QTc Monitoring Research Articles

Dynamic QTc interval changes observed in real-world patients with implanted insertable cardiac monitors taking class III antiarrhythmic drugs

Abstract Background QT prolongation can lead to sustained ventricular arrhythmias . Class III Antiarrhythmic drugs (AAD) are known to cause QT prolongation. Insertable cardiac monitors (ICM) have the capability to continuously monitor and detect dynamic changes in QT. Purpose To investigate the characteristics of QTc interval changes before and after antiarrhythmic drug loading in real-world ICM patients administered with Sotalol, Amiodarone, and Dofetilide in hospital. Methods The QT detection algorithm detects the T-waves and determines the QTc intervals for every beat, thus providing continuous long-term QTc trends from ICM ECG. Real-world patients from de-identified Electronic Health Record (EHR) database linked with ICM device data warehouse with implanted ICM being administered sotalol, amiodarone or dofetilide AAD for the first time in the hospital were analyzed. The patients were broken down into groups based on the AAD taken. Patients not taking AAD were selected as control. QTc intervals 7-days pre and post administered AAD are reported, and a random 14-day period was used for control patients. The paired difference in median QTc 7 days pre and post administered AAD were analyzed using the Wilcoxon signed rank test. The Wilcoxon rank-sum test was used to analyze QTc between the different groups. Results A total of 487 patients with ICM were included in this analysis: 56 sotalol patients (avg. age: 67±10 years, 50% male), 100 amiodarone patients (avg. age: 72±10 years, 50% male), 52 dofetilide patients (avg. age: 66±12 years, 50% male), and 248 control patients (avg. age: 70±13 years, 50% male). Sotalol, amiodarone, and dofetilide patients showed significant increase in QTc 1-7 days post AAD compared to 1-7 days pre AAD (figure 1). For sotalol (post AAD median[IQR] = 426.5[408.8,446.6] msec, pre AAD median[IQR] = 415.9[391,437.3] msec, p=0.004); Dofetilide (post median[IQR] = 432.4[413,458.7] msec; pre median[IQR] = 409.3[397.5,435.2] msec, p<0.001); Amiodarone (post median[IQR] = 426.3[400.9,449] msec, pre median[IQR] = 415.5[397.5,435.2] msec, p = 0.037). The QTc 1-7 days pre AAD compared to 1-7 days post AAD for control patients was insignificant p>0.05. The median change in QTc 1-7 days post AAD from 1-7 days pre AAD was 13.0, 7.5, 21.25 and -1.0 msec for sotalol, amiodarone, dofetilide, and control patients respectively (figure 2). Dofetilide patients had a significantly higher change in QTc compared to the amiodarone patients, p=0.018. QTc for all three AAD groups when compared to control group post AAD were significantly higher, p<0.001. QTc was also higher pre AAD compared to control, p=0.003, p<0.001, p=0.009 for sotalol, amiodarone, and dofetilide respectively. Conclusions There is a significant increase in QTc detected by ICM in patients receiving index drug loading of Sotalol, amiodarone and dofetilide. QTc monitoring via ICM can detect these dynamic changes in QTc allowing for early intervention.Figure 1Figure 2

Use of portable single-lead electrocardiogram device as an alternative for QTc monitoring in critically ill patients.

