Corrected QT Interval Prolongation Research Articles

Prevalence, Outcomes, and Predictors of Prolonged Corrected QT Interval in Hydroxychloroquine-Naïve Hospitalized COVID-19 Patients.

The studies regarding prevalence, outcomes, and predictors of prolonged corrected QT (QTc) among COVID-19 patients not on QTc-prolonging medication are not available in the literature. In this retrospective cohort study, the QTc of 295 hospital-admitted COVID-19 patients was analyzed and its association with in-hospital mortality was determined. The QTc was prolonged in 14.6% (43/295) of the study population. Prolonged QTc was seen in patients with older age (P = 0.018), coronary artery disease (P = 0.001), congestive heart failure (P = 0.042), elevated N-terminal-pro-B-type natriuretic peptide (NT-ProBNP) (P < 0.0001), and on remdesivir (P = 0.046). No episode of torsades de pointes arrhythmia or any arrhythmic death was observed among patients with prolonged QTc. The mortality was significantly high in patients with prolonged QTc (P = 0.003). The multivariate logistic regression analysis showed coronary artery disease (odds ratio (OR): 4.153, 95% CI 1.37-14.86;P = 0.013), and NT-ProBNP (ng/L) (OR: 1.000, 95% CI 1.000-1.000;P = 0.007) as predictors of prolonged QTc. The prolonged QTc was associated with the worst in-hospital survival (p by log-rank 0.001). A significant independent association was observed between prolonged QTc and in-hospital mortality in multivariate cox-regression analysis (adjusted hazard ratio: 3.861; (95% CI 1.719-6.523), P < 0.0001). QTc was found to be a marker of underlying comorbidities among COVID-19 patients. Prolonged QTc in hospitalized COVID-19 patients was independently associated with in-hospital mortality.

Deep Learning–Augmented ECG Analysis for Screening and Genotype Prediction of Congenital Long QT Syndrome

Congenital long QT syndrome (LQTS) is associated with syncope, ventricular arrhythmias, and sudden death. Half of patients with LQTS have a normal or borderline-normal QT interval despite LQTS often being detected by QT prolongation on resting electrocardiography (ECG). To develop a deep learning-based neural network for identification of LQTS and differentiation of genotypes (LQTS1 and LQTS2) using 12-lead ECG. This diagnostic accuracy study used ECGs from patients with suspected inherited arrhythmia enrolled in the Hearts in Rhythm Organization Registry (HiRO) from August 2012 to December 2021. The internal dataset was derived at 2 sites and an external validation dataset at 4 sites within the HiRO Registry; an additional cross-sectional validation dataset was from the Montreal Heart Institute. The cohort with LQTS included probands and relatives with pathogenic or likely pathogenic variants in KCNQ1 or KCNH2 genes with normal or prolonged corrected QT (QTc) intervals. Convolutional neural network (CNN) discrimination between LQTS1, LQTS2, and negative genetic test results. The main outcomes were area under the curve (AUC), F1 scores, and sensitivity for detecting LQTS and differentiating genotypes using a CNN method compared with QTc-based detection. A total of 4521 ECGs from 990 patients (mean [SD] age, 42 [18] years; 589 [59.5%] female) were analyzed. External validation within the national registry (101 patients) demonstrated the CNN's high diagnostic capacity for LQTS detection (AUC, 0.93; 95% CI, 0.89-0.96) and genotype differentiation (AUC, 0.91; 95% CI, 0.86-0.96). This surpassed expert-measured QTc intervals in detecting LQTS (F1 score, 0.84 [95% CI, 0.78-0.90] vs 0.22 [95% CI, 0.13-0.31]; sensitivity, 0.90 [95% CI, 0.86-0.94] vs 0.36 [95% CI, 0.23-0.47]), including in patients with normal or borderline QTc intervals (F1 score, 0.70 [95% CI, 0.40-1.00]; sensitivity, 0.78 [95% CI, 0.53-0.95]). In further validation in a cross-sectional cohort (406 patients) of high-risk patients and genotype-negative controls, the CNN detected LQTS with an AUC of 0.81 (95% CI, 0.80-0.85), which was better than QTc interval-based detection (AUC, 0.74; 95% CI, 0.69-0.78). The deep learning model improved detection of congenital LQTS from resting ECGs and allowed for differentiation between the 2 most common genetic subtypes. Broader validation over an unselected general population may support application of this model to patients with suspected LQTS.

