QT Dispersion Research Articles

A study on QT dispersion and thrombolytic therapy in acute myocardial infarction

Background: Myocardial infarction is a major manifestation of ischemic heart disease, a leading cause of death in developed nations and the third globally. QTc dispersion is an important marker of ventricular repolarization variations and arrhythmogenic risk. This study examines the effects of thrombolytic therapy on QTc dispersion in acute myocardial infarction Materials and methods: 88 patients admitted to Al Ameen Medical College Hospital, Vijayapur, for acute MI were included in the study. Over a period of 8±2 days, all patients underwent monitoring, with standard 12-lead ECGs conducted upon admission and before discharge. QT interval, QTc interval, and QT and QTc dispersion parameters were calculated from these ECGs. Results: Analysis revealed significant variations in QT parameters between patients treated and not treated with thrombolytic therapy. Patients receiving thrombolytic therapy exhibited greater reductions in QT parameters by day 8±2 compared to those without treatment. Additionally, anterior wall infarctions demonstrated significantly higher QT and QTc dispersions compared to inferior wall infarctions, with these differences being statistically significant. Conclusion: In the early stages of acute myocardial infarction, patients, especially those diagnosed with anterior myocardial infarction, exhibited significantly elevated QT and QTc dispersions. Thrombolytic treatment resulted in substantial reductions in these dispersions compared to untreated individuals. Typically peaking within the initial hours of the condition, these dispersions subsequently decline following successful thrombolysis, underscoring their significance in risk assessment for malignant ventricular tachyarrhythmias and reinforcing the efficacy of thrombolytic therapy

The usefulness of QT interval measurement as a screening tool for cascade testing in asymptomatic patients at risk of long QT syndrome

Abstract Background Long QT syndrome (LQTS), an inherited arrhythmic syndrome, remains a public health concern with up to 3000 unexpected deaths in the US annually. A simple 12-lead ECG is the most easily accessible tool for initial screening. Purpose To describe the diagnostic utility of the standard QT correction techniques in 12-Lead ECGs, in a screening population of first-degree relatives of persons with LQTS of known genotype. Methods In this single centre study, data were included on consecutive patients undergoing cascade clinical and genetic testing for LQTS, who had a first degree relative with genotype-positive LQTS, from the years 2019 to 2022. Patient demographics, baseline ECG and genetic results were obtained. The QT interval was manually calculated between three independent readers using the tangent method and corrected using the 4 most commonly used formulae: Bazett (BQTc), Fridericia (FreQTc), Framingham (FraQTc) and Hodges (HQTc). The Mean QT was calculated by taking the average of four consecutive QT measurements in lead II or V5. The QT dispersion (QTd), was also calculated by using the formula: QTd = QT max – QT min. Results Data was available on 97 patients from 14 families. The mean age at screening was 44 years, and 51.5% were males. Two-thirds of patients were asymptomatic (n = 74, 76.3%). Fifteen patients had syncopal events. 72.2% (n = 70) of patients had a family history of arrhythmic death. After clinical screening and genotyping, 46.4% (n = 45) patients were gene positive for either KCNQ1 (75.5%) or KCNH2 (24.5%). Patients with prior syncope were more likely to be gene positive (72.7% vs 39.2%, p = 0.005). The 12-Lead ECG derived QTc result is listed in Table 1, with all correction modalities showing a higher corrected QT in the genotype-positive group (p <0.001). The diagnostic performance of BQTc was similar to that of the newer formulae (FreQTc, FraQTc and HQTc) when correcting for heart rate within the range of 60 – 100bpm as listed in Table 2. At a cut-off value of 440ms, BQTc formula had a sensitivity of 51% and a specificity of 84% for predicting genotype pathogenicity as listed in Table 3. The QT dispersion was higher in patients with KCNH2 compared to those with KCNQ1 (122msec, SD 30.5 vs 74.2 msec, SD 30.4, p value <0.001). Patients with KCNH2 were more likely to require an ICD (83.3% vs 16.7%, p <0.001). The mean Schwartz score in gene positive patient was 2.6 compared to 1.9 (p <0.003). Conclusion Formula correction of QT interval to heart rate had good overall diagnostic performance. Both FreQT and FraQT had high AUROC across different heart rates, though there was no statistically significant difference seen between correction formulae. The ECG remains a good preliminary screening tool method for identifying patients with increased risk LQTS in this population. Larger studies are needed to power for comparisons between QT correction methods.

