Helping You Find Full Text Journal Articles

Search Results:

'Torsade de Pointes' (4361)


Feb
2018

Gastrointestinal sensorimotor dysfunction underlies a wide range of esophageal, gastric, and intestinal motility and functional disorders that collectively constitute nearly half of all referrals to gastroenterologists. As a result, substantial effort has been dedicated toward the development of prokinetic agents intended to augment or restore normal gastrointestinal motility. However, the use of several clinically efficacious gastroprokinetic agents, such as cisapride, domperidone, erythromycin, and tegaserod, is associated with unfavorable cardiovascular safety profiles, leading to restrictions in their use.

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2018

The management of acute agitation in the emergency department often requires the administration of rapid-acting antipsychotic agents. However, there are few comparative studies and little guidance regarding the risks associated with use of such drugs in the acute setting.
This structured evidence-based review compared the safety of antipsychotic pharmacotherapies for acute agitation using data from randomized controlled trials identified by a literature search of the PubMed database.

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2018

In patients with long QT syndrome (LQTS), a sudden increase in heart rate can cause T-wave alternans (TWA) with beat-to-beat alternating polarity of T wave. We hypothesized that LQTS patients at a high risk of Torsade de Pointes (TdP) may exhibit momentary atrial or sinoatrial premature beat-induced T-wave inversion (APB-TWI).
To assess the association of APB-TWI with TdP history and with microvolt TWA.

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2018

Predicting drug-induced arrhythmias by multiscale modeling.

Int J Numer Method Biomed Eng 2018 Feb 9. Epub 2018 Feb 9.
F Sahli Costabal, J Yao, E Kuhl
Drugs often have undesired side effects. In the heart, they can induce lethal arrhythmias such as torsades de pointes. The risk evaluation of a new compound is costly and can take a long time, which often hinders the development of new drugs.

View Full Text PDF Listings View primary source full text article PDFs.

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2018

This study tested the hypothesis that concomitant sympathetic and parasympathetic stimulation ("autonomic conflict") may act as a trigger for arrhythmia in long QT syndrome (LQTS). Studies were performed in isolated innervated rabbit hearts treated with clofilium (100 nmol/L); a potassium channel blocker. The influence of vagus nerve stimulation (VNS) on spontaneous ventricular arrhythmia was assessed in the absence/presence of sustained noradrenaline perfusion (100 nmol/L) and with sudden adrenergic stress (injections of noradrenaline into the perfusion line).

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2018

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 TdP, electrocardiographic (ECG) characteristics of acquired LQTS, its clinical presentation, management, and future directions in the field.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2018

Use of the QT (QTc) interval on the electrocardiogram to predict torsades de pointes (TdP) risk from culprit drugs is neither sensitive nor specific. The ratio of the half-maximum inhibitory concentration of the hERG channel (hERG IC50) to the peak serum concentration of unbound drug (Cmax) is used during drug development to screen out chemical entities likely to cause TdP.
To validate the use of the hERG IC50/Cmax ratio to predict of TdP risk from a culprit drug by its correlation with TdP incidence.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2018

Antazoline is a first-generation antihistamine with antiarrhythmic properties. This study examines potential electrophysiological effects of antazoline in short-QT-syndrome (SQTS) and long-QT-syndrome (LQTS).
Sixty-five rabbit hearts were Langendorff-perfused.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2018

Pain medication and long QT syndrome.

Korean J Pain 2018 Jan 2;31(1):3-9. Epub 2018 Jan 2.
Christoph Klivinyi, Helmar Bornemann-Cimenti
Long QT syndrome is a cardiac repolarization disorder and is associated with an increased risk of torsades de pointes. The acquired form is most often attributable to administration of specific medications and/or electrolyte imbalance. This review provides insights into the risk for QT prolongation associated with drugs frequently used in the treatment of chronic pain.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2018

Polymyalgia rheumatica (PMR) represents the most common inflammatory rheumatic disease of the elderly. It is characterized by synovitis of proximal joints and extra-articular synovial structures, along with chronic high-grade systemic inflammation. PMR is closely related to giant cell arteritis (GCA), a large-vessel vasculitis that involves the major branches of the aorta, particularly the extracranial branches of carotid artery including temporal arteries.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2018

In long QT type-2 (LQT2), women are more prone to lethal arrhythmias called Torsade de Pointes (TdP) than men. We previously reported that 17-β-estradiol (E2) upregulates L-type Ca-channels and current (I) (∼30%) in rabbit ventricular myocytes by a classical genomic-mechanism mediated by estrogen-receptor-α (ER)α. In LQT2 ( I-blockade or bradycardia), the higher Cainflux via I, causes Ca-overload, spontaneous sarcoplasmic reticulum Ca-release, and re-activation of Ithat trigger early afterdepolarizations (EADs) and TdP.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2018

