QTc Values Research Articles

Portable single-lead electrocardiogram device is accurate for QTc evaluation in hospitalized patients.

BackgroundMany commonly used drugs can prolong the QTc interval (QTc), which can lead to potentially life-threatening arrhythmias. In the current era of the COVID-19 pandemic, it is worth mentioning that the disease itself and several drugs used for its treatment have been associated with QTc prolongation.ObjectiveTo evaluate the agreement and clinical precision of a portable single-lead electrocardiogram (ECG) device to measure the QTc interval compared to the standard 12-lead ECG.MethodsIn sequential tests, QTc of ECG recordings obtained with the KardiaMobile (KM-1L) device (AliveCor, San Francisco, CA) were compared to QTc obtained with conventional 12-lead ECG. Agreement was evaluated using Bland-Altman plots and Lin’s concordance coefficient. Consistency between the 2 devices in determining QTc prolongation (QTc ≥470 ms in males or ≥480 ms in females) was evaluated with kappa statistics.ResultsA total of 128 patients with a presumed or confirmed diagnosis of COVID-19 admitted to a university hospital were included. QTc intervals measured with KM-1L were similar to QTc measured with conventional ECG (442.45 ± 40.5 vs 441.65 ± 40.3 ms, P = .15). Bland–Altman analysis showed no significant difference in QTc values (average difference of -0.797, 95% limits of agreement:-13.179; 11.585). Lin’s concordance coefficient showed an excellent agreement (0.988, P < .001). Concordance between the 2 devices for determining QTc prolongation was excellent (kappa >0.90).ConclusionECG recordings obtained with KM-1L allow an accurate QTc interval assessment. Considering its simplicity of use, this approach has advantages over conventional ECG and can provide an alternative for the evaluation of QTc in hospitalized patients, during the current time of the COVID-19 pandemic and beyond.

Prevalence of discordant QTc values among cancer patients by the Bazett, Fridericia, and Framingham formulae: Evidence for a standardized approach.

6575 Background: Many chemotherapies have the potential to prolong the QT interval, requiring monitoring of the corrected QT (QTc) to prevent life-threatening arrhythmias. Most clinical guidelines recommend adjusting/holding chemotherapy with Grade 3 or higher toxicity by CTCAE (QTc≥500). Several formulae are used for QTc monitoring including Bazett, Fridericia, and Framingham. The most commonly used formula, Bazett, is well-documented to result in inappropriately high QTc values although the potential impact of this overcorrection on cancer treatment is unknown. We aimed to describe the prevalence of QTc prolongation among cancer patients and the effects on CTCAE adverse event grading by various QTc formulae to determine the potential impact on clinical management. Methods: We performed a single-center retrospective analysis of QT values from electrocardiograms (ECGs) collected January 2010-April 2020 and evaluated associations between QTc values, medications, and patient characteristics. QTc prolonging agents were determined by FDA package insert and cross-referenced with CredibleMeds.org. Results: 20,017 ECGs were evaluated. 18.6% (3,730) met ACC/ACCF/HRS criteria for prolonged QTc by ≥1 QT correction formula (either Bazett, Fridericia, or Framingham). 7.5% (1,494) were prolonged with all three formulae, and 8.6% (1,635) were prolonged only with Bazett. The CTCAE classification using the Bazett formula differed from both Fridericia and Framingham in 37.9% (7,583) of the ECGs. In contrast, Fridericia and Framingham formulae resulted in the same CTCAE classification in 94.5% (18,912). Of 1,789 ECGs classified as Grade 3 toxicity by Bazett, 72.0% (1,288, 6.4% of all ECGs) were classified as Grade 2 or less by both Fridericia and Framingham. 12.0% (2,340) of all ECGs were taken from patients (n = 421) on 24 different QT-prolonging chemotherapies. In 38.8% (909) of the ECGs, the CTCAE classification using the Bazett formula differed from both Fridericia and Framingham while use of Fridericia and Framingham formulae resulted in the same classification in 93.0% (2,176) of the ECGs. Of 293 ECGs classified as Grade 3 toxicity by Bazett, 65.2% (191) were classified as Grade 2 or less by both Fridericia and Framingham. Conclusions: To our knowledge, this is the largest analysis of discrepancies between different QTc formulae in patients receiving chemotherapy. These findings demonstrate an unacceptably high rate of discordance between formulae. Discordant data can lead to inconsistent clinical management and adverse event grading underscoring the urgent need to standardize QTc monitoring and reporting. These findings support the discontinuation of the routine use of the Bazett correction formula among cancer patients as CTCAE Grade 3 reporting from the Bazett formula is unreliable in over 65% of cases.

