Drug induced QT prolongation and torsades de pointes.
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ABSTRACT:
SUBMITTER: Yap YG
PROVIDER: S-EPMC1767957 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:AimsPatients with particular mutations of type-2 long QT syndrome (LQT2) are at an increased risk for malignant arrhythmia during fever. This study aimed to determine the mechanism by which KCNH2 mutations cause fever-induced QT prolongation and torsades de pointes (TdP).Methods and resultsWe evaluated three KCNH2 mutations, G584S, D609G, and T613M, in the Kv11.1 S5-pore region, identified in patients with marked QT prolongation and TdP during fever. We also evaluated KCNH2 M124T and R269W, which are not associated with fever-induced QT prolongation. We characterized the temperature-dependent changes in the electrophysiological properties of the mutant Kv11.1 channels by patch-clamp recording and computer simulation. The average tail current densities (TCDs) at 35°C for G584S, WT+D609G, and WT+T613M were significantly smaller and less increased with rising temperature from 35°C to 40°C than those for WT, M124T, and R269W. The ratios of the TCDs at 40°C to 35°C for G584S, WT+D609G, and WT+T613M were significantly smaller than for WT, M124T, and R269W. The voltage dependence of the steady-state inactivation curve for WT, M124T, and R269W showed a significant positive shift with increasing temperature; however, that for G584S, WT+D609G, and WT+T613M showed no significant change. Computer simulation demonstrated that G584S, WT+D609G, and WT+T613M caused prolonged action potential durations and early afterdepolarization formation at 40°C.ConclusionThese findings indicate that KCNH2 G584S, D609G, and T613M in the S5-pore region reduce the temperature-dependent increase in TCDs through an enhanced inactivation, resulting in QT prolongation and TdP at a febrile state in patients with LQT2.
| S-EPMC10310978 | biostudies-literature
Project description:BackgroundCombinations of hydroxychloroquine (HCQ) and azithromycin have been promoted as treatments for COVID-19 based on small, uncontrolled clinical trials that have not assessed potential risks. Risks of treatment include QT segment prolongation, Torsades de Pointes (TdP), and death. This comparative pharmacovigilance analysis evaluated the risk of these events.MethodsData from the U.S. Food and Drug Administration's Adverse Event Reporting System (FAERS) (>13 million total reports) were used. Queries extracted reports based on exposures of HCQ/chloroquine (CQ) alone, azithromycin alone, HCQ/CQ + azithromycin, amoxicillin alone, HCQ/CQ + amoxicillin alone. Amoxicillin served as a control. Events of interest included death and TdP/QT prolongation as well as accidents/injuries and depression as control events. Proportional Reporting Ratios (PRR) and 95% confidence intervals (CI) were calculated where a lower limit of the of 95% CI (Lower95CI) value of ≥2.0 is interpreted as a potential safety signal.ResultsLower95CIs for HCQ/CQ alone showed no potential safety signals for TdP/QT prolongation, death, or any of the control events included. The PRRs and 95% CIs for TdP/QT prolongation was 1.43 (1.29-2.59) with HCQ/CQ use alone and 4.10 (3.80-4.42) for azithromycin alone. For the combined HCQ/CQ + azithromycin group, the PRR and 95% CI was 3.77 (1.80-7.87). For the control of amoxicillin, there were no safety signals when used alone or in combination with HCQ/CQ.ConclusionsHCQ/CQ use was not associated with a safety signal in this analysis of FAERS data. However, azithromycin used alone was associated with TdP/QT prolongation events and should be used with caution.
| S-EPMC7166303 | biostudies-literature
Project description:BackgroundPoly ADP-ribose polymerase (PARP) inhibitors target pathogenic BRCA mutations in chemotherapy-resistant malignancies. PARP inhibitors cause modest dose-dependent QT prolongation in the setting of a normal baseline QT interval.Case summaryWe describe a case of PARP inhibitor-induced torsades de pointes (TdP) in an 86-year-old gentleman prescribed rucaparib due to chemotherapy-resistant, metastatic prostate cancer with pre-existing long QT, with an apparent dose-dependent increase in QT interval. The patient presented with syncope and recurrent TdP requiring direct cardioversion reversion (200 J biphasic) and an isoprenaline infusion (2 μg/min). There were no other QT prolonging agents and no electrolyte or metabolic disturbance to account for this arrhythmia. Improvement in QT interval was observed within 72 h of rucaparib cessation.DiscussionPARP inhibitors cause a modest, dose-dependent increase in QT interval in patients with a normal baseline. The safety of PARP inhibitors in patients with pre-existing long QT has not been evaluated. This is the first reported case of rucaparib-associated TdP in a patient with pre-existing long QT, highlighting the amplified effect of this agent in individuals with pre-existing QT prolongation and the risk of fatal arrhythmias.