Electrocardiographic abnormalities in patients with sickle cell disease: A systematic review and meta-analysis.

Previous studies have documented that electrocardiography (ECG) can reveal a range of abnormalities, offering valuable insights into the cardiac evaluation of patients with sickle cell disease (SCD). The objective of this study is to assess the patterns of ECG abnormalities observed in these patients with SCD, and to determine their prevalence. We systematically reviewed the literature using online databases of PubMed, Scopus, Web of Science, Embase, and Google Scholar to identify original studies that reported findings of standard ECG assessments in patients with SCD. Statistical analyses were performed using the random effects model. Additional analyses including sensitivity analysis and subgroup analysis were also conducted. Analysis of data from 59 studies involving 897,920 individuals with SCD revealed that 75% of these patients had abnormal ECG findings (67%-81%), which were predominantly nonspecific ST-T changes, left ventricular hypertrophy, T-wave changes, prolonged corrected QT (QTc) interval, and ischemic changes. Besides, it was shown that these patients had significantly higher odds of having any ECG abnormalities (OR of 17.50, 4.68-65.49), right atrial enlargement (6.09, 1.48-25.09), left ventricular hypertrophy (3.45, 1.73-6.89), right ventricular hypertrophy (7.18, 2.28-22.57), biventricular hypertrophy (10.11, 1.99-51.38), prolonged QTc interval (5.54, 2.44-12.59), ST depression (3.34, 1.87-5.97), and T-wave changes (5.41, 1.43-20.56). Moreover, the mean of QTc interval was significantly higher among those with SCD (23.51milliseconds, 16.08-30.94). Our meta-analysis showed a higher prevalence of abnormal ECG findings among individuals with SCD. A significant proportion of these patients had various ECG abnormalities, suggesting a potential need for regular ECG assessments for patients with SCD.

Functional and clinical characterization of a novel homozygous KCNH2 missense variant in the pore region of Kv11.1 leading to a viable but severe long-QT syndrome

BackgroundAmong KCNH2 missense loss of function (LOF) variants, homozygosity –at any position in the Kv11.1/hERG channel – is very rare and generally leads to intrauterine death, while heterozygous variants in the pore are responsible for severe Type 2 long-QT syndrome (LQTS). We report a novel homozygous p.Gly603Ser missense variant in the pore of Kv11.1/hERG (KCNH2 c.1807G > A) discovered in the context of a severe LQTS. MethodsWe carried out a phenotypic family study combined with a functional analysis of mutated and wild-type (WT) Kv11.1 by two-electrode voltage-clamp using the Xenopus laevis oocyte heterologous expression system. ResultsThe variant resulted in a severe LQTS phenotype (very prolonged corrected QT interval, T-wave alternans, multiple Torsades de pointes) with a delayed clinical expression in later childhood in the homozygous state, and in a Type 2 LQTS phenotype in the heterozygous state. Expression of KCNH2 p.Gly603Ser cRNA alone elicited detectable current in Xenopus oocytes. Inactivation kinetics and voltage dependence of activation were not significantly affected by the variant. The macroscopic slope conductance of the variant was three-fold less compared to the WT (18.5 ± 9.01 vs 54.7 ± 17.2 μS, p < 0.001). ConclusionsWe characterized the novel p.Gly603Ser KCNH2 missense LOF variant in the pore region of Kv11.1/hERG leading to a severe but viable LQTS in the homozygous state and an attenuated Type 2 LQTS in heterozygous carriers. To our knowledge we provide the first description of a homozygous variant in the pore-forming region of Kv11.1 with a functional impact but a delayed clinical expression.

The Heart of Rett Syndrome: A Quantitative Analysis of Cardiac Repolarization.