POS0090 RISK OF QT INTERVAL PROLONGATION ASSOCIATED WITH CHRONIC USE OF HYDROXYCHLOROQUINE IN RHEUMATIC PATIENTS AND THE EFFECT OF COTREATMENTS

Background:Hydroxychloroquine (HCQ) has been used safely for over 60 years in rheumatic patients. However, following its recent use in covid-19 disease, its safety has been questioned, following controversial reports of cardiac toxicity1, possibly related to a prolongation of the QT interval2.Objectives:To explore the influence of chronic treatment with hydroxychloroquine on QT interval in rheumatic patients, and the possible effects of drug-to-drug interference3.Methods:12-lead electrocardiogram tracings were recorded with standard equipment in 229 ambulatory patients (SLE = 53, RA = 52, SSc = 56, UCTD = 38, Others = 30). The present analysis was performed on corrected QT intervals (QTc) calculated according to Framingham formula (QTc = QT+0.154 (1−RR)), with ULN = 449 ms in males, and 467 ms in females. Estimated glomerular filtrate rate (eGFR) was calculated from serum creatinine with the CKD-EPI equation. The influence on QTc values of demographic variables, chronic (≥3 months) HCQ treatment, and of the use of selected comedications -Statins, Angiotensin Converting Enzyme inhibitors (ACEi), Angiotensin Receptor Blockers (ARBs), Selective Serotonin Reuptake Inhibitors (SSRIs), Proton-Pump Inhibitors (PPI), Calcium Channel Blockers (CCBs) – were evaluated by parametric or non parametric statistical methods, as appropriate. All statistic al analyses were performed with the IBM SPSS statistical package version 25.Results:Table 1.Demographic and clinical variables in patients treated with HCQ (HCQ+) and in controls (HCQ-).NAgeYrs±SDFemaleN%eGFRmL/min/1.73m2StatinsN%ACEiN%ARBN%SSRIN%PPIN%CCBN%All22958.02±14.3620690.087.1418.962912.74821.8198.3146.113860.33013.1HCQ+13258.71±14.4912292.487.0020.041813.63224.2118.396.88060.61712.9HCQ-9757.51±14.308486.687.3217.471111.31616.588.255.25859.81313.4p0.5320.1830.8970.6900.1891.0000.7821.0001.000Demographic variables, and the use of evaluated comedications were not different in HCQ+ and HCQ- patients (Table 1). In the whole population, the QTc mean duration was 416.72 ± 20.70 ms, and was correlated with age (r = 0.215, p= 0.001), but not with gender (p = 0.548), eGFR (r = -0.93, p = 0.163), or disease (p = 0.092). In only 4 patients (HCQ+: 3 (2.3%) – HCQ-: 1 (1%), p = 0.639) QTc duration was above ULN.QTc duration was not associated with the use of Statins, ACEi, ARBs, or SSRIs (p = 0.454, 0.276, 0.475, and 0.131 respectively), but was significantly prolonged in patients treated with HCQ (421.26 ± 19.19 vs 410.55 ± 21.18 msec, p &lt; 0.001), PPIs (420.57 ± 21.45 vs 410.89 ± 18.12 ms, p &lt; 0.001), and CCBs (424.22 ± 25.97 vs 415.59 ± 19.62 ms, p &lt; 0.033). Furthermore, as reported in Fig. 1, our data show a trend - albeit not statistically significant - towards an additive effect on QT prolongation of the association of PPIs and CCBs with HCQ, even more evident in the case of association of the 3 drug classes.Conclusion:In this study, the QTc interval was significantly prolonged in patients treated with hydroxychloroquine as compared to controls, although significant prolongation was extremely infrequent. Furthermore, our data revealed signs of drug-drug interference, suggesting that regular monitoring of the electrocardiogram is advisable in these patients, often undergoing cotreatment with multiple drugs.

ECG markers of malignant arrhythmias risk in patients with arterial hypertension hospitalized for COVID-19 pneumonia

Funding AcknowledgementsType of funding sources: None.Introduction.Changes in the myocardium in patients with arterial hypertension (AH) can cause fatal arrhythmias. The effects of inflammation and drugs on the heart in COVID-19 pneumonia can also increase the risk of sudden arrhythmic death.The aim of the paper is to study interrelationship of ECG markers of malignant arrhythmias and clinical and laboratory findings in patients with AH and COVID-19 pneumonia.Methods.48 patients with AH hospitalized for COVID-19 pneumonia (32 women aged 34 to 83, 16 men aged 48-80) were included in the study in October-November 2020. Exclusion criteria: congestive heart failure, previous myocardial infarction, reduced ejection fraction, valvular disease, life-threatening COVID-19 and other serious diseases. Main clinical characteristics and recommended laboratory findings were taken into account. Corrected QT and Tpeak-Tend were analyzed.Results.The QTc fluctuations were from 353 ms to 494 ms. The QTc values were higher than normal in 28%. The QTc duration correlated with C-reactive protein level (Kendall R = 0.59) and NYHA class (Gamma = 0.48). The Tpeak-Tend value correlated with coronary heart disease (Gamma 0.65), C-reactive protein (Kendall R = 0.57) and taking dexamethasone (Gamma 0.44) and fluoroquinolones (Gamma 0.58). Multivariate analysis has showed that high level of C-reactive protein (Wald = 7.4) and the presence of heart failure (Wald = 5.2) were independent predictors of QTc increase. Coronary heart disease (Wald = 4,8) and taking respiratory fluoroquinolones (Wald= 3.7) were independent predictors of Tpeak-Tend increase. Age, SatO2, taking betablockers and other analyzed indicators were not significantly related to QTc and Tpeak-Tend.Conclusion.Systemic inflammatory response, heart diseases and taking respiratory fluoroquinolones can adversely affect the myocardial repolarization indicators associated with the risk of sudden death in patients with AH hospitalized for COVID-19 pneumonia.

