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

Background: 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). Methods: 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. Results: 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). Conclusions: 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.

Relationship between Alzheimer dementia and QT interval: A meta-analysis.

While the link between aging and mortality from dementia is widely appreciated, the mechanism is not clear. The objective of this study was to determine whether there is a direct relationship between Alzheimer dementia (AD) and the QT interval, because the latter has been related to cardiac mortality. A systematic review and meta-analysis were conducted after a Medline and EMBASE search using terms "Alzheimer disease or Dementia AND QT interval, QT dispersion or cardiac repolarization." Four studies with control groups were identified. There were significant differences in QT interval between individuals with AD vs individuals without dementia (controls) (odds ratio (OR)1.665 [random effects model] and 1.879 [fixed effect model]) (p < 0.001). There were significant differences in QT interval between individuals with AD vs individuals with mild cognitive impairment (MCI) (OR 1.760 [random effects] and 1.810 [fixed effect]) (p < 0.001). A significant (p <0.001) correlation exists between the QTc and the Mini-Mental State Exam (MMSE), a test of cognitive function. Two studies examined QT variability (the difference between the longest and shortest QT interval on a 12 lead ECG); the OR for QT variability AD vs MCI was 3.858 [random effects model] and 3.712 [fixed effects model] (p < 0.001). When compared to the control group, the OR for QT dispersion in AD was 6.358 [random effects model] or 5.143 ( P< 0.001) [fixed effects model]. A qualitative analysis of the data raised questions about paucity of data defining the nature of the control groups, the pathophysiologic mechanism, and the uniform use of a poor QT heart rate correction factor. The longer QT in AD, greater QT variability in AD, and the direct relationship between QT interval and AD severity supports a brain-heart connection in AD that might be fundamental to aging-induced AD and mortality. Issues with defining the control group, limited number of studies, conflicting data in population studies, and the lack of a strong electrophysiological basis underscore the need for additional research in this field.

Evaluation of cardiac functions in children with familial Mediterranean fever.

OBJECTIVES: Familial Mediterranean fever is an autosomal recessive autoinflammatory inherited disease. We aimed to evaluate cardiac involvement in children with familial Mediterranean fever during the attack-free period. MATERIAL AND METHODS: The prospective study included 75 familial Mediterranean fever patients during the attack-free period and 50 healthy children. Cardiac evaluation was performed using electrocardiography, 24-hour ambulatory Holter monitoring, and conventional and tissue Doppler echocardiography. Aortic stiffness indices were calculated. RESULTS: There were no differences between the groups in age, height, sex, body mass index, and arterial blood pressure parameters (p > 0.05). QT and corrected QT dispersion parameters were similar in both groups (p > 0.05). The E wave velocity and the E/A ratio of the mitral and tricuspid valves decreased, and the A wave velocity of the tricuspid and mitral valve increased in familial Mediterranean fever by the Doppler echocardiography (p < 0.05). The myocardial contraction velocities (Sd), early relaxation velocity (Ed), and Ed/late relaxation velocity (Ad) of both ventricles were decreased in familial Mediterranean fever group, whereas the Ad of both ventricles and the interventricular septum was increased in familial Mediterranean fever group. Aortic strain and distensibility were decreased, and pressure strain elastic modules (Ep), pressure strain normalised (Ep*) by diastolic pressure, and aortic stiffness ß index were increased in familial Mediterranean fever patients (p < 0.05). When time domain heart rate variability parameters were evaluated, SDNN-i, RMSSD, and PNN50 significantly decreased in familial Mediterranean fever patients (p < 0.05), whereas SDNN and SDANN were similar in both groups (p > 0.05). CONCLUSION: Our findings showed that cardiac involvement could exist in familial Mediterranean fever patients, even during nonattack periods.

Effect of dapagliflozin on ventricular repolarization in patients with heart failure with reduced ejection fraction.

