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Introduction: Reversal of non-depolarizing neuromuscular blocking agent neostigmine is associated with QT prolongation under general anesthesia. To clarify the effects of neostigmine and sugammadex on hemodynamic status, the QT interval and QT dispersion after reversal of neuromuscular blockade were evaluated with a 12-lead electrocardiogram. To exclude QT prolongation due to sevoflurane, the present study was performed under propofol anesthesia.Methods: After receiving approval from the ethics committee of Dokkyo Medical University Hospital, 40 patients with American Society of Anesthesiologists physical status I or II were randomly allocated to group N (n = 20) or group S (n = 20). Group N was administered neostigmine (40 μg/kg) and atropine (20 μg/kg), while Group S was administered sugammadex (4 mg/kg) for reversal of neuromuscular blockade after surgery. The changes in RR interval, QT interval (QT), corrected QT interval (QTc), QT dispersion (QTD), and corrected QT dispersion (QTcD) before and after administration of reversal agents were recorded using computerized measurements. Statistical analysis was performed using two-way analysis of variance.Results: The RR interval significantly decreased after reversal of the neuromuscular blockade in group N, compared with group S (p < 0.05). Compared with group S, the QT decreased, whereas QTc and QTcD increased, in group N (p < 0.05). Sugammadex was not found to alter QT, QTc, QTD, or QTcD throughout the study.Conclusion: In the present study, a mixture of neostigmine and atropine, but not sugammadex, increased QTc and QTcD under propofol anesthesia. Thus, neostigmine may cause electrocardiogram abnormalities that could precede the development of fatal arrhythmias. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the impact of exercise training on QT dispersion and risk factors for cardiovascular disease in patients after coronary artery bypass graft surgery (CABG). 143 patients after CABG, in a sinus rhythm, without atrioventricular or branch blocks, average age 57.5 years, were involved in the study. Patients were randomly divided into the exercise training group (TG: 107 patients) and non-training group (NTG: 36 patients). In addition to clinical examination and laboratory analysis, all the subjects had standard ECGs out of which, QTd was calculated and QT dispersion (QTdc) was corrected. The patients performed the exercise test according to Bruce’s protocol, after that the participants of the training group were involved in the exercise training. According to the results of the exercise test, the TG of patients was subjected to a certain degree of physical activity (gymnastic exercises, using the bicycle ergometer and walking). During the follow-up period, medication therapy was not changed. After the observed follow-up period of 21 days, the standard ECG and the exercise test were performed, once again. In TG of patients, after treatment with exercise training, there was a significant reduction in QTd and QTDc (p < 0.005 for both parameters). In TG of patients, after 3 weeks, there was a significant reduction in systolic and diastolic blood pressure, heart rate, double product, total and LDL cholesterol (p < 0.001 for all parameters). TG of patients, who were on the second exercise test, achieved significantly longer time, while the non-training group showed no significant changes. The study showed that exercise training has favourable effects on QT dispersion in patients after CABG. Exercise training led to significant reduction in blood pressure, heart rate, double product, cholesterol, as well as significantly improved physical exercise capacity, which has a beneficial effect on the prognosis in these patients. [ABSTRACT FROM AUTHOR]

Purpose: The objective of the current study was to evaluate the effect of intravenous methylprednisolone pulse therapy on myocardial repolarization alterations, especially QT dispersion in anticipation of cardiovascular risks in patients with pemphigus vulgaris. Methods: The current study is a prospective-controlled study on the electrocardiographic changes after methylprednisolone pulse therapy in 50 patients with pemphigus vulgaris. Results: A total of 50 patients (28 female and 22 male) were included in our study. The mean heart rate was significantly higher in male patients both before (92 ± 10.80 versus 82.75 ± 12.01 ms) and after pulse therapy (102.73 ± 14.26 versus 91.07 ± 15.02 ms) (p value < .01). The value of heart rate was significantly greater after receiving steroid pulse therapy. Corrected QT dispersion before pulse therapy was 19.92 ± 8.2 ms that increased to 40.68 ± 18.12 ms after treatment (p value < .001). Conclusion: Our study shows that there is a relationship between pulse steroid infusion and increased predisposition to the occurrence of cardiac arrhythmias. QT dispersion could be a good marker to assess this risk in these patients. [ABSTRACT FROM AUTHOR]

Introduction: It is believed that an exaggerated blood pressure response (EBPR) to exercise stress test is associated with a higher risk of cardiovascular events. It is also assumed that QT dispersion (QT-d), which was originally proposed to measure the spatial dispersion of ventricular recovery times, may have a relationship to cardiovascular events. The objective of this study was to examine the difference of changes in QT-d, Maxi-QT, Mini-QT, and QT-c (corrected QT interval) of the electrocardiogram in two groups of patients with exaggerated blood pressure responses (EBPR group) and normal responses (control group) to exercise testing. Also, the diagnostic value of each of these criteria in the prediction of EBPR was studied. Methods: This cross-sectional study was conducted from May 2015 to February 2016 on patients suspected of coronary artery disease (CAD) undergoing exercise testing who had been referred to Ghaem and Imam Reza hospitals in Mashhad (Iran). All patients underwent a treadmill exercise test with the 12-lead ECG, which was optically scanned and digitized for analysis of QT-d, QT max, and QT min. Patients were divided into two groups of normal and EBPR to exercise testing. QT changes of ECG were compared between the two groups, and the diagnostic accuracy of QT variables for prediction of EBPR to exercise testing was studied. A multiple linear regression analysis (MLR), Pearson Chi-qquare, independent samples t-test, and receiver operating characteristic (ROC) curve were used as statistical methods in IBM SPSS version 19. Results: Sixty patients (55% male) with a mean age of 50.48 ± 10.89 years were studied in two groups of normal (n=30) and exaggerated blood pressure response (n=30) to exercise testing. Maximum QT and QT dispersion were statistically different in individuals’ exaggerated blood pressure response to exercise stress test (p < 0.05). The logistic regression analysis revealed that none of our parameters predicted the EBPR. The ROC curve showed that 50 and 345 milliseconds for QT dispersion and Maxi-QT were the optimal cut-off points for the prediction of EBPR. Conclusion: It seems that Maxi-QT and QT-d may be predictors of EBPR during exercise testing. Also, a significant difference in maxi-QT and QT-d was observed between two groups of patients with normal and EBPR during the exercise testing