Validating and implementing cardiac telemetry for continuous QTc monitoring: A novel approach to increase healthcare personnel safety during the COVID-19 pandemic

BackgroundMinimizing direct patient contact among healthcare personnel is crucial for mitigating infectious risk during the coronavirus disease 2019 (COVID-19) pandemic. The use of remote cardiac telemetry as an alternative to 12‑lead electrocardiography (ECG) for continuous QTc monitoring may facilitate this strategy, but its application has not yet been validated or implemented. MethodsIn the validation component of this two-part prospective cohort study, a total of 65 hospitalized patients with simultaneous ECG and telemetry were identified. QTc obtained via remote telemetry as measured by 3 independent, blinded operators were compared with ECG as assessed by 2 board-certified electrophysiologists as the gold-standard. Pearson correlation coefficients were calculated to measure the strength of linear correlation between the two methods. In a separate cohort comprised of 68 COVID-19 patients treated with combined hydroxychloroquine and azithromycin, telemetry-based QTc values were compared at serial time points after medication administration using Friedman rank-sum test of repeated measures. ResultsTelemetry-based QTc measurements highly correlated with QTc values derived from ECG, with correlation coefficients of 0.74, 0.79, 0.85 (individual operators), and 0.84 (mean of all operators). Among the COVID-19 cohort, treatment led to a median QTc increase of 15 milliseconds between baseline and following the 9th dose (p = 0.002), with 8 (12%) patients exhibiting an increase in QTc ≥ 60 milliseconds and 4 (6%) developing QTc ≥ 500 milliseconds. ConclusionsCardiac telemetry is a validated clinical tool for QTc monitoring that may serve an expanding role during the COVID-19 pandemic strengthened by its remote and continuous monitoring capability and ubiquitous presence throughout hospitals.

Factors associated with seizure development after bupropion overdose: a review of the toxicology investigators consortium

Background Bupropion is an aminoketone antidepressant. A major concern in bupropion toxicity is seizure activity, which can occur up to 24 h from ingestion. It is difficult to predict which patients will have seizures. The purpose of this study is to identify clinical features associate with seizure after bupropion overdose. Methods We searched the Toxicology Investigators Consortium registry for a cases of poisoning by bupropion between January 1, 2014 and January 1, 2017 in patients aged 13–65. Demographic variables and clinical features were compared between patients who did and did not experience a seizure and presented as unadjusted odds ratios (OR). Multivariable logistic regression was used to calculate adjusted odds ratios (aOR) between clinical features and seizures. Results There were 256 cases of bupropion overdose remaining after inclusion/exclusion criteria were applied. Clinical features associated with seizure were QTc >500 (OR = 3.4, 95% CI: 1.3–8.8, p = 0.012), tachycardia (p > 140) (OR = 1.9, 95% CI: 1–3.561, p = 0.05), and age 13–18 years (2.4, 95% CI: 1.3–4.3, p = 0.005). The mean QTc value for patients experiencing a seizure was 482 ms (N = 95 IQR: 59 ms) versus 454 ms (N = 103, IQR: 43) in patients who did not experience seizure, however, it was not possible to identify a QTc cutoff with sensitivity or specificity to predict seizures. Conclusion Based on our analysis of data from the ToxIC registry, age (13–18), tachycardia (p > 140) and QTc >500 ms are associated with seizures in bupropion overdose; however, a specific QTc value may not be a useful predictor of seizures.

The electrocardiographic manifestations and derangements of 2019 novel coronavirus disease (COVID-19).

Electrocardiographic (ECG) findings in patients admitted with COVID-19 and a decision tree to predict their survival were assessed. 145 consecutive patients with severe COVID-19 infection were selected. Patient demographics, ECG variables, peak troponins, use of standard medications, and clinical outcomes were analyzed using descriptive and inferential statistics, and a predictive model of survival was developed using classification tree analysis. Of the 145 admitted patients, 38 (26%) died. Deceased patients were more likely to have a significantly higher incidence of poor R-Wave progression [6 of 37 (16.2%) Vs. 0 of 104 (0%), p < 0.001] as well as prolonged QTc values [24 of 37 (64.9%) Vs. 38 of 99 (38.4%), p 0.006]. Significant ST segment depressions were found in 5 of 37 (13.5%) of the deceased category compared to 0% in the non-deceased (p < 0.01). Right and/or left atrial enlargement was more prevalent in the deceased cohort [7 of 37 (18.9%) Vs. 4 of 104 (3.8%), p = 0.03]. Bundle branch blocks were more prevalent in the deceased group [9 of 35 (25.8%) Vs. 7 of 104 (6.7%), p 0.002]. Peak troponins were significantly higher in the deceased group (1.0 Vs 0.07 ng/ml, p < 0.001) A prediction tree built utilizing age, PACs, troponins and QTc had an accuracy of 85.5%. 65 of 74 patients (87.8%) were correctly predicted to survive, while 23 of 29 (79.3%) were correctly predicted to become deceased. Among patients hospitalized with Covid-19, the parameters of age, QT interval, troponin and PACs are useful for prognostication and help predict survival with reasonable accuracy.