Rett syndrome (RTT) is a developmental encephalopathy disorder that is associated with a high incidence of sudden death presumably from cardiorespiratory etiologies. Electrocardiogram (ECG) abnormalities, such as prolonged heart-rate corrected QT (QTc) interval, are markers of cardiac repolarization and are associated with potentially lethal ventricular arrhythmias. This study investigates the cardiac repolarization characteristics of RTT patients, including QTc and T-wave morphology characteristics. A retrospective quantitative analysis on 110 RTT patients and 124 age and sex-matched healthy controls was conducted. RTT patients had longer QTc, more abnormal T-wave morphology, and greater heterogeneity of cardiac repolarization parameters compared to controls. Even RTT patients without prolonged QTc had more abnormal ECG and T-wave characteristics than controls. Among RTT patients, MECP2 patients had prolonged QTc compared to CDKL5 and FOXG1 patients. A subset of five RTT patients who died had normal QTc, but more abnormal T-wave morphology than the remaining RTT patients. Cardiac repolarization abnormalities are present in RTT patients, even without long QTc. T-wave morphology is related to RTT genotype and may be predictive of mortality. These findings could be used to help the management and monitoring of RTT patients.

A Scoping Review of Varying Mobile Electrocardiographic Devices.

The electrocardiogram (ECG) can now be measured using mobile devices. Mobile ECG devices, which are defined as devices capable of recording and transmitting non-standard ECGs, offer numerous advantages such as cost-effectiveness and being user-friendly. Mobile ECG can also extend recording lengths (e.g., 2days, 14days), which is necessary to capture important intermittent events (e.g., cardiac arrhythmias) and evaluate prognostic risk markers (e.g., prolonged corrected QT (QTc) interval). Some mobile ECG devices can even connect to broadband networks allowing patients to remotely transmit their ECG to a clinician. This article systematically examines different mobile ECG devices used in prior studies and provides a detailed assessment of five diverse yet commonly used mobile ECG devices: AliveCor KardiaMobile; AliveCor KardiaMobile 6L; iRhythm ZioPatch; Apple Smartwatch ECG; and CardioSecur System. These mobile ECG devices are diverse in the number of leads measured and the duration of monitoring. Similar to their diversity, there has been a wide range of clinical applications of mobile ECG devices. Despite significant progress, questions regarding data quality, and clinican and patient acceptance and compliance persist.

Impact of Cerium Oxide Nanoparticles on Metabolic, Apoptotic, Autophagic and Antioxidant Changes in Doxorubicin-Induced Cardiomyopathy: Possible Underlying Mechanisms.

In the current study, the effects of cerium oxide nanoparticles (nanocerium; NC) on doxorubicin (DOX)-induced cardiomyopathy and its possible underlying mechanisms were addressed. 32 adult male rats were allocated into 4 groups; i) control group, ii) NC group; rats received NC (0.2 mg/kg, i.p., daily), iii) DOX group; rats received DOX 4 mg/kg (2 injections with a 14-day interval), and iv) DOX+NC group as DOX but rats received NC. At the end of the experiment, ECG and ECHO recordings and assessments of the levels of cardiac enzymes (CK-MB, LDH), and myocardial oxidative stress (MDA, catalase, and GSH), the expression of LC3 and beclin1 (markers of autophagy), caspase3 (marker of apoptosis) by immunohistochemistry, the expression of acetyl-CoA carboxylase alpha (ACCA) by PCR, and 5'adenosine monophosphate-activated protein kinase (AMPK) levels in the heart tissues were performed. The DOX group displayed a prolonged corrected QT interval, an increase in cardiac enzymes (CK-MB and LDH), myocardial oxidative stress (high MDA with low catalase and GSH), expression of ACCA, caspase-3, beclin1, and LC3 in myocardial tissues, with reduction in myocardial AMPK levels, and myocardial contractility (low ejection fraction, and fractional shortening). On the other hand, administration of NC with DOX resulted in significant improvement of all studied parameters. NC offers a cardioprotective effect against DOX-induced cardiomyopathy. This effect might be due to its antioxidant and antiapoptotic effects as well as to the modulation of autophagy and metabolic dysfunctions induced by DOX in the heart tissues.

