Corrected QT Dispersion Research Articles

Evaluating cardiac electrophysiological markers for predicting arrhythmic risk in hypothyroid patients

ABSTRACT Objectives 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). Methods 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. Results 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. Conclusion 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.

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.

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.

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

Prevalence of Increased QTc Dispersion Among Hypertensive Patients and Its Correlation to Clinical Risk Factors: A Hospital-Based Case-Control Study.

Background In Ghana and other sub-Saharan African countries, hypertension (HTN) prevalence is rapidly increasing. Hypertensive left ventricular hypertrophy (LVH) is associated with excess fibrous tissue deposition throughout the myocardium. This could lead to ventricular arrhythmias and sudden cardiac death. Increased corrected QT dispersion (QTcd) can cause ventricular repolarization and be used to identify patients at risk of ventricular tachyarrhythmia. The measurement of increased QTcd among hypertensive patients is a simple screening tool to stratify patients at cardiovascular risk. Methods A case-control hospital-based study was conducted on 200 consecutive hypertensive patients. Age- and sex-matched control groups of 200 normotensive individuals who gave informed consent were also recruited. The baseline clinical and demographic characteristics of participants were acquired using structured questionnaires. A physical examination and a resting 12-lead ECG were performed. Increased QTcd and LVH were determined. Results The mean age of hypertensive patients was 50.99±6.73 and 48.19±7.17 for the controls (p-value 0.63). The study population was predominantly female (1:2.4 male:female ratio). Higher mean values for QTcd and LVH (Sokolow-Lyon) were observed among hypertensive patients compared to controls. The prevalence of increased QTcd was 45.0% among hypertensive patients compared to 16.5% in controls (χ2=38.14, p-value <0.0000001, odds ratio = 4.14). Conclusion Increased QTcd is prevalent among hypertensive Ghanaians. Its measurement can be an effective non-invasive screening tool to risk-stratify hypertensive patients.

Impact of short-term exercise training on QT dispersion and double product in diabetic patients after surgical aortic valve replacement

Abstract Background QT dispersion (QTd) represents the heterogeneity in the repolarization of the ventricular myocardium and electrical instability of the myocardium, reflecting the increased tendency towards ventricular arrhythmias. Abnormally high QTd has been correlated with risk of cardiac death. Purpose The aim of this study was to establish the influence of short-term exercise training on QT dispersion and double product (DP), in diabetic patients after surgical aortic valve replacement (SAVR). Methods The study involved 147 patients after SAVR, in the sinus rhythm without AV blocks or branch blocks. Average age of patients was 59.3 years. 45 patients were with diabetes mellitus, and 102 were without diabetes. Patients were similar as to age and baseline stress test duration. In all subjects clinical examination, standard ECG and exercise test on treadmill according to Bruce protocol, were performed and after that patients were included in program of physical training for three weeks. Patients were instructed to follow a training program using the bicycle ergometer (10 min, 2 times a day), gymnastic exercises and walking. The patients continued to take the same medicaments in same doses. From standard ECG corrected QT dispersion (QTdc) was calculated. Results Before starting with the program of physical training, patients with diabetes had significantly higher values of QTdc (83.4 ± 15.3 vs 74.6 ± 16.9 ms; p&amp;lt;0.005) in comparison to those without diabetes. After three weeks, significant reduction of QTdc was found (from 83.4 ± 15.3 to 77.3 ± 15.4 ms; p&amp;lt;0.02 in patients with diabetes and from 74.6 ± 16.8 to 68.7 ± 17.1 ms; p&amp;lt;0.005 in patients without diabetes). After three weeks, significant reduction of DP was found (from 11763.8 ± 779.9 to 11314.8 ± 635.8 beat/min x mmHg; p&amp;lt;0.005 in patients with diabetes and from 114376.4 ± 792.3 to 10034.2 ± 521.3 beat/min x mmHg; p&amp;lt;0.001 in patients without diabetes). In diabetic patients, after program of physical training, significant reduction of glycemia was found (from 7.0 ± 2.3 to 5.9 ± 1.5 mmol/L; p&amp;lt;0.005), of total cholesterol from 5.2 ± 1.3 to 4.6 ± 1.1 mmol/L (p&amp;lt;0.025), of LDL cholesterol from 3.2 ± 0.8 to 2.8 ± 0.6 mmol/L (p&amp;lt;0.05). After three weeks, both groups of patients in the exercise test reached a significantly longer time (p&amp;lt;0.001). Conclusions The study showed that patients with diabetes have a higher value QTdc, probably due to diffuse interstitial fibrosis. Short-term exercise training has favourable effects on QT dispersion and double product in patients after SAVR. In patients without diabetes physical training had more favourable effects on the followed parameters. Physical training led to the significant decrease of myocardial oxygen uptake at rest and probably decreased the possibility of arrhythmia events.

