Case ascertainment and estimated incidence of drug-induced long-QT syndrome: study in Southwest France

Overdrive Pacing for Persistent Torsades de Pointes and Pulseless Ventricular Tachycardia

A 53-year-old presented to the emergency department following a fall and was found to have recurrent episodes of torsades de pointes and pulseless ventricular tachycardia on cardiac monitoring. He had been abusing nimetazepam for sleep issues over the preceding one month. Despite correction of electrolytes, the arrhythmias were persistent which necessitated temporary overdrive pacing. The patient made an uneventful recovery and the temporary pacing was successfully removed with no recurrence of the malignant arrhythmias prior to discharge.

Spotlight on the 2022 ESC guideline management of ventricular arrhythmias and prevention of sudden cardiac death: 10 novel key aspects

Sudden cardiac death and ventricular arrhythmias are a global health issue. Recently, a new guideline for the management of ventricular arrhythmias and prevention of sudden cardiac death has been published by the European Society of Cardiology that serves as an update to the 2015 guideline on this topic. This review focuses on 10 novel key aspects of the current guideline: As new aspects, public basic life support and access to defibrillators are guideline topics. Recommendations for the diagnostic evaluation of patients with ventricular arrhythmias are structured according to frequently encountered clinical scenarios. Management of electrical storm has become a new focus. In addition, genetic testing and cardiac magnetic resonance imaging significantly gained relevance for both diagnostic evaluation and risk stratification. New algorithms for antiarrhythmic drug therapy aim at improving safe drug use. The new recommendations reflect increasing relevance of catheter ablation of ventricular arrhythmias, especially in patients without structural heart disease or stable coronary artery disease with only mildly impaired ejection fraction and haemodynamically tolerated ventricular tachycardias. Regarding sudden cardiac death risk stratification, risk calculators for laminopathies, and long QT syndrome are now considered besides the already established risk calculator for hypertrophic cardiomyopathy. Generally, 'new' risk markers beyond left ventricular ejection fraction are increasingly considered for recommendations on primary preventive implantable cardioverter defibrillator therapy. Furthermore, new recommendations for diagnosis of Brugada syndrome and management of primary electrical disease have been included. With many comprehensive flowcharts and practical algorithms, the new guideline takes a step towards a user-oriented reference book.

Development in Prescriptions of Contraindicated and Potentially Harmful QT Interval-Prolonging Drugs in a Large Geriatric Inpatient Cohort From 2011 to 2021

Regulatory authorities put major emphasis on QT (interval)-prolonging properties of new molecular entities. Product information/Summaries of Product Characteristics (SmPCs) of multiple drugs contain warnings or contraindications regarding QT prolongation, e.g., on coadministration of QT-prolonging drugs (QT drugs). To characterize the development of the QT drug burden, we performed a trend analysis of prescriptions and co-prescriptions of QT drugs in a large geriatric inpatient cohort. The German SmPCs (status of 2014 and of 2021) and the year-wise listings in the CredibleMeds^® database from 2011 to 2021 were used as sources. There were 402,631 geriatric cases included. The group of QT drugs according to SmPCs in 2014, which must not be combined with other QT drugs, was less frequently involved in contraindicated co-prescriptions in 2021 compared with 2015 (3.0% (2.5-3.7%) of cases with at least one of those drugs in 2021 vs. 4.0% (3.5-4.5%) in 2015), with citalopram, escitalopram, and amiodarone involved in nearly 90% of the co-prescriptions. The number of CredibleMeds-QT-drugs per patient increased from 0.4 (SD=1.1) in 2011 to 1.8 (SD=3.9) in 2021. The percentage of contraindicated co-prescriptions of drugs with known risk for torsade de pointes according to CredibleMeds^® listings at the beginning of the respective years increased from 1.7% in 2011 to 6.1% in 2021. Considering the regularly updated CredibleMeds^® QT drugs list, the contraindicated co-prescriptions of QT drugs markedly increased in the last decade. If prescribers considered only the few most frequently (co-) prescribed QT drugs, then most of the medication errors regarding QT drugs could be prevented.

SGK1 inhibition attenuates the action potential duration in reengineered heart cell models of drug-induced QT prolongation

BACKGROUND

Drug-induced QT prolongation (DI-QTP) is a clinical entity in which administration of a human ether-à-go-go-related gene/rapid delayed rectifier potassium current blocker such as dofetilide prolongs the cardiac action potential duration (APD) and the QT interval on the electrocardiogram. Inhibition of serum and glucocorticoid regulated kinase-1 (SGK1) reduces the APD at 90% repolarization (APD90) in induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) derived from patients with congenital long QT syndrome.

OBJECTIVE

Here, we test the efficacy of 2 novel SGK1 inhibitors-SGK1-I1 and SGK1-I2-in iPSC-CM models of dofetilide-induced APD prolongation.

METHODS

Normal iPSC-CMs were treated with dofetilide to produce a DI-QTP iPSC-CM model. SGK1-I1's and SGK1-I2's therapeutic efficacy for shortening the dofetilide-induced APD90 prolongation was compared to mexiletine. The APD90 values were recorded 4 hours after treatment using a voltage-sensing dye.

RESULTS

The APD90 was prolonged in normal iPSC-CMs treated with dofetilide (673 ± 8 ms vs 436 ± 4 ms; P < .0001). While 10 mM mexiletine shortened the APD90 of dofetilide-treated iPSC-CMs from 673 ± 4 to 563 ± 8 ms (46% attenuation; P < .0001), 30 nM of SGK1-I1 shortened the APD90 from 673 ± 8 to 502 ± 7 ms (72% attenuation; P < .0001). Additionally, 300 nM SGK1-I2 shortened the APD90 of dofetilide-treated iPSC-CMs from 673 ± 8 to 460 ± 7 ms (90% attenuation; P < .0001).