Results of a study to determine whether i.v. administration of a single dose of 4 mg of ondansetron was associated with QT interval prolongation in emergency department (ED) patients are reported.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

cardiac myocyte models present powerful tools for drug safety testing and for predicting phenotypical consequences of ion channel mutations, but their accuracy is sometimes limited. For example, several models describing human ventricular electrophysiology perform poorly when simulating effects of long QT mutations. Model optimization represents one way of obtaining models with stronger predictive power.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2018

Since the introduction of regulatory drug approval guidance on the evaluation of QT interval prolongation, an increasing number of drug monographs has included cautions on the risk of QT prolongation. For example, QT prolongation is mentioned in the Canadian product monographs of 29 drugs commonly seen in oncology practice. This presents two major challenges.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

Blockage of some ion channels and in particular, the hERG (human Ether-a'-go-go-Related Gene) cardiac potassium channel delays cardiac repolarization and can induce arrhythmia. In some cases it leads to a potentially life-threatening arrhythmia known as Torsade de Pointes (TdP). Therefore recognizing drugs with TdP risk is essential.

View Full Text PDF Listings View primary source full text article PDFs.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

To determine whether dedicated pharmacy services improve the rate of electrocardiogram (ECG) monitoring in patients at risk for medication-induced QTc interval prolongation. In addition, determine how pediatric institutions currently monitor patients at risk for medication-induced QTc interval prolongation.
A pharmacist-driven monitoring protocol to detect medication-induced QTc interval prolongation was developed using published literature.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

Antidepressants have been widely prescribed for depression, anxiety, sleep disorders, and in the management of behavioural symptoms of adult-old patients. Although generally safe, newer generation antidepressants are not devoid of the risk of inducing clinically relevant adverse events.
To investigate the association between newer generation antidepressants and the occurrence of cardiovascular adverse events and electrocardiogram (ECG) abnormalities.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2017

Some psychotropic medications have been associated with prolongation of the QT interval and QT prolongation, especially in those with medical illness, and are linked to lethal ventricular arrhythmias, such as Torsades de Pointes (TdP). In 2013, we published a review of QT prolongation, TdP, and psychotropic medications.
We provide an update over the past 5 years on the specific concerns most relevant to clinicians who see medically ill patients.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

Abuse of the common anti-diarrheal loperamide is associated with QT interval prolongation as well as development of the potentially fatal arrhythmia torsades de pointes. The mechanism underlying this cardiotoxicity is high affinity inhibition of the human ether-a-go-go-related gene (hERG) cardiac K+ channel. N-Desmethyl loperamide is the major metabolite of loperamide and is a close structural relative of the parent molecule.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

The incidence of QT prolongation and torsades de pointes is on the rise due to the use of cardiovascular and non-cardiovascular drugs. Robust efforts have been made and are still ongoing to understand the underlying mechanisms that can enhance or prevent the development of drug-induced proarrhythmia. A caveat in the use of antiarrhythmic drugs is the ability to obtain safe action potential prolongation therapeutic effects, through IKr blockade.

View Full Text PDF Listings View primary source full text article PDFs.

Oct
2017

Torsades de Pointes after Ondansetron Infusion in 2 Patients.

Tex Heart Inst J 2017 Oct 1;44(5):366-369. Epub 2017 Oct 1.
Danny Y Lee, Tri Trinh, Sion K Roy
Drugs that prolong the electrocardiographic QT interval increase the risk of ventricular arrhythmias, particularly torsades de pointes. Ondansetron, a 5-hydroxytryptamine type 3 receptor antagonist antiemetic, is one such drug. We present the cases of 2 patients who were given intravenous ondansetron and subsequently developed torsades de pointes.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

Congenital long QT syndrome (LQTS) can cause ventricular arrhythmic events with syncope and sudden death resulting from malignant torsades de pointes (TdP) followed by ventricular fibrillations (VFs). However, the syndrome is often overlooked prior to the development of arrhythmic events in patients with congenital heart diseases demonstrating right bundle branch block on electrocardiogram (ECG). We present a case of an adult patient with congenital heart disease who developed VFs postoperatively, potentially due to his mutation in a LQTS related gene, which was not identified on preoperative assessment due to incomplete evaluation of his family history.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