OBJECTIVE: Epicardial adipose tissue (EAT) secretes various proinflammatory and atherogenic mediators that have several endocrine and paracrine effects on heart. This study investigated the influence of EAT on QT and P wave dispersions (QTd, PWd), as simple, non-invasive tools of proarrhythmia on surface ECG. METHODS: This was a cross-sectional study and included 70 patients with normal coronary arteries who underwent 12-derivation electrocardiography, echocardiography and biochemical examinations in order for QTd, PWd, and EAT thickness to be measured.. RESULTS: Median EAT thickness was 4.1 mm. Correlation analyses revealed that EAT was significantly associated with age (r=0.412, p

The aim of the study was to assess associations between myocardial electrical instability estimates (heart rhythm turbulence, T- wave microvolt alternation, QT dispersion) and structural and functional changes in heart in the settings of IHD with ventricular premature beats. Eighty two subjects with exertional angina (NYHA FC II-III) and Lown Grade 3-5 class ventricular arrhythmia were examined. Controls included 28 pts. with chronic IHD with no arrhythmias. Heart rhythm turbulence, T- wave alternation and QT dispersion were defined based on 12-lead ECG data with record duration of 5 minutes using Intecard-7 apparatus. All patients underwent common clinical examination, 60-lead electrocardiogram (ECTG-60), ECG daily monitoring test (SMECG) (Cardian, Belarus), bicycle ergometric test, short ECG recording vagal sympathetic balance was estimated (using Briz Program Package and SMECG). IHF subjects who had Lown Grade III-V class ventricular arrhythmia had a higher frequency of heart rhythm turbulence disturbance, higher T microvolt alternation estimates and QT dispersion. Close relationship between myocardial electrical instability parameters (heart rhythm turbulence, T microvolt alternation and QT dispersion) and myocardial ischemic signs, LVEF, and heart rhythm variability in chronic IHD have been identified.

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 (P0.05 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.

Objectives: Coeliac disease is an autoimmune intestinal disease that develops with permanent intolerance to gluten and similar cereal proteins. It can damage to many tissues, including myocardium, by autoimmune mechanisms. In our study, we aimed to investigate the effect of coeliac disease on cardiac electrical activity by comparing the Tp-e interval and Qt dispersion values of coeliac patients with healthy children., Methods: Fifty-seven coeliac patients and 57 healthy children were included in the study. Sociodemographic findings, physical examinations, symptoms, laboratory values, dietary compliance, endoscopy, and pathological findings were recorded into a standardised form. Electrocardiogram parameters were calculated, and echocardiography findings were noted., Results: No statistically significant difference was found between the two groups in terms of age, gender, heart rate, electrocardiogram parameters such as p wave, PR interval, QRS complex, QT interval, and QTc values. Tp-e interval, Tp-e / QT ratio, and Tp-e / QTc ratio were statistically significantly higher in the patient group compared to the control group. Ejection fraction and fractional shortening values were significantly lower in the patient group compared to the control group. In the patient group, Tp-e interval, Tp-e / QT ratio, Tp-e / QTc ratio, and QTc dispersion were statistically significantly higher in patients with tissue transglutaminase IgA positive compared to patients with tissue transglutaminase IgA negative., Conclusion: Our study gives important findings in terms of detecting early signs of future cardiovascular events in childhood age group coeliac patients.

QT and corrected QT (QTc) intervals and their increased dispersions (QTd, QTcd) have been linked to the occurrence of arrhythmias in hemodialysis (HD) patients. This study was performed to determine the effects of the angiotensin II receptor blocker losartan on these parameters in HD patients. Our cohort comprised 24 dialysis patients and 14 healthy controls. 15 dialysis patients were treated for 16 weeks with losartan (HD losartan group) but not 9 patients (HD control group). Blood pressures (BP) and electrocardiogram-derived data (Sokolow-Lyon and Cornell voltages, QT, QTd, QTc and QTcd) were measured in all patients. At the beginning of the study, there were no differences in patient characteristics among the 3 groups. Baseline maximum QTc, QTd, QTcd and Socolow-Lyon and Cornell voltages and BPs of the healthy group were lower than those of HD groups. While these parameters were similar in the dialysis groups, only BPs in losartan group were higher. After 16 weeks, BPs, Socolow-Lyon and Cornell voltages values in losartan group significantly decreased but not in the HD control group. Whereas maximum QT and QTc, QTd, QTcd, heart rate and QRS interval did not change in the HD groups. Electrocardiographic LVH of 2 patients improved in the losartan group. Losartan reduced BP and electrocardiographic LVH was improved in HD patients without affecting QTd and QTcd during the 16-week study period. [Med-Science 2014; 3(4.000): 1627-38]

OBJECTIVE: To investigate the correlation between the corrected QT dispersion (QTcd) and serum potassium/sodium levels in order to evaluate their significance for early diagnosis of neonatal asphyxia. PATIENTS AND METHODS: This study included 124 neonatal asphyxia patients. These patients were divided into mild and severe asphyxia groups based on their clinical features and diagnostic indexing. Sixty healthy infants were selected as controls. QTcd, and serum cardiac troponin T (cTNT), potassium and sodium levels in the three groups were compared, and the correlation between QTcd and serum potassium/ sodium was analyzed by Spearman correlation tests. RESULTS: Both mild and severe groups developed significantly higher cTnT and QTcd (p < 0.05), but lower serum potassium and sodium compared with control group (p < 0.05). The severe group had significantly higher cTnT and QTcd (p < 0 .05), b ut l ower s erum p otassium and sodium when compared with mild group (p < 0 .05). T he s erum p otassium a nd sodium were both negatively correlated with QTcd (p < 0.05). CONCLUSIONS: S erum p otassium a nd s odium can be used as indicators for neonatal asphyxia, which may markedly improve early diagnosis, prognosis and treatment efficacy. [ABSTRACT FROM AUTHOR]