Explainable machine learning and multi-modal data for predicting readmission in patients with heart failure

Abstract Background Cardiovascular diseases (CVDs) are among the leading causes of mortality and morbidity globally, with an estimated 1 million hospital admissions for CVD in England in 2019/20, leading to 5.5 million bed days. In addition, patients with CVDs have a notably high rate of hospital readmission, with approximately one in four patients experiencing heart failure (HF) being readmitted within one month of discharge. We explored whether machine learning models trained on electrocardiogram (ECG) and patient electronic health records (EHRs) can support decision-making and risk management and ultimately improve health outcomes for HF patients. Purpose The project aims to develop a machine learning model to predict health outcomes for HF patients. To test the hypothesis, we trained and tested an explainable machine learning model to predict the risk of mortality and hospital readmission rate for HF patients. Methods We used EHR data and tabulated ECG records to train an XGBoost model to predict the risk of 30-day mortality and 30-day hospital readmission for HF patients. EHR data from a cohort of 2,868 patients with their ECG records were used for model development. We extracted a total of 78 features from the ECG data, such as heart rate variability (HRV), P-wave durations, and QT intervals. These ECG features were combined with coded and free-text EHR data (e.g., demographic information, diagnosis, medication history, and lab results) and used as tabular inputs to the XGBoost model. Of the 2,868 patients, an internal set of 574 patients stratified by age, sex, and health outcomes (30-day mortality and 30-day hospital readmission) were held out for testing. Results Among 2,868 HF patients with 10-year follow-up, 1065 patients were reported for mortality or hospital readmission within 30 days of discharge. When the machine learning model was trained on ECG data in addition to EHR data, the model was able to predict patient mortality and hospital readmission rate in the test set with an area under the curve (AUC) of 0.91 and 0.70, respectively. For mortality prediction, the model achieved a sensitivity and specificity of 0.81 and 0.82, respectively, when employing an operating point with minimum difference between the sensitivity and specificity. When the threshold was adjusted to favor sensitivity at 0.91, the model specificity decreased to 0.74. The machine learning model also identified high sensitive troponin levels, QT dispersion, and lactate dehydrogenase levels as features of high importance for predicting the outcomes for HF patients. Conclusions Our developed machine learning model was able to predict mortality and readmission risks in HF patients using multi-modal data. Upon further validation, the machine learning model has the potential to be tested for supporting clinical decision-making and risk management for HF patients.ROC CurveFeature Importance

Evaluating cardiac electrophysiological markers for predicting arrhythmic risk in hypothyroid patients.

This study aimed to evaluate the impact of hypothyroidism and levothyroxine (LT4) treatment on arrhythmic risk by concurrently analyzing multiple electrocardiogram (ECG) parameters such as the Index of Cardio-Electrophysiological Balance (iCEB), frontal QRS-T angle, Tpeak-Tend (Tp-e) interval/QT interval ratio, and QT dispersion (QTd). This cross-sectional study included 132 adult patients with primary hypothyroidism who had been receiving LT4 treatment, and 132 demographically matched healthy controls. The hypothyroid group was also stratified by thyroid-stimulating hormone (TSH) levels (subclinical <4.5 and overt ≥ 4.5). Participants underwent a series of thyroid function and ECG measurements. The hypothyroid and healthy control groups were matched for age and gender (p = 0.080; p = 0.176). Participants with hypothyroidism had higher Tp-e/QT ratios, iCEB, median frontal QRS-T angle, and corrected QT dispersion (cQTd) than healthy controls (p = 0.004; p = 0.025; p = 0.004; p = 0.004, respectively). In the overt group, the Tp-e/QT ratio, iCEB, and median frontal QRS-T angles were all higher (p = 0.012, p = 0.037, and p = 0.016, respectively). Logistic regression analysis indicated that a higher iCEB score (β = 0.60, p = 0.003) was significant for the detection of arrhythmia risk. ROC analysis showed that iCEB had the highest sensitivity (0.80), moderate specificity (0.60), and AUC 0.70. Patients with hypothyroidism have a higher risk of arrhythmia. To assess this risk, it is important to analyze the Tp-e interval, iCEB, frontal QRS-T angle, and QTd. Differentiating between patients with subclinical and overt hypothyroidism can help minimize the risk of arrhythmia. iCEB is the most effective method for identifying arrhythmic risk. Using all these parameters can improve the accuracy of arrhythmic risk detection in patients with hypothyroidism.