Acquired QT prolongation is frequent and leads to a higher mortality rate in critically ill patients. KardiaMobile 1L® (KM1L) is a portable, user-friendly single lead, mobile alternative to conventional 12-lead electrocardiogram (12-L ECG) that could be more readily available, potentially facilitating more frequent QTc assessments in intensive care units (ICU); however, there is currently no evidence to validate this potential use. We conducted a prospective diagnostic test study comparing QT interval measurement using KM1L with conventional 12-L ECG ordered for any reason in patients admitted to an ICU. We compared the mean difference using a paired t-test, agreement using Bland-Altman analysis, and Lin's concordance coefficient, numerical precision (proportion of QT measurements with <10 ms difference between KM1L and conventional 12-L ECG), and clinical precision (concordance for adequate discrimination of prolonged QTc). We included 114 patients (61.4% men, 60% cardiovascular etiology of hospitalization) with 131 12-L ECG traces. We found no statistical difference between corrected QT measurements (427 ms vs. 428 ms, p = .308). Lin's concordance coefficient was 0.848 (95% CI 0.801-0.894, p = .001). Clinical precision was excellent in males and substantial in females (Kappa 0.837 and 0.781, respectively). Numerical precision was lower in patients with vasoactive drugs (-13.99 ms), QT-prolonging drugs (13.84 ms), antiarrhythmic drugs (-12.87 ms), and a heart rate (HR) difference of ≥5 beats per minute (bpm) between devices (-11.26 ms). Our study validates the clinical viability of KM1L, a single-lead mobile ECG device, for identifying prolonged QT intervals in ICU patients. Caution is warranted in patients with certain medical conditions that may affect numerical precision.

QTc prolongation in patients hospitalized in enclosed psychiatric facilities in Corfu

IntroductionAn undeniably significant amount of psychotropic medication can evidently affect the corrected QT (QTc) interval, which puts patients’ lives at risk. More specifically, certain anti-psychotic medication can increase the risk of QTc prolongation and by extension the risk of a potentially fatal arrhythmia or sudden cardiac death.ObjectivesElectrocardiograms (ECG) were contacted in one hundred and four (104) chronic patients, with psychosis, through out their hospitalization in several enclosed psychiatric facilities in Corfu. Almost the entirety of the patients along side their anti-psychotic medication were also taking various other medication for their individual pathological issues. We observed any changes that might have occurred on the ECG in comparison with each patient’s medication and it’s potential effect on the QTc.MethodsThe measurements of the QT interval were made manually in lead V5 and the mathematical conversion was contacted using the Hodges correction formula.ResultsAt least one ECG (n = 104) was performed. Among them 29,8% (n=31) had ECG abnormalities, including 13,5% (n=13) with a prolonged Qtc (481.2 ± 26,8 ms). Covariates significantly associated with the QTc were gender (+17.2 ms if female, p &lt; 0.0001) and age (+0.4 ms/year, p = 0.0001).ConclusionsThe QTc prolongation that was evident in a notable number of patients, emphasizes the importance of QTc monitoring in patients who are taking anti-psychotic medication. QTc prolongation risk factors should be assessed before the administration or prescription of any anti-psychotic medication.Disclosure of InterestNone Declared

Pharmacist Reported Protocols for QTc Monitoring of Psychiatric Medications.

Background Psychiatric medications, such as antipsychotics and antidepressants, are associated with QTc interval prolongation. There is currently no consensus best practice on how to mitigate this risk. This study aimed to collect and analyze information about methods used for QTc monitoring in patients taking psychiatric medications to better understand current practice. Methods An anonymous electronic survey was distributed on September 22, 2022, using a national psychiatric pharmacist organization email list. The survey closed on December 15, 2022. Descriptive statistics were used to analyze the multiple-choice questions. Qualitative analysis applying grounded theory for thematic analysis was performed forfree response questions. Results A total of 48 initiated the survey. Of the respondents, 11.4% (5/44) reported that their institution had a formal protocol for monitoring QTc intervals in patients receiving psychiatric medications, while 32.4% (12/37) reported that their institution had an informal process. Out of those with a protocol or process, approximately half reported that it was drug-specific. Among the respondents, 88.6% (31/35) reported that there was a psychiatric clinical pharmacy specialist at their institutionand 34.3% (12/35) reported that pharmacists could order an electrocardiogram (ECG). Major themes that emerged from the qualitative analysis included pharmacist-driven QTc monitoring, referring the patient to another provider for monitoring, and encountering significant barriers to monitoring. Conclusion A variety of methodsare currently being employed to monitor QTc prolongation risk in patients taking psychiatric medications. Pharmacist authorization to order ECGs may be an opportunity to advance practice and improve care for this population. Further research is needed to more clearly understand best practices for QTc prolongation risk mitigation in patients receiving psychiatric medications.