Abstract 14577: Electrocardiogram Parameters for Predicting the Severity of Coronary Artery Disease in Non-ST Segment Elevation Acute Coronary Syndrome

Background: Quantitative electrocardiogram (ECG) parameters have been found to correlate with severity of coronary artery disease (CAD). Thus, it may serve the purpose of risk stratifying patients with non-ST segment elevation acute coronary syndrome (NSTEACS). But little is known about the accuracy of each parameter.So, this study was done to assess the correlation of ECG parameters with severity of CAD in patients with NSTEACS and to compare the diagnostic accuracy among them. Methods: 178 patients with NSTEACS with left ventricular ejection fraction &gt;50% were selected for the study after excluding patients with heart failure, arrhythmia, prior myocardial infarction or revascularisation. P wave peak time (PWPT), corrected QT dispersion (cQTd) and QT dispersion ratio (QTDR) was calculated in all patients. CAD severity was assessed visually by coronary angiography and calculating the syntax score. Results: PWPT, cQTd and QTDR were increased significantly in patients with left main (LM) or triple vessel disease (TVD) than others. These parameters also showed a strong positive correlation with the syntax score ( P&lt;.001 ). Among these parameters, cQTd showed the best diagnostic accuracy (76% sensitivity and 64% specificity) to detect LM or TVD with a cut-ff value of 74 ms. Conclusion: PWPT, cQTd and QTDR may help to identify high risk patients with NSTEACS and early invasive procedure can be done to salvage a large area of myocardium at jeopardy. These may be particularly helpful to the physicians in periphery who have limited resources. Keywords: coronary artery disease, non-ST segment elevation acute coronary syndrome, P wave peak time, corrected QT dispersion, QT dispersion ratio

Abstract 14282: Electrocardiography Rules out Myocardial Abnormalities on Cardiac Magnetic Resonance Imaging in Post-Hospitalized COVID-19 Patients: A Multicenter Observational Study

Introduction: The diagnostic performance of EKG in ruling out myocardial abnormalities following COVID-19 is unclear. Aim: To assess the ability of EKG to exclude cardiac abnormalities on cardiac magnetic resonance imaging (CMR) in post-hospitalised COVID-19 patients. Methods: Post-hospitalized patients (n=212) &amp; comorbidities matched controls (n=38) underwent CMR and 12-lead EKG. EKG assessments included depolarization &amp; repolarization abnormalities [ QTc , corrected QT dispersion ( QTc disp ), JT ( JTc ) &amp; T peak-end ( cTPe ) intervals]. CMR abnormalities were defined as reduced left ventricular ejection fraction (LVEF), high T1 &amp; T2 Z scores and high extracellular volume and pathological late gadolinium enhancement. Results: At 5.6 months post-discharge, patients had a higher burden of EKG abnormalities vs controls (72.2% vs 42.1%, p=0.001 ) (Figure A) . CMR abnormalities were comparable despite patients having lower LVEF. Abnormal EKG findings and prolonged repolarization were more common in patients with CMR abnormalities vs patients with normal CMR and controls ( Figure A &amp; B ). Area-under-the-receiver-operating curve (AUROC) of routine EKG abnormalities to discriminate abnormal CMR was 0.56 (95% CI 0.47-0.65), p=0.185. Inclusion of JTc &amp; QTc disp improved the AUROC to 0.64 (95% CI 0.55-0.74), p=0.002. Inclusion of JTc ≥340ms &amp; QTc disp ≥40ms improved the sensitivity from 81.6% to 99.9% with higher negative predictive value (84.7% to 99.9%) ( Figure A ). Conclusions: Post-hospitalized COVID-19 patients have more EKG abnormalities than comorbidities-matched controls. A normal EKG with normal repolarization is effective in ruling out significant CMR abnormalities.