Due to its availability, atenolol is the primary beta-blocker used in Australia for children with long QT syndrome. There is limited data on long-term follow-up of its use.
A single-tertiary-center, retrospective, observational study investigating all children and adolescents who had genetically proven long QT syndrome type 1 (LQT1) and type 2 (LQT2) was conducted.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

Drug-induced prolongation of the corrected QT interval (QTc) may lead to serious and potentially life-threatening ventricular tachyarrhythmia, such as torsades de pointes (Tdp), which is worthy of clinical attention. Here, we report 1 case of Tdp after a coadministration of fluoxetine and amiodarone.
A 62-year-old Chinese male who placed with the implanted cardioverter-defibrillator (ICD) appeared the QTc prolongation and Tdp after the concurrent administration of fluoxetine and amiodarone.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

[This corrects the article on p. 616 in vol. 8, PMID: 28878692.

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2018

Several risk factors for development of a potentially fatal ventricular arrhythmia, torsade de pointes, have been observed, including female gender. However, in most investigations, only few torsade events were included and/or rarely were postdose heart rate corrected QT (QTc) measurements included, as a surrogate of drug exposure. We developed a multivariate logistic regression model using data from 22,214 patients (33% women) with 84 torsade events (56% women) to evaluate the relationship between risk factors for torsade using data from four anti-arrhythmic drug development programs.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

The cardiovascular complications of cancer therapeutics are the focus of the burgeoning field of cardio-oncology. A common challenge in this field is the impact of cancer drugs on cardiac repolarization (ie, QT prolongation) and the potential risk for the life-threatening arrhythmia torsades de pointes. Although QT prolongation is not a perfect marker of arrhythmia risk, this has become a primary safety metric among oncologists.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

The ComprehensiveProarrhythmia Assay (CiPA) is a global initiative intended to improve drug proarrhythmia risk assessment using a new paradigm of mechanistic assays. Under the CiPA paradigm, the relative risk of drug-induced Torsade de Pointes (TdP) is assessed using anmodel of the human ventricular action potential (AP) that integratespharmacology data from multiple ion channels. Thus, modeling predictions of cardiac risk liability will depend critically on the variability in pharmacology data, and uncertainty quantification (UQ) must comprise an essential component of theassay.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

Acquired long QT syndrome, mostly as a result of drug block of the Kv11. 1 potassium channel in the heart, is characterized by delayed cardiac myocyte repolarization, prolongation of the T interval on the ECG, syncope and sudden cardiac death due to the polymorphic ventricular arrhythmia Torsade de Pointes (TdP). In recent years, efforts are underway through the Comprehensiveproarrhythmic assay (CiPA) initiative, to develop better tests for this drug induced arrhythmia based in part onsimulations of pharmacological disruption of repolarization.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

Dispersion of repolarization is theorized as one mechanism by which myocardial repolarization prolongation causes lethal torsades de pointes, (TdP). Our primary purpose was to determine whether prolongation of myocardial repolarization as measured by the heart rate-corrected J-to-T peak interval (JTpkc), is associated with repolarization heterogeneity as measured by transmural dispersion, defined as the median duration from the peak to the end of the T wave (TpTe).
A retrospective cohort study was performed at a single urban tertiary ED from July 2011-September 2012.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2017

We report a case of torsades de pointes arrhythmia as the first manifestation of congenital Long QT syndrome in a 77-year-old man with family history of sudden unexplained death. This case illustrates the importance of vigilant clinical assessment and genetic counseling in families with sudden death in order to identify properly asymptomatic relatives at risk for cardiac events. It also demonstrates that Long QT syndrome can still manifest with potentially fatal arrhythmias late in life in previously asymptomatic elderly patients.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2017

Timothy syndrome (TS) is a multisystemic disease that occurs because of a mutation in CACN1C gene and is characterized by prolonged QT interval. Mexiletine is a Class 1B antiarrhythmic drug that causes the disappearance of T-wave alternans by shortening QTc and peak-to-end of the T wave. It may block the development of torsades de pointes in a prolonged QT.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

QTc interval prolongation is a serious diabetic complication and increases mortality rate. Hyperglycemia inhibits the rapid component of delayed rectifier potassium channel currents (Ikr) and prolongs the QTc interval on electrocardiograms. Sevoflurane also inhibits the Ikr and causes QTc interval prolongation.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

A 79-year-old woman who underwent catheter ablation for paroxysmal atrial fibrillation presented with Torsades de Pointes (TdP). Aggravation of prolonged QT interval which is most likely due to neural modulation by catheter ablation, played major role in the initiation of TdP. The patient was successfully treated with isoproterenol during acute stage and discharged after stabilization without implantation of permanent pacemaker or implantable cardioverter defibrillator.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2017

Cancer patients may receive a high number of medications with the potential to prolong QT interval and subsequent TdP (torsades de pointes). This study aimed to identify the prevalence of QT prolonging drugs, their TdP risk, QT prolonging drug-drug interactions (QT-DDIs), levels, predictors, and TdP risk of drugs involved in QT-DDIs.
This multicenter study included cancer patients from three major tertiary care hospitals of Khyber-Pakhtunkhwa, Pakistan.