CONCLUSION

These novel SGK1-Is substantially attenuated the pathological APD prolongation in a human heart cell model of DI-QTP. These preclinical data support the development of this therapeutic strategy to counter and neutralize DI-QTP, thereby increasing the safety profile for patients receiving drugs with torsadogenic potential.

Prevalence and risk factors for acquired long QT syndrome in the emergency department: a retrospective observational study

BACKGROUND

Long QT syndrome (LQTS) is a heterogeneous syndrome that may be congenital or, more frequently, acquired. The real-world prevalence of acquired LQTS (aLQTS) in the emergency department (ED) remains to be determined. The aim of this study was to determine prevalence of aLQTS and its impact on symptoms on ED admissions.

METHODS

Electrocardiograms (ECG) of 5,056 consecutively patients admitted in the ED of a tertiary hospital between January 28th and March 17th of 2020 were reviewed. All patients with aLQTS were included. Clinical data with a focus on QT prolonging drugs and clinical factors were recorded. Statistical comparison was made between the groups with and without corrected QT (QTc) interval greater than 500 ms (value that is considered severely increased).

RESULTS

A total of 383 ECGs with prolonged QTc were recognized, corresponding to a prevalence of aLQTS at admission of 7.82%. Patients with aLQTS were more commonly men (53.3%) with an age of (73.49±14.79) years old and QTc interval of (505.3±32.4) ms. Only 20.4% of these patients with aLQTS were symptomatic. No ventricular arrhythmias were recorded. Patients with QT interval greater than 500 ms were more frequently female (59.5%; P<0.001) and were more frequently on QT prolonging drugs (77.3%; P=0.025). Main contributing factor was intake of antibiotics (odds ratio [OR] 4.680) followed by female gender (OR 2.473) and intake of antipsychotics (OR 1.925).

CONCLUSION

aLQTS is particularly prevalent in the ED. Female patients on antibiotics and antipsychotics are at particularly high risk. Efforts must be made to avoid, detect and treat aLQTS as early as possible.

Antipsychotics and risk of QT prolongation: a pharmacovigilance study

RATIONALE

While meta-analyses of clinical trials found that lurasidone and partial dopamine agonists (brexpiprazole and aripiprazole) were the antipsychotics less likely to cause QTc prolongation, and sertindole, amisulpride, and ziprasidone were the most frequently associated with this adverse drug reaction; no real-world studies have investigated this risk between the different antipsychotics.

OBJECTIVES AND METHODS

Using data recorded from 1967 to 2019 in VigiBase®, the World Health Organization's Global Individual Case Safety Reports database, we performed disproportionality analysis to investigate the risk of reporting QT prolongation between 20 antipsychotics.

RESULTS

Sertindole had the highest risk of reporting QT prolongation, followed by ziprasidone and amisulpride. Lurasidone was associated with the lowest risk. First-generation antipsychotics were associated with a greater QT prolongation reporting risk (ROR, 1.21; 95%CI, 1.10-1.33) than second-generation antipsychotics. A positive correlation was found between the risk of reporting QT prolongation and affinity for hERG channel (R² = 0.14, slope = Pearson coefficient = 0.41, p value = 0.1945).

CONCLUSIONS

This large study in a real-world setting suggests that sertindole and ziprasidone were the antipsychotics drugs associated with the highest risk of QT prolongation reporting. Our results suggest that lurasidone is less associated with QT interval prolongation reports. Our study also suggests that antipsychotics with the higher hERG affinity are more associated with to QT prolongations reports.

Documentation of Drug-Related Problems with ICD-11: Application of the New WHO Code-Set to Clinical Routine Data

Drug-related problems (DRPs), i.e., adverse drug reactions (ADRs) and medication errors (MEs), constitute a serious threat to the patient's safety. DRPs are often insufficiently captured by clinical routine documentation, and thus, they frequently remain unaddressed. The aim of this study was to assess the coverage and usability of the new 11th revision of the WHO International Classification of Diseases (ICD-11) to document DRPs. We refined the 'Quality and Safety Algorithm' from the ICD-11 Reference Guide and used it for DRP reporting to code 100 different anonymized DRPs (50 ADRs and 50 MEs) in a German hospital. The ICD-11 three-part model consisting of harm, cause, and mode was used whenever they were applicable. Of 50 ADRs, 15 (30.0%), such as drug-induced osteoporosis, were fully classifiable and codable by the ICD-11, whereas 35 (70.0%), such as drug-induced hypokalaemia, could not be fully classified due to sanctioning rules preventing the postcoordination (i.e., a combination of specific codes, such as drug and diagnosis). However, coding without the loss of information was possible in the 35 of these 35 (100.0%) ADR cases when we were deviating from the cluster code order of the Reference Guide. In all 50 MEs, the mode could be encoded, but for none of the MEs, postcoordination, i.e., the assignment of the ME to a specific drug, was allowed. In conclusion, the ICD-11 three-part model enables us to acquire more detailed documentation of DRPs than the previous ICD versions did. However, the codability, documentation, and reporting of DRPs could be significantly improved by simple modifications of the current ICD-11 sanctioning rules and by the addition of new ICD-11 codes.