Comprehensive non-invasive assessment of electrocardiographic abnormalities and cardiac arrhythmias in patients with genetically confirmed mitochondrial diseases

BackgroundThere is limited data on cardiac arrhythmias and ventricular repolarization and dispersion abnormalities in patients with mitochondrial diseases (MitD). MethodsConsecutive 40 patients with genetically proven MitD and 35 healthy controls were studied. Among other examinations all subjects underwent 24-h Holter recording and 12‑lead electrocardiography (ECG) with corrected QT (QTc), QT dispersion (QTd), Tp-e and Tp-e/QT ratio assessment. ResultsPatients with MitD were 55.4 ± 15.7 years old, the disease duration was 18.5 ± 10.3 years, presented 6 clinical syndromes while mitochondrial and nuclear DNA type of mutation was present in 40 and 60% of cases, respectively. In MitD more frequently 1st degree atrioventricular block and intraventricular conduction defects were observed and also QRS complex duration was increased. Mean values of QTc (p = 0.001), QTd (p = 0.02), Tp-e (p < 0.00001) and Tp-e/QT (p < 0.00001) were significantly higher in MitD than in controls. Correlations between disease duration and PR interval duration (p = 0.003) and Creatine Kinase MB isoenzyme activity (p = 0.02) were found. No differences in depolarization and dispersion parameters were observed according to type of mutation or dominant clinical syndromes. In addition to supraventricular extrasystoles, nonsustained supraventricular tachycardias occurred more frequently in MitD (in 45.0 vs 14.3%, p = 0.0004). Ventricular arrhythmias were rare and observed almost exclusively in subjects with mitochondrial DNA mutation. ConclusionsIn contrast to healthy controls, in MitD patients intraventricular, repolarization and dispersion disturbances were more frequently observed. In addition to bradyarrhythmias observed in some defined MitD syndromes, supraventricular rather than ventricular arrhythmias are more common.

QT effects of bedaquiline, delamanid, or both in patients with rifampicin-resistant tuberculosis: a phase 2, open-label, randomised, controlled trial

Bedaquiline and delamanid are the first drugs of new classes registered for tuberculosis treatment in 40 years. Each can prolong the QTc interval, with maximum effects occurring weeks after drug initiation. The cardiac safety and microbiological activity of these drugs when co-administered are not well-established. Our aim was to characterise the effects of bedaquiline, delamanid, or both on the QTc interval, longitudinally over 6 months of multidrug treatment, among patients with multidrug-resistant or rifampicin-resistant tuberculosis taking multidrug background therapy. ACTG A5343 is a phase 2, open-label, randomised, controlled trial in which adults with multidrug-resistant or rifampicin-resistant tuberculosis receiving multidrug background treatment were randomly assigned 1:1:1 by centrally, computer-generated randomisation, by means of permuted blocks to receive bedaquiline, delamanid, or both for 24 weeks. Participants were enrolled at TASK in Cape Town and the South African Tuberculosis Vaccine Initiative in Worcester, both in South Africa, and Hospital Maria Auxiliadora in Peru. Individuals with QTc greater than 450 ms were excluded. HIV-positive participants received dolutegravir-based antiretroviral therapy. Clofazimine was disallowed, and levofloxacin replaced moxifloxacin. ECG in triplicate and sputum cultures were done fortnightly. The primary endpoint was mean QTcF change from baseline (averaged over weeks 8-24); cumulative culture conversation at week 8-24 was an exploratory endpoint. Analyses included all participants who initiated study tuberculosis treatment (modified intention-to-treat population). This trial is registered with ClinicalTrials.gov, NCT02583048 and is ongoing. Between Aug 26, 2016 and July 13, 2018, of 174 screened, 84 participants (28 in each treatment group, and 31 in total with HIV) were enrolled. Two participants did not initiate study treatment (one in the delamanid group withdrew consent and one in the bedaquiline plus delamanid group) did not meet the eligibility criterion). Mean change in QTc from baseline was 12·3 ms (95% CI 7·8-16·7; bedaquiline), 8·6 ms (4·0-13·1; delamanid), and 20·7 ms (16·1-25·3) (bedaquiline plus delamanid). There were no grade 3 or 4 adverse QTc prolongation events and no deaths during study treatment. Cumulative culture conversion by week 8 was 21 (88%) of 24 (95% CI 71-97; bedaquiline), 20 (83%) of 24 (65-95; delamanid), and 19 (95%) of 20 (79-100; bedaquiline plus delamanid) and was 92% (77-99) for bedaquiline, 91% (76-99), for delamanid, and 95% (79-100) for bedaquiline plus delamanid at 24 weeks. Combining bedaquiline and delamanid has a modest, no more than additive, effect on the QTc interval, and initial microbiology data are encouraging. This study provides supportive evidence for use of these agents together in patients with multidrug-resistant or rifampicin-resistant tuberculosis with normal baseline QTc values. Division of AIDS, National Institutes of Health.