PO-04-209 A NOVEL MACHINE LEARNING (ML) ALGORITHM TO MEASURE THE CORRECTED QT INTERVAL FROM MOBILE ECGS WITH HIGH ACCURACY AND PRECISION

The heart rate-corrected QT interval (QTc) is an important feature of the electrocardiogram (ECG), as it is an important prognosticator for ventricular arrhythmia and sudden cardiac death. The 12-lead (12L) ECG is used most often for assessment of QTc, and algorithms that have extended QTc detection to mobile ECGs with fewer than 12 leads are prone to wide sample size deviation. For clinical applications requiring serial QTc monitoring, such as titration of QTc-prolonging drugs, both accuracy and precision are critical. The aim was to develop a novel machine-learning (ML) algorithm that measures QTc from mobile ECG data formats with high accuracy as well as precision. The acceptance criteria was defined as error and standard deviation within 20 milliseconds (ms), the human interobserver variability observed for manual ECG measurements (gold standard). The ML algorithm was trained using a database of 13,000 cardiologist-annotated 12L ECG heartbeats, including the following steps: 1) pre-processing including resampling to 300 Hz, 2) normalization of amplitudes using min-max scaling 3) noisy beats with excessive baseline wander were discarded, and 4) applying TabNet and XGBoost models for detection of the end of T-Wave. This ML model for detection of the T-wave endpoint was merged with a signal processing method for detection of the Q-point. The algorithm was then validated on a subset of 1,239 cardiologist-annotated heartbeats, sufficient to assess strong agreement between software and manual methods (95% CI ± 0.2 std, Bland-Altman approach). Results showed high AUC, sensitivity, and specificity for detecting QTc above clinically meaningful thresholds. Mean QTc error was 5.24±7.22 ms, meeting predefined acceptance criteria. The ML algorithm was then applied to a dataset of 150 6L mECGs (AliveCor; Mountain View, CA), which comprise an all-comer population of a combination of healthy (∼40%), outpatient clinic (30%), and hospitalized patients (30%), with error 13.7±7.78 ms, again meeting acceptance criteria. Algorithm validation surpassed the defined acceptance criteria and demonstrated that the algorithm can provide and potentially surpass human QTc measurement capabilities. By enabling automated, dynamic QTc analysis, the algorithm offered the precision required for outpatient use.

Abstract 14826: Single Day Intravenous Sotalol as a Loading Dose to Initiate Oral Sotalol Therapy: Is it Safe and Efficacious?

Introduction: Due to pro-arrhythmic effects associated with Sotalol, inpatient initiation with QTc monitoring for five doses is recommended. An IV loading dose followed by two oral doses has been shown to achieve steady-state concentrations. Hypothesis: To evaluate the safety of single day loading of IV sotalol in patients with atrial fibrillation and atrial flutter (AF/AFL). Methods: We prospectively evaluated 40 patients at our institution who received IV sotalol as single day loading dose for initiation of oral sotalol therapy for AF/AFL. IV sotalol dose was calculated based on target oral dose as indicated by baseline QTc interval and renal function. Patients' QTc (in sinus) was measured via ECG on 15 minutes intervals and after IV loading completion. Loading was considered complete after second oral dose. All patients were monitored via a mobile cardiac outpatient monitor for 3 days followed by a final 12 ECG. Results: A total of 40 patients were included in the study. The mean age was 69 + 8.2 years, 78.9% of patients were men. QTc significantly increased from 435.9 + 26.4 to 462.9 + 31.6 with following IV loading (p&lt;0.001), that stabilized following oral loading completion (450.63 + 44.4; p=0.12). There were no cases of severe bradycardia, sinus node dysfunction, ventricular arrhythmias. reported. Conclusions: Our study sheds evidence that rapid IV sotalol loading in AF/AFL is safe and efficacious. This will not only provide patient convenience but will lead to reduced economic burden on patients and health care systems.

