QT Ratio Research Articles

Value of c Tpeak –Tend \ c QT Ratio in the Prediction of No-reflow in Acute ST-Elevation Myocardial Infarction

Value of c Tpeak –Tend \ c QT Ratio in the Prediction of No-reflow in Acute ST-Elevation Myocardial Infarction

Empagliflozin and Dapagliflozin Therapies Favorably Alter QRS-T Angle and Cardiac Repolarization Parameters in Patients with Heart Failure.

Recent randomized clinical trials demonstrated that treatment with sodium-glucose cotransporter-2 inhibitors (SGLT2is) reduces the risk of cardiac mortality due to sudden cardiac death and progressive pump failure in patients with heart failure (HF). Mechanisms underlying the potential anti-arrhythmic effects of SGLT2is are not well understood. We aimed to examine the effect of SGLT2i treatment on the frontal-plane QRS-T (f[QRS-T]) angle, a novel marker of myocardial repolarization and an independent predictor of adverse cardiac outcomes. The study included 106 patients with HF with reduced ejection fraction (HFrEF) who received an SGLT2i, empagliflozin, or dapagliflozin. All study participants underwent screening 12-lead electrocardiography (ECG) before and ∼90 days after treatment. We compared ECG repolarization parameters before and after treatment. During study enrollment, there were statistically significant decreases in the Tp-e/QT ratio (P ≤ .0001), Tp-e/corrected QT ratio (P = .0002), Tp-e interval (P < .0001), and f(QRS-T) angle (P = .04) in response to SGLT2i therapy. In addition, study participants experienced an improvement in functional capacity (2.06 ± 0.6 vs. 1.82 ± 0.6, P = .0001) and reduced N-terminal pro-b-type natriuretic peptide values. In this retrospective cohort study, SGLT2i therapy was associated with improved cardiac repolarization parameters in patients with HFrEF. More comprehensive studies are needed to evaluate the impact of SGLT2i on cardiac repolarization and its potential relation to cardiac arrhythmia and sudden cardiac death risk.

Diagnostic Indicators of ECG for Coronary Slow Flow Phenomenon; a Systematic Review and Meta-Analysis.

Currently, epicardial coronary angiography is still the only diagnostic tool for Coronary Slow Flow Phenomenon (CSFP). This study aimed to systematically review studies that compared Electrocardiogram (ECG) findings between patients with and without CSFP. Using relevant key terms, we systematically searched MEDLINE, Scopus, Embase, and Web of Science to find relevant studies up to February 5th, 2023. Effect sizes in each study were calculated as mean differences and crude odds ratio; then, random-effect models using inverse variance and Mantel-Haenszel methods were used to pool standardized mean differences (SMD) and crude odds ratios, respectively. Thirty-two eligible articles with a total sample size of 3,937 patients (2,069 with CSFP) were included. CSFP patients had higher P-wave maximum (Pmax) (SMD: 1.02 (95% confidence interval (CI): 0.29 - 1.76); p=0.006) and P-dispersion (Pd) (SMD: 1.63 (95% CI: 0.99 - 2.27); p<0.001) compared to the control group. CSFP group also showed significantly longer QT wave maximum duration (SMD: 0.69 (95% CI: 0.33 - 1.06); p<0.001), uncorrected QTd (SMD: 1.89(95% CI: 0.67 - 3.11); p=0.002), and corrected dispersion (QTcd) (SMD: 1.63 (95% CI: 1.09 - 2.17), p<0.001). The frontal QRS-T angle was significantly higher in the CSFP group in comparison with the control group (SMD: 1.18 (95% CI: 0.31 - 2.04; p=0.007). While CSFP patients had a significantly higher T-peak to T-end (Tp-e) (SMD:1.71 (95% CI: 0.91, 2.52), p<0.001), no significant difference was noted between groups in terms of Tp-e to QT (p=0.16) and corrected QT ratios (p=0.07). Our findings suggest several ECG parameters, such as P max, Pd, QT, QTc, QTd, QTcd, Tp-e, and frontal QRS-T angle, may be prolonged in CSFP patients, and they could be employed as diagnostic indicators of CSFP before angiography.

Investigation of QT Dispersion and T-Peak to T-End/Corrected QT Ratio in Multisystem Inflammatory Syndrome in Children.

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.

