Prevention of torsade de pointes in hospital settings: a scientific statement from the American Heart Association and the American College of Cardiology Foundation

Clinical Efficacy of Hydroxychloroquine in Patients with COVID-19: Findings from an Observational Comparative Study in Saudi Arabia

The aim of this study was to assess the clinical effectiveness of Hydroxychloroquine-based regimens versus standard treatment in patients with the coronavirus disease admitted in 2019 to a hospital in Saudi Arabia. A comparative observational study, using routine hospital data, was carried out in a large tertiary care hospital in Al Baha, Saudi Arabia, providing care to patients with COVID-19 between April 2019 and August 2019. Patients were categorized into two groups: the Hydroxychloroquine (HCQ) group, treated with HCQ in a dose of 400 mg twice daily on the first day, followed by 200 mg twice daily; the non HCQ group, treated with other antiviral or antibacterial treatments according to protocols recommended by the Ministry of Health (MOH) at the time. The primary outcomes were the length of hospital stay, need for admission to the intensive care unit (ICU), time in ICU, and need for mechanical ventilation. Overall survival was also assessed. 568 patients who received HCQ (treatment group) were compared with 207 patients who did not receive HCQ (control group). HCQ did not improve mortality in the treated group (7.7% vs. 7.2%). There were no significant differences in terms of duration of hospitalization, need for and time in ICU, and need for mechanical ventilation among the groups. Our study provides further evidence that HCQ treatment does not reduce mortality rates, length of hospital stay, admission and time in ICU, and need for mechanical ventilation in patients hospitalized with COVID-19.

Assessing Prescriber Behavior with a Clinical Decision Support Tool to Prevent Drug-Induced Long QT Syndrome

OBJECTIVE

Clinical decision support (CDS) alerts built into the electronic health record (EHR) have the potential to reduce the risk of drug-induced long QT syndrome (diLQTS) in susceptible patients. However, the degree to which providers incorporate this information into prescription behavior and the impact on patient outcomes is often unknown.

METHODS

We examined provider response data over a period from October 8, 2016 until November 8, 2018 for a CDS alert deployed within the EHR from a 13-hospital integrated health care system that fires when a patient with a QTc ≥ 500 ms within the past 14 days is prescribed a known QT-prolonging medication. We used multivariate generalized estimating equations to analyze the impact of therapeutic alternatives, relative risk of diLQTS for specific medications, and patient characteristics on provider response to the CDS and overall patient mortality.

RESULTS

The CDS alert fired 15,002 times for 7,510 patients for which the most common response (51.0%) was to override the alert and order the culprit medication. In multivariate models, we found that patient age, relative risk of diLQTS, and presence of alternative agents were significant predictors of adherence to the CDS alerts and that nonadherence itself was a predictor of mortality. Risk of diLQTS and presence of an alternative agent are major factors in provider adherence to a CDS to prevent diLQTS; however, provider nonadherence was associated with a decreased risk of mortality.

CONCLUSION

Surrogate endpoints, such as provider adherence, can be useful measures of CDS value but attention to hard outcomes, such as mortality, is likely needed.

Progress in the risk assessment of hydroxychloroquine in frail elderly people

Hydroxychloroquine (HCQ) is an antimalarial drug also known to have anti-inflammatory and antiviral effects. The antiviral action of HCQ has been a point of interest for many researchers because of its mechanism of action and the potential use it could have during the current COVID-19 pandemic. However, HCQ can cause QT interval prolongation. The current therapies used in COVID-19 are changing as the pandemic develops. The aim of this article is to promote a validated risk score for QT prolongation in multidimensional assessment of COVID-19 patients, especially in elderly and polypathological patients.

Using Medicare Data to Assess the Proarrhythmic Risk of Non-Cardiac Treatment Drugs that Prolong the QT Interval in Older Adults: An Observational Cohort Study

Introduction

Serious cardiac arrhythmias caused by QT-prolonging drugs are difficult to predict based on physiological measurement and pre-approval clinical trials. Post-marketing surveillance and monitoring are important to generate safety data.

Objectives

To assess whether an observational study using Medicare claims data can detect the arrhythmogenic risk of QT-prolonging drugs.

Methods

We identified 17 QT-prolonging drugs with known risk of torsades des pointes (TdP) that were not used to treat cardiac arrhythmias. Amoxicillin and four serotonin-norepinephrine reuptake inhibitors (SNRIs) were used as controls. De-identified claims data of 1.2 million Medicare beneficiaries were accessed. Two separate Cox regressions were done for short-term and chronic-use drugs. The primary outcome was a composite of ventricular arrhythmias and/or sudden death, identified by ICD diagnostic codes. We explored the independent effect of each study drug on the outcomes. Other covariates included patient demographics, comorbidities, and known risk factors for drug-induced cardiac arrhythmia.

Results

We were able to detect increased risk in 14 of 17 study drugs (82.3%), and none of the control drugs. Among the fluoroquinolones, ciprofloxacin was the safest. Azithromycin and clarithromycin were relatively safe compared to erythromycin. Compared to SNRIs, both citalopram and escitalopram had increased risk, more so with escitalopram than citalopram. Comorbidities associated with increased risk included ischemic heart disease, electrolyte imbalance, bradycardia, acute myocardial infarction, heart failure, and chronic kidney and liver disease.

Conclusion

Medicare data can be utilized for post-marketing surveillance and monitoring of the proarrhythmic risk of QT-prolonging drugs in older adults.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40801-021-00230-1.

Clinical guidance for navigating the QTc-prolonging and arrhythmogenic potential of pharmacotherapy during the COVID-19 pandemic

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for coronavirus disease 19 (COVID-19), has rapidly spread since December 2019 to become the focus of healthcare systems worldwide. Its highly contagious nature and significant mortality has led to its prioritization as a public health issue. The race to prevent and treat this disease has led to "off-label" prescribing of medications such as hydroxychloroquine, azithromycin, and Kaletra (lopinavir/ritonavir). Currently, there is no robust clinical evidence for the use of these drugs in the treatment of COVID-19, with most, if not all of these medications associated with the potential for QT interval prolongation, torsades de pointes, and resultant drug-induced sudden cardiac death. The aim of this document is to help healthcare providers mitigate the potential deleterious effects of drug-induced QTc prolongation.