Objective: To observe the alteration of QT dispersion (QTd) and QTc dispersion (QTcd) in hemodialysis patients after oral administration of Zhigancao Decoction (炙甘草汤, Roasted Licorice Decoction, RLD).Methods: To investigate the alteration of QTd and QTcd in 68 routine hemodialysis patients before and after hemodialysis with 12-lead electrocardiogram (ECG) after orally administrated RLD for 4 weeks. Blood was also taken for measurement of plasma electrolytes, liver function, renal function, hemoglobin (Hgb) and hematocrit (HCT).Results: After hemodialysis, QTd and QTcd were prolonged evidently; the difference was significant between before and after hemodialysis (P<0.05). After RLD orally administrated for 4 weeks, QTd and QTcd only slightly increased after dialysis compared with pre-dialysis (P>0.05). The QTd and QTcd of the post-therapy-post-dialysis decreased significantly compared with the pre-therapy-post-dialysis (P<0.05). There were no other significant changes in other variables (post-therapy-pre-dialysis vs. pre-therapy-pre-dialysis, or post-therapy-post-dialysis vs. pre-therapy-post-dialysis;P>0.05). After therapy, the number of patients with supraventricular arrhythmia, occasional ventricular premature beat and multiple ventricular premature beat were decreased from 15 to 4, 10 to 2 and 7 to 1, respectively.Conclusion: RLD therapy not only lowered the increased QTd and QTcd after hemodialysis, but also displayed a safety profile. [ABSTRACT FROM AUTHOR]

Anabolic androgenic steroids are a class of synthetic compounds derived from testosterone, eventually used by athletes, to improve physical performance. However, anabolic steroids can also modify normal cardiovascular function. Thus, we investigated cardiac electrophysiological and autonomic abnormalities in rats, through a electrocardiographic variability protocol during and after interruption of administration of nandrolone decanoate (DECA) anabolic steroid. Twenty male Wistar rats (60–70 days old) received DECA (10 mg. kg −1 i.m ) once a week or vehicle, during eight weeks. Electrocardiogram was recorded in conscious rats by a noninvasive method, and time and domain analysis of heart rate variability as well as electrocardiogram intervals (QTc / QTd) were performed. Body mass was lower in treated rats compared to control after 4th and 8th weeks, but not at the end of 14th week. QTc and QTd were longer in DECA group compared to control on 4th, 8th, 11th, but equal on 14th week. Cardiac autonomic dysfunction (vagal attenuation) was present on DECA group after 4th week and did not normalize after interruption of treatment. The animals of DECA group showed a correlation between attenuated parasympathetic modulation and increased correct QT interval. Our data allow us to conclude that long-term treatment with DECA impairs autonomic cardiac physiology, predisposing to cardiovascular risk and sudden death, and interruption of administration does not recovery the normality immediately. [ABSTRACT FROM AUTHOR]

Abstract: Background: Studies on adults have shown increased dispersion of QT and corrected QT (QTc), peak‐to‐end interval of the T wave (Tp‐e), Tp‐e/QT ratio, and Tp‐e/QTc ratio in subclinical hypothyroidism (SH), but there have been no pediatric studies. Materials and methods: A total of 40 SH patients were compared with 40 healthy children in respect to serum thyroid‐stimulating hormone (TSH), serum‐free level of triiodothyronine, and free level of thyroxine (fT4). SH diagnosis was accepted as TSH above the laboratory accepted upper limit (>4.2 mU/L) and normal fT4 values. The patient and control group data were compared by calculating the QT interval, QTc, QT dispersion (QTd), QTc dispersion (QTcd), Tp‐e, Tp‐e/QT ratio, and Tp‐e/QTc ratio on 12‐lead surface electrocardiogram. Results: The mean age was 7.91 ± 3.6 years in the SH group and 8.8 ± 2.4 years in the control group. In the SH group, the minimum QT (QTmin) was determined to be statistically significantly lower (P < 0.001) and maximum QT (QTmax), QTd, QTcd, Tp‐e, Tp‐e/QT ratio, and Tp‐e/QTc ratio were statistically significantly higher (P = 0.028, P < 0.001, P = 0.003, P < 0.001, P = 0.001, P < 0.001, respectively). A positive correlation was determined between TSH and QTmax (r: +0.331, P = 0.037). Conclusions: The current study is the first to have shown significantly increased QTd, QTcd, Tp‐e, Tp‐e/QT ratio, and Tp‐e/QTc ratio in children diagnosed with SH. A positive correlation was determined between TSH and maximum QT values, Tp‐e, Tp‐e/QT ratio, and Tp‐e/QTc ratio. These results suggest the need to further assess the long‐term risks of prolonged QT dispersion in the setting of subclinical hypothyroidism. [ABSTRACT FROM AUTHOR]

Background: A myocardial bridge (MB) has been associated with ventricular arrhythmia and sudden death during exercise. QT dispersion (QTd) is a measure of abnormal repolarization and may predict ventricular arrhythmia. We investigated the frequency of ventricular arrhythmias during exercise and the QTd at rest and after exercise, in patients with an MB compared to a normal cohort.Methods: We studied the rest and stress ECG tracings of patients with an MB suspected by focal septal buckling on exercise echocardiography (EE) (Echo-MB group, N = 510), those with an MB confirmed by another examination (MB group, N = 110), and healthy controls (Control group, N = 198).Results: The frequency of exercise-induced premature ventricular contractions (PVCs) was significantly higher in the Echo-MB and MB groups compared with the Control group (both p < .001). In all, 25 patients (4.9%) in the Echo-MB group, seven patients (6.4%) in the MB group and no patients in the Control group had exercise-induced non-sustained ventricular tachycardia (NSVT). There was no difference in the baseline QTd between the groups. In the Echo-MB and MB groups, QTd postexercise increased significantly when compared with baseline (both p < .001). Patients with NSVT had a higher frequency of male gender and an even greater increase in QTd with exercise compared with the non-NSVT group.Discussion: There is an increased frequency of exercise-induced PVCs and NSVT in patients with MBs. Exercise significantly increases QTd in MB patients, with an even greater increase in QTd in MB patients with NSVT. Exercise in MB patients results in ventricular arrhythmias and abnormalities in repolarization. [ABSTRACT FROM AUTHOR]