A Study on QT Dispersion before and after Thrombolysis in Acute Myocardial Infarction and its Prognostic Implications: A before and after Comparison Study.

Introduction: Acute myocardial infarction (AMI) stands as one of the most catastrophic occurrences in the progression of coronary artery disease. Measuring QT dispersion (QTd) is a fairly straightforward and noninvasive technique for predicting mortality in patients at high risk following a myocardial infarction (MI). Objective: To measure the QT, corrected QT interval (QTc), QTd, and corrected QT dispersion (QTcd) intervals before and after thrombolysis in patients with AMI and to determine prognostic implications of QTd in AMI. Materials and methods: This was a before and after comparison study conducted in the intensive care unit (ICU) of a tertiary care center in Central India. It was carried out in patients with AMI [ST-elevation myocardial infarction (STEMI)] who underwent thrombolysis in ICU. A total of 160 participants were enrolled over the time period of 24 months using the convenience sampling technique. Results: The most prevalent (68 patients) risk factor among MI patients was hypertension (HTN). QT parameters such as QT, QTd, and QTcd showed significant statistical variation of p-value < 0.0001 when compared at admission and after thrombolysis. No significant difference (p > 0.05) in QT parameters at admission (QTd, QTc, and QTcd) between anterior and inferior wall MI, except for QT interval (p = 0.0010). Among the 33 patients who experienced arrhythmia, ventricular tachycardia was the most prevalent arrhythmia in 22 patients (13.75%). There was a significant statistical correlation between the arrhythmic event and the outcome of the patient (p < 0.0001). Patients who died had higher QT parameter values at admission, and these remained on the higher side even after thrombolysis, whereas those who got discharged had lower QT parameter values at admission, and their values decreased after thrombolysis. Conclusion: Successful thrombolysis significantly decreases the QTd and thereby the arrhythmogenic potential, and thus can also be used as a reliable predictor of arrhythmia in patients of MI. How to cite this article: M A, Khandait H, Guralwar C, et al. A Study on QT Dispersion before and after Thrombolysis in Acute Myocardial Infarction and its Prognostic Implications: A before and after Comparison Study. J Assoc Physicians India 2023;71(10):14-18.

Assessment of Ventricular Arrhythmias Risk in Gastroesophageal Reflux Disease Patients

Abstract Gastroesophageal reflux disease (GERD) is characterized by acid regurgitation and epigastric burning that occur as the result of reflux of gastric content into the esophagus. Disturbances in the autonomic nervous system (ANS) were observed in patients with GERD. The evidence suggests that chronic GERD can cause an autonomic response, which results in ventricular arrhythmias (VAs). Our aim in the study is to examine T wave peak-to-end interval (TpeI) and the TpeI/QT ratio as highly sensitive gauges of ventricular repolarization anomalies and VAs potential in patients with GERD. In our study, The ECG measurements of both GERD and control groups are as follow; The QT wave dispersion (QTd) and corrected QT dispersion (cQTd) were higher in patients with GERD in comparison to controls (p = 0.002 and P = 0.09, respectively). Moreover, TpeI, corrected TpeI (cTpeI), and the TpeI/QT ratio were increased in patients with GERD in comparison to controls (p &amp;lt; 0.001, p = 0.018, and p &amp;lt; 0.001, respectively). We can conclude that patients with GERD may have an increased risk for VAs, and the VAs risk in patients with GERD can be predicted by measuring TpeI and the TpeI/QT ratio, which are the indicators of ventricular repolarization anomalies.

