Alterations in QT dispersion in the surface electrocardiogram of female adolescents diagnosed with restricting-type anorexia nervosa

T-wave morphology among medically treated patients with Anorexia Nervosa

Anorexia nervosa (AN) has the highest rate of mortality of any psychiatric disorder, and cardiovascular complications occur in up to 80% of patients with AN and account for up to 30% of mortality. A controversy exists as to whether patients with AN are prone to develop electrocardiographic abnormalities related to repolarization. We aim to study previously unexplored T wave morphology markers in medically-treated patients with AN. Fifty-eight patients with AN (32 with restricting type and 26 with binge-eating/purging type) and 82 healthy controls were included in the study. ECGs were conducted under strict conditions and total cosine R-to-T (TCRT) and T-wave morphology dispersion (TMD) were computed according to accepted standards for a random beat and for an averaged beat. Forty-six AN patients were hospitalized (79.3%) during the study for a mean duration of 1.5 ± 1.1 months. AN patients had comparable QTc, TCRT, mean TMD, TMDpre, TMDpost and TCRTc values to those of healthy adults. Flattened T wave occurred slightly more often among AN patients than in controls (1.57 ± 1.23 leads affected compared with 1.11 ± 0.80 leads, respectively, p = 0.017). QTc, TCRT and TMD parameters' values were unaffected by the clinical type of AN. In conclusion, weight-restored AN patients are characterized by T wave flattening, but normal other T wave morphology parameters, which seemingly reflects an overall low risk of repolarization-associated ventricular arrhythmias. Long-term follow-up studies should be conducted to evaluate the prognostic significance of these novel repolarization markers in untreated patients or early in the refeeding phase.

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.

QT interval and dispersion in drug-free anorexia nervosa adolescents: a case control study

Long QT values have been reported in patients with anorexia nervosa of the restricting type (ANr) potentially increasing the risk of fatal arrhythmia, especially if psychotropic drug treatment is required. Nevertheless, the previous studies on this topic are biased by drug exposure, long disease durations, and small sample sizes. This study is aimed at assessing QTc and QTcd values in ANr adolescents with recent onset and drug free, as compared to subjects affected by psychiatric disorders other than ANr. We evaluated QTc and its dispersion (QTcd) in a population of 77 drug-free ANr female adolescents and compared to an equal number of healthy controls (H-CTRL) and pathological controls (P-CTRL, mixed psychiatric disorders). The QT determination was performed on a standard simultaneous 12-lead ECG in blind by a single experienced investigator. QTc was calculated by the Bazett's formula and QTcd was determined as the difference between the maximum and minimum QTc intervals in different leads. Only for ANr patients, clinico-demographic data, hormones, and electrolytes were obtained. QTc was slightly reduced in ANr patients (27.7 ms, < 10%, p < 0.0003) vs. controls, while QTcd was increased in P-CTRL (30%, p < 0.0003). Heart rate was significantly lower in ANr patients vs. controls (25%; p < 0.003). Tyroid hormones and serum potassium showed weak although significant positive correlations with QTc in ANr patients. QTcd displayed a weak negative correlation with the BMI percentile (r = - 0.262, p = 0.03). We reject the hypothesis that QTc and QTcd are increased in drug-free ANr adolescents with a relatively short-disease duration. Further studies are needed to understand if the previously reported increase might be related to other associated chronic disorders, such as hormonal or electrolyte imbalance.

Association between depression severity and cardiac autonomic modulation

OBJECTIVE

Changes in autonomic modulation are found in depressive patients. QT dispersion is a convenient measure of cardiac autonomic modulation (CAM). As both QT dispersion and depression are related to changes in CAM, this study aimed to examine if there was an association between depression severity and QT dispersion.

METHODS

The selected sample (n=60) derived from 236 women who were recruited via a campaign for breast cancer prevention. The women selected to participate were all non-smokers and were not taking any drug that could interfere with the results. After applying inclusion and exclusion criteria, 60 women were selected. QT dispersion (QTd) and rate-corrected QTd (QTcD) were calculated in 37 physically and mentally healthy women and 23 nontreated depressive women. Univariate ANOVA(s) were used to test group differences. The 17-item Hamilton Depression Rating Scale (HDRS17) was scored to measure depression severity. The relationship between depression severity and cardiac autonomic modulation was analyzed by the best curve that fit the raw data of the HDRS17 scores and the QT dispersion variables.