Evaluation of Index of Cardio-Electrophysiological Balance in Patients With Atrial Fibrillation on Antiarrhythmic-Drug Therapy

BACKGROUND

Index of cardio-electrophysiological balance (iCEB) has been described as a novel risk marker for predicting malignant ventricular arrhythmia. There remains limited evidence on the effects of amiodarone and propafenone used for sinus rhythm maintenance on iCEB in patients with atrial fibrillation (AF). The aim of this study was to evaluate iCEB in patients with AF on antiarrhythmic-drug therapy.

METHODS

A total of 108 patients with AF (68 patients using amiodarone and 40 patients using propafenone) and 50 healthy subjects were included in the study. All groups underwent a standard 12-lead surface electrocardiogram. QRS duration, QT, T wave peak-to-end (Tp-e) intervals, iCEB (QT/QRS) and iCEBc (heart rate-corrected QT (QTc)/QRS) rates were calculated from the electrocardiogram and compared between groups.

RESULTS

QT, Tp-e intervals and Tp-e/QT ratio were significantly longer in the amiodarone group than the propafenone and control groups (P < 0.001, for all). iCEB was similar in the amiodarone and control groups (4.4 ± 0.6 and 4.2 ± 0.4; P > 0.05), while iCEB values in the propafenone group were significantly lower than the amiodarone group and control groups (3.9 ± 0.5; P < 0.001). There was a significantly difference in iCEBc values among the amiodarone, control and propafenone groups (4.8 ± 0.6, 4.6 ± 0.4 and 4.3 ± 0.6; P < 0.001, respectively).

CONCLUSIONS

In this study, higher iCEBc parameters were observed in patients using amiodarone, while iCEBc values were lowest among patients with AF using propafenone. Further studies are needed to determine whether these electrophysiological changes are associated with ventricular arrhythmias for patients with AF on antiarrhythmic-drug therapy.

Unmasking Long QT Syndrome in the Emergency Department: A Case Report

Introduction

Long QT syndrome (LQTS) is an uncommon disorder that can lead to potentially life-threatening dysrhythmias. LQTS can be genetic, acquired, or both.

Case Report

A 44-year-old female with well-controlled hypertension and asthma presented with chest tightness. An initial electrocardiogram yielded a normal corrected QT interval of 423 milliseconds (ms) (normal <480 ms in females). Albuterol was administered and induced agitation, tremulousness, and tachycardia. Follow-up electrocardiograms demonstrated extreme prolongation of the corrected QT interval to 633 ms and morphology change of the T wave. Lab values were later notable for hypokalemia and hypomagnesemia, attributable to a recently started thiazide diuretic. The patient was ultimately diagnosed with congenital LQTS after initial unmasking by albuterol in the emergency department.

Conclusion

LQTS can be unmasked or exacerbated by electrolyte abnormalities and QT prolonging medications.

Short coupled torsade de pointes: Critical timing of the ventricular premature beats

In this case report, we describe a 73 year old female with structuraly normal heart that developed shortcoupled torsades de pointes (TdP) resulting in an electrical storm unresponsible to several antiarrhythmic drugs, but fully controlled with verapamil. The critical timing of the ventricular premature beats that initiated TdP corresponded to those that occurred at the peak of the previous T wave. This behavior differentiates this entity from other forms of malignant ventricular arrhythmias in patients with structurally normal heart. It is imperative that the clinical set-up and unique electrocardiographic fingerprint of this unusual malignant entity be assiduously recognized since verapamil can be life-saving in this condition.

PONV management in patients with QTc prolongation on the EKG

Postoperative nausea and vomiting (PONV) is a commonly encountered problem in surgical practice. It delays discharge from the post-anesthesia care unit, requires additional resources to treat, and may increase the morbidity in some patients. Many effective drugs are available to treat or prevent PONV, however many of these drugs have the potential to prolong the QTc on the electrocardiogram (EKG) and increase the risk of serious ventricular arrhythmias, in particular, torsade de pointes. The QTc prolongation may be a manifestation of a genetic mutation resulting in abnormal myocyte repolarization or it may be acquired and associated with the use of various medications, electrolyte disorders, and physiological conditions. Patients predisposed to QTc prolongation presenting for surgery constitute a challenging group, since many drugs commonly used for PONV management will put them at risk for perioperative serious arrhythmias. This is an important topic, and our mini-review is an attempt to highlight the problem, summarize the existing experience, and generate recommendations for safe management of PONV for patients, who are at increased risk of QTc prolongation and arrhythmias. Focused prospective studies will help to find definitive answers to the discussed problems and challenges and develop specific guidelines for clinical application.

Bedaquiline for multidrug-resistant tuberculosis and QTc prolongation in California

Background

Bedaquiline (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.

Methods

Based 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.

Results

A 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.

Discussion

BDQ 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.

Comparison of Antipsychotics for the Treatment of Patients With Delirium and QTc Interval Prolongation: A Clinical Decision Analysis

Background: Antipsychotics are frequently used to treat delirium but often induce corrected QT (QTc) prolongation, which can be lethal by causing torsade de pointes. Nonetheless, the selection of antipsychotics to treat delirium patients with prolonged baseline QTc intervals remains unclear. We aimed to assess the utility of antipsychotics based on their effects on treatment outcomes and QTc intervals. Methods: A clinical decision analysis was conducted using data on the effects of antipsychotics on treatment outcomes and QTc intervals from published network meta-analyses. We quantified the utility of six antipsychotics (amisulpride, haloperidol, olanzapine, quetiapine, risperidone, and ziprasidone) using a decision tree and the obtained effect sizes. Subsequently, we conducted sensitivity analyses using multiple utility settings and another dataset. We also performed a probabilistic sensitivity analysis using Monte Carlo simulation, in which the effects of antipsychotics were randomly sampled given the plausible range. Results: Amisulpride showed the highest utility when the baseline QTc interval was 420 ms. Quetiapine showed the highest utility when the baseline QTc interval was ≥450 ms. The sensitivity analyses also showed the superiority of quetiapine when the baseline QTc intervals were prolonged. Conclusions: Decision analysis suggests that quetiapine is the optimal antipsychotic drug for the treatment of patients with delirium and prolonged baseline QTc intervals.