Impact of coronary artery bypass grafting on ventricular repolarization indexes

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Ventricular repolarization indexes (VRI) tend to be altered in patients with chronic coronary artery disease, which are associated with a higher risk of malignant arrhythmias and higher mortality. Coronary artery bypass grafting (CABG) is capable of reducing mortality, as well as improving arrhythmic burden in this population. However, we do not know whether these benefits can be explained by improvement in VRI. Purpose To determine whether there is improvement in VRI after CABG, as well as to analyse possible effects of clinical and surgical variables on these indexes. Methodology A total of 150 patients who underwent CABG were included. Through the evaluation of preoperative and hospital discharge electrocardiograms, the QT interval, the interval from the peak to the end of T wave (Tp-Te) and the Tp-Te/ QT ratio were analysed. The values obtained before and after CABG were compared, as well as their association with clinical and surgical variables. Results The population was predominantly male (77.3 %), mean age of 61.6±8.3 years-old and mean LVEF of 58.8±10.6 %. A reduction in the QT interval (398.93±34.68 vs 365.47±50.38 ms, p &amp;lt; 0.001), in the Tp-Te interval (72.2±17.2 vs 61.6±19.5 ms, p &amp;lt; 0.001) and in the Tp-Te/ QT ratio (0.18±0.17 vs 0.04±0.05, p = 0.004) after CABG. There was no correlation between VRI and clinical and surgical variables. Conclusion CABG had a important impact in the reduction of QT and Tp-Te intervals, as well as the Tp-Te/ QT ratio, suggesting that the acute improvement in the coronary perfusion is directly associated with the improvement in these VRI.

水道水中農薬のGC/MSスクリーニング分析におけるクロマトグラム解析の誤差要因の分析

In order to adopt "screening analysis" in drinking water quality testing, which performs qualitative and quantitative analysis based on information registered in a database without measuring standard materials at the time of each testing, a validation test was conducted to evaluate the difference on the chromatogram data analysis by analysts. In the validation test, chromatograms of 6 water samples were analyzed using the same database and software by 16 analysts in 13 laboratories. Peak identification was performed based on Retention time (RT), (qualifier and target ion) QT ratio, and degree of matching of mass spectra, and if necessary, peak shapes in water samples were compared with those in calibration curve samples. Large differences were observed in the detection of pesticides among the analysts. There were two main reasons for the disagreement. The first is that the judgement of peak detection at low concentrations near the quantification limit of each pesticide, particularly below the concentration at three times of quantification limit, differed depending on the analyst. The other reason was that some analysts made clear misidentifications and identified wrong peaks close to the predicted retention time, despite the QT ratio and mass spectrum didn't match that in the database. In addition, there were some cases where the quantified values were reported by misidentifying the peaks of degradation products and metabolites, even when the peak detection was correctly judged. In order to use screening analysis practically by drinking water quality testing laboratories, it is important to conduct a validation test like this study in advance to use screening analysis and to coordinate criteria for peak identification and quantification among data analysts.

Are Tp-e interval and QT dispersion values important in children with coeliac disease?

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. 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. 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. Our study gives important findings in terms of detecting early signs of future cardiovascular events in childhood age group coeliac patients.

QT Ratio: A Simple Solution to Individual QT Correction

QT Ratio: A Simple Solution to Individual QT Correction

Electrocardiography clues in assessment of patients with premature ventricular contractions

Some electrocardiography (ECG) parameters such as Tp-e interval, Tp-e / QT ratio, fragmented QRS (fQRS), and heart rate variability (HRV) are related to cardiovascular mortality and morbidity. We aim to investigate the relation between premature ventricular contraction burden and these parameters on 24-h ECG recording. The study is a retrospective investigation of the 24-h Holter ECG and echocardiography of 199 patients who underwent the procedures due to complaints of palpitation. A frequency of < 10% PVCs / 24 h was classified as seldom group (98 patients), while > 10% PVCs / 24 h was designated as frequent group (101 patients). Tp-e interval was significantly longer (62 [54–78] vs 75 [60–84], p < 0.001), Tp-e / QT ratio was significantly increased (0.18 [0.16–0.20] vs 0.21 [0.18–0.22], p = 0.001) in frequent PVC group. The percentage of fQRS was significantly increased in frequent PVC group (30.6% vs 47.5%, p = 0.015). When the groups were compared, no significant difference was found in HRV time domain indices. Positive correlations were observed between PVC burden and Tp-e (r = 0.304, p < 0.001), Tp-e / QT (r = 0.275, p < 0.001). Our study showed that Tp-e interval, Tp-e / QT and fQRS are associated with frequency of PVCs. These measurements in patients with PVCs may form part of assessment of cardiovascular risk.