RESULTS

The QTd and QTcD were significantly smaller in non-depressed in relation to the depressed women. The best curve that fit the raw data of depression severity (HDRS17) and the two measurements of cardiac autonomic modulation (QTd and QTcD) was a cubic equation for both QTd and QTcD. An increase in QTd and QTcD were observed until the HDRS17 score reached 20 points.

CONCLUSION

There is a significant positive relationship between depression severity and cardiac autonomic modulation in mild and moderate depression.

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.

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.

QT interval dispersion in the patients with central serous chorioretinopathy

AIM

To evaluate QT dispersion (QTD) in patients with central serous chorioretinopathy (CSC).

METHODS

This clinical, comperative, case-control study included 30 patients with CSC at acute phase (Group 1) and 30 age- and sex-matched healthy subjects (Group 2, the control group). From all subjects, a 12-lead surface electrocardiography was obtained. The heart rate (HR), QT maximum (QTmax), QT minimum (QTmin), QT corrected (QTc), QTD and Tmean were manually measured and analyzed. Student's t-test and Pearson's method of correlation were used for statistical analysis.

RESULTS

The patient and control groups were matched for age, smoking status (rate and duration) and gender. There were no significant differences with regard to these among the groups (P>0.05). The participants included 19 men (63.3%) and 11 women (36.7%) in Group 1, 20 men (66.7%) and 10 women (33.3%) in Group 2. QTmax, QTD and QTc were significantly higher than those of healthy controls (P<0.001 for QTmax, P=0.01 for QTD and P=0.001 for QTc). QTmin, Tmean and HR did not differ significantly between the study groups (P=0.28 for QTmin, P=0.56 for Tmean and P>0.05 for HR). No significant correlation was found between duration of the disorder and QTD values (r=0.13, P>0.05).

CONCLUSION

These findings suggest that CSC may be associated with an increase in QTD and that the patients might be at risk for ventricular arrhythmia.

QT variability among weight-restored patients with anorexia nervosa

OBJECTIVE

Anorexia nervosa (AN) may be complicated by cardiac arrhythmias and sudden death. A single study reported an increased QT variability index (QTVI), a marker for cardiac arrhythmogenicity, in AN patients. The aim of the current study was to further evaluate repolarization dynamics in a large cohort of patients with AN without electrolyte abnormalities and to evaluate previously unreported repolarization dynamics parameters.

METHODS

Forty-three AN patients and 45 age- and sex-matched controls were included in the study. Twenty-nine AN patients were hospitalized for a mean time of 1.5±1.1 months. The rest were ambulatory AN patients. Electrocardiograms were conducted under strict standards. QT variability index, normalized QT variability (QTVN) and power spectral analysis of QT dynamics were conducted with designated computer software.

RESULTS

None of the patients had an electrolyte imbalance. Although mean QT was higher in AN patients compared with controls, QTc results were similar following corrections for RR interval. There was no significant difference in QTVI, QTVN and power spectral analysis parameters among groups. The results of QTVI and QTVN were comparable to those previously published for healthy individuals. During 3 years of follow-up, no patient developed arrhythmias or suddenly died.

CONCLUSIONS

Medically treated AN patients who gained weight and had normal serum electrolytes appeared to have normal QTc and QT variability indexes, reflecting a nonincreased risk for cardiac arrhythmias. We suggest that weight normalization, medical treatment and lack of electrolyte abnormalities are responsible in part for these results. Further evaluation of the prognostic significance of QTVI and QTVN in AN is warranted.

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

Increased QT dispersion (QTd) reflects cardiac autonomic imbalance and indicates elevated risk for cardiac arrhythmias. In the present study, we assessed heart rate, QT and corrected QT intervals, and QTd in 20 acutely ill bulimia nervosa adolescent inpatients on admission and discharge. A significant decrease in QTd was found between admission and discharge (67 +/- 13 milliseconds vs 55 +/- 12 milliseconds, respectively; P = .0005). The decrease in QTd values correlated significantly with the decrease in the frequency of bingeing/purging behaviors (r = 0.51, P = .022). No significant correlations were found between the electrocardiographic indices and other clinical and laboratory measures. The elevated QTd in malnourished bulimia nervosa patients might indicate a cardiac autonomic imbalance that is most likely corrected after symptomatic improvement.