Ischemia-induced ventricular proarrhythmia and cardiovascular autonomic dysreflexia after cardioneuroablation

Cardioneuroablation (CNA) is an attractive treatment of vasovagal syncope. Its long-term efficacy and safety remain unknown. The purpose of this study was to develop a chronic porcine model of CNA to examine the susceptibility to ventricular tachyarrhythmia (ventricular tachycardia/ventricular fibrillation [VT/VF]) and cardiac autonomic function after CNA. A percutaneous CNA model was developed by ablation of left- and right-sided ganglionated plexi (n = 5), confirmed by histology. Reproducible bilateral vagal denervation was confirmed after CNA by extracardiac vagal nerve stimulation (VNS) and histology. Chronic studies included 16 pigs randomized to CNA (n= 8) and sham ablation (n = 8, Control). After 6 weeks, animals underwent hemodynamic studies, assessment of cardiac sympathetic and parasympathetic function using sympathetic chain stimulation and direct VNS, respectively, and proarrhythmic potential after left anterior descending(LAD) coronary artery ligation. After CNA, extracardiac VNS responses remained abolished for 6 weeks despite ganglia remaining in ablated ganglionated plexi. In the CNA group, direct VNS resulted in paradoxical increases in blood pressure, but not in sham-ablated animals (CNA group vs sham group: 8.36% ± 7.0% vs -4.83% ± 8.7%, respectively; P = .009). Left sympathetic chain stimulation (8 Hz) induced significant corrected QT interval prolongation in the CNA group vs the sham group (11.23% ± 4.0% vs 1.49% ± 4.0%, respectively; P < .001). VT/VF after LAD ligation was more prevalent and occurred earlier in the CNA group than in the control group (61.44 ± 73.7 seconds vs 245.11 ± 104.0 seconds, respectively; P = .002). Cardiac vagal denervation is maintained long-term after CNA in a porcine model. However, chronic CNA was associated with cardiovascular dysreflexia, diminished cardioprotective effects of cardiac vagal tone, and increased susceptibility to VT/VF in ischemia. These potential long-term negative effects of CNA suggest the need for rigorous clinical studies on CNA.

Remote Monitoring of the QT Interval During Polychemotherapy

Aim To evaluate the incidence of prolonged corrected QT interval (QTc) by remote single-channel electrocardiogram (ECG) monitoring in primary oncological patients with elective polychemotherapy (PCT).Material and methods This study included 49 oncological patients with elective PCT. A single-channel portable CardioQVARK electrocardiograph was used to record single-channel, one-lead ECG between the first and second courses of PCT.Results Analysis of QTc interval detected a prolonged QTc interval &gt;500 msec in 8.2 % of cases, prolonged QTc &gt;480 msec in 18.3 % f cases, and prolonged QTc interval &gt;60 msec compared to baseline in 12.2 % of cases.Conclusion Remote recording of single-channel ECG using a portable electrocardiograph is an effective method for recording and detecting various forms of heart rhythm disorders.

Thoracic epidural analgesia prolongs postoperative QT interval on electrocardiogram in major non-cardiac surgery: a randomized comparison and a prospective cohort analysis.

Introduction: Prolongation of QT interval on electrocardiogram can be associated with perioperative lethal arrhythmia. Epidural analgesia is a commonly used modality to relieve surgical pain by blocking sensory nerves, which also blocks the autonomic nervous system and can affect QT interval. Since patient monitoring becomes much less frequent after surgery than intraoperative period, we investigated the effects of epidural analgesia on postoperative QT interval with a randomized clinical trial and a prospective cohort study. Methods: In a randomized study, we assigned 60 patients undergoing thoracic epidural analgesia to an epidural analgesia or no-epidural analgesia group, in which 3ml/h of 0.25% epidural levobupivacaine (7.5mg/h) was administered only in the epidural analgesia group during surgery. The primary outcome was the postoperative heart rate-corrected QT interval. In a prospective cohort study, patients were assigned to receive 5ml/h epidural levobupivacaine (12.5mg/h). The plasma concentration of levobupivacaine was measured using liquid chromatography-mass spectrometry. Results: The median postoperative corrected QT interval interval with 3ml/h epidural levobupivacaine was significantly longer than that without epidural analgesia. Using multiple regression analysis for the factors known to affect postoperative corrected QT interval interval, epidural analgesia was found to be an independent variable for prolongation, and the mean difference of the corrected QT interval interval with or without epidural analgesia was 23ms after adjustment. The median plasma concentration of levobupivacaine at the end of surgery was 164ng/ml with 3ml/h epidural levobupivacaine, and the correlation coefficient to the postoperative corrected QT interval interval was 0.14, showing a not significant correlation. A prospective cohort study showed that 5ml/h epidural levobupivacaine significantly prolonged postoperative corrected QT interval interval compared to preoperative baseline. The median plasma concentration of levobupivacaine was 166ng/ml with 5ml/h, the correlation coefficient of which showed no significant correlation. Conclusion: Thoracic epidural analgesia could enhance postoperative corrected QT interval prolongation after general anesthesia. The mechanism is possibly caused by blocking neighboring or part of the cardiac sympathetic nerves, rather than by systemic effects of epidurally administered levobupivacaine. Clinical trial number: UMIN000013347 for the randomized study and UMIN000041518 for the prospective cohort study, which were registered at University hospital Medical Information Network Center.