QT Dispersion and Echocardiographic Features in Male Athletes: Geometric Pattern Related Differences

QT Dispersion and Echocardiographic Features in Male Athletes: Geometric Pattern Related Differences

Left Ventricular Geometric Pattern Impacts QT Dispersion in Males Athletes and Sedentary Men.

To (1) compare QT dispersion (QTd) and echocardiographic features between athletes with concentric left ventricular (LV) hypertrophy, athletes with eccentric LV hypertrophy, and sedentary controls with a normal LV geometric pattern and (2) quantify associations between QTd and echocardiographic features within these groups. Male athletes competing in different sports and sedentary men were stratified into groups according to their LV geometric pattern. These groups included eccentric LV hypertrophy (LV index > 115g/m2, relative wall thickness [RWT] < 0.42) consisting of 38 athletes, concentric LV hypertrophy (LV index > 115g/m2, RWT > 0.42) consisting of 40 athletes, and normal LV geometric pattern (LV index < 115g/m2, RWT < 0.42) consisting of 40 sedentary controls. Following a cross-sectional design, participants underwent electrocardiographic (ECG) and echocardiographic screening. Data were compared between groups using one-way analyses of variance with Bonferroni post hoc tests. Associations between corrected QTd and echocardiographic variables were quantified using Pearson correlations. Alongside structural disparities between groups, corrected QTd was significantly (p < 0.001) lower in athletes with eccentric LV hypertrophy compared to athletes with concentric LV hypertrophy and sedentary controls. Significant,moderate-to-very-largecorrelations were found between corrected QTd and interventricular septal wall thickness in athletes with concentric (r = 0.416, p = 0.008) or eccentric LV hypertrophy (r = 0.734, p < 0.001), and sedentary controls (r = 0.464, p = 0.003). The provided comparative and relationship data may inform the development of more precise approaches for ECG and echocardiographic screening in athletes, particularly in those with concentric LV hypertrophy who may be at greater risk for developing prolonged QTd.

The Effects of Pediatric Acute Lymphoblastic Leukemia Treatment on Cardiac Repolarization.

Background: In recent years, cardiac dysfunction in childhood cancer survivors has become an important issue. Studies are focusing on identifying means for the early identification of patients at risk. Considering this, our study aims to investigate 24-hour Holter electrocardiogram (ECG) repolarization changes throughout doxorubicin (DOX) and cyclophosphamide (CPM) administration in pediatric patients treated for acute lymphoblastic leukemia (ALL). Methods: This was an investigator-driven, single-center, prospective, observational study. Enrolled children had a baseline bedside ECG examination performed before starting chemotherapy (T0). Serial Holter ECG examinations were conducted at three moments during their treatment protocol: day 8 (T1), day 29 (T2), and day 36 (T3). This study evaluated several ECG repolarization parameters, such as the QT interval, corrected QT interval (QTc), and QTc dispersion, as well as ST segment variations. Results: We evaluated 37 children diagnosed with ALL. The T0 examination revealed that over a third of patients had a resting heart rate (HR) outside the normal range for their age and sex. During chemotherapy, statistically significant increases in both HR as well as QT and QTc dispersion values were noticed, especially during the first DOX administration. What is more, a significant increase in the percentage of patients with ST segment depression from T1 to T2 and T3 was noticed. Rhythm disturbances were rare in the study population, with only a few patients presenting ventricular or supraventricular extrasystoles. Conclusions: This study reveals silent repolarization changes occurring early during anticancer treatment in children treated for ALL. These findings could aid in a better understanding of the cardiac toxicity mechanism, and they could potentially improve cardiac risk stratification for oncologic patients. Because of the small number of patients, our results need to be validated by larger studies.

Are adolescents with premenstrual disorder at risk for cardiac arrhythmias?