Evaluation of electrocardiographic predictors of brugada type response during flecainide challenge

Abstract Background/Introduction Brugada syndrome (BrS) is a hereditary channelopathy with an increased risk of sudden cardiac death. Most BrS patients manifest non type 1 Brugada pattern electrocardiography (ECG). Sodium channel blockade is a well-established diagnostic tool for Brugada syndrome. However, intravenous sodium channel blockade is not readily available in all parts of the world. In addition, severe ventricular arrhythmias during drug challenge have an estimated prevalence of 1%. Determining the predictors of a positive test would improve our understanding and facilitate appropriate use of these tests. Purpose We aimed to identify ECG predictors of Brugada type response during flecainide challenge and provide an independent assessment of current published ECG criteria predictive of a positive flecainide challenge. Methods We analysed the clinical and electrocardiographic data of 526 consecutive individuals referred from a national pre-participation exercise screening program who underwent flecainide challenge for an ECG suspicious of Brugada pattern. ECG recordings included both conventional and high precordial leads (1 and 2 space up ECGs in V1 and V2 – 1V1, 1V2, 2V1, 2V2). Twelve-lead ECGs were evaluated for the width of the β angle, β score, baseline J wave elevation, width of QRS, absence of isoelectric segment in lead II, ST/ QT ratio, presence of S wave in Leads II, III and V5 as well as the presence of R wave in aVR. Results Flecainide challenge was positive in 121 (23%) of the 526 cases. Baseline QRS duration was greater in the conventional lead placement [V1 (102.4±20.0 ms vs 97.6±14.0 ms, p=0.003), V2 (111.1±33.5 ms vs 100.9±13.1 ms, p=0.001)] as well as 1 space up [1V1 (108.9±21.0 ms vs 100.6±18.2 ms, p&amp;lt;0.001), 1V2 (117.4±26.6 ms vs 103.2±18.3, p&amp;lt;0.001)] and 2 space up [2V1 (113.6±23.4 ms vs 102.5±19.3 ms, p&amp;lt;0.001), 2V2 (121.6±26.1 ms vs 106.8±19.1 ms, p&amp;lt;0.001)] in cases with a subsequent positive response. A QRS duration of ≥120ms in V2 yielded a sensitivity of 16.5%, specificity of 93.8%, positive predictive value of 44.4% and negative predictive value of 79% for a positive flecainide challenge. Other predictors of positivity included that of a shorter ST duration in lead II (107.0±19.9 ms vs 118.1±24.4, p&amp;lt;0.001) and a shorter ST/ QT ratio (0.30±0.09 vs 0.32±0.07, p=0.006). Conclusion In this population, a wider QRS duration, shortened ST segment in lead II and ST/QT ratio were predictors of a positive response to flecainide challenge when BrS was suspected on a baseline ECG. Prior published ECG parameters such as β angle, β score, baseline J wave elevation, presence of S wave in Leads II, III and V5 as well as the presence of R wave in aVR did not perform as well in predicting for a positive response to flecainide challenge in our population. Funding Acknowledgement Type of funding sources: None. Baseline CharacteristicsECG Findings

The assessment of Tp-e interval and Tp-e/QT ratio in patients with hyperthyroidism before and after thyroid surgery.