A Cross-Sectional Study to Determine the Association of Corrected QT Interval With Microalbuminuria in Type 2 Diabetes Mellitus.

Introduction Cardiac autonomic neuropathy (CAN) is a frequent and life-threatening complication of type 2 diabetes. Failure to diagnose can lead to high mortality and morbidity. In patients who have diabetes mellitus, microalbuminuria is an independent marker for cardiovascular disease. This study aimed to assess the corrected QT interval with microalbuminuria in type 2 diabetes mellitus. The objective of this study was to estimate the corrected QT interval in subjects with type 2 diabetes mellitus and to determine the association of the corrected QT interval with microalbuminuria type 2 diabetes mellitus. Methodology Ninety-five adult patients (>18 years to 65 years) diagnosed with type 2 diabetes mellitus with microalbuminuria were included in this study. Data were collected on the proforma through history taking and a general physicalandsystemic examination. An electrocardiograph was taken on the day of admission; the most prolonged QT interval was measured, and the RR interval was calculated. The data were statistically analyzed using IBMSPSSStatistics for Windows, Version 24 (Released 2016; IBM Corp., Armonk, New York, United States). Results There was a significant difference in the corrected QT interval prolongation prevalence between diabetic patients with microalbuminuria and without microalbuminuria(P-value <0.001). The mean corrected QT interval distribution did not differ significantly across various age groups of cases studied with microalbuminuria(P-value 0.98). The distribution of mean corrected QT interval did not differ significantly between the group of male cases and group of female cases studied with microalbuminuria(P-value 0.66). The mean corrected QT interval distribution did not differ significantly across various duration of diabetes groups among the cases studied with microalbuminuria(P-value 0.60). The mean corrected QT interval distribution did not differ significantly across different types of anti-diabetic treatment groups among the cases studied with microalbuminuria(P-value 0.64). Conclusion Type 2 diabetes has been prevalent in Indian and Asian populations. The early management of type 2 diabetes is necessary since the early stages of the disease can reduce the risk of CAN. Therefore, these patients should be diagnosed as early as possible and treated to reduce associated mortality and risk and to improve quality of care.

Association between corrected QT interval and long-term cardiovascular outcomes in elderly patients who had undergone endovascular therapy for lower extremity arterial disease.