Leading 20 drug-drug interactions, polypharmacy, and analysis of the nature of risk factors due to QT interval prolonging drug use and potentially inappropriate psychotropic use in elderly psychiatry outpatients

BACKGROUND

Psychotropic medications extend corrected QT (QTc) period in the electrocardiogram (ECG). Psychiatric patients exposed to ⩾1 psychotropic medication(s) represent a group with marked probability of drug-activated QTc-prolongation. Prolonged QTc interval in elderly patients (age > 60 years) is connected to greater risk of all-cause and coronary heart disease deaths. This study aimed at investigating pattern of utilization of QTc-interval protracting medications, QT-extending drug interactions, and prevalence of QTc-interval extending hazard factors in elderly patients.

METHODS

This was a cross-sectional, prospective study at the Psychiatry OPD at All India Institute of Medical Sciences (AIIMS), Rishikesh, Uttarakhand, India from 1 October 2017 to 30 August 2019 employing the pertinent prescriptions.

RESULTS

A total of 832 elderly patients (age 60 years or more) visiting the Psychiatry OPD during the aforementioned study duration were investigated. About 420 (50.5%) patients were males while 412 (49.5%) were females. Of the 832 patients, 588 (70.7%) were using interacting agents with capacity to produce TdP. Almost 1152 interacting torsadogenic medication pairs were unraveled. As per AzCERT/CredibleMeds Classification, 1016 (48.8%), 724 (34.8%), and 248 (12%) agents with potential to interact were identified with 'known', 'possible', and 'conditional risk of TdP', respectively. The common interacting medications belonged to antidepressant (288), proton pump inhibitor (364), antipsychotic (340), antinausea (184), antimicrobial (156), and H2 receptor antagonist (60) therapeutic categories. The all-inclusive frequency of potentially inappropriate psychotropic (PIP) agents administered was 62% (1343/2166) with Beers Criteria 2019, and 46% (997/2166) with STOPP Criteria 2015.

CONCLUSION

Many geriatric patients were administered drugs and drug combinations with heightened proclivity toward QT-interval prolongation. Furthermore, reliable evidence-based online drug knowledge resources, such as AzCERT/CredibleMeds Drug Lists, Medscape Drug Interactions Checker, Epocrates Online Interaction Check, and Drugs.com Drug Interactions Checker, can facilitate clinical professionals in selecting drugs for psychiatric patients. A wise choice of medications is imperative to preclude serious adverse sequelae. Therefore, we need to exigently embrace precautionary safety means, be vigilant, and forestall QT-extension and TdP in clinical environments.

Lethal Arrhythmia (Torsade de Pointes) in COVID-19: An Event Synergistically Induced by Viral Associated Cardiac Injury, Hyperinflammatory Response, and Treatment Drug?

Arrhythmias in patients with coronavirus disease 2019 (COVID-19) are prevalent and deserve special attention because they are associated with an increased risk of fatal outcome. The mechanism of arrhythmia in COVID-19 remains unclear. Here, we report our first case of confirmed COVID-19 with documented Torsade de Pointes (TdP). A 64-year-old woman, previously healthy, presented to our emergency department with progressive shortness of breath, dry cough, and 1 week of fever. She was treated with chloroquine phosphate, meropenem, and ciprofloxacin. After 5 days of admission, her condition deteriorated and she was admitted to the intensive care unit. The patient had two episodes of malignant arrhythmias within 24 hours. The former was TdP, and the latter was a fatal pulseless ventricular tachycardia that occured even after chloroquine was discontinued. There was evidence of cardiac injury shown by increased serum level of troponin I. We propose a synergistic concept of lethal arrhythmia due to direct severe acute respiratory syndrome coronavirus (SARS-CoV)-2-associated cardiac injury, hyperinflammatory response, and drug-induced arrhythmia.

Top 20 drug - drug interactions, polypharmacy and analysis of the nature of risk factors due to QT interval prolonging drug use in elderly psychiatry outpatients

INTRODUCTION AND OBJECTIVES

Psychotropic medications extend the corrected QT (QTc) period in the ECG. Psychiatric patients exposed to ≥ 1 psychotropic medication (s) represent a group with a marked probability of drug-activated QTc-prolongation. Prolonged QTc interval in elderly patients (age > 60 years) is connected to a greater risk of all-cause and coronary heart disease deaths. We investigated the pattern of utilization of QTc-interval prolonging medications, QT-extending interactions between drugs, and prevalence of QTc-interval prolonging risk factors in elderly patients.

METHODS

This was a cross-sectional, prospective study at the Psychiatry OPD at All India Institute of Medical Sciences (AIIMS), Rishikesh, Uttarakhand, India from October 1, 2017 to December 31, 2018 employing the pertinent prescriptions.

RESULTS

A total of 208 elderly patients (age 60 years or more) visiting the Psychiatry OPD during the aforementioned study period were investigated. 105 (50.5%) patients were males whereas 103 (49.5%) were females in our study. 147 out of 208 patients (70.7%) were using interacting agents with the capacity to produce TdP. 288 interacting torsadogenic medication pairs were unraveled. As per AzCERT/CredibleMeds Classification, 254 (48.8%), 181 (34.8%), and 62 (12%) interacting medications were identified with known, possible, and conditional risk of TdP, respectively. The common interacting medications belonged to antidepressant (144), proton pump inhibitor (91), antipsychotic (85), anti-nausea (46), antimicrobial (39), and H2 receptor antagonist (15) therapeutic categories.

CONCLUSIONS

Many geriatric patients were administered drugs and drug combinations with heightened proclivity towards QT-interval prolongation. Therefore, we need to exigently embrace precautionary safety interventions, to be vigilant, and forestall QT-prolongation and TdP in clinical settings. Online evidence-based drug information resources can aid clinicians in choosing drugs for psychiatric patients.

Impact of a clinical decision support tool targeting QT-prolonging medications

PURPOSE

To evaluate the impact of a newly implemented clinical decision support (CDS) tool targeting QT interval-prolonging medications on order verification and provider interventions.

METHODS

A multicenter, retrospective quasi-experimental study was conducted to evaluate provider response to CDS alerts triggered during ordering of QT-prolonging medications for adult patients. The primary outcome was the proportion of orders triggering QTc alerts that were continued without intervention during a specified preimplementation phase (n = 49) and during a postimplementation phase (n = 100). Patient risk factors for QTc prolongation, provider alert response, and interventions to reduce the risk of QTc-associated adverse events were evaluated.