One of the most commonly experienced symptoms of premenstrual disorder (PMD) is anxiety, and there is a notable rise in sympathomimetic activity in this patient group. Studies have linked fluctuations in systemic autonomic tone to electrocardiography (ECG) changes. This study aims to investigate the relationship between anxiety, a common symptom of PMD, and alterations in QT dispersion (QTd) and P-wave dispersion (Pd) in adolescent females. This cross-sectional study included female adolescents aged 12-18 with regular menstruation for at least 3 months. Participants completed the premenstrual syndrome scale (PMSS) and were divided into two groups, PMD and control, according to the PMSS score. A standard 12-lead body surface ECG was performed and QTd and Pd values were determined in each participant. Of the 43 participants, 27 were categorized into the PMD group, with a mean age of 15.15 ± 1.43 years. Age at menarche and menstrual cycle patterns were comparable between the PMD and control groups. Statistical analysis revealed significantly higher Pmin (p = 0.010) and Pd values (p < 0.001) in the PMD group compared to controls. A positive correlation between PMSS scores and Pd (p = 0.049) was also observed. Changes in atrial conduction and ventricular repolarization due to the pathophysiology of PMD may increase the risk of developing atrial and ventricular tachyarrhythmias over time. Screening patients with PMD using an ECG may be useful in identifying potentially at-risk adolescents.

Arrhythmias in thyroid dysfunction

Thyroid dysfunction is associated with characteristic changes in heart rate and arrhythmias. Thyroid hormones act through genomic and non-genomic effects on myocytes and influence contractility, relaxation and action potential duration through avariety of mechanisms. Atrial fibrillation is the most common arrhythmia associated with thyroid dysfunction, it occurs in both euthyroidism and hyperthyroidism in clear association with T4 levels. Mechanistically, in the hyperthyroid state, increased automaticity and triggered activity, together with ashortened refractory period and slowing of the conduction speed, lead to the initiation and maintenance of multiple intraatrial reentry circuits. Influences from the autonomic nervous system and hemodynamics controlled by thyroid hormones act as modulators for arrhythmias, which are promoted by acorresponding substrate (significant impact of comorbidities). Concerning therapy, in addition to treating hyperthyroidism, the initial therapeutic focus is on adequate rate control and anticoagulation in patients with ahigh risk of thromboembolism. Ablation of atrial fibrillation can be considered later on, although there is an increased likelihood of recurrence compared to patients without hyperthyroidism.Prolongation of the QT interval and increase in QT dispersion are involved in the formation of ventricular arrhythmias. Epidemiological data suggest an association of elevated T4 levels with ventricular arrhythmias and sudden cardiac death. However, this seems to be mainly relevant for patients with underlying cardiac disease (e.g. ICD users).

Is the development of arrhythmia predictable in rheumatoid arthritis?

This study aimed to determine whether there is a difference in the electrocardiography (ECG) measurements of healthy controls and rheumatoid arthritis (RA) patients and to predict whether they can be used to determine the risk of arrhythmia in patients. The prospective study included 50 cardiac asymptomatic RA patients (38 males, 12 females; mean age: 46.8±9.1 years; range, 18 to 60 years) who met the 2010 American College of Rheumatology/European Alliance of Associations for Rheumatology RA criteria and 50 healthy volunteers (34 males, 16 females; mean age: 43.4±10.4 years; range, 18 to 60 years) as a control group between June 1, 2022, and August 31, 2022. Disease activity of the patients was calculated with the Disase Activity Score (DAS28). Heart rate, minimum and maximum QT intervals, QT dispersion, minimum and maximum P waves, P wave dispersion (Pd), minimum and maximum Tp-e intervals, Tp-e dispersion, minimum and maximum corrected QT (QTc) intervals, QTc dispersion, and the Tp-e/QTc ratio in ECGs were calculated. The mean disease duration of the RA group was 9.09±5.74 years. The mean C-reactive protein level was 9.83±8.29, the mean erythrocyte sedimentation rate was 26.12±16.28 mm/h, and the mean DAS28 was 3.03±0.37. There was a statistically significant increase in the maximum P wave, Pd, maximum QT, QT dispersion, maximum QTc, QTc dispersion, maximum Tp-e, Tp-e dispersion, and Tp-e/QTc dispersion parameters in the RA group compared to the control group, while there was a significant decrease in the minimum P wave, minimum QT, and minimum QTc parameters. In our study, the Pd, QTc dispersion, Tp-e dispersion, and Tp-e/QTc dispersion values of our patients, which indicate the risk of atrial and ventricular arrhythmia, were found to be significantly higher. This finding suggests that our patients had an increased risk of cardiac morbidity and mortality. Arrhythmias are the likely source of the increase in sudden cardiac death in RA, and these new indicators measured on ECG can be used as standardized cardiovascular morbidity and mortality indicators in the future.

