[Risk management with regard to QT-prolonging drugs]. / Risicomanagement rond QT-verlengende geneesmiddelen.

Drug-induced QT prolongation increases the risk of Torsade de Pointes (TdP). Drug-induced QT prolongation is a complex and unpredictable system due to many uncertainties. Risk factors such as electrolyte disturbances, heart failure and genetics play an important role in estimating the effect on QT prolongation. Moreover, the degree of QT prolongation is not always directly related to the risk of TdP and the assessment of the QT-interval is variable depending on the type and timing of QT measurement. Therefore, the variation in QT measurement may be larger than the effect of certain drugs on the QT interval. Because of the potentially lethal risk, several measures are undertaken to reduce the risk of QT prolongation and TdP, while their effect and proportionality are unclear. We suggest we should be less stringent in certain settings when risk of TdP is extremely low given the limited availability of our resources.

[Asymptomatic channelopathies : Risk stratification and primary prophylaxis]. / Asymptomatische Ionenkanalerkrankungen : Risikostratifizierung und Primärprophylaxe.

In general, asymptomatic patients with channelopathies are at increased risk of sudden cardiac death (SCD), due to pathogenic variants in genes encoding ion channels that result in pathological ion currents. Channelopathies include long-QT syndrome (LQTS), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and short-QT syndrome (SQTS). In addition to the patient's clinical presentation, history and clinical tests, the main diagnostic tools are electrocardiography and genetic testing to identify known gene mutations. Early and correct diagnosis as well as further risk stratification of affected individuals and their relatives are paramount for prognosis. The recent availability of risk score calculators for LQTS and BrS allows SCD risk to be accurately estimated. The extent to which these improve patient selection for treatment with an implantable cardioverter-defibrillator (ICD) system is currently unknown. In most cases, initiation of basic therapy in asymptomatic patients in the form of avoidance of triggers, which are usually medication or stressful situations, is sufficient and contributes to risk reduction. In addition, there are other risk-reducing prophylactic measures, such as permanent medication with nonselective ß­ blockers (for LQTS and CPVT) or mexiletine for LQTS3. Patients and their family members should be referred to specialized outpatient clinics for individual risk stratification in the sense of primary prophylaxis.

Piperaquine-Induced QTc Prolongation Decreases With Repeated Monthly Dihydroartemisinin-Piperaquine Dosing in Pregnant Ugandan Women.

BACKGROUND: Intermittent preventive treatment with monthly dihydroartemisinin-piperaquine (DHA-PQ) is highly effective at preventing both malaria during pregnancy and placental malaria. Piperaquine prolongs the corrected QT interval (QTc), and it is possible that repeated monthly dosing could lead to progressive QTc prolongation. Intensive characterization of the relationship between piperaquine concentration and QTc interval throughout pregnancy can inform effective, safe prevention guidelines. METHODS: Data were collected from a randomized controlled trial, where pregnant Ugandan women received malaria chemoprevention with monthly DHA-PQ (120/960 mg DHA/PQ; n = 373) or sulfadoxine-pyrimethamine (SP; 1500/75 mg; n = 375) during the second and third trimesters of pregnancy. Monthly trough piperaquine samples were collected throughout pregnancy, and pre- and postdose electrocardiograms were recorded at 20, 28, and 36 weeks' gestation in each woman. The pharmacokinetics-QTc relationship for piperaquine and QTc for SP were assessed using nonlinear mixed-effects modeling. RESULTS: A positive linear relationship between piperaquine concentration and Fridericia corrected QTc interval was identified. This relationship progressively decreased from a 4.42 to 3.28 to 2.13 millisecond increase per 100 ng/mL increase in piperaquine concentration at 20, 28, and 36 weeks' gestation, respectively. Furthermore, 61% (n = 183) of women had a smaller change in QTc at week 36 than week 20. Nine women given DHA-PQ had grade 3-4 cardiac adverse events. SP was not associated with any change in QTc. CONCLUSIONS: Repeated DHA-PQ dosing did not result in increased risk of QTc prolongation and the postdose QTc intervals progressively decreased. Monthly dosing of DHA-PQ in pregnant women carries minimal risk of QTc prolongation. CLINICAL TRIALS REGISTRATION: NCT02793622.