RESULTS

The rate of order continuation without intervention was 82% in the preimplementation phase and 37% in the postimplementation phase, representing an 55% reduction in continued verified orders following implementation of the QT-focused CDS tool. Most alerts were initially responded to by the prescriber, with pharmacist intervention needed in only 33% of cases. There were no significant differences in patient QTc-related risk factors between the 2 study groups (P = 0.11); the postimplementation group had a higher proportion of patients using at least 2 QTc-prolonging medications (48%, compared to 26% in the preimplementation group; P = 0.02).

CONCLUSION

Implementation of the CDS tool was associated with a reduction in the proportion of orders continued without intervention in patients at high risk for QTc-related adverse events.

Drug-induced proarrhythmia: Discussion and considerations for clinical practice

The clinical practice of pharmaceutical medicine includes contributions from physicians, pharmacists, nurse practitioners, and physician assistants. Drug safety considerations are of considerable importance. This article discusses drug-induced proarrhythmia, with a specific focus on Torsade de Pointes (Torsade), a polymorphic ventricular tachycardia that typically occurs in self-limiting bursts that can lead to dizziness, palpitations, syncope, and seizures, but on rare occasions can progress to ventricular fibrillation and sudden cardiac death. A dedicated clinical pharmacology study conducted during a drug's clinical development program has assessed its propensity to induce Torsade using prolongation of the QT interval as seen on the surface electrocardiogram (ECG) as a biomarker. Identification of QT-interval prolongation does not necessarily prevent a drug from receiving marketing approval if its overall benefit-risk balance is favorable, but, if approved, a warning is placed in its Prescribing Information. This article explains why drugs can have a proarrhythmic propensity and concludes with a case presentation.

Cardiovascular Toxicity Related to Cancer Treatment: A Pragmatic Approach to the American and European Cardio-Oncology Guidelines

The considerable progress made in the field of cancer treatment has led to a dramatic improvement in the prognosis of patients with cancer. However, toxicities resulting from these treatments represent a cost that can be harmful to short- and long-term outcomes. Adverse events affecting the cardiovascular system are one of the greatest challenges in the overall management of patients with cancer, as they can compromise the success of the optimal treatment against the tumor. Such adverse events are associated not only with older chemotherapy drugs such as anthracyclines but also with many targeted therapies and immunotherapies. Recognizing this concern, several American and European governing societies in oncology and cardiology have published guidelines on the cardiovascular monitoring of patients receiving potentially cardiotoxic cancer therapies, as well as on the management of cardiovascular toxicities. However, the low level of evidence supporting these guidelines has led to numerous discrepancies, leaving clinicians without a consensus strategy to apply. A cardio-oncology expert panel from the French Working Group of Cardio-Oncology has undertaken an ambitious effort to analyze and harmonize the most recent American and European guidelines to propose roadmaps and decision algorithms that would be easy for clinicians to use in their daily practice. In this statement, the experts addressed the cardiovascular monitoring strategies for the cancer drugs associated with the highest risk of cardiovascular toxicities, as well as the management of such toxicities.

Saudi Heart Rhythm Society Task Force on Management of Potential Arrhythmogenicity Associated with Pharmacotherapy for COVID-19

Evidence of cardiovascular complications associated with the COVID-19 global pandemic continues to evolve. These include direct and indirect myocardial injury with subsequent acute myocardial ischemia, and cardiac arrhythmia. Some results from a limited number of trials of antiviral medications, along with chloroquine/hydroxychloroquine and azithromycin, have been beneficial. However, these pharmacotherapies may cause drug-induced QT prolongation leading to ventricular arrhythmias and sudden cardiac death. Mitigation of the potential risk in these susceptible patients may prove exceptionally challenging. The Saudi Heart Rhythm Society established a task force to perform a review of this subject based on has recently published reports, and studies and recommendations from major medical organizations. The objective of this review is to identify high-risk patients, and to set clear guidelines for management of patients receiving these pharmacotherapies.

Is QTc-Interval Prolongation an Inherent Feature of Eating Disorders? A Cohort Study

BACKGROUND

Anorexia nervosa is associated with a markedly increased risk of sudden cardiac death, but the mechanism has not been elucidated. Whether QT prolongation is an intrinsic feature of eating disorders is uncertain because previous studies are limited by small sample size, and extrinsic factors associated with QT prolongation were inconsistently reported. This study set to determine population-mean heart-rate-corrected QT interval (QTc) in an unselected cohort of patients with eating disorders.

METHODS

Electrocardiogram (ECG) data from 1026 consecutive adults admitted into residential treatment were stratified by subtype: anorexia nervosa (caloric restriction only), anorexia nervosa binge-purge, and bulimia nervosa. Eating disorders not otherwise specified were excluded. Population-mean Fridericia-corrected QTc and categorical QTc threshold analysis were performed. Multivariable regression, controlling for age sex, duration of illness, body mass index (BMI), hypokalemia, QTc-prolonging drugs, purging behaviors, and laxatives was assessed.

RESULTS

Among 906 patients, population-mean QTc (424 ± 25 standard deviation [SD]) was normal and lowest among patients with anorexia nervosa (417.3 ± 22.3, P <0.001 vs other subgroups). Only 1.2% (N = 11) had marked QTc prolongation (QTc >500 ms); all 11 patients had hypokalemia and were receiving QTc-prolonging medications or laxatives. After controlling for clinically relevant covariates, differences in mean QTc across eating disorder subtypes diminished yet persisted (P = 0.048).

CONCLUSIONS

In the largest study of patients with eating disorders, population-mean QTc was normal and varied by subtype. Marked QTc prolongation occurred solely in the presence of extrinsic factors, suggesting that QTc prolongation is not intrinsic to eating disorders. Therefore, further study is needed to define the etiology of sudden death in patients with eating disorders.