Incorporation of Pharmacist in Conducting Medication Reviews for Identification of Risk of QT Prolongation: A Neglecting Latent Approach in Cardiology

Sudden cardiac arrest correlates with QT-interval prolongation and torsade de points (TdP). Several medicines frequently used in geriatric aged care populations can cause QT prolongation. Major predisposing factors and QT-prolonging medications enhance QT interval prolongation incidence in medical inpatients. Pharmacists can help ensure safe drug therapy and in-hospital patient safety by paying attention to QT prolongation and extra risk factors for prolonged QT intervals during medication reconciliation. We recommend pharmacists improve knowledge and awareness of corrected QT prolongation (QTc) when conducting drug reviews. Implementation of Pharmacist-driven QTc monitoring is required to lower the risk of QTc prolongation.

3.100 Evaluating the Need for Standardized Recommendations for ECG Monitoring in Pediatric Patients Who Take Psychotropic Medications

The number of pediatric patients on Q wave to T wave interval (QTc)-prolonging psychotropic medications has been on the rise. Although there have been reports of inconsistent ECG monitoring practices among those treating adults, knowledge is limited regarding the guidelines used among those who treat pediatric patients. This literature review sought to evaluate recent data on QTc monitoring practices with a specific focus on patients receiving PRN medications.

Accuracy of mobile 6-lead electrocardiogram device for assessment of QT interval: aprospective validation study.

Ambulatory assessment of the heart rate-corrected QT interval (QTc) can be of diagnostic value, for example in patients on QTc-prolonging medication. Repeating sequential 12-lead electrocardiograms (ECGs) to monitor the QTc is cumbersome, but mobile ECG (mECG) devices can potentially solve this problem. As the accuracy of single-lead mECG devices is reportedly variable, amultilead mECG device may be more accurate. This prospective dual-centre study included outpatients visiting our cardiology clinics for any indication. Participants underwent an mECG recording using asmartphone-enabled 6‑lead mECG device immediately before or immediately after aconventional 12-lead ECG recording. Multiple QTc values in both recordings were manually measured in leadsI andII using the tangent method and subsequently compared. In total, 234 subjects were included (mean ± standard deviation (SD) age: 57 ± 17years; 58% males), of whom 133 (57%) had cardiac disease. QTc measurement in any lead was impossible due to artefacts in 16mECGs (7%) and no 12-lead ECGs. Mean (±SD) QTc in leadII on the mECG and 12-lead ECG was 401 ± 30 and 406 ± 31 ms, respectively. Mean (±SD) absolute difference in QTc values between both modalities was 12 ± 9 ms (r = 0.856; p < 0.001). In 55% of the subjects, the absolute difference between QTc values was < 10 ms. A6-lead mECG allows for QTc assessment with good accuracy and can be used safely in ambulatory QTc monitoring. This may improve patient satisfaction and reduce healthcare costs.

Safety monitoring practice during the initiation of tyrosine kinase inhibitors (TKIs) for NSCLC treatment.