Objectives: Sudden unexpected death in epilepsy (SUDEP) is attributed to peri-ictal cardiopulmonary abnormalities. In the present study, epilepsy patients on monotherapy (carbamazepine [CBZ], oxcarbazepine [OXZ], valproic acid [VPA]) were compared with a healthy control group to investigate the effects of epilepsy and various antiepileptic drugs on QTmax, QTmin, and QTd. Methods: Seventy eight (51.3% females) epilepsy patients with a mean age of 32.7±11.4 (range, 17-63) years and 71 (56.3% female) healthy subjects with a mean age of 36.3±13.6 (range, 18-64) years participated in the study. The shorter and longer QT were measured by electrocardiography (ECG) and then differences between them (QTd) were calculated. SPSS for Windows 21.0 package software was used to compare the findings between groups. Results: QTmin (p<0.000), QTmax (p<0.000), and QTd (p=0.069) were longer in the epilepsy group than in the control group. On the other hand, we found that 20 epilepsy patients, and none of the control subjects, had a long QT. Conclusion: In this study, we found that cardiac repolarization parameters were different between epileptic and healthy subjects. These results showed the importance of ECG controls at follow-up of epilepsy patients. [ABSTRACT FROM AUTHOR]

Introduction: Obstructive sleep apnea syndrome (OSAS) is associated with sudden cardiac death (SCD). In this study we aimed to evaluate the ventricular recovery time in OSAS patients without chronic systemic diseases, such as hypertension, diabetes, thyroid dysfunction, electrolyte imbalance, cardiac disease and the relationship of OSAS with SCD. Materials and Methods: In the study, between January 2008-January 2010, we analyzed 170 patientswith a mean age of 44.45±10.1 (21-75) years, who were clinically suspected of having OSAS. Following overnight polysomnography (PSG), 12 lead surface electrocardiogram (ECG), recordings were perforned and QT minimum, QT maximum and QT dispersion were computed from ECG. Results: The patients were divided into to the following 4 groups; AHI (apnea-hypopnea index) ≤5, 5< AHI ≤15, 15< AHI

Aim. Benefits of CRT on mortality and morbidity in patients with severe CHF are clear but the effect of CRT on sudden cardiac death is more controversial. It has been suggested that CRT may catalyze arrhythmogenicity by reversing the normal depolarization pattern. The purpose of this study was to examine the effect of CRT on dispersion of repolarization as assessed by ECG. We also sought to determine the value of dispersion of repolarization ECG parameters in predicting the occurrence of major arrhythmic events (MAE) in follow-up.Material and methods. A total of 48 patients with end-stage heart failure and QRS duration >120 ms underwent CRT. QT dispersion (QTd), T peak t end interval (Tpe) and T peak t end dispersion (Tpe dispersion) were measured before and immediately after CRT implantation. All patients were followed at least 12 months for ventricular tachycardia or fibrillation that were treated with antitachicardia pace or cardioversion.Results. Over 16±7.1 months, 14 patients had a MAE. Compared to baseline, after CRT, QTc dispersion (84.66±37.7 vs 100.36±47.4, p=0.04) and Tpe interval (104.1±20.4 vs 122.03±33, p=0.02) increased significantly. Increase in QTD (ΔQTD) (31.66±39.5 vs 5.57±5.59, p=0.03), and QTc dispersion (ΔQTc dispersion) (40.19±46.6 vs 4.39±14.35, p=0.04) from baseline was signifcantly higher in MAE group. In multiple regression analyses, ΔQTc dispersion predicted MAE (p=0.045, CI: 1.000–1.033).Conclusion. Immediately after CRT implantation QTc dispersion and Tpe interval increases and increase in QTc dispersion predicts MAE in one year follow up.

Background The 12-lead surface electrocardiographic (ECG) analysis is able to provide independent predictors of prognosis in several cardiovascular settings, including hypertrophic cardiomyopathy (HCM). The present single-center study investigated the possible ability of several ECG-derived variables in stratifying sudden cardiac death (SCD) risk and, possibly, in improving the accuracy of the 2014 European Society of Cardiology guidelines. Methods A total of 221 consecutive HCM outpatients were recruited and prospectively followed. All of them underwent a full clinical and instrumental examination, including a 12-lead surface ECG to calculate the dispersion for the following intervals: QRS, Q-Tend (QT), Q-Tpeak (QTp), Tpeak-Tend (TpTe), J-Tpeak (JTp), and J-Tend (JT). The study composite end-point was SCD, aborted SCD, and appropriate implantable cardioverter defibrillator (ICD) interventions. Results During a median follow-up of 4.4 years (25th–75th interquartile range: 2.4–9.4 years), 23 patients reached the end-point at 5-years (3 SCD, 3 aborted SCD, 17 appropriate ICD interventions). At multivariate analysis, the spatial QT dispersion corrected according to Bazett's formula (QTcd) remains independently associated to the study endpoint over the HCM Risk-SCD score (C-index 0.737). A QTcd cut-off value of 93 ms showed the best accuracy in predicting the SCD endpoint within the entire HCM study cohort (sensitivity 56%, specificity 75%, positive predictive value 22%, negative predictive value 97%). Conclusion Our data suggest that the QTcd might be helpful in SCD risk stratification, particularly in those HCM categories classified at low-intermediate SCD risk according to the contemporary guidelines. [ABSTRACT FROM AUTHOR]