Pseudo-colouring an ECG enables lay people to detect QT-interval prolongation regardless of heart rate

Drug-induced long QT syndrome (diLQTS), characterized by a prolongation of the QT-interval on the electrocardiogram (ECG), is a serious adverse drug reaction that can cause the life-threatening arrhythmia Torsade de Points (TdP). Self-monitoring for diLQTS could therefore save lives, but detecting it on the ECG is difficult, particularly at high and low heart rates. In this paper, we evaluate whether using a pseudo-colouring visualisation technique and changing the coordinate system (Cartesian vs. Polar) can support lay people in identifying QT-prolongation at varying heart rates. Four visualisation techniques were evaluated using a counterbalanced repeated measures design including Cartesian no-colouring, Cartesian pseudo-colouring, Polar no-colouring and Polar pseudo-colouring. We used a multi-reader, multi-case (MRMC) receiver operating characteristic (ROC) study design within a psychophysical paradigm, along with eye-tracking technology. Forty-three lay participants read forty ECGs (TdP risk n = 20, no risk n = 20), classifying each QT-interval as normal/abnormal, and rating their confidence on a 6-point scale. The results show that introducing pseudo-colouring to the ECG significantly increased accurate detection of QT-interval prolongation regardless of heart rate, T-wave morphology and coordinate system. Pseudo-colour also helped to reduce reaction times and increased satisfaction when reading the ECGs. Eye movement analysis indicated that pseudo-colour helped to focus visual attention on the areas of the ECG crucial to detecting QT-prolongation. The study indicates that pseudo-colouring enables lay people to visually identify drug-induced QT-prolongation regardless of heart rate, with implications for the more rapid identification and management of diLQTS.

Effects of Short-Term Hydroxychloroquine Plus Moxifloxacin Therapy on Corrected QT Interval and Tp-e Interval in Patients With COVID-19

Background

Limited data are available regarding hydroxychloroquine (HCQ) and moxifloxacin (MOX) in patients with possible coronavirus disease 2019, (COVID-19). Both drugs may increase risk of malignant ventricular arrhythmias associated with prolongation of QT interval.

Methods

A total of 76 subjects with chest tomography findings compatible with COVID-19 pneumonia were enrolled in the study. Standard 12-lead electrocardiogram (ECG) was repeated on days 2 and 5 in patients receiving a combination of HCQ + MOX. Heart rate, QT interval, Tp-e interval, and Tp-e/QT ratio were measured.

Results

The mean age of the patients was 61.7 ± 14.8 years and 54% had hypertension. Compared to day 2, ECG on day 5 showed significant increases in QT interval (370.8 ± 32.5 vs. 381.0 ± 29.3, respectively, P = 0.001), corrected QT (QTc) interval (424 (403 - 436) vs. 442 (420 - 468), respectively, P < 0.001), Tp-e interval (60 (55 - 70) vs. 65 (57 - 75), respectively, P < 0.001), cTp-e interval (72.2 ± 12.9 vs. 75.4 ± 12.7, respectively, P < 0.001). Moreover, a slight decrease in Tp-e/QT ratio was observed (0.17 ± 0.03 vs. 0.17 ± 0.02, P = 0.030). QTc was > 500 ms in 5% of the patients, and 8% of patients had an increase in QTc interval > 60 ms. Tp-e/QT ratio was > 0.23 in 4% of patients. Five patients died due to pulmonary failure without evidence of ventricular arrhythmia. No ventricular arrhythmia events, including torsades de pointes (TdP), were observed.

Conclusions

HCQ + MOX combination therapy led to increases in QTc interval, Tp-e interval, and cTp-e interval. However, this therapy did not cause ventricular arrhythmia in the short-term observation.

Management of COVID-19 in people with epilepsy: drug considerations

People with epilepsy (PWE) are neither more likely to be infected by the coronavirus nor are they more likely to have severe COVID-19 manifestations because they suffer from epilepsy. However, management of COVID-19 in PWE may be more complicated than that in other individuals. Drug-drug interactions could pose significant challenges and cardiac, hepatic, or renal problems, which may happen in patients with severe COVID-19, may require adjustment to antiepileptic drugs (AEDs). In this review, we first summarize the potential drug-drug interactions between AEDs and drugs currently used in the management of COVID-19. We then summarize other challenging issues that may happen in PWE, who have COVID-19 and are receiving treatment.

Walk the Line-The Importance of Well-Informed Interpretation of QT Prolongation

Acute care pharmacists play an integral role in identifying drug-drug interactions that may predispose patients to QT prolongation. Although most pharmacists are equipped with a baseline understanding of drug interactions and the risks of QTc prolongation, few understand the limitations of QTc calculation and interpretation. In this commentary, we put forth the notion that at times health care providers, including pharmacists, place an overemphasis on the QTc interval. In the context of using the QTc to guide pharmacotherapy decisions, unintended consequences may include a cascade of effects leading to delays in treatment, suboptimal medication selection, alert fatigue, and overutilization of resources.

A current understanding of drug-induced QT prolongation and its implications for anticancer therapy

The QT interval, a global index of ventricular repolarization, varies among individuals and is influenced by diverse physiologic and pathophysiologic stimuli such as gender, age, heart rate, electrolyte concentrations, concomitant cardiac disease, and other diseases such as diabetes. Many drugs produce a small but reproducible effect on QT interval but in rare instances this is exaggerated and marked QT prolongation can provoke the polymorphic ventricular tachycardia 'torsades de pointes', which can cause syncope or sudden cardiac death. The generally accepted common mechanism whereby drugs prolong QT is block of a key repolarizing potassium current in heart, IKr, generated by expression of KCNH2, also known as HERG. Thus, evaluation of the potential that a new drug entity may cause torsades de pointes has relied on exposure of normal volunteers or patients to drug at usual and high concentrations, and on assessment of IKr block in vitro. More recent work, focusing on anticancer drugs with QT prolonging liability, is defining new pathways whereby drugs can prolong QT. Notably, the in vitro effects of some tyrosine kinase inhibitors to prolong cardiac action potentials (the cellular correlate of QT) can be rescued by intracellular phosphatidylinositol 3,4,5-trisphosphate, the downstream effector of phosphoinositide 3-kinase. This finding supports a role for inhibition of this enzyme, either directly or by inhibition of upstream kinases, to prolong QT through mechanisms that are being worked out, but include enhanced inward 'late' sodium current during the plateau of the action potential. The definition of non-IKr-dependent pathways to QT prolongation will be important for assessing risk, not only with anticancer therapies but also with other QT prolonging drugs and for generating a refined understanding how variable activity of intracellular signalling systems can modulate QT and associated arrhythmia risk.