Use of Artificial Intelligence and Deep Neural Networks in Evaluation of Patients With Electrocardiographically Concealed Long QT Syndrome From the Surface 12-Lead Electrocardiogram

Long QT syndrome (LQTS) is characterized by prolongation of the QT interval and is associated with an increased risk of sudden cardiac death. However, although QT interval prolongation is the hallmark feature of LQTS, approximately 40% of patients with genetically confirmed LQTS have a normal corrected QT (QTc) at rest. Distinguishing patients with LQTS from those with a normal QTc is important to correctly diagnose disease, implement simple LQTS preventive measures, and initiate prophylactic therapy if necessary. To determine whether artificial intelligence (AI) using deep neural networks is better than the QTc alone in distinguishing patients with concealed LQTS from those with a normal QTc using a 12-lead electrocardiogram (ECG). A diagnostic case-control study was performed using all available 12-lead ECGs from 2059 patients presenting to a specialized genetic heart rhythm clinic. Patients were included if they had a definitive clinical and/or genetic diagnosis of type 1, 2, or 3 LQTS (LQT1, 2, or 3) or were seen because of an initial suspicion for LQTS but were discharged without this diagnosis. A multilayer convolutional neural network was used to classify patients based on a 10-second, 12-lead ECG, AI-enhanced ECG (AI-ECG). The convolutional neural network was trained using 60% of the patients, validated in 10% of the patients, and tested on the remaining patients (30%). The study was conducted from January 1, 1999, to December 31, 2018. The goal of the study was to test the ability of the convolutional neural network to distinguish patients with LQTS from those who were evaluated for LQTS but discharged without this diagnosis, especially among patients with genetically confirmed LQTS but a normal QTc value at rest (referred to as genotype positive/phenotype negative LQTS, normal QT interval LQTS, or concealed LQTS). Of the 2059 patients included, 1180 were men (57%); mean (SD) age at first ECG was 21.6 (15.6) years. All 12-lead ECGs from 967 patients with LQTS and 1092 who were evaluated for LQTS but discharged without this diagnosis were included for AI-ECG analysis. Based on the ECG-derived QTc alone, patients were classified with an area under the curve (AUC) value of 0.824 (95% CI, 0.79-0.858); using AI-ECG, the AUC was 0.900 (95% CI, 0.876-0.925). Furthermore, in the subset of patients who had a normal resting QTc (<450 milliseconds), the QTc alone distinguished those with LQTS from those without LQTS with an AUC of 0.741 (95% CI, 0.689-0.794), whereas the AI-ECG increased this discrimination to an AUC of 0.863 (95% CI, 0.824-0.903). In addition, the AI-ECG was able to distinguish the 3 main genotypic subgroups (LQT1, LQT2, and LQT3) with an AUC of 0.921 (95% CI, 0.890-0.951) for LQT1 compared with LQT2 and 3, 0.944 (95% CI, 0.918-0.970) for LQT2 compared with LQT1 and 3, and 0.863 (95% CI, 0.792-0.934) for LQT3 compared with LQT1 and 2. In this study, the AI-ECG was found to distinguish patients with electrocardiographically concealed LQTS from those discharged without a diagnosis of LQTS and provide a nearly 80% accurate pregenetic test anticipation of LQTS genotype status. This model may aid in the detection of LQTS in patients presenting to an arrhythmia clinic and, with validation, may be the stepping stone to similar tools to be developed for use in the general population.

Artificial Intelligence-Enabled Assessment of the Heart Rate Corrected QT Interval Using a Mobile Electrocardiogram Device.

Heart rate-corrected QT interval (QTc) prolongation, whether secondary to drugs, genetics including congenital long QT syndrome, and/or systemic diseases including SARS-CoV-2-mediated coronavirus disease 2019 (COVID-19), can predispose to ventricular arrhythmias and sudden cardiac death. Currently, QTc assessment and monitoring relies largely on 12-lead electrocardiography. As such, we sought to train and validate an artificial intelligence (AI)-enabled 12-lead ECG algorithm to determine the QTc, and then prospectively test this algorithm on tracings acquired from a mobile ECG (mECG) device in a population enriched for repolarization abnormalities. Using >1.6 million 12-lead ECGs from 538 200 patients, a deep neural network (DNN) was derived (patients for training, n = 250 767; patients for testing, n = 107 920) and validated (n = 179 513 patients) to predict the QTc using cardiologist-overread QTc values as the "gold standard". The ability of this DNN to detect clinically-relevant QTc prolongation (eg, QTc ≥500 ms) was then tested prospectively on 686 patients with genetic heart disease (50% with long QT syndrome) with QTc values obtained from both a 12-lead ECG and a prototype mECG device equivalent to the commercially-available AliveCor KardiaMobile 6L. In the validation sample, strong agreement was observed between human over-read and DNN-predicted QTc values (-1.76±23.14 ms). Similarly, within the prospective, genetic heart disease-enriched dataset, the difference between DNN-predicted QTc values derived from mECG tracings and those annotated from 12-lead ECGs by a QT expert (-0.45±24.73 ms) and a commercial core ECG laboratory [10.52±25.64 ms] was nominal. When applied to mECG tracings, the DNN's ability to detect a QTc value ≥500 ms yielded an area under the curve, sensitivity, and specificity of 0.97, 80.0%, and 94.4%, respectively. Using smartphone-enabled electrodes, an AI DNN can predict accurately the QTc of a standard 12-lead ECG. QTc estimation from an AI-enabled mECG device may provide a cost-effective means of screening for both acquired and congenital long QT syndrome in a variety of clinical settings where standard 12-lead electrocardiography is not accessible or cost-effective.