e21090 Background: TKIs are standard treatment for non-small cell lung cancer (NSCLC) which harbors an actionable mutation. TKIs have a unique toxicity profile, distinct from conventional chemotherapy. Although the manufacturer of each TKI often issues a specific safety precaution on its label, no set schedule has been widely adopted. We surveyed the safety monitoring practice at a large academic institution. Methods: Electronic medical records of patients with ROS1, ALK or EGFR-mutated NSCLC who began a TKI during 2017-2021 were retrospectively reviewed. For each patient, the observation period started from the date of TKI prescription and lasted through day 60. Safety metrics were formulated based on drug label recommendations of each TKI. For each treatment course, the occurrence of 2 index safety monitoring activities (Table) were recorded. Results: Analysis included 130 treatment courses: 82 osimertinib, 20 alectinib, 15 crizotinib and 13 lorlatinib. Median age was 64.3 years, with 66% female, 81% white, 91% ECOG 0/1, 28% zero comorbidity, and 99% non-smoker. For osimertinib, EKG was obtained at baseline (within 30 days of treatment initiation) in 69.5% of observations, and LVEF, in 26.8%. By 60 days, these numbers barely increased (Table). Overall, absence of any index safety monitoring activity occurred in 41 of 130 (32%) treatment courses. Multivariable logistic regression analysis found a trend toward less monitoring among non-white patients: Odds ratio 0.35 (95% CI 0.11-1.09, p = 0.07). No association was found between the number of cardiac risk factors and LVEF monitoring or the use of QT prolonging medication and QTc monitoring. Conclusions: We observed a wide variation in the safety monitoring practice during TKI initiation. Deviation from the manufacturer recommendation was most pronounced for CPK monitoring in alectinib. Future study is needed to define the clinical significance of deviation and to identify barriers to safety monitoring.[Table: see text]

QTc interval prolongation in patients infected with SARS-CoV-2 and treated with antiviral drugs

IntroductionMany antiviral agents, such as hydroxychloroquine, have been used to treat COVID-19, without being broadly accepted. QTc prolongation is a worrisome adverse effect, scarcely studied in pediatrics. Patients and methodsPaediatric patients affected from COVID-19 who received antivirals were matched (1:2) with controls not infected nor exposed. Electrocardiograms were prospectively analyzed at baseline, during the first 72 h of treatment and after 72 h. ResultsEleven (22.9%) out of 48 patients admitted due to COVID-19 (March–July 2020) received antiviral therapy. All had underlying diseases: congenital heart disease (4/11; 36.4%) and immunosuppression (3/11; 27.3%) stand out. 5/11 (45.5%) received treatment at baseline with a potential effect on QTc. There where no differences observed in the baseline QTc between cases and controls: 414.8 ms (49.2) vs 416.5 ms (29.4), (P = .716). Baseline long QT was observed in 2/11 cases and 2/22. Among cases, 10/11 (90.9%) received hydroxychloroquine, mainly associated with azithromycin (8/11; 72.7%), 3 received lopinavir/ritonavir and one remdesivir. The median increase in QTc after 72 h under treatment was 28.9 ms [IQR 48.7] (P = .062). 4/11 (36.4%) patients had a long QTc at 72 h, resulting in 3 patients ≥500 ms; treatment was stopped in one (QTc 510 ms) but ventricular arrhythmias were not documented. ConclusionsThe use of antivirals caused an increase on the QTc interval after 72 h of treatment, being the QTc long in 36.3% of the patients, although no arrhythmic events were observed. The use of hydroxychloroquine and antivirals requires active QTc monitoring and it is recommended to discontinue treatment if QTc > 500 ms.

Improving Corrected QT Interval Monitoring in Critical Care Units: A Single Center Report.

Corrected QT (QTc) interval prolongation is a type of ventricular tachyarrhythmia. Recommendations for QTc interval monitoring for critical care nurses are limited and variable. The intensive care unit at the study institution had no policies for QTc interval monitoring. A quality improvement initiative for identifying and monitoring at-risk patients was begun. A QTc interval monitoring protocol was developed according to current recommendations for electrocardiogram monitoring and input from experts. Nursing staff received education on the QTc monitoring protocol. Numbers of patients with indications for monitoring were collected for 60 days before and 60 days after implementation. The rate of protocol adherence was collected for 60 days after implementation. Aknowledge assessment was administered to nurses at baseline, immediately after education, and 4 months after education. Before protocol implementation, 537 patients had indications for monitoring. No QTc intervals were documented by nurses. After protocol implementation, 544 patients had indications for monitoring. Protocol adherence was higher during day shifts than during night shifts (45.3% and 38.4%, respectively). Of 170 documented QTc prolongation events, 26 (15%) were reported to physicians. Nurses' knowledge significantly improved after education and was retained 4 months after education (correct responses to assessment questions: 59% at baseline, 96% immediately after education, and 86% at 4 months after education). This QTc interval monitoring protocol improved nurses' ability to identify and monitor patients with increased risk of QTc interval prolongation. Adherence was less than desired, suggesting that further protocol revisions are required.