QT prolongation, torsades de pointes, and sudden death with short courses of chloroquine or hydroxychloroquine as used in COVID-19: A systematic review

Chloroquine and hydroxychloroquine are now being widely used for treatment of COVID-19. Both medications prolong the QT interval and accordingly may put patients at increased risk for torsades de pointes and sudden death. Published guidance documents vary in their recommendations for monitoring and managing these potential adverse effects. Accordingly, we set out to conduct a systematic review of the arrhythmogenic effect of short courses of chloroquine or hydroxychloroquine. We searched on MEDLINE and Embase, as well as in the gray literature up to April 17, 2020, for the risk of QT prolongation, torsades, ventricular arrhythmia, and sudden death with short-term chloroquine and hydroxychloroquine usage. This search resulted in 390 unique records, of which 41 were ultimately selected for qualitative synthesis and which included data on 1515 COVID-19 patients. Approximately 10% of COVID-19 patients treated with these drugs developed QT prolongation. We found evidence of ventricular arrhythmia in 2 COVID-19 patients from a group of 28 treated with high-dose chloroquine. Limitations of these results are unclear follow-up and possible publication/reporting bias, but there is compelling evidence that chloroquine and hydroxychloroquine induce significant QT-interval prolongation and potentially increase the risk of arrhythmia. Daily electrocardiographic monitoring and other risk mitigation strategies should be considered in order to prevent possible harms from what is currently an unproven therapy.

Predictive Validity of a QTc Interval Prolongation Risk Score in the Intensive Care Unit

BACKGROUND

Torsade de pointes is a form of polymorphic ventricular tachycardia associated with heart rate-corrected QT (QT_c ) interval prolongation. With approximately 24-61% of critically ill patients experiencing QT_c interval prolongation, a predictive tool to identify high-risk patients could assist in the monitoring and management in the intensive care unit (ICU). The Tisdale et al. Risk Score (TRS) is a predictive tool that was developed and validated in a cardiac critical care unit.

OBJECTIVES

The objective of this study was to evaluate the predictive validity (sensitivity and specificity) and likelihood ratios of the TRS in a medical ICU.

METHODS

This was a longitudinal, retrospective, cohort study of consecutive patients who met the inclusion criteria from October 2017 to June 2018 with a sample size of 264 patients. The sample size was derived based on the number of TRS covariates and an exploratory variable. Baseline characteristics and risk factors were documented from electronic health records. The first occurrence of QT_c interval prolongation, defined as a QT_c interval > 500 ms or an increase ≥ 60 ms above baseline, was the primary endpoint.

MAIN RESULTS

The sensitivity and specificity of the TRS for low-risk patients against the moderate-risk and high-risk patients were 97% (95% CI 91-99%) and 16% (95% CI 11-23%), respectively. These results corresponded to a positive likelihood ratio of 1.15 (95% CI 1.07-1.24) and a negative likelihood ratio of 0.20 (95% CI 0.06-0.65).

CONCLUSIONS

In conclusion, the TRS showed a high sensitivity, making it useful in identifying patients at risk of developing QT_c interval prolongation. Furthermore, patients categorized as low risk by the tool can be considered as having minimal risk of developing QT_c interval prolongation. Given the tool's low specificity, it does not reliably identify all patients at low risk of QT_c interval prolongation.

Discovery and characterization of a monogenetic insult, caveolin-3-V37L, that precipitated oligo-proteomic perturbations governing repolarization reserve

BACKGROUND

Caveolin-3 (Cav-3) is an essential scaffolding protein for caveolae formation in cardiomyocytes and targets multiple long QT syndrome (LQTS)-associated ion channels. Mutations in CAV3 have caused an LQT3-like accentuation in late sodium current, I_Na (Nav1.5). Here, we characterize a novel CAV3-V37L variant and determine whether it is the substrate for the patient's LQTS.

METHODS

The proband was a 39-year-old female with drug-induced, sudden cardiac arrest (SCA) with profound QT prolongation (QTc > 600 ms). Genetic testing revealed a rare CAV3-V37L variant of uncertain significance (VUS). Whole-cell patch clamp technique was used to measure I_Ks, I_Kr, I_Na, and I_{Ca, L} currents co-expressed with either CAV3-WT or CAV3-V37L in TSA201 cells and to measure the action potential duration (APD) in control human induced pluripotent stem cells-derived cardiomyocytes (hiPSC-CMs) overexpressed with CAV3-WT or CAV3-V37L.

RESULTS

CAV3-V37L did not affect Nav1.5 late current. Instead, CAV3-V37L resulted in 1) I_{Ca, L} with slower inactivation, a 1.5 fold increase in peak I_{Ca, L} current density and a 1.1 fold increase in I_{Ca, L} persistent current, 2) dramatically reduced I_Ks peak current density by 74.9%, 3) significantly reduced I_Kr peak current density by 31.1%, and 4) significantly prolonged the APD in hiPSC-CMs.

CONCLUSIONS

These functional validation assays enabled the promotion of CAV3-V37L from VUS status to a likely pathogenic variant. Although Nav1.5 was spared, this monogenetic insult precipitated an oligo-proteomic impact with a concomitant gain-of-function of I_{Ca, L} and loss-of-function of both I_Ks and I_Kr culminating in a marked prolongation of the cardiomyocyte's action potential duration.

Plasma concentrations of antipsychotics and QTc prolongation: a pilot study

Background: Certain antipsychotics are known to cause QTc interval prolongation, which has been associated with increased risk of arrhythmia and sudden death. Previous studies have investigated whether there is an association between oral antipsychotic dose and QTc interval prolongation, however only few have examined the association between antipsychotic plasma concentrations and QTc interval.Material and methods: We performed a cross-sectional study with 22 forensic psychiatric in-patients. We measured the plasma concentration of the prescribed antipsychotics and performed an ECG simultaneously. We used Bazett's formula to calculate QTc and defined QTc as prolonged when: >460 ms for women and >450 ms for men.Results: Seventy-seven percent (n = 17) of the subjects were men (mean age = 40 years) and 91% (n = 20) were diagnosed with schizophrenia. QTc's ranged from 369 to 437 ms. Patients receiving QTc prolonging drugs had significantly greater QTc interval compared to patients receiving non-prolonging drugs. Weak to moderate negative correlations were found between QTc interval and both defined daily dose (DDD) and antipsychotic plasma concentration. There was no statistical difference between the correlations for DDD and plasma concentration versus QTc interval.Conclusion: We did not find a stronger association between antipsychotic plasma concentration and QTc than between antipsychotic dose and QTc. We suggest close monitoring with regular electroencephalogram's until the development of a better marker for predicting the risk of cardiac arrhythmia.