Diagnostic utility of electrocardiogram for screening of cardiac injury on cardiac magnetic resonance in post-hospitalised COVID-19 patients: a prospective multicenter study

BackgroundThe role of ECG in ruling out myocardial complications on cardiac magnetic resonance (CMR) is unclear. We examined the clinical utility of ECG in screening for cardiac abnormalities on CMR among post-hospitalised COVID-19 patients. MethodsPost-hospitalised patients (n = 212) and age, sex and comorbidity-matched controls (n = 38) underwent CMR and 12‑lead ECG in a prospective multicenter follow-up study. Participants were screened for routinely reported ECG abnormalities, including arrhythmia, conduction and R wave abnormalities and ST-T changes (excluding repolarisation intervals). Quantitative repolarisation analyses included corrected QT (QTc), corrected QT dispersion (QTc disp), corrected JT (JTc) and corrected T peak-end (cTPe) intervals. ResultsAt a median of 5.6 months, patients had a higher burden of ECG abnormalities (72.2% vs controls 42.1%, p = 0.001) and lower LVEF but a comparable cumulative burden of CMR abnormalities than controls. Patients with CMR abnormalities had more ECG abnormalities and longer repolarisation intervals than those with normal CMR and controls (82% vs 69% vs 42%, p < 0.001). Routinely reported ECG abnormalities had poor discriminative ability (area-under-the-receiver-operating curve: AUROC) for abnormal CMR, AUROC 0.56 (95% CI 0.47–0.65), p = 0.185; worse among female than male patients. Adding JTc and QTc disp improved the AUROC to 0.64 (95% CI 0.55–0.74), p = 0.002, the sensitivity of the ECG increased from 81.6% to 98.0%, negative predictive value from 84.7% to 96.3%, negative likelihood ratio from 0.60 to 0.13, and reduced sex-dependence variabilities of ECG diagnostic parameters. ConclusionPost-hospitalised COVID-19 patients have more ECG abnormalities than controls. Normal ECGs, including normal repolarisation intervals, reliably exclude CMR abnormalities in male and female patients.

Do Different TSH Suppression Levels Effect Heart Rate Variability and QT Dispersions in Patients with Differentiated Thyroid Cancer?

ABSTRACT Objective The aim of this study was to investigate changes in heart rate variability (HRV) and QT dispersion (QTd) in patients with differentiated thyroid cancer at different TSH suppression levels. Methods The study included 125 DTC patients, who had been on TSH suppression treatment (TSHST) for at least 1 year. The patients were categorized into three groups: patients with TSH < 0.1 mIU/L (n:30), those with TSH 0.1 to 0.5 mIU/L (n:56), and those with TSH 0.5 to 2 mIU/L (n:39). The first two groups were classified as suppression groups, and the last as replacement (control) group. All patients underwent 12-lead electrocardiogram (ECG) recording and 24-hour rhythm holter echocardiography analysis. Results The HRV results derived from a 24-hour rhythm holter did not exhibit any significant difference (p < 0.05). In dispersion evaluations, the QTd was significantly longer in the suppression groups (groups 1 and 2), than in the replacement group (group 3) (p < 0.001 and p:0.002, respectively). The same was found for corrected QT dispersion (QTcd) (p < 0.001 and p: 0.008, respectively). In multivariate linear regression analysis, TSH was found to affect QTd (β = -0.299; p = 0.002) and QTcd (β = -0.300; p = 0.002) values independently. Conclusion In this study, it was shown that in patients with DTC receiving TSHST, QT dispersion prolonged as the TSH suppression level increased. Especially in high-risk DTC patients, evaluation of QTd may be useful in terms of evaluating cardiovascular risk and regulating TSHST level.