Temporal changes of QT dispersion in patients with acute ischemic stroke

Aim: Ischemic stroke is a significant cause of morbidity and mortality and can lead to fatal arrhythmias even in the absence of underlying cardiac pathology. The objective of this study was to investigate the impact of acute ischemic stroke on QT dispersion and its temporal changes over time. Methods: A total of 124 patients with acute ischemic stroke who did not receive any reperfusion treatment were included in the study. Corrected QT dispersion (QTcd) values were obtained from 12-lead surface electrocardiograms taken within the first 12 hours and after 48 hours of stroke onset. These values were compared with those of 93 age and sex-matched control subjects. The effects of diabetes and lesion lateralization on QT dispersion were also analyzed. Stroke patients whose lesions were clearly localized to either the right or left hemisphere were divided into two subgroups. The change in QT dispersion overtime during the follow-up period was also determined. Results: The study included 124 patients with acute ischemic stroke (54 females and 70 males) with a mean age of 67±11 years, as well as a control group of 93 subjects (49 females and 44 males) with a mean age of 69±8 years. The QTcd values of the stroke group were significantly longer than the control group in the first 12 hours of symptom onset. However, after 48 hours, the QTcd values of the stroke group decreased and the difference between the two groups was not statistically significant. The presence of diabetes mellitus caused a more significant increase in QT dispersion, and after 48 hours, the QTcd values of diabetic stroke patients were still significantly longer. The QTcd values of patients with left hemispheric lesions were significantly longer than those of patients with right hemispheric lesions, and this difference persisted after 48 hours. Conclusion: This study found that QT dispersion increases during the first few hours of ischemic stroke and decreases during the treatment period. This increase is more obvious and lasts longer in stroke patients with diabetes and left hemispheric lesions. The results suggest that QT dispersion may be a useful prognostic indicator for patients with acute ischemic stroke.

Effect of reperfusion strategy on QT dispersion in patients with acute myocardial infarction: Impact on in-hospital arrhythmia.

Myocardial ischemia and ST-elevation myocardial infarction (STEMI) increase QT dispersion (QTD) and corrected QT dispersion (QTcD), and are also associated with ventricular arrhythmia. To evaluate the effects of reperfusion strategy [primary percutaneous coronary intervention (PPCI) or fibrinolytic therapy] on QTD and QTcD in STEMI patients and assess the impact of the chosen strategy on the occurrence of in-hospital arrhythmia. This prospective, observational, multicenter study included 240 patients admitted with STEMI who were treated with either PPCI (group I) or fibrinolytic therapy (group II). QTD and QTcD were measured on admission and 24 hr after reperfusion, and patients were observed to detect in-hospital arrhythmia. There were significant reductions in QTD and QTcD from admission to 24 hr in both group I and group II patients. QTD and QTcD were found to be shorter in group I patients at 24 hr than those in group II (53 ± 19 msec vs 60 ± 18 msec, P = 0.005 and 60 ± 21 msec vs 69+22 msec, P = 0.003, respectively). The occurrence of in-hospital arrhythmia was significantly more frequent in group II than in group I (25 patients, 20.8% vs 8 patients, 6.7%, P = 0.001). Furthermore, QTD and QTcD were higher in patients with in-hospital arrhythmia than those without (P = 0.001 and P = 0.02, respectively). In STEMI patients, PPCI and fibrinolytic therapy effectively reduced QTD and QTcD, with a higher observed reduction using PPCI. PPCI was associated with a lower incidence of in-hospital arrhythmia than fibrinolytic therapy. In addition, QTD and QTcD were shorter in patients not experiencing in-hospital arrhythmia than those with arrhythmia.

The Effect of Percutaneous Coronary Intervention on QT Dispersion and the Association Between Them: A Systematic Review.

Electrocardiography (ECG) parameters are significant in the prognosis of ischemia and other cardiovascular conditions. Reperfusion or revascularization techniques are essential in reestablishing blood flow to ischemic tissues. This study aims to demonstrate the association between percutaneous coronary intervention (PCI), a revascularization technique, and the electrocardiography (ECG) parameter, QT dispersion (QTd). We conducted a systematic review of the association between PCI and QTd through a literature search in three electronic databases, ScienceDirect, PubMed, and Google Scholar, for empirical studies published in English. Review Manager (RevMan) 5.4 (CochraneCollaboration, Oxford, England) was used for statistical analysis. Of 3,626 studies, 12 articles met the inclusion criteria, enrolling a total of 1,239 patients. After a successful PCI procedure, QTd and corrected QT (QTc) tremendously reduced at various time intervals with statistical significance in most of the studies. There was a clear association between ECG parameters QTd, QTc, and corrected QT dispersion (QTcd), and PCI, in that there is a considerable reduction in these ECG parameters after PCI treatment.

QRS and QT Interval Modifications in Patients with Type 2 Diabetes Mellitus.