Chloroquine-induced QTc prolongation in COVID-19 patients

BACKGROUND

In the battle against the SARS-CoV‑2 pandemic, chloroquine has emerged as a new potential therapeutic option for the treatment of infected patients. A safety consideration for the application of chloroquine is its QTc-prolonging potential. Thus far, no data are available on the QTc-prolonging potential of chloroquine in COVID-19 patients.

OBJECTIVE

To assess the degree of chloroquine-induced QTc prolongation in hospitalised COVID-19 patients.

METHODS

A baseline electrocardiogram (ECG) and ECGs recorded during chloroquine treatment were retrospectively collected in patients suspected of having COVID-19. The QTc interval was calculated by computerised and manual interpretation. Baseline and follow-up QTc intervals were compared using the paired samples t-test.

RESULTS

A total of 95 patients had a baseline ECG recording and at least one ECG recording during chloroquine therapy. Chloroquine treatment resulted in a mean QTc prolongation of 35 ms (95% CI 28-43 ms) using computerised interpretation and 34 ms (95% CI 25-43 ms) using manual interpretation. No torsade de pointes was observed during chloroquine treatment. After manual review, 22 patients (23%) had a QTc interval exceeding 500 ms during chloroquine treatment. None of these patients had a prolonged QTc interval prior to the initiation of chloroquine treatment.

CONCLUSIONS

Chloroquine significantly prolongs the QTc interval in a clinically relevant matter. This highlights the need for ECG monitoring when prescribing chloroquine to COVID-19 patients.

Drug use and torsades de pointes cardiac arrhythmias in Sweden: a nationwide register-based cohort study

OBJECTIVE

To study the occurrence of torsades de pointes (TdP) ventricular tachycardia in relation to use of drugs labelled with TdP risk, using two nationwide Swedish registers.

DESIGN

Prospective register-based cohort study.

SETTING

Entire Sweden.

PARTICIPANTS

Persons aged ≥18 years prescribed and dispensed any drug classified with TdP risk during 2006-2017, according to CredibleMeds. Persons with a registered TdP diagnosis during the study period, using drugs labelled with known (TdP 1), possible (TdP 2) or conditional (TdP 3) risk at the incident of TdP were examined.

PRIMARY OUTCOME MEASURES

Occurrence of TdP in relation to exposure rates for individual drugs with TdP risk.

SECONDARY OUTCOME MEASURES

Concurrent use of more than one TdP-labelled drug in a person with a TdP diagnosis.

RESULTS

During the study period, 410 TdP cases using drugs with TdP risk labels at the incident were registered; 205 women and 205 men, mean age 74.0 and 71.5 years, respectively. Antidepressants dominated (129/410, 30%), followed by antiarrhythmics (17%). Diuretics and gastric acid-secretion inhibitors, with TdP risk related to induction of hypokalaemia or hypomagnesaemia, were used in 56% and 32% of the 410 TdP cases, respectively. Among the most used antidepressants, citalopram with known TdP 1 risk was associated with both a higher absolute number and incidence of TdP per 100 000 users (two to four times), compared with mirtazapine with possible (TdP 2), and sertraline with conditional (TdP 3) risk. Multiple risk factors, including advanced age, cardiovascular disease and treatment with more than one TdP-classified drug, were frequently observed.

CONCLUSIONS

Antidepressants followed by antiarrhythmics dominated among TdP risk drugs used by adults with TdP diagnosis, the majority being ≥65 years. TdP risk class and concomitant medication should be considered when prescribing antidepressants to older patients.

Effects of medications on ventricular repolarization in children with attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a multifactorial neurodevelopmental disorder that manifests during childhood. Methylphenidate (MPH), which is a psychostimulant drug, has been often prescribed for the treatment of ADHD in patients. It may increase the risk of fatal arrhythmias by impairing ventricular repolarization. Indicators of ventricular repolarization in ECG are intervals of QT, corrected QT (QTc), QT dispersion (QTd), T-peak to T-end (Tp-e), and Tp-Te/QTc ratio. We aimed to determine ventricular repolarization findings before and after MPH drug therapy in children with ADHD. The study retrospectively examined the medical records of 33 children aged 6-15 years who received MPH for ADHD and who had a control ECG one month after medication. The ECG parameters, heart rate, intervals of QRS, QT, QTc, QTd, Tp-Te, and Tp-Te/QTc ratio, were compared for each patient before and after drug therapy. No significant change was observed in heart rate, QRS, QT, QTc, and QTd interval in ECGs of patients after treatment but pre and posttreatment mean Tp-Te interval was 73.4 ± 9.72 ms and 79.7 ± 10.48 ms, and mean Tp-Te/QTc ratio was 0.17 ± 0.024 and 0.18 ± 0.023, respectively (P = 0.015, P = 0.028). Tp-Te intervals and Tp-Te/QTc ratios remained within normal values after treatment with MPH, but values were higher than baseline.

Osborn Wave Is Related to Ventricular Fibrillation and Tachycardia in Hypothermic Patients

BACKGROUND

The Osborn wave (OW) is often observed in hypothermic patients; however, whether OW in hypothermic patients is related to the development of fatal ventricular arrhythmia, including ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT), remains undetermined. This study aimed to estimate the association between OW and the incidence of fatal ventricular arrhythmias.

METHODS AND RESULTS

This retrospective study used the Japanese Accidental Hypothermia Network registry database and included 572 hypothermic patients. Patients were divided into the OW group (those with OW) and non-OW group (those without OW). The relationship between the development of fatal arrhythmias and presence of OW was assessed using the chi-squared test. All patients who developed VF/VT (n=10) had OW on electrocardiogram upon hospital arrival. The presence of OW had a sensitivity of 100%, specificity of 47.8%, positive predictive value of 4.0%, and negative predictive value of 100% for VF/VT development. The in-hospital mortality rate was 22.3% in the OW group and 21.2% in the non-OW group (P=0.781).

CONCLUSIONS

OW was observed in all hypothermic patients with VF/VT. The occurrence of ventricular arrhythmias is highly unlikely in the absence of OW on the electrocardiogram. Although the presence of OW might be used to predict these fatal arrhythmias in hypothermic patients, there was no association between the presence of OW and in-hospital mortality.