Ventricular repolarisation is assessed using the Tp-e interval and QT interval corrected by the heart rate (QTc) via an electrocardiogram (ECG). Prolonged Tp-e/QTc is related with an increased risk of arrhythmias and cardiac mortality. This study was conducted at a single centre in collaboration with general surgery and cardiology clinics. We aimed to appraise the assessment of Tp-e interval and Tp-e/QT ratio in patients with hyperthyroidism before and after thyroid surgery. Totally 65 patients with hyperthyroidism before and after thyroid surgery were enrolled in our study. In presurgical hospitalisation and six months after the thyroid surgery, we measured the electrocardiographic parameters again on same patients. All subjects who were investigated in this study were in sinus rhythm. Tp-e interval, Tp-e/QT and Tp-e/QTc ratios were measured from the 12-lead electrocardiogram. Heart rate (P=.073), QT interval (P=.432) and QTc interval (P=.179) were similar before and after thyroid surgery. Tp-e interval (84.6±13.1 vs 77.2±10.9; P=.031), Tp-e/QT ratio (0.23±0.04 vs 0.21±0.04; P<.001), Tp-e/QTc ratio (0.21±0.04 vs 0.19±0.03; P<.001) and QTc dispersion (52.4±7.2 vs 48.4±7.4; P<.001) were significantly different before and after thyroid surgery. In correlation analysis, there was a significant correlation between preprocedural Tp-e/QTc ratio and preprocedural fT4 in patients with hyperthyroidism (r=0.275, P=.026). Our study demonstrated that Tp-e interval, Tp-e/QT and Tp-e/QTc ratios were shortened in patients with hyperthyroidism after thyroid surgery than before procedure. This study is considerable to display that hyperthyroidism may have a negative effect on cardiac conduction system, which potentially may induce formation of ventricular arrhythmias.

Evaluation of Tp-e interval, Tp-e/QT ratio and index of cardiac-electrophysiological balance in patients with tinnitus

BackgroundTinnitus is a common auditory symptom. Dysfunction in the autonomic nervous system (ANS) is an essential part of the etiopathogenesis of tinnitus. ANS regulates heart rate and heart rhythm and can lead to ventricular repolarization changes, which can cause malignant ventricular arrhythmias. T wave peak-to-end T(p-e) interval and T(p-e)/QT ratio are known ventricular arrhythmia indexes, and the index of cardiac-electrophysiological balance (iCEB) is a novel index that can be used to predict the risk of malignant ventricular arrhythmia. The goal of the study was to investigate these ventricular arrhythmia indexes in patients with tinnitus.MethodsThe study population consisted of 240 patients with tinnitus and 240 healthy subjects. A standard 12-channel surface electrocardiogram was applied to both groups. T(p-e) interval, QT interval and QRS duration were determined. Corrected QT (QTc) was determined via Bazett’s formula. To predict ventricular arrhythmia, iCEB (QT/QRS), T(p-e)/QT, corrected iCEB (QTc/QRS) and T(p-e)/QTc values were determined and compared between groups.ResultsCompared to the control group, QT (376.46 ± 36.54 vs 346.52 ± 24.51 ms), QTc (426.68 ± 24.68 vs 390.42 ± 24.04 ms), T(p-e) (75.86 ± 14.68 vs 62.42 ± 8.64 ms), T(p-e)/QT (0.201 ± 0.06 vs 0.180 ± 0.01) and T(p-e)/QTc (0.177 ± 0.06 vs 0.159 ± 0.02) were significantly higher in patients with tinnitus (p < 0.001 for all). QT/QRS (3.92 ± 0.68 vs 3.56 ± 0.32) and QTc/QRS (4.44 ± 1.03 vs 4.01 ± 0.64) were also significantly higher in patients with tinnitus (p = 0.018 and p = 0.008, respectively). In addition, significant positive correlations were found between T(p-e), T(p-e)/QTc ratio and disease duration (r = 0.792, p < 0.001; r = 0.500, p < 0.001, respectively).ConclusionAs a result, patients with tinnitus may have an increased risk of malignant ventricular arrhythmia.

QT interval and repolarization dispersion changes during the administration of hydroxychloroquine/chloroquine with/without azithromycin in early COVID 19 pandemic: A prospective observational study from two academic hospitals in Indonesia.