Some patients with unstable angina and critical stenosis of the left anterior descending coronary artery (LAD) present with Wellens syndrome (WS), i.e., inverted or biphasic T-waves in the anterior precordial leads. We assessed clinical, angiographic, electro- and echocardiographic characteristic of patients with WS. In this retrospective study, clinical, angiographic, electro- and echocardiographic characteristic of 35 patients with WS were compared to 57 patients with critical LAD stenosis and normal resting electrocardiogram (ECG), and 45 subjects with normal coronary angiogram. QTc dispersion was measured from the 12-lead ECG as the difference between longest and shortest QTc intervals. Mechanical dispersion was defined as the time difference between the longest and shortest contraction durations which were measured as the time from the first deflection of the QRS complex to maximum myocardial shortening of each 18 segmental longitudinal strain curves derived by speckle tracking echocardiography. There were no significant differences in the complexity and location of the LAD lesion, anterograde and collateral flow in LAD and coronary artery dominance between patients with WS and normal ECG (P > 0.05, for all). Patients with WS had lower global longitudinal strain (GLS) and more pronounced both QTc and myocardial mechanical dispersion than patients with critical LAD stenosis and normal ECG, and control subjects (P < 0.05). T-wave changes in patients with WS are associated with more profound regional myocardial dysfunction and increased QTc and myocardial mechanical dispersion. Similar angiographic characteristics of the LAD lesion were seen in patients with WS and normal ECG. [ABSTRACT FROM AUTHOR]

There is evidence for premature atherosclerosis and systemic arterial stiffening during follow-up of children with Kawasaki disease (KD) and coronary artery abnormalities (CAA). Moreover, patients with KD may also have subclinical myocardial involvement and inhomogeneous ventricular repolarization. The inhomogeneous ventricular repolarization manifests as increased QT dispersion on electrocardiography. There is a paucity of studies in endothelial dysfunction and QT dispersion in children with KD and transient CAA. Twenty children with KD and transient CAA were studied at least 1 year after resolution of CAA. Mean follow-up period between KD onset and enrolment in the study was 53.7 months. Twenty age and sex-matched controls were enrolled. High-resolution B-mode ultrasonography was used to analyze brachial artery dilatation in response to reactive hyperemia (cases and controls) and sublingual nitroglycerine (cases only). Carotid artery intima-media thickness (cIMT) and stiffness index were calculated. The difference between maximum and minimum QTc intervals on 12 lead electrocardiogram was calculated as QTc dispersion (QTcd). No statistically significant difference was noted in percent flow-mediated dilatation of brachial arteries in response to reactive hyperemia between cases (13.31 ± 10.41%) and controls (12.86 ± 7.09%). Sublingual nitroglycerine-mediated dilatation in children with KD was 14.88 ± 12.03%. Mean cIMT was similar in cases (0.036 ± 0.015 cm) and controls (0.035 ± 0.076 cm; p = 0.791). No statistically significant difference between groups was observed in mean QTcd values (0.057 ± 0.018 s vs. 0.059 ± 0.015 s in controls, p = 0.785). No evidence of significant endothelial dysfunction or increased QT dispersion in patients with KD and transient coronary artery abnormalities was found in our cohort when studied at a mean follow-up of 53.7 months. This is reassuring, and indicates that risk of subclinical atherosclerosis and myocarditis in a subset of children with KD and transient coronary artery abnormalities is not significant. [ABSTRACT FROM AUTHOR]

Prediabetic states and diabetes are important risk factors for cardiovascular morbidity and mortality. Determination of short-term QT interval variability (STVQT) is a non-invasive method for assessment of proarrhythmic risk. The aim of the study was to evaluate the STVQT in patients with impaired glucose tolerance (IGT). 18 IGT patients [age: 63 ± 11 years, body mass index (BMI): 31 ± 6 kg/m2, fasting glucose: 6.0 ± 0.4 mmol/l, 120 min postload glucose: 9.0 ± 1.0 mmol/l, hemoglobin A1c (HbA1c): 5.9 ± 0.4%; mean ± SD] and 18 healthy controls (age: 56 ± 9 years, BMI: 27 ± 5 kg/m2, fasting glucose: 5.2 ± 0.4 mmol/l, 120 min postload glucose: 5.5 ± 1.3 mmol/l, HbA1c: 5.4 ± 0.3%) were enrolled into the study. ECGs were recorded, processed, and analyzed off-line. The RR and QT intervals were expressed as the average of 30 consecutive beats, the temporal instability of beat-to-beat repolarization was characterized by calculating STVQT as follows: STVQT = Σ ∣QTn + 1 - QTn∣ (30x2)-1. Autonomic function was assessed by means of standard cardiovascular reflex tests. There were no differences between IGT and control groups in QT (411 ± 43 vs 402 ± 39 ms) and QTc (431 ± 25 vs 424 ± 19 ms) intervals or QT dispersion (44 ± 13 vs 42 ± 17 ms). However, STVQT was significantly higher in IGT patients (5.0 ± 0.7 vs 3.7 ± 0.7, P < 0.0001). The elevated temporal STVQT in patients with IGT may be an early indicator of increased instability of cardiac repolarization during prediabetic conditions. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate cardiac autonomic nervous system function using Holter-derived and standard electrocardiographic parameters in patients with myotonic dystrophy (dystrophia myotonica, DM) and no clinically overt heart involvement. Methods: Eighty-four DM patients without conditions potentially influencing cardiac autonomic function were enrolled in the study: 44 with DM type 1 and 40 with DM type 2 (mean age 34.9 ± 11.5 and 47.8 ± 13.5 years, respectively). Two corresponding control groups of aged-matched healthy subjects were selected for DM1 ( n = 35) and for DM2 ( n = 30). Standard electrocardiography for QT interval dispersion and 24-h Holter monitoring with time-domain heart rate variability and heart rate turbulence were performed. Results: No significant differences in time-domain heart rate variability parameters between DM1 or DM2 subjects and controls were observed. However, heart rate turbulence parameters were significantly impaired in DM1 patients as compared to their controls: turbulence onset ( p = 0.025), and turbulence slope ( p = 0.018). Moreover, turbulence slope was also impaired in DM2 patients ( p = 0.042). As compared to controls, we observed an increased QT dispersion, both in DM1 ( p = 0.003) and also in DM2 patients ( p < 0.0001). No relationship between disease duration or neurological status and time-domain heart rate variability, heart rate turbulence, and QT dispersion was observed. Interpretation: Despite normal time-domain heart rate parameters, impaired heart rate turbulence and increased QT dispersion may suggest cardiac autonomic nervous system dysfunction in DM patients. The present study is the first one in which heart rate turbulence and QT dispersion assessment were examined both in DM1 and DM2 patients. [ABSTRACT FROM AUTHOR]