Corrected QT interval and QT dispersion in temporal lobe epilepsy in children and adolescent

&lt;b&gt;Aim&lt;/b&gt;: The purpose of this research was to contrast (heart-rate corrected QT interval) QTc, and (QT dispersion) QTd intervals in individuals with (temporal lobe epilepsy) TLE and those without TLE using a standard 12-lead electrocardiogram.&lt;br /&gt; &lt;b&gt;Patients &amp;amp; methods&lt;/b&gt;: This cross-sectional research was undertaken on 100 cases aged 10 to 20 diagnosed with epilepsy in accordance with 2017 ILAE criteria. The patients’ informed written permission was acquired. In our study, we included 100 cases: 50 with TLE and 50 with non-TLE verified by seizure semiology. All patients were subjected to a comprehensive history, clinical examination (heart rate, pulse, and blood pressure), and clinical evaluation, which included a comprehensive epilepsy history. On the basis of neurology service documents or the initial publication of the international classification of diseases, 9&lt;sup&gt;th&lt;/sup&gt; revision (ICD9) diagnostic or 10&lt;sup&gt;th&lt;/sup&gt; revision (ICD10) codes for epilepsy, diagnostic age for epilepsy was calculated.&lt;br /&gt; &lt;b&gt;Results: &lt;/b&gt;The mean QT interval in group I was 418.30±25.48 ms while that of group II was 406.20±27.63 ms, the mean QTc of group I was 513.60±61.94 ms and was 488.70±50.65 in group II. The calculated QTd was with a mean of 57.60±25.05 ms while that of group II was 43.60±31.89 ms. It means that the QT interval, QTc, and QTd values were considerably greater in the group I (temporal epilepsy) contrasted with group II (non-temporal epilepsy); (p=0.025, 0.030, and 0.016, respectively). The mean QT, QTc, and QTd values for FE were 409.20±20.80, 500.70±55.60, and 52.60±29.70 ms, respectively. QT, QTc, and QTd mean values for patients with widespread epilepsy were 412.00±25.60, 505.00±68.60, and 46.20±28.70 ms. QT, QTc, and QTd interval were insignificantly different between focal and generalized epilepsy. The longer an illness progresses, the longer the QT and QTc intervals, as there was a substantial positive correlation among illness’s course and QT interval (r=0.391, p&amp;lt;0.001) and QTc interval (r=0.289, p=0.011), but there was no noticeable impact on QTd due to the illness’s duration, as we found an insignificant correlation among duration of illness and QTC and QTd.&lt;br /&gt; &lt;b&gt;Conclusions: &lt;/b&gt;Our findings indicate that; QTc interval and QTd are longer in epilepsy cases more among TLE cases contrasted with non-TLE. Since there was no distinction among different epilepsy types (focal and generalized).

Progranulin, sICAM-1, and sVCAM-1 May Predict an Increased Risk for Ventricular Arrhythmias in Patients with Systemic Sclerosis.

In systemic sclerosis (SSc), fibrosis of the myocardium along with ongoing autoimmune inflammation can alter the electric function of the cardiac myocytes, which may increase the risk for ventricular arrhythmias and sudden cardiac death. We analyzed the electrocardiographic (ECG) variables describing ventricular repolarization such as QT interval, QT dispersion (QTd), T wave peak-to-end interval (Tpe), and arrhythmogeneity index (AIX) of 26 patients with SSc and 36 healthy controls. Furthermore, echocardiographic and laboratory parameters were examined, with a focus on inflammatory proteins like C-reactive ptotein (CRP), soluble intracellular adhesion molecule-1 (sICAM-1), soluble vascular adhesion molecule-1 (sVCAM-1), and progranulin (PGRN). The CRP, sICAM-1, and sVCAM-1 levels were positively correlated with the length of the QT interval. Although the serum PGRN levels were not increased in the SSc group compared to the controls, in SSc patients, the PGRN levels were positively correlated with the QT interval and the AIX. According to our results, we conclude that there may be a potential association between autoimmune inflammation and the risk for ventricular arrhythmias in patients with SSc. We emphasize that the measurement of laboratory parameters of inflammatory activity including CRP, PGRN, sVCAM-1, and sICAM-1 could be helpful in the prediction of sudden cardiac death in patients with SSc.

Defective recovery of QT dispersion due to no-reflow following acute interventional therapy in patients with ST-segment elevation myocardial infarction.