Emergency room admissions induced by drug-drug interactions in the elderly: a cross-sectional study

The elderly people are increasingly exposed to polymedication and therefore to the risks of drug–drug interactions (DDIs). However, there are few data available on the clinical consequences of these drug combinations. We investigated the impact of the various DDIs classified as severe in terms of emergency admissions in the elderly. A cross‐sectional study was conducted using information from the emergency department admissions of Bordeaux University Hospital between September 2016 and August 2017. Events of interest were frequency of concomitant uses of interacting drugs that are contraindicated or warned against and frequency of emergency admissions due to contraindicated or warned against concomitant uses of interacting drugs. Five thousand, eight hundred sixty (5860) admissions to the emergency department were analyzed. A total of 375 (6.4%) contraindicated or warned against concomitant uses were identified, including 163 contraindicated (43.5%) and 212 warned against (56.5%). Reason for admission appeared likely related to the underlying DDI in 58 cases. Within these, 36 admissions were assessed as probably due to a DDI (0.6% of hospitalizations) and 22 as certainly (0.4% of hospitalizations). Of these, there were 24 (45%) admissions related to a long QT syndrome (LQTS), nine (16%) related to a drug overdose, and eight (14%) related to a hemorrhage. An antidepressant was involved in 22 of the 24 cases of LQTS. Seven of the eight cases of hemorrhage involved the antithrombotic agents / non‐steroidal anti‐inflammatory drugs combination. Elderly patients admitted to emergency departments are particularly exposed to high‐risk potential DDIs. These drug combinations lead mainly to LQTS and involve certain antidepressants.

Vomiting, electrolyte disturbance, and medications; the perfect storm for acquired long QT syndrome and cardiac arrest: a case report

Background

Acquired long QT syndrome is an important and preventable cause of cardiac arrest. Certain medications and electrolyte disturbance are common contributors, and often coexist. In this case, we report five contributors to cardiac arrest.

Case presentation

This case is of a 51-year-old Caucasian female patient who presented with vomiting associated with hypokalemia and hypomagnesemia. She subsequently received ondansetron and metoclopramide, on the background of chronic treatment with fluoxetine. She then suffered an in-hospital monitored cardiac arrest, with features of long QT and torsades de pointes retrospectively noted on her prearrest electrocardiogram. She was diagnosed with acquired long QT syndrome, and her QT interval later normalized after removal of offending causes.

Conclusions

This case highlights the importance of proper consideration prior to prescribing QT prolonging medications, especially in patients who have other risk factors for prolonged QT, such as electrolyte disturbances and pretreatment with QT prolonging medications.

Obesity Potentiates the Risk of Drug-Induced Long QT Syndrome - Preliminary Evidence from WNIN/Ob Spontaneously Obese Rat

Drug-induced long QT syndrome (DI-LQTS) is fatal and known to have a higher incidence in women rather than in men. Multiple risk factors potentiate the incidence of DI-LQTS, but the actual contribution of obesity remains largely unexplored. Correspondingly, the present study is aimed to evaluate the susceptibility of DI-LQTS in WNIN/Ob rat in comparison with its lean counterpart using 3-lead electrocardiography. Four- and eight-month-old female WNIN/Ob and their lean controls were used for the experimentation. Non-invasive blood pressure measurement and total body electric conductivity (TOBEC) analysis were carried out. After the baseline evaluations, animals were anesthetized with Ketamine (50 mg/kg). Haloperidol (12.5 mg/kg single dose) was administered intraperitoneally and ECG was taken at 0, 10, 20, 30, 60 min, and 24 h time points. Myocardial lystes were used to assess the BNP, protein carbonylation, and hydroxyproline content. Adiposity, as assessed by TOBEC, is higher in obese rats with elevated mean arterial blood pressure. Baseline-corrected QT interval (QTc) is significantly higher in the obese rat with a wider QRS complex. The incidence of PVC and VT are more intense in the obese rat. Haloperidol-induced QT prolongation in obese rats was rapidly induced than in lean, which was observed to remain till 24 h in obese groups while normalized in lean controls. Higher levels of BNP, protein carbonylation, hydroxyproline content, and relative heart weights indicated the presence of cardiac hypertrophy. The study provides preliminary evidence that obesity can be a potential risk factor for DI-LQTS with faster onset and longer subsistence.

Genetic and Molecular Aspects of Drug-Induced QT Interval Prolongation

Long QT syndromes can be either acquired or congenital. Drugs are one of the many etiologies that may induce acquired long QT syndrome. In fact, many drugs frequently used in the clinical setting are a known risk factor for a prolonged QT interval, thus increasing the chances of developing torsade de pointes. The molecular mechanisms involved in the prolongation of the QT interval are common to most medications. However, there is considerable inter-individual variability in drug response, thus making the application of personalized medicine a relevant aspect in long QT syndrome, in order to evaluate the risk of every individual from a pharmacogenetic standpoint.

Hospitalization for adverse events under abiraterone or enzalutamide exposure in real-world setting: A French population-based study on prostate cancer patients

AIMS

Safety profiles of abiraterone and enzalutamide rely mainly on Phase III clinical trials. Our objective was to estimate the incidence rate ratio (IRR) for certain adverse events leading in real life to hospitalization (atrial fibrillation, acute heart failure, ischaemic heart disease, acute kidney injury [AKI], ischaemic stroke, torsade de pointe/QT interval prolongation, hepatitis and seizure), comparing abiraterone to enzalutamide. We also set out to discuss previously identified safety signals.

METHOD

Using the French National Health Insurance System database, all patients newly exposed to abiraterone or enzalutamide between 2013 and 2017 and followed until 31 December 2018 were targeted. IRRs for each event were estimated using a Poisson model in a sub-population of patients without contraindications or precautions for use for either treatment.

RESULTS

Among 11 534 new users of abiraterone and enzalutamide, AKI (IRR 1.42, 95% CI: 1.01-2.00), liver monitoring suggestive of hepatic damage (IRR 3.06, 95% CI: 2.66-3.53) and atrial fibrillation (IRR 1.12, 95% CI: 1.05-1.19) were significantly more often observed with abiraterone than with enzalutamide.

CONCLUSION

Our study provides knowledge on abiraterone and enzalutamide real-life safety profiles, especially for events leading to hospitalization. Despite several limitations, including the lack of clinical data, the safety signal for AKI under abiraterone is in line with results of an analysis of the French pharmacovigilance database, which requires further specific investigations. Enlightening the clinicians' therapeutic choices for patients treated for prostate cancer, our study should lead to clinicians being cautious in the use of abiraterone.