Whether sodium-glucose cotransporter-2 inhibitors (SGLT2is) reduce ventricular arrhythmias and sudden cardiac death is controversial. Ventricular repolarization heterogeneity is associated with ventricular arrhythmias; however, the effect of SGLT2is on ventricular repolarization in patients with heart failure with reduced ejection fraction (HFrEF) has not been fully investigated. We prospectively evaluated 31 HFrEF patients in sinus rhythm who were newly started on dapagliflozin 10 mg/day. Changes in QT interval, corrected QT interval (QTc), QT dispersion (QTD), corrected QTD (QTcD), T peak to T end (TpTe), TpTe/QT ratio, and TpTe/QTc ratio were evaluated at 1-year follow-up. QT interval, QTc interval, QTD, QTcD, TpTe, and TpTe/QTc ratio decreased significantly at 1-year follow-up (427.6 ± 52.6 ms vs. 415.4 ± 35.1 ms; p = 0.047, 437.1 ± 37.3 ms vs. 425.6 ± 22.7 ms; p = 0.019, 54.1 ± 11.8 ms vs. 47.6 ± 14.7 ms; p = 0.003, 56.0 ± 11.2 ms vs. 49.4 ± 12.3 ms; p = 0.004, 98.0 ± 15.6 ms vs. 85.5 ± 20.9 ms; p = 0.018, and 0.225 ± 0.035 vs. 0.202 ± 0.051; p = 0.044, respectively). TpTe/QT ratio did not change significantly (0.231 ± 0.040 vs. 0.208 ± 0.054; p = 0.052). QT interval, QTD, and TpTe were significantly reduced 1 year after dapagliflozin treatment in patients with HFrEF. The beneficial effect of dapagliflozin on the heterogeneity of ventricular repolarization may contribute to the suppression of ventricular arrhythmias.Registry information https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000049428 . Registry number: UMIN000044902.

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.

Evaluation of the changes in electrocardiographic ventricular repolarization parameters after COVID-19 recovery in hemodialysis patients.

INTRODUCTION: Coronavirus disease-2019 (COVID-19) has cardiac manifestations. Data about electrocardiogram (ECG) changes after COVID-19 recovery is limited in hemodialysis patients. We aimed to investigate the changes in ventricular repolarization parameters after COVID-19 recovery in hemodialysis patients. METHODS: Fifty-five hemodialysis patients who recovered from COVID-19 infection were included. QT interval, Tp-e interval, corrected QT (QTc), QTc dispersion, and Tp-e dispersion values were determined on the patients' ECGs, taken before COVID-19 and at least 1 month after recovery. The patients' data before COVID-19 infection and after recovery were compared. RESULTS: It was found that longest QTc (QTcmax) and QTc dispersion values after recovery were prolonged compared with pre-infection period (427 ± 28 ms vs. 455 ± 26 ms, p = 0.000 and 39 ± 16 ms vs. 65 ± 20 ms, p = 0.000). CONCLUSION: In our hemodialysis patients, ventricular repolarization parameters increased after COVID-19 recovery. In hemodialysis patients, already predisposed to arrhythmic deaths, arrhythmia risk after COVID-19 recovery may become more pronounced.

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 (Cochrane Collaboration, 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.

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

BACKGROUND: Myocardial ischemia and ST-elevation myocardial infarction (STEMI) increase QT dispersion (QTD) and corrected QT dispersion (QTcD), and are also associated with ventricular arrhythmia. AIM: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Changes in QT Interval in Maintenance Hemodialysis Patients: Pre-Dialysis, One Hour after Initiation of Dialysis, and Post-Dialysis.

INTRODUCTION: This study aimed to evaluate the effects of dialysis on change of QT interval in pre-dialysis, 1 h after dialysis initiation, and post-dialysis period in patients on maintenance dialysis (MHD). METHODS: An observational prospective study was conducted, including 61 patients, on thrice-weekly MHD ≥3 months, and without acute diseases, at the Nephrology-Dialysis Department of a tertiary hospital in Vietnam. The exclusive criteria were atrial fibrillation, atrial flutter, branch block, prolonged QT recorded in medical history, and taking antiarrhythmic drugs lengthening QT interval before entering the study. Twelve-lead electrocardiographs and blood chemistries were done simultaneously before, 1 h after initiation, and after the dialysis session. RESULTS: The proportion of patients with prolonged QT interval increased significantly from 44.3% in pre-dialysis to 77% 1 h after dialysis initiation and 86.9% in post-dialysis session. Immediately after dialysis, the QT and QTc intervals on all 12 leads were significantly longer. Post-dialysis levels of potassium, chloride, magnesium, and urea decreased significantly from 3.97 (0.7), 98.6 (4.7), 1.04 (0.2), and 21.4 (6.1) to 2.78 (0.4), 96.6 (2.5), 0.87 (0.2), and 6.33 (2.8) mmol/L, respectively, whereas the calcium increased significantly from 2.19 (0.2) to 2.57 (0.2) mmol/L. There were significant differences in the potassium level at the dialysis initiation and its speed of reduction between the group without and with prolonged QT interval. CONCLUSIONS: There was an increased risk of prolonged QT interval in MHD patients regardless of the absence of the previous abnormal QT interval. Notably, this risk increased rapidly 1 h after the initiation of dialysis.

