia than in those without (QTcD: 52.9 (17.4) v 40.9 (13.1); QTc-SD: 17.5 (5.9) v 13.2 (4.0); p < 0.001).

CONCLUSIONS

As calculation of QTc dispersion is affected by sinus arrhythmia, which is common in childhood, we suggest that QT dispersion should not be corrected for heart rate in children.

Cardiac arrest and delirium: presentations of the refeeding syndrome in severely malnourished adolescents with anorexia nervosa

AIM

To describe the clinical presentation of the refeeding syndrome and highlight the dangers of performing nutritional rehabilitation too rapidly in a severely malnourished patient.

DESIGN

Retrospective case review of adolescents admitted with anorexia nervosa who developed the refeeding syndrome.

RESULTS

Between July 1993 and July 1994, 3 of 48 adolescent females developed the refeeding syndrome. While the cardiac complications occurred in the first week of refeeding, the delirium characteristic of this syndrome occurred later and was more variably related to hypophosphatemia.

OBSERVATIONS

Refeeding malnourished patients with anorexia nervosa can be associated with hypophosphatemia, cardiac arrhythmia and delirium. Refeeding patients with anorexia nervosa who are < 70% of ideal body weight should proceed with caution, and the caloric prescription should be increased gradually. Supplemental phosphorus should be commenced early and serum levels maintained above 3.0 mg/dL. Cardiac and neurologic events associated with refeeding are most likely to occur within the first weeks, justifying close monitoring of electrolyte and cardiac status.