Population-based studies have reported the association between prolonged corrected QT (QTc) intervals and an increased risk of adverse cardiovascular events. Data regarding the association between longer QTc intervals and incident cardiovascular outcomes in patients with lower extremity arterial disease (LEAD) are scarce. To examine the impact of QTc interval on long-term cardiovascular outcomes in elderly patients with symptomatic LEAD. This cohort study extracted data from the Tzu-chi Registry of ENDovascular Intervention for Peripheral Artery Disease (TRENDPAD) and enrolled 504 patients aged ≥ 70 treated with endovascular therapy for atherosclerotic LEAD from July 1, 2005, to December 31, 2019. The main outcomes of interest were all-cause mortality and major adverse cardiovascular events (MACE). Multivariate analysis was conducted using the Cox proportional hazard model to determine independent variables. We performed interaction analysis between corrected QT and other covariates and Kaplan-Meier analysis to compare the outcome of interest among the groups stratified by the tercile of QTc intervals. A total of 504 patients [235 men (46.6%); mean age, 79.9 ± 6.2 years; mean QTc interval, 459 ± 33 msec] entered the final data analysis. We categorized the baseline patient characteristics according to terciles of QTc intervals. During the median follow-up time of 3.15 (interquartile ranges, 1.65-5.42) years, we noted 264 deaths and 145 MACEs. The 5-year rates of freedom from all-cause mortality (71% vs. 57% vs. 31%, P < 0.001) and MACEs (83% vs. 67% vs. 46%, P < 0.001) were significantly different among the tercile groups. Multivariate analysis showed that a 1-SD increase in the QTc interval increased the risk of all-cause mortality [hazard ratio (HR) 1.49, P < 0.001] and MACEs (HR 1.59, P < 0.001) after adjusting for other covariates. The interaction analysis showed that QTc interval and C-reactive protein levels were most strongly associated with death (HR = 4.88, 95% CI 3.09-7.73, interaction P < 0.001) and MACEs (HR = 7.83, 95% CI 4.14-14.79, interaction P < 0.001). In elderly patients with symptomatic atherosclerotic LEAD, a prolonged QTc interval is associated with advanced limb ischemia, multiple medical comorbidities, increased risk of MACEs, and all-cause mortality.

Pharmacological options for Candida albicans Endocarditis at the roadblock with irrecoverable prosthetics and drug interactions: a case report and review of literature

BackgroundCandidemia is the fourth most common nosocomial bloodstream infection. Endocarditis from candidemia is a rare but possibly fatal complication. The efficacy of amphotericin and echinocandins for induction and azoles for suppression has been well studied. Source control of infection, including removal of foreign bodies, remains the cornerstone for the success of any antifungal therapy.Case PresentationWe are describing a case of a 63-years old patient with multiple comorbidities who developed candidemia secondary to Candida albicans. The prospect of curing the fungemia was made difficult by prosthetic devices, including prosthetic heart valves, intracardiac defibrillator, and inferior vena filter, which could not be extracted due to poor cardiovascular status and higher postoperative mortality risk. Combination therapy with amphotericin and 5-Flucytosine (5FC) was used with the first recurrence. Suppression with fluconazole was contraindicated due to prolonged corrected QT (QTc) interval. Isavuconazole was employed for chronic lifelong suppression.ConclusionRetaining prosthetics in higher surgical risk patients presents us with unique clinical and pharmacological challenges regarding breakthrough infections, drug interaction, and side effects from prolonged suppressive therapies.

An explainable artificial intelligence-enabled electrocardiogram analysis model for the classification of reduced left ventricular function.

The black box nature of artificial intelligence (AI) hinders the development of interpretable AI models that are applicable in clinical practice. We aimed to develop an AI model for classifying patients of reduced left ventricular ejection fraction (LVEF) from 12-lead electrocardiograms (ECG) with the decision-interpretability. We acquired paired ECG and echocardiography datasets from the central and co-operative institutions. For the central institution dataset, a random forest model was trained to identify patients with reduced LVEF among 29 907 ECGs. Shapley additive explanations were applied to 7196 ECGs. To extract the model's decision criteria, the calculated Shapley additive explanations values were clustered for 192 non-paced rhythm patients in which reduced LVEF was predicted. Although the extracted criteria were different for each cluster, these criteria generally comprised a combination of six ECG findings: negative T-wave inversion in I/V5-6 leads, low voltage in I/II/V4-6 leads, Q wave in V3-6 leads, ventricular activation time prolongation in I/V5-6 leads, S-wave prolongation in V2-3 leads, and corrected QT interval prolongation. Similarly, for the co-operative institution dataset, the extracted criteria comprised a combination of the same six ECG findings. Furthermore, the accuracy of seven cardiologists' ECG readings improved significantly after watching a video explaining the interpretation of these criteria (before, 62.9% ± 3.9% vs. after, 73.9% ± 2.4%; P = 0.02). We visually interpreted the model's decision criteria to evaluate its validity, thereby developing a model that provided the decision-interpretability required for clinical application.