QTc prolongation Safety and Effectiveness of Teneligliptin in Indian patients with type 2 Diabetes Mellitus: A real world study (QSET 2).

AIMS: To evaluate the safety with respect to QTc prolongation and effectiveness of Teneligliptin in Indian Type 2 Diabetes Mellitus (T2DM) patients. METHODS: Retrospective data of T2DM patients on teneligliptin 20 mg or 40 mg once daily as a monotherapy or add-on therapy and having ECG records (before and after teneligliptin initiation) was collected. Safety was evaluated by change in QTc interval and effectiveness was evaluated by changes in fasting plasma glucose (FPG), postprandial plasma glucose (PPG), and haemoglobin A1C (HbA1c) from baseline to 12-weeks. RESULTS: There was no significant change in mean QTc interval from baseline [418.68 milli seconds (ms) to 419 ms; mean change +0.33 ms; P = 0.1023] to follow up visit (mean duration 91 days). There was a significant reduction from baseline to 12 weeks in FPG [173.1 mg/dl (9.61 mmol/L) to 128.4 mg/dl (7.12 mmol/L), mean change - 44.64 mg/dl (2.47 mmol/L), P ≤ 0.001], PPG [242.5 mg/dl (13.46 mmol/L) to 176.5 mg/dl (9.79 mmol/L), mean change - 65.93 mg/dl (3.66 mmol/L), P ≤ 0.001], and HbA1c [8.2% (66 mmol/mol) to 7.2% (55 mmol/mol), mean change - 1.00% (10.9 mmol/mol), P ≤ 0.001]. CONCLUSION: Teneligliptin did not cause QTc interval prolongation and was significantly effective in improving glycemic control.

Remote Monitoring of the QT Interval and Emerging Indications for Arrhythmia Prevention.

QT interval prolongation is a marker of increased risk for life-threatening arrhythmias, and needs to be promptly recognized. Many effective drugs, however, prolong QTc (QT interval corrected for heart rate) in genetically predisposed subjects. The possibility of remote monitoring and QTc measurement for up to 2 weeks, continuously providing physicians with real time data, allows life-saving interventions or changes in drug therapy. This applies especially to patients with the long QT syndrome and to those taking drugs blocking the IKr current and prolonging the QT interval. Patch monitors recording ECG traces continuously are available and contribute to effective arrhythmic prevention.

How circadian variability of the heart rate and plasma electrolytes concentration influence the cardiac electrophysiology - model-based case study.

The circadian rhythm of cardiac electrophysiology is dependent on many physiological and biochemical factors. Provided, that models describing the circadian patterns of cardiac activity and/or electrophysiology which have been verified to the acceptable level, modeling and simulation can give answers to many of heart chronotherapy questions. The aim of the study was to assess the performance of the circadian models implemented in Cardiac Safety Simulator v 2.2 (Certara, Sheffield, UK) (CSS), as well as investigate the influence ofcircadian rhythms on the simulation results in terms of cardiac safety. The simulations which were run in CSS accounted for inter-individual and intra-individual variability. Firstly, the diurnal variations in QT interval length in a healthy population were simulated accounting for heart rate (HR) circadian changes alone, or with concomitant diurnal variations of plasma ion concentrations. Next, tolterodine was chosen as an exemplary drug for PKPD modelling exercise to assess the role of circadian rhythmicity in the prediction of drug effects on QT interval. The results of the simulations were in line with clinical observations, what can serve as a verification of the circadian models implemented in CSS. Moreover, the results have suggested that the circadian variability of the electrolytes balance is the main factor influencing QT circadian pattern. The fluctuation of ion concentration increases the intra-subject variability of predicted drug-triggered QT corrected for HR (QTc) prolongation effect and, in case of modest drug effect on QTc interval length, allows to capture this effect.