Androgens, QT, sex and ventricular repolarization–a double-edged sword: A case series

The prevalence and incidence of cardiac pro-arrhythmic disorders are often influenced by sex due to specific effects on the QT interval. Androgens shorten QT, which may be protective against acquired long QT syndromes and their related arrhythmias in men such as torsade de pointes (TdP). On the other hand, androgens can potentiate Brugada and early repolarization syndromes, which are most prevalent in men. In this case series, we highlight four male patients with aborted SCD in the setting of abnormal testosterone status; two patients with TdP in a setting of testosterone deprivation (of which one drug-induced) and 2 patients with ventricular fibrillation associated with exogenous androgenic booster (Tribulus terrestris) intake. From this case series, we review the current available literature of the effects of androgen as a double-edged sword on the QTc interval and emphasize the importance of QTc monitoring in this subset of patients.

Influence of heart rate correction formulas on QTc interval stability

Monitoring of QTc interval is mandated in different clinical conditions. Nevertheless, intra-subject variability of QTc intervals reduces the clinical utility of QTc monitoring strategies. Since this variability is partly related to QT heart rate correction, 10 different heart rate corrections (Bazett, Fridericia, Dmitrienko, Framingham, Schlamowitz, Hodges, Ashman, Rautaharju, Sarma, and Rabkin) were applied to 452,440 ECG measurements made in 539 healthy volunteers (259 females, mean age 33.3 ± 8.4 years). For each correction formula, the short term (5-min time-points) and long-term (day-time hours) variability of rate corrected QT values (QTc) was investigated together with the comparisons of the QTc values with individually corrected QTcI values obtained by subject-specific modelling of the QT/RR relationship and hysteresis. The results showed that (a) both in terms of short-term and long-term QTc variability, Bazett correction led to QTc values that were more variable than the results of other corrections (p < 0.00001 for all), (b) the QTc variability by Fridericia and Framingham corrections were not systematically different from each other but were lower than the results of other corrections (p-value between 0.033 and < 0.00001), and (c) on average, Bazett QTc values departed from QTcI intervals more than the QTc values of other corrections. The study concludes that (a) previous suggestions that Bazett correction should no longer be used in clinical practice are fully justified, (b) replacing Bazett correction with Fridericia and/or Framingham corrections would improve clinical QTc monitoring, (c) heart rate stability is needed for valid QTc assessment, and (d) development of further QTc corrections for day-to-day use is not warranted.

QT Interval Monitoring with Handheld Heart Rhythm ECG Device in COVID-19 Patients.

Background:QTc prolongation is an adverse effect of COVID-19 therapies. The use of a handheld device in this scenario has not been addressed.Objectives:To evaluate the feasibility of QTc monitoring with a smart device in COVID-19 patients receiving QTc-interfering therapies.Methods:Prospective study of consecutive COVID-19 patients treated with hydroxychloroquine ± azithromycin ± lopinavir-ritonavir. ECG monitoring was performed with 12-lead ECG or with KardiaMobile-6L. Both registries were also sequentially obtained in a cohort of healthy patients. We evaluated differences in QTc in COVID-19 patients between three different monitoring strategies: 12-lead ECG at baseline and follow-up (A), 12-lead ECG at baseline and follow-up with the smart device (B), and fully monitored with handheld 6-lead ECG (group C). Time needed to obtain an ECG registry was also documented.Results:One hundred and eighty-two COVID-19 patients were included (A: 119(65.4%); B: 50(27.5%); C: 13(7.1%). QTc peak during hospitalization did significantly increase in all groups. No differences were observed between the three monitoring strategies in QTc prolongation (p = 0.864). In the control group, all but one ECG registry with the smart device allowed QTc measurement and mean QTc did not differ between both techniques (p = 0.612), displaying a moderate reliability (ICC 0.56 [0.19–0.76]). Time of ECG registry was significantly longer for the 12-lead ECG than for handheld device in both cohorts (p < 0.001).Conclusion:QTc monitoring with KardiaMobile-6L in COVID-19 patients was feasible. Time of ECG registration was significantly lower with the smart device, which may offer an important advantage for prevention of virus dissemination among healthcare providers.