BackgroundHydroxychloroquine/chloroquine (HCQ/CQ) treatment for COVID‐19 was associated with QT interval prolongation and arrhythmia risks. This study aimed to investigate QTc interval and ventricular repolarization dispersion changes, as markers of arrhythmia risks, after HCQ/CQ administration with/without azithromycin (AZT) during COVID‐19 pandemic.MethodsA prospective observational study was performed in two academic hospitals in Indonesia. Adult patients who received HCQ/CQ alone and HCQ/CQ + AZT concomitant treatments for COVID‐19 infection were enrolled. Baseline and post HCQ/CQ treatment electrocardiograms were obtained. Baseline and post HCQ/CQ treatment QT interval by Bazett (B‐QTc) and Fridericia (F‐QTc) formulas and ventricular repolarization dispersion indices by Tpeak‐Tend (Tp‐e) interval and Tpeak‐Tend/QT (Tp‐e/QT) ratio were calculated and analyzed.ResultsThe study enrolled 55 (HCQ/CQ alone) and 77 subjects (HCQ/CQ + AZT concomitant). F‐QTc interval significantly lengthened in subjects with HCQ/CQ + AZT (mean difference 11.89 ms [P = .028]). The incidences of severe B‐QTc and F‐QTc lengthening were 13.1% and 12.3%, B‐QTc and F‐QTc prolongation were 25.4% and 12.3%, and severe B‐QTc and F‐QTc prolongation were 6.2% and 3.2%. Tp‐e interval lengthened significantly from baseline to posttreatment in HCQ/CQ alone and HCQ/CQ + AZT (mean difference 10.83 ms [P = .006] and 18.73 ms [P < .001], respectively). Tp‐e/QT ratio increased significantly from baseline to posttreatment in HCQ/CQ + AZT concomitant (mean difference 0.035 [P < .001]). No fatal arrhytmia occurred.ConclusionsDuring COVID‐19 pandemic, HCQ/CQ + AZT concomitant treatment caused significant F‐QTc lengthening, significantly increased Tp‐e interval and increased Tp‐e/QT ratio. HCQ/CQ alone only caused significant increase of Tp‐e interval. Incidences of severe QTc lengthening and prolongation were low in both HCQ/CQ alone and HCQ/CQ + AZT concomitant.

Evaluation of ventricular repolarization variables in pediatric COVID-19

INTRODUCTION: Although the childhood clinic of COVID-19 is more innocent than adults, its unknown aspects continue to cause concern among pediatricians. One of these unsettling aspects is the cardiovascular system effects. We investigate the role of ventricular repolarization parameters in predicting arrhythmia risk in pediatric COVID-19. METHODS: Twelve-channel surface electrocardiograms of a total of 166 participants, including children diagnosed with COVID-19 and healthy controls, were analyzed. The QT interval, corrected QT interval, QTc dispersion, Tpeak-Tend, Tp-e dispersion, Tp-e / QT and Tp-e / QTc ratio were calculated. The correlations between ventricular repolarization parameters and laboratory values were examined. RESULTS: In our study, the COVID-19 patients had a significantly longer Tpeak-Tend (64.51 ± 8.64 and 57.62 ± 7.96; p < 0.001), Tp-e dispersion (21.77 ± 6.4 and 18.01 ± 6.78; p < 0.001), and corrected QT interval (393.18 ± 20.06 and 380 ± 22.3; p < 0.001) duration than the control group. There was a significantly higher Tp-e / QT ratio (0.17 ± 0.02 and 0.15 ± 0.02; p < 0.001), Tp-e / QTc ratio (0.16 ± 0.02 and 0.15 ± 0.02; p < 0.001) in group with COVID-19 than the controls. In addition a positive correlation was found between Tpeak-Tend interval, Tp-e dispersion and white blood cells in the group with SARS CoV2 infection. DISCUSSION AND CONCLUSION: Evaluating these ventricular repolarization parameters in pediatric SARS CoV2 infection may be useful in predicting the risk of ventricular arrhythmia.

Investigation of the effect of tens treatment on cardiac electrical activity using proarrhythmogenic markers

Objective: It was aimed to investigate the effect of transcutaneous electrical nerve stimulation (TENS) treatment, which is widely used for pain, on cardiac electrical activity by using new proarrhythmogenic markers that give an idea on cardiac arrhythmia. &#x0D; Material Method: Forty patients (21 females, 19 males, mean age 56.60 ± 10.38) who applied to our outpatient clinic with the complaint of pain in the left shoulder or limitation of motion were included in our study. A fifteen-session physical therapy program was applied to the patients. Twelve-lead electrocardiography (ECG) was performed before treatment, at the end of the first day of treatment, and after treatment; and heart rate, QT interval (cQT) corrected according to Bazett formula, Tp-e / QT and electrophysiological balance index (iCEB) ratio were measured. The relationship of the measurements before treatment-first day after treatment, before treatment-fifteenth day after treatment and first day after treatment-fifteenth day after treatment was evaluated by Paired-Samples T test analysis. &#x0D; Results: In our study, when heart rate, cQT, Tp-e / QT and iCEB values were statistically analyzed, no significant difference was observed between measurements, since p&gt; 0.05. &#x0D; Conclusion: In our study, when the heart rate, new proarrhythmogenic markers cQT, Tp-e / QT and iCEB values were examined in patients who received physical therapy to the left shoulder region, it was seen that TENS treatment did not have a significant effect on cardiac rhythm.