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.

Norquetiapine blocks the human cardiac sodium channel Nav1.5 in a state-dependent manner.

Quetiapine, an atypical antipsychotic drug, is used for the treatment of schizophrenia and acute mania. Although a previous report showed that quetiapine blocked hERG potassium current, quetiapine has been considered relatively safe in terms of cardiovascular side effects. In the present study, we used the whole-cell patch-clamp technique to investigate the effect that quetiapine and its major metabolite norquetiapine can exert on human cardiac sodium channels (hNav1.5). The half-maximal inhibitory concentrations of quetiapine and norquetiapine at a holding potential of -90 mV near the resting potential of cardiomyocytes were 30 and 6 µM, respectively. Norquetiapine as well as quetiapine was preferentially bound in the inactivated state of the hNav1.5 channel. Norquetiapine slowed the recovery from inactivation of hNav1.5 and consequently induced strong use-dependent inhibition. Our results indicate that norquetiapine blocks hNav1.5 current in concentration-, state- and use-dependent manners, suggesting that the blockade of hNav1.5 current by norquetiapine may shorten the cardiac action potential duration and reduce the risk of QT interval prolongation induced by the inhibition of hERG potassium currents.

Reintegrating droperidol into emergency medicine practice.

PURPOSE: After a long period of low utilization, droperidol has become easier to obtain in the US market. This comprehensive review discusses the safety, indications, clinical efficacy, and dosing of droperidol for use in the emergency department (ED) setting. SUMMARY: In 2001 the US Food and Drug Administration (FDA) mandated a boxed warning in the labeling of droperidol after reports of QT interval prolongation associated with droperidol use. Since that time, it has been difficult to access droperidol in the United States; as a result, many practicing clinicians lack experience in its clinical use. Multiple studies have been conducted to assess the clinical efficacy and safety of droperidol use in ED patients. Results consistently show the safety of droperidol and its clinical efficacy when used as an analgesic, antiemetic, and sedative. Now that droperidol is more widely available for use in the US market, pharmacists and prescribers need to reliably translate safety and efficacy data compiled since 2001 to help ensure appropriate and effective use of the medication. CONCLUSION: Droperidol is an effective and safe option for the treatment of acute agitation, migraine, nausea, and pain for patients in the ED setting. Healthcare professionals can adopt droperidol for use in clinical practice, and they should become familiar with how to dose and monitor droperidol for safe and effective use.

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.

QT interval evaluation associated with the use of hydroxychloroquine with combined use of azithromycin among hospitalised children positive for coronavirus disease 2019.

INTRODUCTION AND AIM: Hydroxychloroquine alone or in combination with azithromycin has been increasingly used for patients with coronavirus disease 2019, in both children and adults. Drugs are generally well tolerated in clinical practice; however, both can cause corrected QT prolongation. We aimed to report our experience of QT interval evaluation associated with the use of hydroxychloroquine with concurrent azithromycin among children testing positive for coronavirus disease 2019. METHODS: Our single-centre; retrospective, study evaluated children with coronavirus disease 2019 disease admitted to the Pediatric Department at Sancaktepe Training and Research Hospital Istanbul, Turkey from 10 March, 2020 to 10 April, 2020. The data including demographics, clinical symptoms, co-morbid diseases, laboratory, radiological findings as well as electrocardiographs of the patients were obtained from our records. Electrocardiograms were evaluated before, one day after and at the termination of the treatment. RESULTS: 21 patients aged 9 to 18 years were evaluated. The median age was 170 months (range 112-214), 51.1% of them were girls and 48.9% were boys. Their laboratory results did not reveal any abnormalities. None of them needed intensive care. We did not detect QT prolongation during or at the termination of the treatment. CONCLUSION: We did not detect QT prolongation during or at the termination of the treatment in our patients due to the fact that they were not severely affected by the disease. Patients were treated in our inpatient clinic and none of them required intensive care. Laboratory results were also insignificant. Furthermore, they did not need other medications.