Diabetes Mellitus imbricates inflammatory processes on their pathophysiology, it could affect cardiac electrophysiology. Cardiac inflammatory process leads electrocardiogram changes. Nevertheless, there are discrepancies about whether it prolongs or decreases waves and intervals such as QRS and QT. Furthermore, QRS dispersion has not been studied. To identify QRS complex and QT interval modifications in type 2 diabetic patients. A descriptive cross-sectional study was carried out in 59 type 2 diabetic patients selected by non-probabilistic sampling. Electrocardiogram was performed, QRS and QT interval were measured manually by two observers. Dispersion of both variables was calculated to compare with normal values. Two variables showed differences for sex, QRS dispersion was higher in females (45.84), p=0.0001 vs. reference value; QT dispersion (63.12) showed significance difference (p=0.0246) vs. reference value for males. Greater than five years of illness was related to higher QRS values (124.11 vs. 137.28), p=0.005 and corrected QT dispersion (61.81 vs. 78.79), p=0.022. The electrocardiographic differences between sexes may suggest a gender influence. The longer duration of diabetes diseases could increase cardiovascular risk of arrhythmias due to greater QRS duration and corrected QT interval prolongation.

Association of QT Markers of Arrhythmia and Familial Mediterranean Fever: A Meta-Analysis

BackgroundSome studies found no association between Familial Mediterranean fever (FMF) patients and abnormal QT markers of arrhythmia, others found prolongation of these markers in FMF patients. The aim of this study is to perform a met-analysis to find whether there is an actual association between FMF and abnormal QT markers. MethodsWe searched PUBMED, WOS, OVID and SCOPUS databases. We included in the meta-analysis any observational study that reported QT and its markers in FMF patients without any age restriction. Meanwhile reviews, case reports, editorials, and animal studies were excluded. RevMan software (5.4) was used to do the meta-analysis. ResultsAfter complete screening,14 studies were eligible for the meta-analysis. The total number of patients included in the analysis is 1154. The pooled analyses between FM group and control group in QT interval, corrected QT (QTc), QT dispersion (QTd) and corrected QT dispersion (QTcd) outcomes, were (MD= 2.34, 95% CI = -1.21 to 5.89, p value = 0.20), (MD= 7.06, 95% CI = 2.68 to 11.43, p value = 0.002), (MD= 6.08, 95% CI = 0.84 to 11.32, p value= 0.02), and (MD= 4.82,95% CI = -0.57 to 10.20, p value = 0.08), respectively. No heterogeneity was observed in QT interval outcome (p = 0.21) but heterogeneity was found in QTc outcome and was solved after performing leave- one out test by removing (Koca, 2011) study (p= 0.12) and the pooled analysis was significant (p= 0.005), and the heterogeneity in QTd and QTcd was not solved by leave- one out test or subgroup analysis. No publication bias was observed in each outcome. After performing subgroup analysis based on age, a significant associations were found between increased QTc and QTd markers and FMF in children and adults subgroups, p values = (0.002), (0.02), (0.04), (0.05), respectively. ConclusionQTc and QTd are prolonged in FMF patients compared with healthy controls. FMF patients are at increased risk of developing arrhythmia. More multi-center clinical trials are needed to support our findings.

Relation Between Familial Mediterranean Fever and QT Markers (QTc, QTd, and QTcd): A Systematic Review and Meta-Analysis.

The aim of this study is to perform a meta-analysis to evaluate the possible association betweenQT markersand familial Mediterranean fever (FMF). PUBMED, Web of Science,OVID, and SCOPUS databases were searched. Inclusion criteria were randomized control trials or observational studies that compared measurement of the QT markers in FMFpatients and healthy controls in both males and females without any age restriction or other comorbidities. RevMan software (5.4) was used to perform the analysis. A total of 14 studies with 1,154 individuals were included in the study. The pooled effect estimate showed a statistically significant association between FMF group and prolonged corrected QT (QTc) and QT dispersion (QTd) (MD= 7.06, 95% CI = 2.68 to 11.43, p-value = 0.002) and (MD= 6.08, 95% CI = 0.84 to 11.32, p-value= 0.02), respectively. No statistically significant difference between FMF group and QT interval and corrected QT dispersion (QTcd) (MD= 2.34, 95% CI = -1.21 to 5.89, p-value = 0.20) and (MD= 4.82, 95% CI = -0.57 to 10.20, p-value = 0.08), respectively. Our findings revealed a statistically significant relationship between FMF and extended QTcand QTd. More randomized multicenter trials are required to confirm our findings.