QTc Prolongation and Risk of Torsades de Pointes in Hospitalized Pediatric Oncology Patients

OBJECTIVE

To evaluate the prevalence of torsades de pointes and to identify risk factors associated with QTc prolongation of ≥500 milliseconds in hospitalized pediatric oncology patients. A QTc prolongation of ≥500 milliseconds is associated with higher mortality in hospitalized adults but has not been demonstrated in pediatrics.

STUDY DESIGN

A single-center, retrospective review of all hospitalized oncology patients ≤21 years of age was performed from 2014 to 2016. Patients with long/short QT syndrome or a QRS interval of ≥120 ms were excluded. Rapid response events were reviewed to determine the prevalence of torsades. In patients with ECGs for review, data were compared between patients with a QTc of <500 and ≥500 ms via logistic regression.

RESULTS

There were 1934 hospitalized patients included. Rapid response events occurred in 90 patients (4.7%) with 2 torsades events (0.1%). There were 1412 electrocardiograms performed in 287 unique patients (10.6 ± 6.3 years of age; 43% female). The mean QTc was 448 ± 31 ms; 25 patients (8.7%) had ≥1 ECG with a QTc of ≥500 ms. The prevalence of torsades was greater in patients with a QTc of ≥500 ms (8% vs 0%; P<.01). In multivariate analysis, factors associated with a QTc of ≥500 ms included female sex, (OR 2.95) and ≥2 QT-prolonging medications (OR, 2.95).

CONCLUSIONS

The prevalence of torsades in hospitalized pediatric oncology patients was low (0.1%), although the risk was significantly greater in patients with a QTc of ≥500 ms. Routine monitoring of electrocardiograms and electrolytes is essential in patients with risk factors predisposing to QTc prolongation.

Drug-induced proarrhythmia: Discussion and considerations for clinical practice

Clinical practice includes contributions from physicians, pharmacists, NPs, and physician assistants. Drug safety considerations are of considerable importance. This article discusses drug-induced proarrhythmia, with a specific focus on torsades de pointes, a polymorphic ventricular tachycardia that typically occurs in self-limiting bursts that can lead to dizziness, palpitations, syncope, and seizures, but on rare occasions can progress to ventricular fibrillation and sudden cardiac death. A dedicated clinical pharmacology study conducted during a drug's clinical development program has assessed its propensity to induce torsades using prolongation of the QT interval as seen on the ECG as a biomarker.Identification of QT-interval prolongation does not necessarily prevent a drug from receiving marketing approval if its overall benefit-risk balance is favorable, but, if approved, a warning is placed in its prescribing information. This article explains why drugs can have a proarrhythmic propensity.

Perianesthesia Implications and Considerations for Drug-Induced QT Interval Prolongation

Prolongation of the QT interval can predispose patients to fatal arrhythmias such as torsade de pointes. While arrhythmias can occur spontaneously in patients with a genetic predisposition, drugs such as ondansetron and droperidol, which are frequently used in the perioperative period, have been implicated in the prolongation of the QT interval. As the list of medications that cause QT prolongation grows, anesthesia providers and perioperative nurses must be informed regarding the importance of the QT interval. This article reviews the physiology and measurement of the QT interval, the risk factors of QT prolongation, the mechanism of drug-induced QT prolongation, and perioperative considerations for patient care.

Drug interactions and creatinine levels are associated with QTc prolongation in intensive care units: a prospective, observational study

Background Prolongation of the QTc interval may lead to life threatening arrhythmias. QTc prolongation is common in intensive care unit (ICU) patients. The objectives of this study were to identify the role of drug-drug interactions (DDIs) and other predictors (age, sex, cardiovascular diseases, and electrolyte abnormalities) in life threatening QTc prolongation in patients admitted to medical (M), surgical (S) and emergency (E) ICUs. Methods This prospective, observational study included patients above the age of 18 years who were admitted to SICU, EICU, and MICU at a tertiary respiratory referral center. Electrocardiogram (ECG) monitoring was performed during the first 5 days of ICU admission. Risk factors and DDIs which were anticipated to be associated with the prolongation of the QTc interval were assessed for all patients. Results Two hundred patients were included in the study. QTc prolongation occurred in 10.7% of patients and the majority of patients presenting with QTc prolongation had creatinine levels above 1.3 mg/dL during their 5 days of ICU admission. Incidence of pharmacodynamic (PD) DDIs was significantly higher in patients with QTc prolongation vs. other patients. Creatinine levels above 1.3 mg/dL and PD DDIs were associated with QTc prolongation during 5 days of ICU admission. Conclusions High serum creatinine and PD DDIs can increase the risk of QTc prolongation in patients admitted to the ICU. QTc interval measurements should be performed prior to initiation or after starting any drug that is associated with QT prolongation, specifically in patients with the known risk factors.

Reining in the QTc: reducing the risk of Torsades de Pointes across a major health system

Hospitalized patients have a high prevalence of prolonged QTc and are a high-risk population for Torsades de Pointes (TdP). One modifiable risk factor for TdP is the use of QT prolonging drugs. Electronically alerting providers who are ordering QT prolonging drugs in at-risk patients may help to achieve safer prescribing practices. Our previous study decreased inappropriate prescription of IV haloperidol by 36% using a targeted "smart" electronic alert. We wanted to assess an approach to expanding this type of electronic alert to commonly used QT prolonging medications and evaluate how this would affect prescribing practice. This retrospective cohort study evaluated the impact of these alerts for 12 frequently prescribed high-risk medications across a major health system. Between October 2016 and June 2017, a total of 6453 alerts fired and resulted in 3020 (46.8%) orders being cancelled by the provider. Our focused electronic alert significantly decreased prescribing of QT prolonging medications in high-risk patients.

[Proarrhythmic adverse effects of nonarrhythmic drugs]

Acquired QT prolongation is almost exclusively the result of inhibition of the potassium channel Ikr. Especially hospitalized patients have a high risk to suffer from Torsade de points (TdP). Therefore, any prescription of drugs with the potential for QT prolongation should involve the consideration of the necessity of the agent and interaction with other QT prolonging drugs. The website www.crediblemed.com helps to identify the risk for TdP of each drug. During drug prescription, it is necessary to monitor QTc with regular ECGs; QTc prolongation >500 ms or QTc increase >60 ms should trigger end of drug administration followed by monitoring of the patient according to the individual risk for TdP.