Introduction: The angiotensin-converting enzyme (ACE) gene insertion or deletion in long-term hemodialysis patients may be associated with corrected QT interval prolongation, leading to fatal arrhythmias. The ACE D allele is known to increase the risk of malignant ventricular arrhythmias and is also associated with increased QT dispersion after myocardial infarction and hypertension. This study aimed to evaluate the relationship between ACE gene polymorphism and QT dispersion in hemodialysis patients.Materials and Methods: In 70 hemodialysis patients, electrocardiography was performed and QT dispersion was calculated. Corrected QT interval was calculated using Bazett Formula. The ACE gene polymorphism was determined by polymerase chain reaction.Results: The mean age of the patients was 60 ± 12 years. The mean QT dispersion and corrected QT dispersion were 61.71 ± 21.99 and 73.18 ± 25.51, respectively. QT dispersion inversely correlated with serum calcium and potassium levels and positively correlated with ACE gene polymorphism and residual urine. Calcium level was the predictor factor for QT dispersion. The ACE genotype correlated with QT dispersion, corrected QT dispersion, hemoglobin, and residual urine, and inversely correlated with serum potassium. Corrected QT dispersion correlated with ACE gene polymorphism and residual urine. The DD genotype of ACE had significally greater QT dispersion and corrected QT dispersion than the II and ID genotypes.Conclusions: Our study showed that the most important parameter affecting corrected QT dispersion was ACE gene polymorphism on the background of D allelle. Patients carrying this allelle need special attention regarding optimal suppression of renin-angiotensin-aldosteron system activity. [ABSTRACT FROM AUTHOR]

Objective: We aimed to investigate in a clinical setting, the effects of different classes of psychotropic drugs on cardiac electrophysiological measures linked with an increased risk of sudden cardiac death.Methods: We conducted a cross-sectional study in a population of 1059 psychiatric inpatients studying the effects of various psychotropic drugs on the T-peak to T-end (TpTe) interval, QT dispersion and QT interval.Results: Methadone use showed a strong association with TpTe prolongation (odds ratio (OR)=12.66 (95% confidence interval (CI), 3.9-41.1), p<0.001), an effect independent from action on QT interval. Mood stabilisers showed significant effects on ventricular repolarisation: lithium was associated with a TpTe prolongation (OR=2.12 (95% CI, 1.12-4), p=0.02), while valproic acid with a TpTe reduction (OR=0.6 (95% CI, 0.37-0.98), p=0.04). Among antipsychotics, clozapine increased TpTe (OR=9.5 (95% CI, 2.24-40.39), p=0.002) and piperazine phenothiazines increased QT dispersion (OR=2.73 (95% CI, 1.06-7.02), p=0.037).Conclusions: Treatment with psychotropic drugs influences TpTe and QT dispersion. These parameters might be considered to better estimate the sudden cardiac death risk related to specific medications. Beyond antipsychotics and antidepressants, mood stabilisers determine significant effects on ventricular repolarisation. [ABSTRACT FROM AUTHOR]

Aims: Hypoglycaemia is associated with increased risk of cardiovascular events and mortality in patients with diabetes, but the extent and mechanisms of this link are ill defined. We here prospectively studied cardiac repolarization abnormalities during insulin-induced hypoglycaemia in humans.Methods: 119 individuals (69 males, age 47.5±13.4years, range 18-82years) were assessed during hypoglycaemia after the injection of 0.1-0.25units/kg human insulin. Corrected QT intervals (QTc) and QT dispersion (QTd) were calculated from serially recorded twelve lead electrocardiograms, and plasma glucose and other endocrine markers were studied.Results: QTc increased from 415.1±21.9ms (mean±standard deviation) at baseline to 444.9±26.5ms during hypoglycaemia (plasma glucose nadir, 1.6±0.5mmol/L, p=0.001), accompanied by an increase of QTd from 45.0±22.7ms to 64.1±40.0ms (p<0.001). Hypoglycaemia-induced abnormal QTc prolongation (defined as ⩾460ms in females and ⩾450ms in males) occurred in 17% (9/54) of females and 26% (17/65) of males. 97 of 119 of individuals (82%) developed transient hypokalaemia (K+ ⩽3.6mmol/L), and plasma epinephrine increased from 220.4±169.5pmol/L at baseline to 2945.6±2421.4pmol/L during hypoglycaemia. Baseline QTc, but not age or gender, was a significant predictor of hypoglycaemia-induced QTc prolongation (p=0.001).Conclusions: Insulin-induced hypoglycaemia frequently causes abnormal QT prolongation and is associated with hypokalaemia and sympathoadrenal activation, thereby increasing the potential risk for ventricular arrhythmias, particularly in individuals with pre-existing high normal QTc. [ABSTRACT FROM AUTHOR]

Introduction Multisystem inflammatory syndrome in children (MIS-C) is characterized by hyperinflammation, heart involvement, and multiorgan failure, which develop following coronavirus disease 2019. Ventricular arrhythmias have been identified during this syndrome. It is known that the risk of ventricular arrhythmia is associated with ventricular repolarization changes. The aim of this study was to investigate the corrected QT interval, QT dispersion, T wave peak-to-end interval, and T-peak to T-end/corrected QT ratio in MIS-C. Methods The study included 35 patients diagnosed with MIS-C and 35 subjects as the control group. The ventricular diameters, ejection fraction, valve insufficiency, and coronary artery were examined in both groups using echocardiography. Corrected QT interval, QT dispersion, T wave peak-to-end interval, and T-peak to T-end/corrected QT ratio were determined by 12-lead electrocardiogram. Results The patient group had increased corrected QT interval (p<0.05), QT dispersion (p = 0.001), T-peak to T-end interval (p=0.001), and T-peak to T-end/corrected QT ratio (p = 0.001) compared to the control group. Moreover, there was a correlation between increased QT dispersion, T-peak to T-end, T-peak to T-end/corrected QT ratio, and decreased ejection fraction (r = -0.51 and p = 0.001, r = -0.71 and p < 0.001, r = -0.69 and p < 0.001, r = -0.56 and p < 0.001, respectively). Conclusions Our study demonstrated increased QTc interval, QT dispersion, T-peak to T-end interval, T-peak to T-end/corrected QT ratio in MIS-C. This result may indicate an increased risk of ventricular arrhythmia for these patients., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Turan et al.)