Previous studies have suggested that adequate myocardial reperfusion after percutaneous coronary intervention (PCI) can improve the inhomogeneity of myocardial repolarization. However, it remains unclear whether no-reflow (NR) following emergency PCI involves disadvantages related to ventricular repolarization indices. The present study aimed to determine the effect of NR on QT dispersion (QTd) in patients with ST-segment elevation myocardial infarction (STEMI) and to evaluate the prognostic value of the relative reduction of QTd on ventricular arrhythmia events (VAEs). A prospective case-control study was conducted. According to the inclusion criteria, 275 patients with STEMI who underwent primary PCI treatment at the First People's Hospital of Anqing affiliated to Anhui Medical University from January 2020 to May 2023 were enrolled. According to whether NR occurred during PCI, these patients were divided into two groups: an NR group and a non-NR group. Subsequently, the QT intervals were measured before and at 12 hours after PCI. Afterward, the QTd, corrected QTd (QTcd), and the relative reduction of QTd and QTcd 12 hours pre- and postprocedure (ΔQTd-R and ΔQTcd-R, respectively) were calculated. Finally, multivariable logistic regression analysis was performed to predict the risk of VAE occurrence. In the non-NR group, there was a significant decrease from baseline in postprocedure QTd (48±17 vs. 73±22 ms; P=0.009) and QTcd (54±19 vs. 80±23 ms; P=0.01); in contrast, the NR group showed no significant difference in QTd (64±20 vs. 75±23 ms; P=0.58) or QTd (70±22 vs. 82±26 ms; P=0.45). Furthermore, the ΔQTd-R and ΔQTcd-R were both lower in the NR group than in the non-NR group (P<0.05); however, the rate of VAEs was higher in the NR group than in the non-NR group (15.2% vs. 6.2%; P=0.02). The multivariable logistic regression analysis results revealed that each increase of 12% in ΔQTcd-R was an independent predictor of VAEs (odds ratio: 0.547; 95% confidence interval: 0.228-0.976). The NR phenomenon following primary PCI in patients with STEMI leads to the defective recovery of QTd and QTcd. Furthermore, ΔQTcd-R can be viewed as an effective indicator for evaluating the myocardial repolarization inhomogeneity, and short-term clinical outcomes.

The assessment of adolescent obesity's effects on ventricular repolarization

BackgroundCurrently, there is a lack of research on the Tp-Te interval and Tp-e/QT ratio in obese adolescents who have metabolic syndrome. AimOur study aims to compare established ventricular repolarization parameters with these intervals and ratios in obese adolescents with or without metabolic syndrome, alongside a healthy control group, while exploring the association of these repolarization parameters with cardiovascular risk factors and echocardiographic variables. MethodsThe study included 100 obese adolescents and 50 lean subjects, with the obese participants categorized into two subgroups. The Tp-Te interval was identified as the duration from the peak to the end of the T wave. ResultsThe metabolic and non-metabolic syndrome obese groups exhibited significantly elevated QTc and TpTe values compared to the control group, with no statistically significant differences observed in minimum QT, maximum QT, QT dispersion, QTc dispersion, TpTe dispersion, and TpTe/QT ratio values among obese subjects with metabolic or non-metabolic syndrome and controls. Specifically, TpTe values were significantly elevated in the non-metabolic syndrome obese groups compared to controls, while minimum TpTe values were significantly elevated in the metabolic syndrome obese groups compared to controls, and the prolongation of the QTc interval was notably elevated in the obese groups than in controls. ConclusionsObese adolescents demonstrated an elevated TpTe interval compared to healthy controls, without any significant differences observed in TpTe dispersion, and TpTe/QT ratio values between the two groups. Results of our study showed that a negative correlation between TpTe and HDL-cholesterol and a positive correlation between the TpTe/QT ratio and insulin sensitivity indices in adolescents with metabolic syndrome.

The Effect of Obesity on Repolarization and Other ECG Parameters.