The association between nonalcoholic fatty liver disease and corrected QT interval prolongation among generally healthy Iranian population: Fasa Cohort Study (FACS).

There are limited studies about the association between nonalcoholic fatty liver disease (NAFLD) and corrected QT interval(QTc) prolongation worldwide. Therefore, we designed the current study to determine this association in a large cohort of a generally healthy population. We analyzed the data of 4603 individuals aged 35-70 who participated in the Fasa Cohort Study (FACS). Based on 12-lead electrocardiograms, QT intervals were calculated and corrected by Bazzet's formula. A QTc interval of more than 430 ms in men and 450 ms in women was considered prolonged. The Fatty Liver Index was used to identify the participants with NAFLD. Of all participants, 1550 (33.6%) met the NAFLD criteria. In subjects of both genders with NAFLD, the mean values of the QTc interval were considerably higher than in those without NAFLD (p < .001). After adjusting for a wide range of confounders, including age, gender, smoking status, physical activity, total cholesterol,high-density lipoprotein-cholesterol levels, diabetes, and hypertension status, in linear regression analysis, the standardized β coefficient of QTc interval among participants with NAFLD was 2.56 ms (95% confidence interval[CI]: 0.49-4.64). After controlling the same confounders, the odds ratio of NAFLD for a prolonged QTc interval in men was 1.47 (95% CI: 1.18-1.84; p < .001) and in women was 1.39 (95% CI: 1.15-1.68; p < .001) using logistic regression analysis. NAFLD was a risk factor for QTc interval prolongation. Awareness about the risk of NAFLD in increasing the potential cardiac arrhythmias should be raised to lower cardiac mortality.

Incidence of Myocarditis Associated with Diphtheria, Tetanus, and Pertussis Vaccine: A Rare Case Series

AbstractMyocarditis induced by diphtheria–tetanus–pertussis (DTP) vaccination is extremely rare, accounting for only two cases thus far. Hence, to supplement knowledge regarding its pathogenesis and treatment, we reported two cases of myocarditis associated with DTP vaccination in adults.Two patients (a 40-year-old female and a 43-year-old male) presented with mild symptoms and were hemodynamically stable. In both patients, the DTP vaccination was given 4 and 6 days before admission. Both patients had prolonged corrected QT interval (QTc), poor left ventricular function, and high troponin levels at admission. However, numerous ST segment depression was only noted in the first case. Bacteriology and virology study results were negative for any pathogen. No atherosclerotic lesions were observed by coronary angiography. Cardiac magnetic resonance imaging was only performed in the second case, which confirmed the diagnosis of myocarditis. Initial therapy was administered with a beta-blocker, angiotensin-converting enzyme inhibitor, and intravenous methylprednisolone. Nonetheless, in the first case, rapid clinical deterioration and sudden cardiac death occur within 3 days of hospitalization. Learn from the first case, a high-dose intravenous immunoglobulin (IVIG) treatment was initiated in the second case, which resulted in an improvement in left ventricular function and clinical symptoms, as well as a significant reduction in QTc interval and troponin levels.Rapid diagnostic testing and early recognition of the fulminant course is mandatory, allowing clinicians to aggressively treat the patient with high-dose intravenous immune globulin, thus obtaining a better outcome.

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.

Prognostic significance of prolonged corrected QT interval in cerebral contusion.

Cerebral contusion (CC) results in a release of catecholamines, autonomic dysfunction and neural stimulation that can lead to a number of cardiac adverse events, so it is critical to determine these. So the objective of this study was to investigate the prognostic significance of electrocardiographic changes, particularly the effects of a prolonged corrected QT (QTc) interval in CC. In this retrospective cohort study, 110 patients with CC were evaluated. Age, sex, concomitant diseases, Glasgow Coma Scale on admission, radiological assessment of the contusion (location, size, course and presence of cerebral oedema), need for surgical intervention, length of hospital stay and the extended Glasgow Outcome Scale (GOS-E) were statistically analysed within the QTc interval by routine electrocardiography (ECG) on admission. The prolonged QTc interval was found to be associated with a higher incidence of cerebral oedema and a significantly higher risk of needing surgery. Patients with a prolonged QTc interval had a significantly larger contusion volume, greater midline shift and longer hospital stay, so their GOS-E score was significantly lower. A prolonged QTc interval on admission resulted in a hospital stay of more than eight days (sensitivity: 0.97 and specificity: 0.86), a higher risk of midline shift of more than 0.45 cm (P=0.006, sensitivity: 0.80 and specificity: 0.99) and a GOS-E score of <7 (sensitivity: 0.97 and specificity: 0.85). ECG changes on admission showing a prolonged QTc interval have prognostic significance in CC. This simple and easily applicable information should be taken into consideration at the time of clinical decision making which may prevent an adverse events survivor.