| S-EPMC7047052 | biostudies-literature
Project description:BackgroundDrugs belonging to diverse therapeutic classes can prolong myocardial refractoriness or slow conduction. These drugs may be effective and well-tolerated, but the risk of sudden cardiac death from torsades de pointes (TdP) remains a major concern. The corrected QT interval has significant limitations when used for risk stratification. Measurement of global electrical heterogeneity (GEH) could help identify the substrate vulnerable to drug-induced ventricular arrhythmias.ObjectiveThe purpose of this study was to improve risk stratification for drug-induced TdP by measuring GEH on the electrocardiogram (ECG).MethodsWe analyzed ECG data from a case-control study of patients with a history of drug-induced TdP as well as age- and sex-matched controls. Vectorcardiograms were constructed from ECGs. GEH was measured via the spatial ventricular gradient (SVG) vector (magnitude, azimuth, and elevation). Log odds coefficients for TdP were estimated using multivariable logistic regression.ResultsAmong 17 cases (47% male; age 58.9 ± 12.5 years) and 17 controls (29% male; age 61.0 ± 12.2 years), 34 ECGs were analyzed. SVG azimuth was significantly different between cases and controls (3.4 vs 22.0 degrees, respectively; P = 0.02). After adjusting for sex and QTc interval, odds of TdP increased by a factor of 3.2 for each 1 SD change in SVG azimuth from the control group mean (95% confidence interval 1.07-9.14; P = .04). QTc was not significant in the multivariable analysis (P = .20).ConclusionSVG azimuth is correlated with a history of drug-induced TdP independent of QTc. GEH measurement may help identify patients at high risk for drug-induced arrhythmias.
| S-EPMC7796973 | biostudies-literature
Project description:Mounting evidence indicates that in chronic inflammatory arthritis (CIA), QTc prolongation is frequent and correlates with systemic inflammatory activation. Notably, basic studies demonstrated that inflammatory cytokines induce profound changes in potassium and calcium channels resulting in a prolonging effect on cardiomyocyte action potential duration, thus on the QT interval on the electrocardiogram. Moreover, it has been demonstrated that in rheumatoid arthritis (RA) patients, the risk of sudden cardiac death is significantly increased when compared to non-RA subjects. Conversely, to date no data are available about torsades de pointes (TdP) prevalence in CIA, and the few cases reported considered CIA only an incidental concomitant disease, not contributing factor to TdP development. We report three patients with active CIA developing marked QTc prolongation, in two cases complicated with TdP degenerating to cardiac arrest. In these patients, a blood sample was obtained within 24?h from TdP/marked QTc prolongation occurrence, and levels of IL-6, TNF?, and IL-1 were evaluated. In all three cases, IL-6 was markedly elevated, ~10 to 100 times more than reference values. Moreover, one patient also showed high circulating levels of TNF? and IL-1. In conclusion, active CIA may represent a currently overlooked QT-prolonging risk factor, potentially contributing in the presence of other "classical" risk factors to TdP occurrence. In particular, a relevant role may be played by elevated circulating IL-6 levels via direct electrophysiological effects on the heart. This fact should be carefully kept in mind, particularly when recognizable risk factors are already present and/or the addition of QT-prolonging drugs is required.
| S-EPMC5029147 | biostudies-literature
Project description:Background Systemic inflammation and male hypogonadism are 2 increasingly recognized "nonconventional" risk factors for long-QT syndrome and torsades de pointes (TdP). Specifically, inflammatory cytokines prolong, while testosterone shortens the heart rate-corrected QT interval (QTc) via direct electrophysiological effects on cardiomyocytes. Moreover, several studies demonstrated important interplays between inflammation and reduced gonad function in men. We hypothesized that, during inflammatory activation in men, testosterone levels decrease and that this enhances TdP risk by contributing to the overall prolonging effect of inflammation on QTc. Methods and Results We investigated (1) the levels of sex hormones and their relationship with inflammatory markers and QTc in male patients with different types of inflammatory diseases, during active phase and recovery; and (2) the association between inflammatory markers and sex hormones in a cohort of male patients who developed extreme QTc prolongation and TdP, consecutively collected over 10 years. In men with active inflammatory diseases, testosterone levels were significantly reduced, but promptly normalized in association with the decrease in C-reactive protein and interleukin-6 levels. Reduction of testosterone levels, which also inversely correlated with 17-β estradiol over time, significantly contributed to inflammation-induced QTc prolongation. In men with TdP, both active systemic inflammation and hypogonadism were frequently present, with significant correlations between C-reactive protein, testosterone, and 17-β estradiol levels; in these patients, increased C-reactive protein and reduced testosterone were associated with a worse short-term outcome of the arrhythmia. Conclusions During systemic inflammatory activation, interleukin-6 elevation is associated with reduced testosterone levels in males, possibly deriving from an enhanced androgen-to-estrogen conversion. While transient, inflammatory hypotestosteronemia is significantly associated with an increased long-QT syndrome/TdP risk in men.