Quality improvement in remote prescribing

Quality improvement in remote prescribing

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.

Medication safety in a pandemic: A multicentre point prevalence study of QTc monitoring of hydroxychloroquine for COVID-19.

What is known and ObjectiveA pandemic can strain all aspects of the healthcare system, including the ability to monitor the safety of medication use. Reviewing the adequacy of medication safety practices during the COVID‐19 pandemic is critical to informing responses to future pandemics. The purpose of this study was to evaluate medication safety practices at a height of both COVID‐19 cases and hydroxychloroquine use.MethodsThis was a multicentre observational point prevalence study. Adult inpatients receiving hydroxychloroquine for COVID‐19 between March 22 and 28, 2020 were included. The primary outcome was the percentage of patients receiving appropriate QTc monitoring. Secondary outcomes included QTc prolongation, early discontinuation of hydroxychloroquine and ventricular arrhythmias.Results and discussionA total of 59% (167/284) of patients treated with hydroxychloroquine received appropriate QTc monitoring. QTc prolongation occurred in 25%. Hydroxychloroquine was prematurely discontinued in 1.4% of patients, all due to QTc prolongation. Ventricular arrhythmia occurred in 1.1%.What is new and ConclusionMedication safety practices were suboptimal with regard to hydroxychloroquine monitoring at the height of the COVID‐19 pandemic. Preparation for future pandemics should devote considerable attention to medication safety.

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.

Evolución del intervalo QTc en pacientes con infección SARS-CoV-2 tratados con fármacos antivirales

IntroductionMany antiviral agents, such as hydroxychloroquine, have been used to treat COVID-19, without being broadly accepted. QTc prolongation is a worrisome adverse effect, scarcely studied in pediatrics. Patients and methodsPediatric patients affected from COVID-19 who received antivirals were matched (1:2) with controls not infected nor exposed. Electrocardiograms were prospectively analyzed at baseline, during the first 72 h in treatment and after 72 h. ResultsEleven (22.9%) out of 48 patients admitted due to COVID-19 (March–July 2020) received antiviral therapy. All had underlying diseases: congenital heart disease (4/11; 36.4%) and immunosuppression (3/11; 27.3%) stand out. 5/11 (45.5%) received treatment at baseline with a potential effect on QTc. There where no differences observed in the baseline QTc between cases and controls: 414.8 ms (49.2) vs. 416.5 ms (29.4) (p = 0.716). Baseline long QT was observed in 2/11 cases and 2/22. Among cases, 10/11 (90.9%) received hydroxychloroquine, mainly associated with azithromycin (8/11; 72.7%), 3 received lopinavir/ritonavir and one remdesivir. The median increase in QTc after 72 h under treatment was 28.9 ms (IQR 48.7) (p = 0.062). 4/11 (36.4%) patients had a long QTc at 72 h, resulting in 3 patients ≥500 ms; treatment was stopped in one (QTc 510 ms) but ventricular arrhythmias were not documented. ConclusionsThe use of antivirals caused an increase on the QTc interval after 72 h of treatment, being the QTc long in 36.3% of the patients, although no arrhythmic events were observed. The use of hydroxychloroquine and antivirals requires active QTc monitoring and it is recommended to discontinue treatment if QTc >500 ms.