View Full Text PDF Listings View primary source full text article PDFs.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2017

We present a case of a middle-aged man admitted to an inpatient detoxification facility for withdrawal of intranasal heroin, alprazolam, and ethanol. The patient was placed on methadone and chlordiazepoxide tapers. Ondansetron and trazodone were prescribed as needed for symptom control.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

While pre-clinical Torsades de Pointes (TdP) risk classifiers had initially been based on drug-induced block of hERG potassium channels, it is now well established that improved risk prediction can be achieved by considering block of non-hERG ion channels. The current multi-channel TdP classifiers can be categorized into two classes. First, the classifiers that take as input the values of drug-induced block of ion channels (direct features).

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

Translation of non-clinical markers of delayed ventricular repolarization to clinical prolongation of the QT interval corrected for heart rate (QTc) (a biomarker for torsades de pointes proarrhythmia) remains an issue in drug discovery and regulatory evaluations. We retrospectively analysed 150 drug applications in a US Food and Drug Administration database to determine the utility of established non-clinical in vitro IKr current human ether-à-go-go-related gene (hERG), action potential duration (APD) and in vivo (QTc) repolarization assays to detect and predict clinical QTc prolongation.
The predictive performance of three non-clinical assays was compared with clinical thorough QT study outcomes based on free clinical plasma drug concentrations using sensitivity and specificity, receiver operating characteristic (ROC) curves, positive (PPVs) and negative predictive values (NPVs) and likelihood ratios (LRs).

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

The antidiarrheal loperamide has had a recent, drastic increase in off-label use as an alternative treatment for symptoms of opioid withdrawal. The concept of this is easily discovered on the Internet and social media, where there are multiple blogs and forums promoting loperamide use at doses of 70 to 200 mg per day. Unfortunately, the serious side effects are not well recognized.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2018

Patients with long QT syndrome (LQTS) are at a high risk of cardiac events. Many patients with LQTS are treated with antidepressant drugs (ADs). We investigated the LQTS genotype-specific risk of recurrent cardiac arrhythmic events (CAEs) associated with AD therapy.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2018

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

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2018

Prolongation of the QTc interval may result in Torsade de Pointes, a ventricular arrhythmia. Numerous risk factors for QTc interval prolongation have been described, including the use of certain drugs. In clinical practice, there is much debate about the management of the risks involved.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

Anti-arrhythmic drugs are a mainstay in the management of symptoms related to arrhythmias, and are adjuncts in prevention and treatment of life-threatening ventricular arrhythmias. However, they also have the potential for pro-arrhythmia and thus the prediction of arrhythmia predisposition and drug response are critical issues. Clinical trials are the latter stages in the safety testing and efficacy process prior to market release, and as such serve as a critical safeguard.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2017

The QTc interval is widely used in Safety Pharmacological studies to predict arrhythmia risk, and the electromechanical window (EMW) and short-term variability of QT intervals (STV) have been studied as new biomarkers for drug-induced Torsades de Pointes (TdP). However, the use of EMW and STVto predict ventricular fibrillation (VF) has not been elucidated. This study aimed to evaluate EMW and STVto predict VF in anesthetized rabbit model of VF.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2017

Gastroparesis: pharmacotherapy and cardiac risk.

Scand J Gastroenterol 2017 Nov 20:1-6. Epub 2017 Nov 20.
Per M Hellström, Ahmad Al-Saffar
Gastroparesis is characterized by abnormal gastric motility and delayed emptying with symptoms of early satiety, postprandial fullness, bloating, nausea, vomiting and abdominal pain. Pharmacological discovery has been lagging because potential drugs often are associated with abnormalities of electrical conduction of the myocardium due to interaction with cardiac ion channels leading to limited pharmaceutical options for development of new drugs.
Addresses the safety of drugs for gastroparesis in terms of cardiotoxicity related to the clinical use of prokinetics and antiemetics.

View Full Text PDF Listings View primary source full text article PDFs.

Back to top