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

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

Effect of Sodium-Glucose Co-transporter-2 Inhibitors on Ventricular Repolarization Markers in Heart Failure with Reduced Ejection Fraction.

BACKGROUND AND AIM: Sodium-glucose co-transporter-2 (SGLT2) inhibitors added to optimal medical therapy have been shown to reduce the risk of cardiovascular death and recurrent heart failure (HF) hospitalization in HF patients. We aimed to evaluate the effect of SGLT2 inhibitors on the ventricular repolarization markers (VRM) in patients with HF with reduced ejection fraction (HFrEF). METHODS: 51 patients with HFrEF who had symptoms New York Heart Association (NYHA) class II-IV despite optimal medical treatment and were added SGLT2 inhibitors to their treatment were included in the study. Electrocardiography (ECG) and laboratory results obtained before the treatment and at the first-month follow-up visit were compared. QT, QTc (corrected by Bazett formula), QT dispersion (QTd), QTc dispersion (QTc-d), Tpeak to Tend (Tp-e) interval, Tp-e/QT, and Tp-e/QTc ratios were measured and defined as VRM. RESULTS: A significant decrease was observed in HR, QT, QTc intervals, and QTd compared to pre-treatment. While the mean Tp-e interval was 101.5 ± 11.7 ms before treatment, it decreased to 93.1 ± 12.7 ms after treatment (p < 0.001). There was a significant decrease in N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels after treatment [2859 ± 681vs.1266 ± 763, respectively (p < 0.001)] and QTd, Tp-e interval, and Tp-e/QTc ratio was positively correlated with the change in NT-proBNP level. CONCLUSIONS: The addition of SGLT2 inhibitors to optimal medical therapy in HFrEF patients positively changes VRM (QT, QTc, QTd, Tp-e, and Tp-e/QTc).

Evaluation of the Cardiac Conduction System in Fibromyalgia Patients With Complaints of Palpitations.

Objective This study aimed to investigate the influence of fibromyalgia syndrome (FMS) on the cardiac conduction system and assess patients' palpitation complaints using 24-h ambulatory ECG (Holter {Maynard, MA: Northeast Monitoring, Inc.}) monitoring. Methods Ninety patients with FMS and 70 healthy controls were included in this research. ECG was performed on all participants, and ECG parameters were calculated. Holter monitoring was conducted, and the recordings were analyzed. The results of time-domain heart rate variability (HRV) were evaluated. Results The patient group's mean age was 38.3±6.3 years. There were no statistically significant differences in demographic or laboratory parameters across the groups (p>0.05). The findings of a 24-h Holter ECG recording did not vary significantly between the groups (p=0.182). In the study group, the values for the standard deviation of R-R intervals (SDNN), low frequency (LF), and low/high frequency (LF/HF), which are known as HRV indicators, were substantially different between the two groups (p<0.05). Conclusions The study indicated that the risk of arrhythmias did not increase even though FM patients complained of palpitations.

COVID-19 and arrhythmia: The factors associated and the role of myocardial electrical impulse propagation. An observational study based on cardiac telemetric monitoring.