Is there a relation between computed tomography findings and electrocardiography findings in COVID-19?

COVID-19 can cause lung damage and may present with pneumonia in patients. In the present study, the correlation between the severity of pneumonia and electrocardiography parameters of COVID-19 were examined. A total of 93 COVID-19 patients and a control group consisting of 62 volunteers were studied. Computed thorax tomography evaluation was performed; each lung was divided into three zones. For each affected zone, scores were given. The main computed thorax tomography patterns were described in line with the terms defined by the Fleischner Society and peer reviewed literature on viral pneumonia. We compared Computed thorax tomography of patients with corrected QT (QTc) and P wave dispersion (Pd) time. There is a significant difference between the patient and control groups in terms of QTc values (413.5±28.8 msec vs. 395.6±16.7 msec p<0.001). Likewise, the Pd value of the patient group is statistically significantly higher than that of the control group (50.0±9.6 ms computed thorax tomography ec vs. 41.3±5.8 msec p<0.001). In the patient group, a reverse correlation was detected between computed thorax tomography score and Pd value according to partial correlation coefficient analysis (correlation coefficient: -0.232, p=0.027). In the patient group, the correlation between computed thorax tomography score and QTc value was similarly determined according to partial correlation coefficient analysis (Correlation coefficient:0.224, p=0.017). COVID-19 prolongs QTc and P wave dispersion values; and as the severity of pneumonia increases, QTc value increases. However, whereas the severity of pneumonia increases, P wave dispersion value decreases.

Electrocardiographic markers of increased risk of sudden cardiac death in patients with COVID-19 pneumonia.

BackgroundLittle is known about the role of ECG markers of increased risk of sudden cardiac death during the acute period of coronavirus disease 2019 ( COVID‐19) pneumonia.ObjectivesTo evaluate ECG markers of sudden cardiac death on admission, including the index of cardiac electrophysiological balance (iCEB) (QTc/QRS) and transmural dispersion of repolarization (TDR) (T from peak to end (Tp‐e) interval and Tp‐e/QTc), in patients with COVID‐19 pneumonia.Patients and methodsThis cross‐sectional study included 63 patients with newly diagnosed COVID‐19 pneumonia who presented to the outpatient clinic or admitted to the respiratory care unit between August 20 and September 15, 2020. Forty‐six persons matched for sex and age were selected from data collected before COVID‐19 pandemic.ResultsQRS and QTc showed a significant prolongation in patients with COVID‐19 pneumonia compared to the controls (87 vs. 78, p < .00, and 429 versus. 400, p < .00, respectively). After categorization of patients with COVID‐19 pneumonia into 3 groups according to the severity of pneumonia as mild‐moderate, severe, and critical groups, a decreased values of QRS were observed in the critical COVID‐19 pneumonia group compared to severe and mild‐moderate COVID‐19 pneumonia groups (p = .04) while increased values of QTc and iCEB(QTc/QRS) were noted in critical COVID‐19 pneumonia group compared to other 2 groups(p < .00).ConclusionsPatients with COVID‐19 pneumonia showed significant changes in repolarization and conduction parameters compared to controls. Patients with mild to severe COVID‐19 pneumonia may be at low risk for torsades de pointes development.

Bedaquiline for multidrug-resistant tuberculosis and QTc prolongation in California

BackgroundBedaquiline (BDQ) is recommended for the treatment of multidrug-resistant tuberculosis (MDR TB), however, it has the potential to prolong QTc interval. We assessed the frequency and severity of QTc prolongation in patients receiving BDQ in California. MethodsBased on chart review for patients receiving BDQ as part of MDR TB therapy from January 2013–May 2019, we analyzed QTc values at six pre-specified time points during BDQ therapy (baseline, 2, 4, 8, 12, and 24 weeks), as well as peak QTc, time to peak QTc, and the clinical characteristics of patients who had QTc elevation >500 milliseconds (ms) during therapy. ResultsA total of 37 patients were treated with BDQ during the analysis period, with a total of 449 QTc measurements available for analysis. Most patients (89%) received at least one QTc-prolonging drug in addition to BDQ. Median QTc values at all pre-specified time points were <450 ms. Median peak QTc was 455 ms (interquartile range [IQR]: 437–486) and median time to peak was 57 days (IQR: 19–156). Four patients (11%) had a non-transient elevation in QTc to >500 ms, including one patient with profound hypokalemia and one receiving concurrent chemotherapy, but none had cardiac arrhythmia. Less than 10% of patient in our cohort had ECGs performed at all six pre-specified time points. DiscussionBDQ was generally well-tolerated in a cohort of patients treated for MDR TB in California, with 11% of patients experiencing a non-transient QTc elevation >500 ms, and no episodes of arrhythmia. Frequent ECG monitoring during BDQ therapy presents a challenge for TB clinicians, even in well-resourced countries.