| S-EPMC9075210 | biostudies-literature
Project description:Drug-induced torsades de pointes (TdP) remains a significant public health concern that has challenged scientists who have the responsibility of advancing new medicines through development to the patient, while assuring public safety. As a result, from the point of discovering a new molecule to the time of its registration, significant efforts are made to recognize potential liabilities, including the potential for TdP. With this background, the ILSI (HESI) Proarrhythmia Models Project Committee recognized that there was little practical understanding of the relationship between drug effects on cardiac ventricular repolarization and the rare clinical event of TdP. A workshop was therefore convened at which four topics were considered including: Molecular and Cellular Biology Underlying TdP, Dynamics of Periodicity, Models of TdP Proarrhythmia and Key Considerations for Demonstrating Utility of Pre-Clinical Models. The series of publications in this special edition has established the background, areas of debate and those that deserve scientific pursuit. This is intented to encourage the research community to contribute to these important areas of investigation in advancing the science and our understanding of drug-induced proarrhythmia.
| S-EPMC2492097 | biostudies-other
Project description: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.
| S-EPMC7211688 | biostudies-literature
Project description:BackgroundDrug-induced QT interval prolongation, a risk factor for life-threatening ventricular arrhythmias, is a potential side effect of many marketed and withdrawn medications. The contribution of common genetic variants previously associated with baseline QT interval to drug-induced QT prolongation and arrhythmias is not known.MethodsWe tested the hypothesis that a weighted combination of common genetic variants contributing to QT interval at baseline, identified through genome-wide association studies, can predict individual response to multiple QT-prolonging drugs. Genetic analysis of 22 subjects was performed in a secondary analysis of a randomized, double-blind, placebo-controlled, crossover trial of 3 QT-prolonging drugs with 15 time-matched QT and plasma drug concentration measurements. Subjects received single doses of dofetilide, quinidine, ranolazine, and placebo. The outcome was the correlation between a genetic QT score comprising 61 common genetic variants and the slope of an individual subject's drug-induced increase in heart rate-corrected QT (QTc) versus drug concentration.ResultsThe genetic QT score was correlated with drug-induced QTc prolongation. Among white subjects, genetic QT score explained 30% of the variability in response to dofetilide (r=0.55; 95% confidence interval, 0.09-0.81; P=0.02), 23% in response to quinidine (r=0.48; 95% confidence interval, -0.03 to 0.79; P=0.06), and 27% in response to ranolazine (r=0.52; 95% confidence interval, 0.05-0.80; P=0.03). Furthermore, the genetic QT score was a significant predictor of drug-induced torsade de pointes in an independent sample of 216 cases compared with 771 controls (r2=12%, P=1×10-7).ConclusionsWe demonstrate that a genetic QT score comprising 61 common genetic variants explains a significant proportion of the variability in drug-induced QT prolongation and is a significant predictor of drug-induced torsade de pointes. These findings highlight an opportunity for recent genetic discoveries to improve individualized risk-benefit assessment for pharmacological therapies. Replication of these findings in larger samples is needed to more precisely estimate variance explained and to establish the individual variants that drive these effects.Clinical trial registrationURL: http://www.clinicaltrials.gov. Unique identifier: NCT01873950.
| S-EPMC5380476 | biostudies-literature
Project description:Background and purposeDrug candidates must be thoroughly investigated for their potential cardiac side effects. During the course of routine toxicological assessment, the compound RO5657, a CCR5 antagonist, was discovered to have the rare liability of inducing torsades de pointes (polymorphic ventricular arrhythmia) in normal, healthy animals. Studies were conducted to determine the molecular mechanism of this arrhythmia.Experimental approachToxicological effects of repeat dosing were assessed in naïve monkeys. Cardiovascular effects were determined in conscious telemetry-implanted monkeys (repeat dosing) and anaesthetized instrumented dogs (single doses). Mechanistic studies were performed in guinea-pig isolated hearts and in cells recombinantly expressing human cardiac channels.Key resultsIn cynomolgus monkeys, RO5657 caused a low incidence of myocardial degeneration and a greater incidence of ECG abnormalities including prolonged QT/QTc intervals, QRS complex widening and supraventricular tachycardia. In telemetry-implanted monkeys, RO5657 induced arrhythmias, including torsades de pointes and in one instance, degeneration to fatal ventricular fibrillation. RO5657 also depressed both heart rate (HR) and blood pressure (BP), with no histological evidence of myocardial degeneration. In the anaesthetized dog and guinea-pig isolated heart studies, RO5657 induced similar cardiovascular effects. RO5657 also inhibited Kv11.1 and sodium channel currents.Conclusions and implicationsThe molecular mechanism of RO5657 is hypothesized to be due to inhibition of cardiac sodium and Kv11.1 potassium channels. These results indicate that RO5657 is arrhythymogenic due to decreased haemodynamic function (HR/BP), decreased conduction and inhibition of multiple cardiac channels, which precede and are probably the causative factors in the observed myocardial degeneration.
| S-EPMC3423261 | biostudies-literature