Increased QT dispersion and related factors in patients with systemic sclerosis

Introduction: Cardiac arrhythmias and sudden death may occur as a result of ventricular myocardial fibrosis or ischemia in patients with systemic sclerosis (SSc). QT prolongation and QT dispersion, which facilitate the development of ventricular fibrillation, are important cardiac problems associated with increased mortality. In this study, we aimed to investigate the prevalence of corrected QT dispersion (cQTD) and related factors in our patients with systemic sclerosis compared to healthy controls. Material and Method: The 12-lead electrocardiograms with a rate of 25 mm/s of patients with no previous history of cardiovascular disease and controls were analyzed. cQTD was defined as the difference between the maximum QT interval and the minimum QT interval. Nailfold capillaroscopy examination was performed. Disease activity was evaluated using revised European Scleroderma Study Group activity index. Results: Forty-nine SSc patients (45 females, mean age 53.26±10.63 years, and disease duration 8.0 (1-25) years) and 41 controls (37 females, mean age 49.29±8.02 years) were included. While the frequency of smoking was significantly higher in controls (p=0.025), erythrocyte sedimentation rate was higher in patients (p&amp;lt;0.001). cQTD was significantly higher in the patient group compared to the control group (65.14±17.57 ms and 42.73±10.03 ms, respectively, p&amp;lt;0.001). A significant positive correlation was found between erythrocyte sedimentation rate and cQTD in the patient group. We found no association between cQTD and disease activity, medications, anti-SSA/Ro positivity, capillaroscopy paterns, presence of interstitial lung disease and pulmonary arterial hypertension. Conclusion: In our study, cQTD, which indicates an increased risk for ventricular arrhythmia and cardiovascular mortality, was found to be significantly higher in the patients compared to the controls. Determining cardiac risks with an electrocardiogram, which is a non-invasive and easily available method, is important in the follow-up of SSc patients.

Effect of particulate matter 2.5 on QT dispersion in patients with chronic respiratory disease

PM2.5 air pollutants increased risk of ventricular arrhythmias. The prolonged corrected QT interval (QTc) and QT dispersion (QTd) is common in patients with chronic airway disease and is associated with heightened risk of ventricular tachyarrhythmia. We sought to examine the effect of PM2.5 exposure on QTc and QTd in patients with chronic airway disease. We enrolled 73 patients with chronic airway disease into the study. The 12-lead ECGs were recorded during high-exposure and low-exposure periods of PM2.5. QTc and QTd were compared between 2 periods. Mean age was 70 ± 10 years. Mean FEV1/FVC was 63 ± 14%. There was no difference in QTc between PM2.5 high-exposure and low-exposure periods. However, QTd was significantly increased during PM2.5 high-exposure compared to low-exposure periods in male patients (43.5 ± 15.0 vs. 38.2 ± 12.1 ms, P = 0.044) but no difference was found in females. We found that patients who worked mostly indoor had less QTd than those working outdoor during PM2.5 low-exposure period. In addition, those who wore face mask tended to have less QTd during low-exposure period than those who did not. High PM2.5 exposure increased QTd in male patients with chronic airway disease. Working indoors and wearing face mask were associated with less QTd.

Effect and benefit of percutaneous coronary intervention in chronic total occlusion on ventricular repolarization: QT correction and dispersion.

ST segment, T wave changes, QT interval changes, and QTc dispersion are among the parameters used to diagnose ischemic heart disease. The increase in the QT dispersion can be caused by myocardial ischemia, among other heart diseases, whereas cardiac diseases such as coronary artery disease (CAD) can be diagnosed by observing an abnormally high QTc dispersion. This study aimed to evaluate the variations in the QTc dispersion (depolarization and repolarization) of surface electrocardiography as a result of percutaneous coronary intervention (PCI) in patients with chronic total occlusion. This study took place in the Iraqi Center for Heart Disease from October 2020 to February 2021. 110 patients who suffered from chronic occlusion of the coronary artery and underwent PCI revascularization were examined. Twelve-lead electrocardiograms were recorded at the time of admission (12 hours before intervention) and more than one hour after the intervention. The measured ECG parameters included corrected QT interval durations and corrected QT dispersion in both pre and post-PCI electrocardiograms, and their values were compared. The average corrected QT interval and QTC dispersion changed significantly before and after the percutaneous coronary intervention. Performing percutaneous coronary intervention on patients who suffer from coronary artery total occlusion shows a major reduction in the corrected QT dispersion.