Drug-Induced Arrhythmias: A Scientific Statement From the American Heart Association

Many widely used medications may cause or exacerbate a variety of arrhythmias. Numerous antiarrhythmic agents, antimicrobial drugs, psychotropic medications, and methadone, as well as a growing list of drugs from other therapeutic classes (neurological drugs, anticancer agents, and many others), can prolong the QT interval and provoke torsades de pointes. Perhaps less familiar to clinicians is the fact that drugs can also trigger other arrhythmias, including bradyarrhythmias, atrial fibrillation/atrial flutter, atrial tachycardia, atrioventricular nodal reentrant tachycardia, monomorphic ventricular tachycardia, and Brugada syndrome. Some drug-induced arrhythmias (bradyarrhythmias, atrial tachycardia, atrioventricular node reentrant tachycardia) are significant predominantly because of their symptoms; others (monomorphic ventricular tachycardia, Brugada syndrome, torsades de pointes) may result in serious consequences, including sudden cardiac death. Mechanisms of arrhythmias are well known for some medications but, in other instances, remain poorly understood. For some drug-induced arrhythmias, particularly torsades de pointes, risk factors are well defined. Modification of risk factors, when possible, is important for prevention and risk reduction. In patients with nonmodifiable risk factors who require a potentially arrhythmia-inducing drug, enhanced electrocardiographic and other monitoring strategies may be beneficial for early detection and treatment. Management of drug-induced arrhythmias includes discontinuation of the offending medication and following treatment guidelines for the specific arrhythmia. In overdose situations, targeted detoxification strategies may be needed. Awareness of drugs that may cause arrhythmias and knowledge of distinct arrhythmias that may be drug-induced are essential for clinicians. Consideration of the possibility that a patient's arrythmia could be drug-induced is important.

Summary of Torsades de Pointes (TdP) Reports Associated with Intravenous Drug Formulations Containing the Preservative Chlorobutanol

INTRODUCTION

Drug-induced torsades de pointes (TdP) is a potentially lethal ventricular arrhythmia that is associated with drugs that prolong the QT interval on the electrocardiogram (ECG) due to their interference with the cardiac potassium current, I_KR. Intravenous (IV) formulations of methadone have been associated with TdP and contain the preservative chlorobutanol, which, like methadone, blocks I_KR. The combinations of chlorobutanol with methadone or terfenadine, another I_KR blocker, produce synergistic I_KR block.

OBJECTIVE

The aim of this study was to examine and summarize the evidence available to address the question: what other IV drug formulations contain chlorobutanol and are they associated with TdP?

METHODS

IV drug products containing the preservative chlorobutanol were identified by searching the websites DailyMed ( https://dailymed.nlm.nih.gov/dailymed/index.cfm ) and Drugs@FDA ( https://www.accessdata.fda.gov/scripts/cder/daf/ ). For each drug identified, PubMed and the FDA's Adverse Event Reporting System (FAERS) were searched for reports of TdP and/or QT prolongation and FAERS data were analyzed for disproportionality of reports.

RESULTS

The search found nine drugs (methadone, epinephrine, papaverine, oxytocin, vasopressin, testosterone, estradiol, isoniazid, and desmopressin) that contain chlorobutanol 2.5 (n = 1) or 5.0 mg/mL. All nine drugs had reports of QT prolongation or TdP reported in FAERS and all but estradiol, testosterone, desmopressin, and isoniazid had reports of QT prolongation or TdP in PubMed. Two of the nine drugs (epinephrine and methadone) had positive signals (by disproportionality analysis) for TdP in FAERS (EB₀₅ 2.88 and 23.81, respectively) and four (methadone, epinephrine, papaverine, and vasopressin) were reported in published articles as the suspect drugs in cases of TdP.

CONCLUSION

The pharmacologic profile of chlorobutanol (synergistic I_KR block) and its association with reports of TdP and QT prolongation suggest the need for a full evaluation of its cardiac safety when used as a preservative in IV drug and vitamin formulations.

[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.

Acquired Long QT Syndrome and Electrophysiology of Torsade de Pointes

Congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. Although congenital LQTS remains the domain of cardiologists, cardiac electrophysiologists and specialised centres, the much more frequently acquired LQTS is the domain of physicians and other members of healthcare teams required to make therapeutic decisions. This paper reviews the electrophysiological mechanisms of acquired LQTS, its ECG characteristics, clinical presentation, and management. The paper concludes with a comprehensive review of the electrophysiological mechanisms of torsade de pointes.

Risk of sudden unexplained death after use of dihydroartemisinin-piperaquine for malaria: a systematic review and Bayesian meta-analysis

BACKGROUND

Dihydroartemisinin-piperaquine is an effective and well tolerated artemisinin-based combination therapy that has been assessed extensively for the prevention and treatment of malaria. Piperaquine, similar to several structurally related antimalarials currently used, can prolong cardiac ventricular repolarisation duration and the electrocardiographic QT interval, leading to concerns about its proarrhythmic potential. We aimed to assess the risk of potentially lethal iatrogenic ventricular arrhythmias in individuals receiving dihydroartemisinin-piperaquine.