Background: The heart is commonly involved in COVID-19, and rhythm disorders have been largely reported. Objective: To evaluate the association of some non-cardiac and cardiac comorbidities and QT dispersion with arrhythmias and their impact on outcomes in hospitalized patients with COVID-19. Methods: Each patient underwent cardiac telemetry monitoring through the entire hospitalization period, laboratory analyses, 12-lead ECG, and lung imaging examination. Patients with arrhythmia were divided into three groups (bradyarrhythmias, tachyarrhythmias, and tachy- and bradyarrhythmias). Results: Two-hundred patients completed the study (males, 123; mean age, 70.1 years); of these, 80 patients (40%) exhibited rhythm disorders on telemetry. Patients with arrhythmia were older (p < 0.0001), had a greater number of comorbidities (p < 0.0001), higher values of creatinine (p = 0.007), B-type natriuretic peptide (p < 0.0001), troponin (p < 0.0001), C-reactive protein (p = 0.01), ferritin (p = 0.001), D-dimer (p < 0.0001), procalcitonin (p = 0.0008), QT interval (p = 0.002), QTc interval (p = 0.04), and QTc dispersion (p = 0.01), and lower values of sodium (p = 0.03), magnesium (p = 0.04), glomerular filtration rate (p < 0.0001), and hemoglobin (p = 0.008) as compared to patients without arrhythmia. By comparing the three subgroups of patients, no significant differences were found. At multivariate analysis, age [odds ratio (OR) = 1.14 (95% CI: 1.07-1.22); p = 0.0004], coronary artery disease [OR = 12.7 (95% CI: 2.38-68.01); p = 0.005], and circulating troponin [OR = 1.05 (95% CI: 1.003-1.10); p = 0.04] represented risk factors independently associated with arrhythmia. All-cause in-hospital mortality was ∼40-fold higher among patients with arrhythmia [OR = 39.66 (95% CI: 5.20-302.51); p = 0.0004]. Conclusion: Arrhythmias are associated with aging, coronary artery disease, subtle myocardial injury, hyperinflammatory status, coagulative unbalance, and prolonged QTc dispersion in patients with COVID-19, and confer a worse in-hospital prognosis. Given its usefulness, routinary use of cardiac telemetry should be encouraged in COVID wards.

The association between QTc, QTd, TPE, and fragmented QRS before and after PPCI with hospital mortality in STEMI patients.

INTRODUCTION: ST-elevation myocardial infarction (STEMI) is known to be associated with significant arrhythmia and consequent mortality. QT prolongation is a risk factor for arrhythmia in STEMI patients who underwent primary percutaneous coronary intervention (PPCI). The aim of this investigation was to evaluate the association of corrected QT interval (QTc), QT dispersion (QTd), T-wave peak to end (TPE), and fragmented QRS with mortality in these patients. METHODS: Eligible patients with the characteristic symptoms of STEMI who underwent PPCI were included. QTc, QTd, TPE, and fragmented QRS were measured before and after the PPCI. These predictors were compared between patients who died during hospitalization and discharged patients. RESULTS: After coronary angiography, 10 patients (4%) died during the hospitalization after PPCI. Comparing the non-survivers and discharged patients in terms of arrhythmia predictors showed that the mean QT dispersion and TPE before intervention were significantly higher in the non-survivors. Also, the number of patients who experienced fragmented QRS both before and after the intervention was significantly higher in the non-survivors. CONCLUSION: These data suggested that evaluating such arrhythmia predictors, especially before PPCI, could be used as a predictor of mortality in STEMI patients who underwent PPCI.

Ventricular repolarization indicators in risk stratification of decompensated heart failure patients with ventricular systolic dysfunction.

Background: Ventricular repolarization measurement by QTc interval and QT dispersion can recognize high-risk patients. Previous research tended to evaluate the act of repolarization indicators alone but this study aimed to elucidate their prognostic utility before and after modifying confounding parameters in risk stratification of different aspects of prognosis in decompensated heart failure patients with systolic dysfunction. Methods: Data of 98 variables were evaluated to determine their predictive value concerning arrhythmic events, in-hospital, and long-term mortality. Results: From 858 cases that presented with acute heart failure, 19.2% (n=165) were enrolled in the study. During hospitalization, arrhythmic events and cardiac-related mortality occurred in 56(33.9%) and 11(7%) patients, respectively. QTc and QT dispersion were independent predictors of arrhythmia and in-hospital mortality after adjustment of the variables (arrhythmic events: QTc interval OR 1.085, P=0.007, QT dispersion OR 1.077, P=0.007, in-hospital mortality: QTc interval OR 1.116, P=0.009, QT dispersion OR 1.067, P=0.011). After being discharged, they were tracked for 181±56 days. Within the 16 deaths in follow-up time, 6 sudden cardiac deaths were documented. Cox regression, defined QTc as the predictor of all-cause and sudden death mortality (all-cause: HR 1.041, 95% CI 1.015-1.067, P=0.002; sudden death: HR 1.063, 95% CI 1.023-1.105, P=0.002); nevertheless, efforts to demonstrate QT dispersion as the predictor failed. Conclusion: The predictive nature of QT parameters was significant after modification of the variables; therefore, they should be measured for risk stratification of ventricular repolarization arrhythmia and death in decompensated heart failure patients.