Validation of Corrected and Dispersed QT as Predictors of Adverse Outcomes in Acute Cardiotoxicities.

Acute cardiovascular poisoning is a major cause of adverse outcomes in poisoning emergencies. The prognostic validity of corrected QT (QTc) and dispersed QT (QTd) in these outcomes is still limited. The present study aimed to determine the risk factors of mortality, adverse cardiovascular events (ACVE), and intensive care unit (ICU) admission in patients with acute cardiovascular toxicities and assess the validity of QTc and QTd intervals in predicting these outcomes. This study was conducted on adult patients admitted to Tanta University Poison Control Center with a history of acute cardiotoxic drugs or toxins exposure. The demographic and toxicological data of patients were recorded. Clinical examination, routine laboratory investigations, ECG grading, and measurement of QTc and QTd were performed. The patients were grouped according to their adverse outcomes. Among the included patients, 51 (31.48%) patients died, 61 (37.65%) patients had ACVE, and 68 (41.98%) patients required ICU admission. The most common cause of poisoning is aluminum phosphide, followed by cholinesterase inhibitors. QTd and QTdc showed no significant difference among outcome groups. The best cut-off values of QTc to predict mortality, ACVE, and ICU admission were > 491.1ms, > 497.9ms, and ≥ 491.9ms, respectively. The derived cut-off QTc values were independent predictors for all adverse outcomes after adjusting for poison type, serum HCO3, and pulse. The highest odds ratios for all adverse outcomes were observed in aluminum phosphide poisoning and low HCO3 < 18mmol/L. Thus, serum HCO3 and QTc interval should be monitored for acute cardiotoxicities, especially in aluminum phosphide and cholinesterase inhibitors poisoning.

Prevalence and characteristics of atrial fibrillation in Makassar city population: A telemedicine study

ObjectiveAtrial fibrillation (AF) is one of the most commonly occurring arrhythmias and a major modifiable risk factor of stroke, especially in women. The incidence of AF in Indonesia is not well-characterized yet. This is a community-based study to determine the prevalence and characteristics of AF in the Makassar city population. MethodStandard ECG recording showing atrial fibrillation obtained between January 1, 2014 and September 31, 2018 from Telemedicine Study Center in Hasanuddin University Hospital were collected in form of portable document format (pdf) and were analyzed. ECG with incomplete interpretation and/or epidemiological data were excluded. ECG interpretation and analysis were performed by the first author as an electrophysiologist (MA). Epidemiological data, heart rate, P wave amplitude, QRS axis, QRS complex duration and configuration, QRS rate (ventricular response), corrected QT interval according to Bazzett's formula, presence of QRS complex abnormalities and ST-T changes were analyzed. Data analysis were performed using SPSS 20.0 for Windows. ResultA total of 19.718 ECG data were obtained, taken from the Makassar Telemedicine study data center at Hasanuddin University Hospital which cover all Public Health Center and a private clinic in Makassar city. From this population, AF was found in 189 (0.96%) ECGs. 98 (51.9%) are males’ and 91 (48.1%) of which are females’. AF is increasingly prevalent with increasing ages. There was a significant difference on the QRS axis between male and female with a p value of <0.001. The duration of the QRS complex between men and women was significantly different (p=0.038). QTc value was also found to be significantly different between male and female (p=0.001). AF was accompanied by PVC in 9 males and 2 females. ConclusionThe prevalence of AF in the Makassar population is 0.96%, more common in men and elderly.

The effect of hydroxychloroquine and azithromycin combination treatment on T peak-end, QT, corrected QT intervals and T peak-end/QT and T peak-end/corrected QT ratios in patients with COVID-19

Background: Hydroxychloroquine and azithromycin are frequently used agents in the treatment of COVID-19. We aimed to investigate the effect of hydroxychloroquine and azithromycin combination therapy on repolarization markers of malignant ventricular arrhythmia. Methods: A total of 107 patients, 54 males, and 53 females, who was positive for COVID-19 in terms of the Polymerase Chain Reaction test (PCR) and had typical viral pneumonia on thoracic computed tomography included in the study. These patients were given a combination of 5-day hydroxychloroquine and azithromycin therapy. Electrocardiograms (ECG) were taken before and after this treatment. T peak-end (Tp-e) interval, QT interval, corrected QT (QTc) interval, Tp-e / QT, and Tp-e / QTc values were calculated in the recorded ECGs. Results: Tp-e, QT, QTc intervals, and Tp-e / QT and Tp-e / QTc ratios increased significantly after treatment in both men and women compared to before the treatment. Conclusions: Superficial ECG markers of malignant ventricular arrhythmias were significantly increased in both men and women receiving hydroxychloroquine and azithromycin combination treatment for COVID-19.