METHODS

We did a systematic review and Bayesian meta-analysis. We searched clinical bibliographic databases (last on May 24, 2017) for studies of dihydroartemisinin-piperaquine in human beings. Further unpublished studies were identified with the WHO Evidence Review Group on the Cardiotoxicity of Antimalarials. We searched for articles containing "dihydroartemisinin-piperaquine" as title, abstract, or subject heading keywords, with synonyms and variant spellings as additional search terms. We excluded animal studies, but did not apply limits on language or publication date. Eligible studies were prospective, randomised, controlled trials or cohort studies in which individuals received at least one 3-day treatment course of dihydroartemisinin-piperaquine for mass drug administration, preventive therapy, or case management of uncomplicated malaria, with follow-up over at least 3 days. At least two independent reviewers screened titles, abstracts, and full texts, agreed study eligibility, and extracted information about study and participant characteristics, adverse event surveillance methodology, dihydroartemisinin-piperaquine exposures, loss-to-follow up, and any deaths after dihydroartemisinin-piperaquine treatment into a standardised database. The risk of sudden unexplained death after dihydroartemisinin-piperaquine with 95% credible intervals (CI) generated by Bayesian meta-analysis was compared with the baseline rate of sudden cardiac death.

FINDINGS

Our search identified 94 eligible primary studies including data for 197 867 individuals who had received dihydroartemisinin-piperaquine: 154 505 in mass drug administration programmes; 15 188 in 14 studies of repeated courses in preventive therapies and case management of uncomplicated malaria; and 28 174 as single-course treatments of uncomplicated malaria in 76 case-management studies. There was one potentially drug-related sudden unexplained death: a healthy woman aged 16 in Mozambique who developed heart palpitations several hours after the second dose of dihydroartemisinin-piperaquine and collapsed and died on the way to hospital (no autopsy or ECG was done). The median pooled risk estimate of sudden unexplained death after dihydroartemisinin-piperaquine was 1 in 757 950 (95% CI 1 in 2 854 490 to 1 in 209 114). This risk estimate was not higher than the baseline rate of sudden cardiac death (0·7-11·9 per 100 000 person-years or 1 in 1 714 280 to 1 in 100 835 over a 30-day risk period). The risk of bias was low in most studies and unclear in a few.

INTERPRETATION

Dihydroartemisinin-piperaquine was associated with a low risk of sudden unexplained death that was not higher than the baseline rate of sudden cardiac death. Concerns about repolarisation-related cardiotoxicity need not limit its current use for the prevention and treatment of malaria.

FUNDING

Wellcome Trust, UK Medical Research Council, WHO, Bill & Melinda Gates Foundation, and University of Oxford.

Acquired long QT syndrome and torsade de pointes

Since its initial description by Jervell and Lange-Nielsen in 1957, the congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. Although congenital LQTS continues to remain the domain of cardiologists, cardiac electrophysiologists, and specialized centers, the by far more frequent acquired drug-induced LQTS is the domain of all physicians and other members of the health care team who are required to make therapeutic decisions. This report will review the electrophysiological mechanisms of LQTS and torsade de pointes, electrocardiographic characteristics of acquired LQTS, its clinical presentation, management, and future directions in the field.

Algorithms used to identify ventricular arrhythmias and sudden cardiac death in retrospective studies: a systematic literature review

Drug-induced QT interval prolongation may increase the risk of sudden cardiac death or ventricular arrhythmias (SCD/VA), and therefore affects the safety profile of medications. Administrative databases can be used to inform pharmacoepidemiologic drug safety studies for such rare events. In order to compare event rates between studies, validated operational definitions of these events are needed. We conducted a systematic literature review in PubMed to identify algorithms for SCD/VA. Twenty-two studies were included in the review. Fifteen (68%) studies evaluated International Classification of Diseases, 9th revision (ICD-9) based medical data, of which six utilized a common, validated operational definition. This algorithm was based on principal hospitalization discharge diagnosis or first-listed emergency department visit diagnosis, with an average positive predictive value (PPV) of 85%. Four studies evaluated ICD-9 based death data, of which three utilized a common algorithm with an average PPV of 88%. Further validation of ICD, 10th revision algorithms are needed. In conclusion, we identified a validated algorithm for SCD/VA in medical data, as well as in death data. As such, to ensure comparability between new research and the existing literature, pharmacoepidemiologic research in this area should utilize common, validated algorithms, such as the ones identified in our review, to operationally define these events.

Predicting the Unpredictable: Drug-Induced QT Prolongation and Torsades de Pointes

Drug-induced long QT syndrome (diLQTS) and congenital LQTS (cLQTS) share many features, and both syndromes can result in life-threatening torsades de pointes (TdP). Our understanding of their mechanistic and genetic similarities has led to their improved clinical management. However, our inability to prevent diLQTS has resulted in removal of many medicines from the market and from development. Genetic and clinical risk factors for diLQTS and TdP are well known and raise the possibility of TdP prevention. Clinical decision support systems (CDSS) can scan the patient's electronic health records for clinical risk factors predictive of diLQTS and warn when a drug that can cause TdP is prescribed. CDSS have reduced prescriptions of QT-prolonging drugs, but these relatively small changes lack the power to reduce TdP. The growing genetic evidence linking diLQTS to cLQTS suggests that prevention of TdP in the future may require inclusion of both genetic and clinical predictors into CDSS.

Incidence of drug-induced torsades de pointes with intravenous amiodarone

AIM

To define the incidence, presentation, and outcomes of drug-induced Torsades de Pointes (TdP) with intravenous (IV) amiodarone.

METHODS

From January 2014 to August 2016 a total of 268 patients received IV amiodarone, 142 for ventricular tachycardia, 104 for atrial flutter/fibrillation, and 22 for incessant atrial tachycardia. A uniform dosing of amiodarone to yield 1gm/day was used in all patients.

RESULTS

Four of the 268 patients (M:F 1:3) with mean age of 51.25+9.17years developed pause dependent TdP degenerating to VF, after a mean dose of 690+176.63mg, infused over 12+5.88h. The QTc that was 505+9.02ms at the time of TdP normalized to 433.75+6.13ms 48-72h after stopping amiodarone. There was no immediate or late mortality, and patients are well at 5-10 months of follow-up. None of the patients tested positive for LQTS genes.