Objective: Preeclampsia is an important cause of maternal and fetal mortality and morbidity worldwide. P-wave dispersion (Pd) and QT interval dispersion (QTd) are direct measures of the nonhomogenity of atrial depolarization and ventricular repolarization, respectively, in electrocardiography (ECG). Recent studies have reported a significant role of prolonged Pd and QTd in various cardiovascular diseases. Because the effect of acute pressure overload, which occurs in a preeclamptic setting, on the intra- and/or interatrial and ventricular conduction times remains unknown, we aimed to investigate the relation of Pd and QTd with the presence and severity of preeclampsia. Methods: Forty-eight consecutive pregnant women with preeclampsia and 55 healthy, age-matched pregnant women were included in this retrospective study between January and September 2015. The pregnant women with preeclampsia were divided into two groups according to disease severity as follows: mild and severe preeclampsia. A 12-lead ECG was performed for all the pregnant women before cesarean section operation. Results: Compared with the healthy pregnant women, Pd and QTd were significantly prolonged in patients with preeclampsia. Moreover, in the subgroups of preeclampsia, Pd was significantly increased in the severe group. Pd and QTd were directly related to systolic and diastolic blood pressure, which are well-known validated indicators for the severity of preeclampsia. Conclusion: Preeclampsia triggers an alteration of atrial depolarization and ventricular repolarization, which are evidenced by the prolongation of ECG parameters such as Pd and QTd. ECG is a noninvasive, easy to use, and easily available diagnostic tool, which can be used in the assessment of atrial and ventricular electrical activity in pregnant women with preeclampsia. [ABSTRACT FROM AUTHOR]

Objective: Fibromyalgia (FM) is a chronic disease characterized by widespread pain. Somatic complaints associated with the cardiovascular system, such as chest pain and palpitations, are frequently seen in FM patients. P and QT dispersions are simple and inexpensive measurements reflecting the regional heterogeneity of atrial and ventricular repolarization, respectively. QT dispersion can cause serious ventricular arrhythmias. The aim of the present study was to evaluate QT dispersion and P wave dispersion in patients with FM. Material and Methods: The study involved 48 FM patients who fulfilled the established criteria and 32 healthy controls (HC). A standard 12-lead electrocardiogram was performed on all participants. QT dispersion was defined as the difference between the longest and the shortest QT intervals. Similarly, the differences between the shortest and longest P waves were defined as P wave dispersion. Results: The QT dispersion and corrected QT dispersion were shorter in the FM group compared with the HC group (p<0.001 for both). In terms of the P wave dispersion value, there was no significant difference between the FM and HC groups (p=0.088). Conclusion: Longer QT and P wave dispersions are not problems in patients with FM. Therefore, it may be concluded that fibromyalgia does not include an increased risk of atrial and/or ventricular arrhythmias. [ABSTRACT FROM AUTHOR]

Summary: We evaluated the effects of zoledronic acid (ZA) therapy on electrocardiographic (ECG) parameters for the first time in the literature. Measurements were performed on ECGs obtained before and after ZA infusion on the same day as well as 1 month after the infusion. ZA infusion did not have any short- or long-term effect on any parameter that might be associated with the tendency for atrial fibrillation or ventricular arrhythmias. Introduction: The aim of the present study was to evaluate the early and late effects of ZA therapy on ECG parameters which might be associated with the tendency for atrial and ventricular arrhythmias. Methods: Consecutive patients with osteoporosis who were admitted to our clinic between December 2013 and December 2014 and who were scheduled to receive ZA infusion constituted our study population. Twelve-lead surface ECGs were obtained from all patients before and after ZA infusion on the same day as well as 1 month after the infusion. All ECG parameters were measured and compared with each other for each patient. Results: Data of 100 patients were used in the analysis (9 male; 70.5 ± 11.6 years of age). There were no significant differences between repeated measurements regarding pmax, pmin, and p dispersion values. QT max and QT min values were significantly increased after infusion; however, there were no significant changes in QT dispersion, Tp-e interval, and Tp-e dispersion values. Conclusions: ZA infusion did not affect P wave dispersion both at the immediate post-infusion period and 1 month after infusion. QT values were significantly increased early after ZA infusion; however, there were no significant differences in parameters reflecting disparity of ventricular recovery times and transmural dispersion of ventricular repolarization. Based on these observations, it may be suggested that ZA infusion did not have any short- or long-term effect on any parameter that might be associated with the tendency for atrial fibrillation or ventricular arrhythmias. [ABSTRACT FROM AUTHOR]

Purpose: Sevoflurane is known to prolong the QT interval. This study aimed to determine the effect of the interaction between intravenous anesthetics and sevoflurane on the QT interval. Methods: The study included 48 patients who underwent lumbar spine surgery. Patients received 3 μg/kg fentanyl and were then randomly allocated to either Group T, in which they received 5 mg/kg thiamylal, or Group P, in which they received 1.5 mg/kg propofol, at 2 min after administration of fentanyl injection for anesthetic induction. Vecuronium (1.5 mg/kg) and sevoflurane (3 % inhaled concentration) were administered immediately after loss of consciousness and tracheal intubation was performed 3 min after vecuronium injection. Heart rate (HR), mean arterial pressure (MAP), bispectral index score (BIS), and the heart rate-corrected QT (QTc) interval on a 12-lead electrocardiogram were recorded immediately before fentanyl administration (T1), 2 min after fentanyl injection (T2), immediately before intubation (T3), and 2 min after intubation (T4). Results: There were no significant differences between the two groups in baseline patient characteristics. BIS and MAP significantly decreased after anesthesia induction in both groups. At T3, MAP in Group T was higher than in Group P, while HR had reduced in both groups. The QTc interval was prolonged after anesthesia induction in Group T, but did not change at any time point in Group P. The QTc interval after anesthesia induction in Group T was longer than in Group P. Conclusion: We concluded that an injection of propofol could counteract QTc interval prolongation associated with sevoflurane anesthesia induction. [ABSTRACT FROM AUTHOR]