Comparison of QT Interval between Neonates with Maternal Gestational Diabetes and Healthy Mothers

Background: The risk of developing metabolic syndrome and diseases, such as diabetes mellitus, has been increased as a worldwide rise in obesity. Gestational diabetes mellitus (GDM) or maternal hyperglycemia is a risk factor for cardiac dysfunction in neonates. The present study compared the QT interval in neonates with maternal GDM and healthy mothers. Methods: This case-control study was carried out on term neonates with maternal GDM (case group; n=42) and healthy non-diabetic mothers (control group; n=42) in Sayyad-e-Shirazi hospital in Gorgan, Northeast of Iran, within March 2016 and February 2017. A pediatric cardiologist evaluated septal hypertrophy by Doppler echocardiography (Zonare ZS3) during the first 2 weeks after birth. A standard 12-lead electrocardiogram was recorded for 10 sec, and a corrected QT (QTc) value was calculated. The data were analyzed by the latest version of SPSS software (version 16) using the Chi-square and t-test for the assessment of the differences in the QT values and other indices between the two groups. P-values less than 0.05 were considered statistically significant. Results: The results of the present study showed congenital heart diseases (CHDs) in six neonates. Significantly higher QT (249±36 and 245± 28 ms), septal thickness (6.09±1.07 and 5±1 mm), and lower QTc value (382±44.06 and 392± 34 ms) were observed in the case group, compared to those reported for the control group (p <0.001). The QTc dispersion was significantly different between the subjects under insulin therapy and participants receiving an antihyperglycemic oral regimen. Conclusion: In this study, significant thicker cardiac septum and higher QT interval were observed in the neonates born from mothers with GDM in comparison to those from healthy mothers. This could suggest close cardiac monitoring of these neonates due to the higher probability of CHDs.

QTc Prolongation due to Psychotropic Drugs Intoxication and Its Risk Assessment

Purpose: The aims of the present study were twofold. First, the research investigated the effect of an individual's risk factors and the prevalence of psychotropic drugs on QTc prolongation, TdP (torsades de pointes), and death. Second, the study compared the risk scoring systems (the Mayo Pro-QT risk score and the Tisadale risk score) on QTc prolongation. Methods: The medical records of intoxicated patients who visited the emergency department between March 2010 and February 2019 were reviewed retrospectively. Among 733 patients, the present study included 426 psychotropic drug-intoxicated patients. The patients were categorized according to the QTc value. The known risk factors of QTc prolongation were examined, and the Mayo Pro-QT risk score and the Tisadale risk score were calculated. The analysis was performed using multiple logistic regression, Spearman correlation, and ROC (receiver operating characteristic). Results: The numbers in the mild to moderate group (male: 470≤QTc&lt;500 ms, female: 480≤QTc&lt;500 ms) and severe group (QTc≥500 ms or increase of QTc at least 60ms from baseline, both sex) were 68 and 95, respectively. TdP did not occur, and the only cause of death was aspiration pneumonia. The statically significant risk factors were multidrug intoxications of TCA (tricyclic antidepressant), atypical antipsychotics, an atypical antidepressant, panic disorder, and hypokalemia. The Tisadale risk score was larger than the Mayo Pro-QT risk score. Conclusion: Multiple psychotropic drugs intoxication (TCA, an atypical antidepressant, and atypical antipsychotics), panic disorder, and hypokalemia have been proven to be the main risk factors of QTc prolongation, which require enhanced attention. The present study showed that the Tisadale score had a stronger correlation and predictive accuracy for QTc prolongation than the Mayo Pro-QT score. As a result, the Tisadale risk score is a crucial assessment tool for psychotropic drug-intoxicated patients in a clinical setting.

What Every Intensivist should Know about Impairment of Cardiac Function and Arrhythmias in Liver Disease Patients: A Review.

ObjectivesImpairment of cardiac function and arrhythmias often coexist in patients with liver diseases. Many studies have proved this coexistence and put forward various theories toward its pathophysiology. This narrative review tries to find the answers with supporting evidence on five main questions:Do high serum bilirubin levels have a strong association with cardiac arrhythmias?Can corrected QT interval (QTc) be relied upon for predicting a risk factor toward imminent arrhythmias?Is there an association between QTc prolongation and mortality?Are high serum bilirubin and cardiac dysfunction closely associated?What is the probable pathophysiology behind this association?Materials and methodsClinical evidence was obtained by using search engines, namely, Cochrane Library, PubMed, and Google Scholar. Studies published in journals in the English language, between January 1969 and December 2019, which mentioned the relationship between cardiac arrhythmia and liver disease, were included. We used the keywords: jaundice, bilirubin, arrhythmia, ECG, QTc interval, QT dispersion, liver, and cirrhosis. Relevant animal or human studies answering the five main questions were extracted and reviewed.ConclusionThe evidence included in our review sheds light on the fact that approximately 50% of liver cirrhosis cases develop cirrhotic cardiomyopathy (CC) and there has been an association between liver abnormalities and cardiac pathology. The present review also supports that there exists a strong association between high levels of serum bilirubin levels and cardiac arrhythmias, QTc value can be relied upon as a risk factor for predicting imminent arrhythmias, and that it is associated with mortality. Its basic pathophysiology can be explained by the potential action of bile acids in prolonging the QT interval. It also causes cardiac hypertrophy and apoptosis of cardiomyocytes leading to cardiac dysfunction.How to cite this articleArya S, Kumar P, Tiwari B, Belwal S, Saxena S, Abbas H. What Every Intensivist should Know about Impairment of Cardiac Function and Arrhythmias in Liver Disease Patients: A Review. Indian J Crit Care Med 2020;24(12):1251–1255.