Background: Overweight and obesity are important risk factors in the development of cardiovascular diseases. New repolarization markers, such as the Tpeak-Tend interval and JTpeak intervals, have not yet been profoundly studied in obese patients. The study aims to analyze whether, in patients with obesity and overweight, repolarization markers, including the Tpeak-Tend interval, are prolonged and simultaneously check the frequency of other ECG pathologies in a 12-lead ECG in this group of patients. Methods: A study group consisted of 181 adults (90 females and 91 males) with overweight and first-class obesity. The participants completed a questionnaire, and the ECG was performed and analyzed. Results: When analyzing the classic markers, only QT dispersion was significantly higher in obese people. The Tpeak-Tend parameter (97.08 ms ± 23.38 vs. 89.74 ms ± 12.88, respectively), its dispersion, and JTpeak-JTend parameters were statistically significantly longer in the obese group than in the controls. There were also substantial differences in P-wave, QRS duration, and P-wave dispersion, which were the highest in obese people. Tpeak-Tend was positively correlated with body mass and waist circumference, while JTpeak was with BMI, hip circumference, and WHR. Tpeak/JT was positively correlated with WHR and BMI. In backward stepwise multiple regression analysis for JTpeak-WHR, type 2 diabetes and smoking had the highest statistical significance. Conclusions: Only selected repolarization markers are significantly prolonged in patients with class 1 obesity and, additionally, in this group, we identified more pathologies of P wave as well as prolonged QRS duration.

Determinants/Predictors of QT Abnormalities in Patients on Psychotropic Medications in a Nigerian Tertiary Hospital.

Cardiovascular disease is a major global burden and a leading cause of premature death among patients with severe mental illness. Over time, research and clinical practice have paid increased attention to the impact of psychiatric medications on cardiac repolarization. In a resource-limited setting, it is common for psychotropic medications to be initiated and maintained in an outpatient setting without baseline or follow up ECG. This study evaluated the determinants and predictors of QT abnormalities among patient taking psychotropic drugs. We conducted a cross-sectional study in a population of 150 psychiatric patients on psychotropics and 75 controls. We studied the effects of various psychotropic drugs on QT dispersion (QTd) and corrected QT interval (QTc) as well as correlation with the types and dosages of psychotropic drugs used. All the subjects had detailed clinical examination and resting electrocardiogram (ECG) at 25mm/sec done. QTc was determined using Bazett formula and QTd was determined by subtracting shortest from longest QT in 12-lead ECG. The prevalence of prolonged QTc and QTd as well as the mean QTc and QTd were significantly higher in patients than the control group. The mean QTc was significantly higher in patient on typical antipsychotics compared to those on atypical antipsychotics. Age, heart rate and antipsychotic dose in chlorpromazine equivalent were predictors of QTc with the heart rate being the most powerful predictor among them. Psychotropic drugs use is associated with QTc and QTd prolongation with age, heart rate and antipsychotic dose as predictors of QTc.

44. The Relationship between P Wave and Corrected QT Dispersion with The Left Ventricular Ejection Fraction (LVEF) and The Severity of Coronary Artery Stenosis in Coronary Artery Disease: A Cross-sectional study

44. The Relationship between P Wave and Corrected QT Dispersion with The Left Ventricular Ejection Fraction (LVEF) and The Severity of Coronary Artery Stenosis in Coronary Artery Disease: A Cross-sectional study

THE EFFECT OF LINAGLIPTIN ON ARRHYTHMIA IN PATIENTS WITH TYPE 2 DIABETES MELLITUS

OBJECTIVE: Linagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that prevents the inactivation of incretin hormones and also stimulates the release of glucose-dependent insulin. Electrocardiographic abnormalities such as P wave dispersion and QT dispersion are associated with ventricular tachyarrhythmias and atrial fibrillation, respectively. In this study, we seek to determine if the introduction of linagliptin has any impact on the P wave dispersion and QT dispersion in individuals with Type 2 diabetes mellitus (Type 2 DM). MATERIAL AND METHODS: The study included 60 random patients (28 females- 46.7 % , 18 hypertension- 30 %, 16 smokers- 26.7 % ) who were admitted to the Training and Research Hospital internal medicine policlinic between October 2019 and May 2021 and who started linagliptin. The patients' electrocardiograms were taken at the start and the conclusion of the sixth month. Echocardiography was performed at treatment initiation and at the 6th month. RESULTS: When basal and 6th month electrocardiograms were compared, significant changes were observed in P wave dispersion (0.0435 ± 0.014 - 0.0312 ± 0.011 p&amp;lt;0.01), QT interval dispersion (0.0496 ± 0.01 - 0.0402 ± 0.01 p&amp;lt;0.01) and QTc interval dispersion (0.051 ± 0.01 - 0.038 ± 0.14 p&amp;lt;0.01). CONCLUSIONS: We demonstrated in this study that linagliptin had no detrimental effects on heart rhythm. Our study will be a guide for longer follow-up studies.