تغییرات در پراکندگی QT در نوار قلب سطحی بیمار بستری دختران نوجوان با بولیمیای تشخیص داده شده

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. Gadget timed out while loading

Anorexia nervosa (AN) is a psychiatric disorder associated with particularly high mortality and morbidity rates [1]. These are mostly attributed to cardiac complications, primarily ventricular arrhythmias that are related to various conduction abnormalities, including prolonged QT interval and elevated QT dispersion (QTd) [1], [2] and [3]. QT dispersion, defined as the maximal interlead difference in QT intervals, has been found to serve as a measure of myocardial repolarization inhomogeneity [4]. QT dispersion has been found to be positively correlated with heart rate variability, suggesting that increased QTd may indicate the likelihood of increased sympathetic tone and/or decreased vagal tone [5] and [6]. Accordingly, elevated QTd values (in the range of 60-80 milliseconds in comparison with values between 20 and 50 milliseconds in healthy subjects) may represent a predisposing factor for arrhythmic events and sudden death [7], [8] and [9]. Several studies have found that the QT interval and QTd are greater in AN female patients compared with non–eating disorder (ED) controls, with the QTd in these patients being inversely correlated with the left ventricular mass [10] and [11]. Furthermore, a significant decrease in QTd may occur after weight restoration [12] and [13]. Previous research has also found that higher QTd values may be found in normal-weight physically healthy patients diagnosed with psychiatric disorders such as major depression and social anxiety disorder in comparison with healthy controls [14] and [15]. This suggests that reduced vagal modulation, potentially lowering the threshold of lethal arrhythmias, may occur also in normal-weight psychiatric patients. The findings in emaciated malnourished AN patients and in normal-weight patients with psychiatric disorders that are often comorbid with EDs led us to examine whether these electrocardiographic (ECG) changes would be found also in bulimia nervosa (BN). Reviewing the literature, we found that only one group analyzed QTd in BN patients [11] and [16]. In their earlier study, Takimoto et al showed increased QT interval and QTd in both AN and BN patients compared with healthy controls [11]. Later on, this group found that BN patients with elevated depression or anxiety had significantly longer QT intervals and increased QTd compared with patients with lower mood disturbance [16]. These findings suggested that mood disturbances might increase the risk for arrhythmias in BN. From a different perspective, late potentials, a predictor of ventricular arrhythmias, measured from the signal-averaged electrocardiogram were reported to be more common in BN patients with a history of AN, suggesting the likelihood of increased risk for cardiac morbidity in these conditions [17]. The aim of the present study was to assess the QT interval, its rate-corrected value (QTc), and QTd in female adolescent BN inpatients in the acute condition of their illness on admission and upon achieving symptomatic stabilization at discharge. We hypothesized that these indices would be elevated in acutely ill BN patients, but decrease to reference range after clinical improvement.