CONCLUSION

The incidence of drug-induced TdP with IV amiodarone is about 1.5%. Risk factors include female sex, left ventricular dysfunction, electrolyte abnormalities, baseline prolonged QTc, concomitant beta-blocker, and digoxin therapy. Amiodarone induced TdP has favorable prognosis if recognized and treated promptly, and these patients should not receive amiodarone by any route in future.

Incidence of Torsade de Pointes in a tertiary hospital population

BACKGROUND

Multiple risk factors play a role in the development of QTc-prolongation and Torsade de Pointes (TdP). Cases of TdP are underreported and data on the incidence of TdP is scarce. The aim of this study was to investigate the incidence of TdP in a Belgian university hospital and describe the characteristics of TdP-cases using a risk score.

METHODS

All cases from 2011 till 2013 coded with the ICD-9 code 427.1 in the University Hospitals of Leuven were selected. The medical files were reviewed and demographical, medical, medication and electrocardiographic data were collected. We focused on TdP-cases that were probably caused by the acquired long QT-syndrome. The RISQ-PATH score was used to quantify the risk in these cases (≥10 points as high risk for QTc-prolongation/TdP).

RESULTS

Over three years, 41 TdP-cases were identified of which 19 cases were secondary to the acquired long QT-syndrome (52.6% females, mean age of 74±12years). This corresponds with an incidence of 0.16‰/year in a hospital population. Most of the patients (N=17) were treated with at least one QTc-prolonging drug (most frequently amiodarone, sotalol and furosemide) of whom 12 patients with ≥1 QTc-prolonging drug of list 1 of CredibleMeds. Fifteen patients had an electrocardiogram in a 24-hours interval before the TdP with a prolonged QTc-interval (≥450/470ms). All the patients had a RISQ-PATH score≥10.

CONCLUSIONS

Although the incidence of 0.16‰/year might seem low, this means that approximately 173 possibly lethal TdP-cases can be expected in Belgian hospitals each year. All TdP-cases were associated with a high RISQ-PATH score.

Electrocardiographic surveillance in a psychiatric institution: avoiding iatrogenic cardiovascular death

OBJECTIVE

To describe a new initiative developed to optimise patient safety in a mental health setting in order to prevent serious cardiac events.

MATERIALS AND METHODS

A longitudinal study of all in-patients admitted at the hospital, comprised of 197 beds distributed among three units, was conducted for 12 months. All admitted patients at the hospital underwent electrocardiogram surveillance, as it was described in our new local guideline for sudden cardiac death prevention. When electrocardiographic alterations were detected, treating physicians searched for patient's risk factors and suspicious medication and communicated the adverse event to the Pharmacy Department. These data were registered in electronic medical record system.

RESULTS

Over the 12-month study period, 225 patients were evaluated and 9 cases (4%) of long QT segment were detected. A multidisciplinary evaluation was done and it resulted in treatment modification and patient close monitoring. No sudden cardiac deaths occurred during the study period. Drugs more often involved in QT segment prolongation were: olanzapine, clomipramine, clozapine and risperidone.

CONCLUSION

QT segment interval enlargement is a frequent clinical problem that affects patients with mental pathology. This inexpensive initiative has allowed identifying patients at risk of sudden cardiac death and has helped to avoid mayor side effects.

Targeted Cancer Therapies and QT Interval Prolongation: Unveiling the Mechanisms Underlying Arrhythmic Complications and the Need for Risk Stratification Strategies

The care and treatment of cancer patients has significantly changed in the last decade with a remarkable shift towards novel targeted therapies. These promising new drugs may represent effective and potentially life-saving therapeutic options in cancer patients, but are also emerging in the cardiotoxicity scenario for their arrhythmogenic potential due to their QT-prolonging activity. In this article we review the mechanisms underlying drug-induced QT interval prolongation and the classes of anticancer-targeted therapies most frequently responsible for this adverse event, with a particular focus on tyrosine kinase-targeting molecules. Since up to 49 % of serious adverse drug reactions (ADRs) and 58 % of potentially fatal ADRs may not appear on initial drug safety labels, we also review and discuss data from the post-marketing VigiBase^® safety reporting system, the World Health Organization's global database of ADRs. Finally, we discuss arrhythmic risk stratification and prevention strategies in the complex multiple-risk setting of cancer patients, paying particular attention to drug-drug interactions with common antimicrobial, psychotropic and antiemetic supportive care, and we also provide an electrocardiographic QT monitoring algorithm for patients who are candidates for targeted cancer therapies.

Determinants of torsades de pointes in older patients with drug-associated long QT syndrome: a case-control study

OBJECTIVE

Many elderly patients are routinely exposed to drugs that may prolong the cardiac QT interval and cause Torsades de pointes (TdP). However, predictors of TdP in patients with drug-associated long QT syndrome (LQTS) are not fully understood, especially in the geriatric population. The objective of this study was to identify risk factors of TdP in elderly patients with drug-associated LQTS.

METHODS

In this retrospective, case-control study, documented reports of drug-associated LQTS plus TdP (n = 125) and LQTS without TdP (n = 81) in patients ≥65 years of age were retrieved from the French Pharmacovigilance Database over a 10-year period. Available clinical, biological, and drug therapy data were compared in the two groups and logistic regression was performed to identify significant predictors of TdP.

RESULTS

The uncorrected QT interval was significantly longer in patients with TdP than in patients without TdP (577 ± 79 vs. 519 ± 68 ms; p = 0.0001). The number of drugs with a known risk of TdP administered to each patient was not a predictor of arrhythmia, nor was female gender. Logistic regression analysis identified the uncorrected QT interval as the only significant predictor of TdP. The receiver operating characteristic curve analysis was characterized by an area under the curve of 0.77 (95 % confidence interval 0.64-0.88) and a QT cutoff of 550 ms.

CONCLUSION

The uncorrected QT interval was significantly associated with the probability of TdP in elderly patients with acquired, drug-associated LQTS.