The relationship between vitamin B12 levels and electrocardiographic ventricular repolarization markers / La relación entre los niveles de vitamina B12 y los marcadores electrocardiográficos de repolarización ventricular

Background: it has been shown that vitamin B12 deficiency, which can cause hematological and neuropsychiatric disorders, may also be associated with cardiac autonomic dysfunction, heart rate variability, endothelial dysfunction, and a decrease in myocardial deformation. Aims: the aim of our study is to evaluate the relationship between vitamin B12 levels and electrocardiographic repolarization disorders, which are indicators of arrhythmogenic predisposition in healthy individuals. Methods: our study population consisted of 214 healthy adults. Considering the distribution of vitamin B12 levels and accepting 25 % and 75 % percentiles as the cut-off values, the participants were divided into 3 groups. Laboratory, echocardiography and electrocardiography (ECG) measurements were compared between three groups. ECG measurements were performed manually and Tpeak-Tend (Tp-e), Tp-e corrected (Tp-ec), QT and QT corrected (QTc) intervals were calculated. Results: the patients in Group 1 (vitamin B12 < 253 pg/ml) were found to have significantly higher QT and QTc dispersions, Tp-e interval, Tp-e/QT and Tp-e/QTc ratios when compared to those in Group 2 (253 pg/ml < vitamin B12 > 436 pg/ml) and Group 3 (vitamin B12 > 436 pg/ml). On the other hand, a negative significant correlation was detected between vitamin B12 levels and Tp-e, Tp-e/QT, Tp-e/QTc ratios, QT and QTc dispersions. Conclusion: a low level of vitamin B12 in healthy individuals can be a significant indicator of arrhythmogenic susceptibility. A close follow-up of these subjects in terms of arrhythmogenic predisposition can be useful (AU)

Fundamento: se ha demostrado que la deficiencia de vitamina B12, que puede causar trastornos hematológicos y neuropsiquiátricos, también puede estar asociada con disfunción autonómica cardíaca, variabilidad de la frecuencia cardíaca, disfunción endotelial y disminución de la deformación miocárdica. Objetivos: el objetivo de nuestro estudio es evaluar la relación entre los niveles de vitamina B12 y los trastornos de repolarización electrocardiográfica que son indicadores de predisposición arritmogénica en individuos sanos. Métodos: la población del estudio fue de 214 adultos sanos. Considerando la distribución de los niveles de vitamina B12 y aceptando los percentiles del 25 % y 75 % como valores de corte, los participantes se dividieron en 3 grupos. Se compararon las mediciones de laboratorio, ecocardiografía y electrocardiografía (ECG) entre tres grupos. Las mediciones del ECG se realizaron manualmente y se calcularon los intervalos Tpeak-Tend (Tp-e), Tp-e corregido (Tp-ec), QT y QT corregido (QTc). Resultados: se encontró que los pacientes del grupo 1 (vitamina B12 < 253 pg/ml) tenían dispersiones QT y QTc, intervalo Tp-e, cocientes Tp-e/QT y Tp-e/QTc significativamente más altos cuando se compararon con los del grupo 2 (253 pg/ml < vitamina B12 > 436 pg/ml) y el grupo 3 (vitamina B12 > 436 pg/ml). Por otro lado, se detectó una correlación significativa negativa entre los niveles de vitamina B12 y las relaciones Tp-e, Tp-e/QT, Tp-e/QTc, dispersiones QT y QTc.Conclusión: el bajo nivel de vitamina B12 en los individuos sanos puede ser un indicador significativo de susceptibilidad arritmogénica. Un seguimiento estrecho de estos sujetos en términos de predisposición arritmogénica podría ser útil (AU)

Electrocardiographic alterations in patients with chronic obstructive pulmonary disease.

Patients with chronic obstructive pulmonary disease (COPD) have an increased risk for cardiovascular events, and electrocardiography has an important role in detecting cardiac side effects of COPD-related hypoxia.

Ventricular fibrillation during carotid endarterectomy and bailout stenting: a case report.