Current updates on arrhythmia within Timothy syndrome: genetics, mechanisms and therapeutics.

Timothy syndrome (TS), characterised by multiple system malfunction especially the prolonged corrected QT interval and synchronised appearance of hand/foot syndactyly, is an extremely rare disease affecting early life with devastating arrhythmia. In this work, firstly, the various mutations in causative gene CACNA1C encoding cardiac L-type voltage-gated calcium channel (LTCC), regard with the genetic pathogeny and nomenclature of TS are reviewed. Secondly, the expression profile and function of CACNA1C gene encoding Cav1.2 proteins, and its gain-of-function mutation in TS leading to multiple organ disease phenotypes especially arrhythmia are discussed. More importantly, we focus on the altered molecular mechanism underlying arrhythmia in TS, and discuss about how LTCC malfunction in TS can cause disorganised calcium handling with excessive intracellular calcium and its triggered dysregulated excitation-transcription coupling. In addition, current therapeutics for TS cardiac phenotypes including LTCC blockers, beta-adrenergic blocking agents, sodium channel blocker, multichannel inhibitors and pacemakers are summarised. Eventually, the research strategy using patient-specific induced pluripotent stem cells is recommended as one of the promising future directions for developing therapeutic approaches. This review updates our understanding on the research progress and future avenues to study the genetics and molecular mechanism underlying the pathogenesis of devastating arrhythmia within TS, and provides novel insights for developing therapeutic measures.

Association between pre-operative prolonged corrected QT interval and all-cause mortality after non-cardiac surgery.

Prolonged corrected QT interval (QTc) has been linked to risk of arrhythmias and mortality in the general population. Pre-operative electrocardiography is often obtained for patient-and procedural cardiovascular risk assessment. The aim of this study was to investigate the association of pre-operative QTc and all-cause mortality in a non-cardiac surgical cohort. A retrospective study of all patients over 18 years undergoing non-cardiac surgery at Landspitali-the National University Hospital in Iceland between 2 January 2005 to 31 December 2015, with follow-up through 20 May 2016. Patients were separated into five categories according to their pre-operative QTc interval ≤ 379, 380-439 (reference group), 440-479, 480-519 and ≥520 ms. Primary outcome was long-term mortality and secondary outcome was 30-day mortality. A total of 10,209 surgeries for 10,209 individuals were included. The median follow-up for mortality was 2691 days (interquartile range [IQR] 1620-3705 days). Patients with longer QTc interval had a higher comorbidity burden, were more likely to undergo emergency surgery and were often prescribed cardiac medications. After adjustment for confounding variables, the hazard ratio (HR) for long-term mortality compared with reference (QTc 380-439 ms) was 0.85 [CI: 0.66-1.09] for QTc ≤379, 1.08 [CI: 0.99-1.17] for QTc 440-479 ms, 1.26 [CI: 1.10-1.43] for QTc between 480 and 519 ms and 0.97 [CI: 0.78-1.21] for QTc ≥520 ms. When compared with reference, only patients with QTc interval between 480 and 519 ms had higher odds ratio for 30-day mortality as odds ratio for other groups were following; 1.12 [CI: 0.18-3.8] for ≤379 ms, 1.03 [CI: 0.70-1.51] for QTc 440-479 ms, 1.64 [CI: 1.02-2.60] for QTc 480-519 ms and 0.98 [0.44-2.06] for QTc ≥520 ms. Pre-operative QTc between 480 and 519 ms is associated with both higher long-term and 30-day mortality after non-cardiac surgery. The results suggest that this could reflect an underlying cardiovascular risk.