Pronounced effects of HERG-blockers E-4031 and erythromycin on APD, spatial APD dispersion and triangulation in transgenic long-QT type 1 rabbits

Background

Prolongation of action potential duration (APD), increased spatial APD dispersion, and triangulation are major factors promoting drug-induced ventricular arrhythmia. Preclinical identification of HERG/I_Kr-blocking drugs and their pro-arrhythmic potential, however, remains a challenge. We hypothesize that transgenic long-QT type 1 (LQT1) rabbits lacking repolarizing I_Ks current may help to sensitively detect HERG/I_Kr-blocking properties of drugs.

Methods

Hearts of adult female transgenic LQT1 and wild type littermate control (LMC) rabbits were Langendorff-perfused with increasing concentrations of HERG/I_Kr-blockers E-4031 (0.001–0.1 µM, n = 9/7) or erythromycin (1–300 µM, n = 9/7) and APD, APD dispersion, and triangulation were analyzed.

Results

At baseline, APD was longer in LQT1 than in LMC rabbits in LV apex and RV mid. Erythromycin and E-4031 prolonged APD in LQT1 and LMC rabbits in all positions. However, erythromycin-induced percentaged APD prolongation related to baseline (%APD) was more pronounced in LQT1 at LV base-lateral and RV mid positions (100 µM, LQT1, +40.6±9.7% vs. LMC, +24.1±10.0%, p<0.05) and E-4031-induced %APD prolongation was more pronounced in LQT1 at LV base-lateral (0.01 µM, LQT1, +29.6±10.6% vs. LMC, +19.1±3.8%, p<0.05) and LV base-septal positions. Moreover, erythromycin significantly increased spatial APD dispersion only in LQT1 and increased triangulation only in LQT1 in LV base-septal and RV mid positions. Similarly, E-4031 increased triangulation only in LQT1 in LV apex and base-septal positions.

Conclusions

E-4031 and erythromycin prolonged APD and increased triangulation more pronouncedly in LQT1 than in LMC rabbits. Moreover, erythromycin increased APD dispersion only in LQT1, indicating that transgenic LQT1 rabbits could serve as sensitive model to detect HERG/I_Kr-blocking properties of drugs.

ICD-10 codes used to identify adverse drug events in administrative data: a systematic review

BACKGROUND

Adverse drug events, the unintended and harmful effects of medications, are important outcome measures in health services research. Yet no universally accepted set of International Classification of Diseases (ICD) revision 10 codes or coding algorithms exists to ensure their consistent identification in administrative data. Our objective was to synthesize a comprehensive set of ICD-10 codes used to identify adverse drug events.

METHODS

We developed a systematic search strategy and applied it to five electronic reference databases. We searched relevant medical journals, conference proceedings, electronic grey literature and bibliographies of relevant studies, and contacted content experts for unpublished studies. One author reviewed the titles and abstracts for inclusion and exclusion criteria. Two authors reviewed eligible full-text articles and abstracted data in duplicate. Data were synthesized in a qualitative manner.

RESULTS

Of 4241 titles identified, 41 were included. We found a total of 827 ICD-10 codes that have been used in the medical literature to identify adverse drug events. The median number of codes used to search for adverse drug events was 190 (IQR 156-289) with a large degree of variability between studies in the numbers and types of codes used. Authors commonly used external injury (Y40.0-59.9) and disease manifestation codes. Only two papers reported on the sensitivity of their code set.

CONCLUSIONS

Substantial variability exists in the methods used to identify adverse drug events in administrative data. Our work may serve as a point of reference for future research and consensus building in this area.

Assessment of drug-induced torsade de pointes risk for hospitalized high-risk patients receiving QT-prolonging agents

BACKGROUND

Although risk factors for torsade de pointes (TdP) are known, identifying hospitalized patients at greatest risk for QTcP who should receive cardiac monitoring is poorly defined.

OBJECTIVES

Describe the prevalence of risk for TdP in patients and associations between risk factors and QTc prolongation (QTcP) at a tertiary teaching hospital.

METHODS

This retrospective analysis assessed physiological and pharmacological risk factors for TdP of adult patients receiving ≥1 QTc-prolonging medications (QTcMed) during hospitalization. The QTcMeds were stratified by risk for causing TdP (probable, possible, and conditional). Baseline electrocardiograms (ECGs) were assessed for QTcP associated with risk for TdP.

RESULTS

During a 6-month period, 12,401 (51%) hospitalizations received ≥1 QTcMed. A baseline ECG was obtained for 2381 (19%) patients. A total of 386 (16%) patients with a baseline ECG were found to have QTcP. Significant associations for QTcP were found with the following physiological risk factors: female (P = .021), left-ventricular ejection fraction <40% (P < .0001), cardiac arrest (P < .0001), and cardioversion (P = .007). Significantly more patients with QTcP (n = 209, 54%) received probable-risk QTcMeds than those without QTcP (n = 542, 27%; P < .0001). Probable-risk QTcMeds administered alone or concomitantly with other QTcMeds were more frequently associated with QTcP. No documented cases of TdP were identified.

CONCLUSIONS

Of the population receiving QTcMeds, only a small portion had a baseline ECG, identifying a large population at risk of QTcP without appropriate monitoring. Patients with cardiac disease receiving probable-risk QTcMeds were associated with the highest risk of QTcP and should be monitored closely.

Acquired Long QT Syndrome Manifesting with Torsades de Pointes in a Patient with Panhypopituitarism due to Radiotherapy

We describe a 64-year-old male patient with panhypopituitarism who experienced polymorphic ventricular tachycardia (VT) associated with long QT intervals. The panhypopituitarism developed as a sequelae of radiation therapy administered 20 years prior to his current presentation and was recently aggravated by urinary tract infection with sepsis. In this case, polymorphic VT was resistant to conventional therapy (including magnesium infusion), and QT prolongation and T wave inversion were normalized after the administration of steroid and thyroid hormones. Thyroid hormone is generally known to be associated with torsades de pointes (TdP), but steroid or other hormones may also provoke TdP. Hormonal disorders should be considered as a cause of polymorphic VT with long QT intervals. Some arrhythmias can be life-threatening, and they can be prevented with supplementation of the insufficient hormone.