BACKGROUND: Carotid artery manipulation is not a special technique but reports of intraoperative ventricular fibrillation are rare. The risk of fatal arrhythmias may be hidden behind routine surgical techniques and anesthetic management. We focused on QT prolongation and QT dispersion. CASE PRESENTATION: A 77-year-old man underwent carotid endarterectomy and bailout stenting. Although there were no obvious preoperative risk factors for intraoperative ventricular tachyarrhythmia, ventricular fibrillation (VF) had occurred during a maneuver of the carotid artery under hypercapnia. QTc was prolonged from 317 ms before surgery to 458 ms before the onset of VF. QTc dispersion between leads II and III was also increased to 50 ms. Hypomagnesemia was noted after resuscitation by electrical defibrillation, adrenaline, and noradrenaline. CONCLUSIONS: We considered that the combination of multiple risk factors led to the development of ventricular fibrillation. It should be noted that carotid artery manipulation has the potential to cause arrhythmias.

Comparison of QT dispersion before and after PDA device closure in pediatrics.

BACKGROUND: Numerous studies have shown that QT dispersion (QTd) can be a suitable criterion for risk assessment of arrhythmia in patients with congenital heart disease. Pulmonary arterial hypertension (PAH) increases the risk of cardiac arrhythmia by changing ventricular repolarization homogeneity. In this study, we assessed QTd changes after PDA device closure and the effect of PAH on these changes. METHODS: Between October 2018 and March 2021, 97 patients (48 males; 49 females; mean age 31.36 ± 4.26 months; range 3 months to 14 years) who satisfied the primary inclusion criteria and did not meet the exclusion criteria and underwent PDA device closure intervention were included in the study. Echocardiography was performed before the procedure. QT corrected (QTc), and QTd and PR intervals were measured according to the patients' standard 12-lead ECGs in two periods, preoperative (1 day) and after (3 months). RESULTS: In the general group, QTc and QTd decreased significantly after PDA closure. Based on our classification of the patients in two groups of high PAP and normal PAP, the three parameters QTc, QTd, and PR interval were assessed separately in the two groups. All three parameters decreased significantly in the normal PAP and high PAP groups. CONCLUSIONS: However, a left-to-right shunt through the patent ductus arteriosus can affect ventricular repolarization; this effect seems to be particularly more significant when there is pulmonary hypertension.

Effects of azithromycin on ventricular repolarization in children with COVID-19.

Introduction: Azithromycin is used to treat pediatric COVID-19 patients. It can also prolong the QT interval in adults. This study assessed the effects of azithromycin on ventricular repolarization in children with COVID-19. Method: The study prospectively enrolled children with COVID-19 who received azithromycin between July and August 2020. An electrocardiogram was performed before, one, three, and five days post-treatment. Using ImageJ®, the following parameters were measured: QT max, QT min, Tp-e max, and Tp-e min. The parameters QTc max, QTc min, Tp-ec max, Tp-ec min, QTcd, Tp-ecd, and the QTc/Tp-ec ratio were calculated using Bazett's formula. Results: The study included 105 pediatric patients (mean age 9.8±5.3 years). The pretreatment heart rate was higher than after treatment (before 92 [79-108]/min vs. Day 1 82 [69-108)]/min vs. Day 3 80 [68-92.2]/min vs. Day 5 81 [70-92]/min; p=0.05). Conclusion: Azithromycin does not affect the ventricular repolarization parameters on ECG in pediatric COVID-19 cases.

Introdução: A azitromicina (AZ) é utilizada no tratamento da COVID-19 em pediatria. Como este fármaco pode prolongar o intervalo QT nos adultos, este estudo avaliou os efeitos da AZ na repolarização ventricular de crianças com COVID-19. Método: Este estudo prospetivo incluiu crianças com COVID-19 que foram tratadas com AZ em julho-agosto 2020. Foi efetuado um eletrocardiograma (ECG) antes e um, 3 e 5 dias após o tratamento. Utilizando ImageJ ®, foram medidos os parâmetros seguintes: QT max, QT min, Tp-e max, e Tp-e min. Os parâmetros QTc min, Tp-ec max, Tp-ec min, QTcd, Tp-ecd e QTc/Tp-ec ratio foram calculados utilizando a fórmula Bazett. Resultados: O estudo incluiu 105 doentes pediátricos (idade média 9,8±5,3 anos). A frequência cardíaca no pré-tratamento foi mais elevada do que após o tratamento (antes 92 [79­108]/min versus dia 1 82 [69­108)]/min versus dia 3 80 [68­92,2]/min versus dia 5 81 [70­92]/min; p=0,05). Conclusão: A AZ não afeta os parâmetros de repolarização ventricular no ECG nos casos pediátricos da COVID-19.