The impact of hydroxychloroquine-azithromycin combination on Tpeak-to-end and Tpeak-to-end/QT ratio during a short treatment course.

BackgroundSince there was no proven treatment of coronavirus disease 2019 (COVID‐19), hydroxychloroquine–azithromycin (HCQ‐AZM) combination is being used in different countries as a treatment option. Many controversies exist related to the safety and effectiveness of this combination, and questions about how HCQ‐AZM combination affects the ventricular repolarization are still unknown.ObjectiveThe aim of the study was to show whether the hydroxychloroquine–azithromycin (HCQ‐AZM) combination prolonged Tpeak‐to‐end (TpTe) duration and TpTe/QT interval ratio or not.MethodsOne hundred and twenty‐six consequent COVID‐19(+) patients meeting the study criteria were enrolled in this study. Baseline ECGs were obtained immediately after hospitalization and before commencing the HCQ‐AZM combination. On‐treatment ECG was obtained 24–48 hr after the loading dose of HCQ/AZM. ECG parameters including PR interval, QRS duration, QT interval, QTc interval, TpTe duration, and TpTe/QT interval ratio were assessed. Demographic and laboratory findings were collected from an electronic recording system.ResultsECGs of 126 COVID‐19(+) patients who received HCQ‐AZM combination were assessed. Mean baseline QTc (by Fridericia formula), TpTe, and TpTe/QT ratio were 420.0 ± 26.5 ms, 82.43 ± 9.77 ms, and 0.22 ± 0.02, respectively. On‐treatment QTc, TpTe and TpTe/QT ratio were 425.7 ± 27.18 ms, 85.17 ± 11.17 ms, and 0.22 ± 0.03, respectively. No statistically significant acute impacts of HCQ‐AZM combination on TpTe duration and TpTe/QT interval ratio were observed compared with baseline values. No ventricular tachycardia/fibrillation and the significant conduction delays were seen during in‐hospital follow‐up.ConclusionHCQ‐AZM combination increased TpTe duration. However, no significant impact on TpTe/QT interval ratio was observed.

Effects of treatment with hydroxychloroquine and azithromycin on the index of cardiac electrophysiological balance in patients with COVID-19: A retrospective cohort study

Background/Aim: The common cardiac toxicities of hydroxychloroquine (HCQ) and azithromycin (AZ) are not well defined in COVID-19 patients. Index of cardiac electrophysiological balance (iCEB) is used as a novel risk marker for drug-induced arrhythmias. The purpose of this study was to evaluate ventricular repolarization using iCEB and other conventional ECG parameters such as the end of electrocardiographic T wave (Tp-e) interval, Tp-e/QT ratio, and Tp-e/ heart rate-corrected QT (QTc) ratio in COVID-19 patients treated with HCQ and AZ. Methods: This retrospective study enrolled 164 patients diagnosed with COVID-19 pneumonia in the Emergency Department (ED) and then transferred to the ward or the intensive care unit in April 2020. Results: A total of 164 patients with a mean age of 47 (18) years (range: 18-97 years) included 83 (50.6%) females. There were 38 and 126 patients in Groups HTQ and HTQ+AZ, respectively. On the 5th day of hospitalization, all patients’ heart rates were significantly lower (P

Risk Assessment for Arrhythmia in Pediatric Renal Transplant Recipients.