Acquired long QT syndrome: frequency, onset, and risk factors in intensive care patients

BACKGROUND

Acquired long QT syndrome is a reversible condition that can lead to torsades de pointes and sudden cardiac death.

OBJECTIVE

To determine the frequency, onset, frequency of medications, and risk factors for the syndrome in intensive care patients.

METHODS

In a retrospective chart review of 88 subjects, hourly corrected QT intervals calculated by using the Bazett formula were collected. Acquired long QT syndrome was defined as a corrected QT of 500 milliseconds or longer or an increase in corrected QT of 60 milliseconds or greater from baseline level. Risk factors and medications administered were collected from patients' medical records.

RESULTS

The syndrome occurred in 46 patients (52%); mean time of onset was 7.4 hours (SD, 9.4) from time of admission. Among the 88 patients, 52 (59%) received a known QTc-prolonging medication. Among the 46 with the syndrome, 23 (50%) received a known QT-prolonging medication. No other risk factor studied was significantly predictive of the syndrome.

CONCLUSIONS

Acquired long QT syndrome occurs in patients not treated with a known QT-prolonging medication, indicating the importance of frequent QT monitoring of all intensive care patients.

QT interval abnormalities: risk factors and perioperative management in long QT syndromes and Torsades de Pointes

Electrophysiological abnormalities of the QT interval of the standard electrocardiogram are not uncommon. Congenital long QT syndrome is due to mutations of several possible genes (genotype) that result in prolongation of the corrected QT interval (phenotype). Abnormalities of the QT interval can be acquired and are often drug-induced. Torsades de Pointes (TP) is an arrhythmia that is a result of aberrant repolarization/QT abnormalities. If not recognized and corrected quickly, QT interval abnormalities may precipitate potentially fatal ventricular dysrhythmias. The main mechanism responsible for the development of QT prolongation is blockade of the rapid component of the delayed rectifier potassium current (I kr), encoded for by the human-ether-a-go-go-related gene (hERG). The objectives of this review were (1) to describe the electrical pathophysiology of QT interval abnormalities, (2) to differentiate congenital from acquired QT interval abnormalities, (3) to describe the currently known risk factors for QT interval abnormalities, (4) to identify current drug-induced causes of acquired QT interval abnormalities, and (5) to recommend immediate and effective management strategies to prevent unanticipated dysrhythmias and deaths from QT abnormalities in the perioperative period.

Drug-induced arrhythmia: pharmacogenomic prescribing?

Drug-induced Torsades de Pointes is a rare, unpredictable, and life-threatening serious adverse event. It can be caused by both cardiac and non-cardiac drugs and has become a major issue in novel drug development and for the regulatory authorities. This review describes the problem, predisposing factors, and the underlying genetic predisposition as it is understood currently. The future potential for pharmacogenomic-guided and personalized prescription to prevent drug-induced Torsades de Pointes is discussed. Database searches utilized reports from www.qtdrugs.org up to January 2012, case reports and articles from www.pubmed.com up to January 2012, and the British National Formulary edition at www.bnf.org.

QT interval prolongation: prevalence, risk factors and pharmacovigilance data among methadone-treated patients in France

Several reports have suggested the role of methadone in QT prolongation, Torsades de Pointes (TdP), and ventricular arrhythmia. The aim of this study was to identify the frequency of QT interval prolongation and QT dispersion among a population of addict patients treated with methadone, completed by the description of cardiac events reported to the French pharmacovigilance system. QT interval (corrected with the Bazett's method) and dispersion were measured on a cohort of patients treated with methadone during their visit to addiction specialized centers in Southwest of France. Whenever possible, methadone blood concentrations were measured. In addition, reports concerning methadone were searched in the French Pharmacovigilance database from 1996 to 2007. The cohort included 42 patients with mean QTc length of 414.3 ± 28.5 ms and mean QT dispersion of 66.0 ± 41.1 ms. None of the patient presented a QTc above 500 ms. These values were higher in patients with recent increase in methadone dose, use of tobacco or drugs prolonging QT, and history of cardiac disease. We found five cases of QT prolongation (3 TdP) and seven cases of sudden deaths in the French pharmacovigilance database (2.2% of methadone reports). Most of these events occurred after introducing methadone or another drug potentially interacting with methadone. Methadone can prolong the QT interval at dose usually used for addiction maintenance treatment in France. A cardiac evaluation, with at least a systematic ECG, could be useful during methadone treatment, particularly in case of recent modification of the regimen.

Drug-induced arrhythmias

The objective of this review is to characterize the mechanisms, risk factors, and offending pharmacotherapeutic agents that may cause drug-induced arrhythmias in critically ill patients. PubMed, other databases, and citation review were used to identify relevant published literature. The authors independently selected studies based on relevance to the topic. Numerous drugs have the potential to cause drug-induced arrhythmias. Drugs commonly administered to critically ill patients are capable of precipitating arrhythmias and include antiarrhythmics, antianginals, antiemetics, gastrointestinal stimulants, antibacterials, narcotics, antipsychotics, inotropes, digoxin, anesthetic agents, bronchodilators, and drugs that cause electrolyte imbalances and bradyarrhythmias. Drug-induced arrhythmias are insidious but prevalent. Critically ill patients frequently experience drug-induced arrhythmias; however, enhanced appreciation for this adverse event has the potential to improve prevention, treatment, patient safety, and outcomes in this patient population.