OBJECTIVE:To probe into the clinical efficacy of irbesartan combined with amiodarone in treatment of heart failure complicated with arrhythmia. METHODS:100 patients with heart failure complicated with arrhythmia admitted into Henan Tanghe County People’s Hospital from Apr. 2015 to Mar. 2017 were selected and divided into observation group and control group via blind extraction method, with 50 cases in each. The control group was treated with amiodarone, while the observation group was given irbesartan combined with amiodarone. After 6-month treatment, the differences in clinical efficacy, QT dispersion of electrocardiogram, cardiac function indices [left ventricular end-diastolic dimension(LVEDD), stroke volume(SV) and left ventricular ejection fraction(LVEF)] and incidences of adverse drug reactions between two groups were compared. RESULTS:The total effective rate of observation group was 96.00%(48/50), which was significantly higher than that of the control group(80.00%, 40/50), with statistically significant difference(P<0.05); after treatment, the QT dispersion of electrocardiogram and LVEDD of observation group were significantly lower than those of the control group, while the SV and LVEF of observation group were significantly higher, with statistically significant differences(P<0.05); the incidences of adverse drug reactions of observation group and control group were respectively 6.00%(3/50) and 10.00%(5/50), the difference had no statistical significance(P>0.05). CONCLUSIONS:The combination of irbesartan and amiodarone can improve the clinical efficacy in treatment of heart failure complicated with arrhythmia, which can promote patients’ cardiac function, with few adverse drug reactions and high safety. [ABSTRACT FROM AUTHOR]

Previous studies assessing effect of ischemia on ventricular repolarization are mostly directed towards patients with coronary artery disease (CAD); however, similar reports on cardiac syndrome X (CSX) are scarce. Whether microvascular dysfunction of CSX and ischemia induced by CAD produce comparable effect on ventricular repolarization is unclear and deserve further studies. In the present study, ECG measures of ventricular repolarization were compared between CAD and CSX patients (40 subjects in each group). Following evaluation of sociodemographic characteristics, medical and past medical history, a resting ECG was used to assess measurements of ventricular repolarization in each patient, namely, QT interval (QT), corrected QT interval (QTc), QT dispersion (QTd), corrected QT dispersion (QTcd), adjacent QT dispersion (AdQTd), QT dispersion ratio (QTdR), JT dispersion (JTd) and Corrected JT dispersion (JTcd). Results showed comparable QT intervals and QTd in CAD and CSX patients even after adjustment for the possible variations in gender, age and body mass index of the studied groups. Although JTd was increased in CSX subjects (26.6±7.2 ms) compared with CAD patients (22.7±6.5 ms, p = 0.019), statistical significance disappeared after correcting JT for variations in heart rate. QT and QTc were significantly below 440 ms in CAD as well as CSX patients (p < 0.001). In contrast, maximum QTd, maximum QTcd and AdQTd of CAD and CSX patients were significantly above 440 ms (p < 0.001). The means of JTd and JTcd were significantly above 22 ms and 24 ms respectively (p < 0.001, p = 0.001) in CSX but not CAD patients (p = 0.529, p = 0.281). The present findings clearly demonstrate comparable measures of ventricular repolarization in CAD and CSX patients and consequently the risk of cardiac events.

Introduction: We aimed to evaluate the relation between QT variables and left ventricular geometry in athletes and obese children. Material and Methods: This study included 209 children and adolescents. Thirty-eight of them were obese, 140 were athletes and 31 were normal weighted. Children with history of functional and structural cardiovascular diseases (acquired and congenital), chronic systemic diseases, hypertension, sleep apnea, endocrinological disorders were excluded. All subjects underwent detailed electrocardiographic and echocardiographic examination. Results: QT dispersion was significantly higher in obese children, basketball players, football players and swimmers compared to control group (p < 0.05, p < 0.001, < 0.001 and < 0.01 respectively). Basketball players had the highest QT dispersion. Left ventricular endsystolic diameter (mm/m2) was higher in footballers, swimmers, wrestlers and tennis players compared to obese subjects. Interventricular septal thickness at diastole was highest in swimmers compared to control group (p < 0.001) and left ventricular posterior wall thickness was significantly higher in footballers and swimmers compared to healthy subjects (p < 0.01 and p < 0.001 respectively). Left ventricular geometry was normal in 84 patients (47.1%), but 34 patients (19.1%) had concentric remodelling, 20 (22.4%) had concentric hypertrophy and 40 (28.6%) had eccentric hypertrophy. No concentric and eccentric hypertrophy was observed in obese subjects. Left ventricle hypertrophy was prominent in dynamic and combined groups but it was not statistically significant (p = 0.204). QT dispersion was statistically higher in obese, dynamic sports and combined sports compared to control group (p < 0.05, p < 0.001 and p < 0.001 respectively). Discussion: In this study we determined that QT dispersion is elevated in dynamic and combined sports types and obese children. Conclusion: QT dispersion is prolonged in obese and athletes who participate dynamic and combined sports.

The measurement of QT dispersion in the surface electrocardiogram has been proposed as a non invasive method for assessing inhomogeneity of myocardial repolarization and has been linked to an increased risk of arrhythmic cardiac death. Several studies have evaluated the use of QTd in a wide variety of cardiac diseases and have reached conflicting conclusions regarding its clinical significance.

Introduction: Conventionally, QT interval is measured in lead II. There are no data to select an alternative lead for QT measurement when it cannot be measured in Lead II for any reason. Methods and results: We retrospectively analyzed ECGs from 1906 healthy volunteers from 41 phase I studies. QT interval was measured on the median beat in all 12 leads. The mean difference in QT interval between lead aVR and in Lead II was the least, followed by aVF, V5, V6 and V4; lead aVL had maximum difference. The T wave was flat (