Renal transplant recipients are at risk for ventricular arrhythmia and sudden death. To assess that risk, we compared the ventricular repolarization markers of pediatric renal transplant recipients with those of healthy children. We included 30 children and adolescents who were followed for at least 6 months after renal transplant; 30 age- and sex-matched children were included for the control group. Demographic features, medications, and laboratory findings were recorded. Blood pressure measurements, ventricular repolarization indexes including QT dispersion, corrected QT dispersion, T-wave peak-to-end interval dispersion, the T-wave peak-to-end interval∕QT ratio, the T-wave peak-to-end interval∕corrected QT ratio, left ventricular mass index, and relative wall thickness were compared between groups. In addition, the correlations of ventricular repolarization indexes with other variables were evaluated. Blood pressure standard deviation scores, the mean heart rate, QT dispersion, corrected QT dispersion, the T-wave peak-to-end interval∕QT ratio, the T-wave peak-to-end interval/corrected QT ratio, left ventricular mass index, and relative wall thickness values were significantly higher in renal transplant patients, whereas T-wave peak-to-end interval dispersion, ejection fraction, and fractional shortening were similar between groups. Although ventricular repolarization indexes were similar in patients with and without left ventricular hypertrophy, only corrected QT dispersion was significantly higher in patients with hypertension (P = .006). The only variable that significantly predicted prolonged corrected QT dispersion was the systolic blood pressure standard deviation score (P = .005, β = .403). Ventricular repolarization anomalies, hypertension, left ventricular hypertrophy, and cardiac geometry irregularity may be observed after renal transplant in pediatric recipients despite acceptable allograft functions and normal serum electrolyte levels. Control of systolic blood pressure would decrease the risk of ventricular repolarization abnormalities, namely, the corrected QT dispersion. Follow-up of cardiovascular risks with noninvasive methods is recommended in all pediatric renal transplant recipients.

The relationship between management ability and investment opportunities with an emphasis on the role of political connection

Purpose: With the expansion of the quality level of activity as well as the widespread development of economic affairs, financial and investment decisions are among the most complex issues that arise in order to obtain the best return and desirability in the best conditions. In this regard, financial managers, given the primary responsibility for these decisions, seek to establish relationships between the factors of the firms in the firm, including investment opportunities. The purpose of this paper is to examine the relationship between management ability and political connection with investment opportunities. The QT ratio and market to book ratio (MTB) are used to measure corporate investment opportunities. Methodology: Corporate political connection is defined by Fasio's political cost variables and the use of the TOPSIS multi-criteria decision-making models and the Shannon entropy weighting method. In order to test the hypotheses, 116 companies listed in Tehran Stock Exchange during the period 2014-2019 were selected for the sample. Findings: The results of the analysis using the generalized least squares hybrid regression (GLS) method indicate that there is a significant and positive relationship between management ability and investment opportunities in Tehran Stock Exchange companies. There is a negative and significant relationship between political connection and investment opportunities. The political connection also does not affect the relationship between management ability and investment opportunities. Originality/Value: The purpose of this paper is to examine the relationship between management ability and political connection with investment opportunities. The QT ratio and market to book ratio (MTB) are used to measure corporate investment opportunities.

Electrocardiography indices in healthy metabolic syndrome patients: Markers for future cardiovascular risk

Background: Metabolic syndrome is a constellation of cardiovascular risk factors characterized by insulin resistance, prothrombotic and pro-inflammatory state. This study was an attempt to evaluate ECG changes as markers for metabolic syndrome before development of overt cardiovascular disease. Aims: We evaluated association between metabolic syndrome and ECG indices: QT dispersion, QTc dispersion, TpTe interval and TpTe/QT ratio. Settings and Design: Cross-sectional study Methods and Material: The study was conducted on 108 patients with metabolic syndrome and compared with age and sex matched 50 controls. Indices were measured from 12 lead ECG and data was compared. Statistical analysis used: SPSS Results: Metabolic syndrome was more common in females with most common criteria present being waist circumference followed by hypertriglyceridemia Metabolic syndrome group had higher levels of BMI, waist circumference, fat percentage, serum triglycerides and fasting glucose, systolic and diastolic pressure as well as lower HDL levels than control subjects. The QTc dispersion, QT dispersion, TpTe intervals and TpTe/QT ratio were significantly increased in Metabolic syndrome group compared to the control group. Increased Odd's ratio of the ECG parameters in comparison with the control group was also calculated. ROC curve revealed that QTc dispersion and TpTe/ QT ratio were better predictors for future metabolic syndrome. Conclusions: Hence ECG indices (QT dispersion, QTc dispersion, TpTe interval and TpTe/ QT ratio) can be used to predict cardiovascular risk in such patients.