View clinical trials related to Long QT Syndrome.
Filter by:The list of medications that prolong the QT interval and can provoke torsade de pointes keeps expanding. This list includes not only antiarrhythmic drugs, but also medications with no cardiac indications. All these medications prolong the QT interval because they block a specific potassium channel on the myocardial cell membrane: the channel for the rapid component of the delayed rectifier potassium current or "IKr". The risk for developing torsade de pointes for patients taking any of the medications with IKr blockade capabilities varies from >4% for antiarrhythmic drugs to <0.01% for non-cardiac medications. The risk depends on the strength of IKr blockade, but also on specific patient characteristics. The majority of patients who develop torsade de pointes from non-cardiac medications have identifiable risk factors. In this regard, patients with a congenital long QT syndrome are prone to develop torsade de pointes when treated with QT-prolonging medications. This is because, due to their genetically defective ion channels, patients with Long QT Syndrome (LQTS) have impaired ventricular repolarization and reduced "repolarization reserve." Therefore, it is common medical practice to strongly advise patients with congenital LQTS to avoid all medications that have IKr channel blocker capabilities. it was reported that some flavonoids contained in pink-grapefruit juice block the IKr channel. These investigators also reported that drinking 1 liter of pink-grapefruit juice causes QT prolongation in healthy volunteers. The magnitude of the QT prolongation provoked by grapefruit juice was small However, drugs causing minor QT prolongation in healthy volunteers may provoke major QT prolongation in rare or sick individuals who are then at risk for developing torsade de pointes. Consequently, one could argue that, until proven otherwise, pink-grapefruit should be added to the list of "drugs" that are forbidden for patients with LQTS
The drug-induced long QT syndrome (diLQTS) describes a clinical entity in which administration of a drug produces marked prolongation of the QT interval of the electrocardiogram, associated with the development of a polymorphic ventricular tachycardia, termed torsades de pointes (TdP). The heart rate is an important variable affecting the QT interval. The QT interval normally shortens as the heart rate accelerates; however, the adaptation of the QT interval to sudden heart rate acceleration is not instantaneous. Interestingly, Holter studies show that the speed of response of the QT interval to sudden changes in heart rate (that is, the time it takes the QT interval of a given person to reach a new steady-state QT/RR relation) in healthy persons is highly individual and independent of the basic QTc. The investigators and others recently proposed the "quick standing" test as a simple bedside test that facilitates the diagnosis of congenital LQTS. The test takes advantage of the fact that as one stands up, the heart rate acceleration is abrupt while the associated QT-interval shortening is gradual. As the R-R interval shortens faster than the QT interval, the QT appears to "stretch" toward the next P wave and the corrected QT interval (QTc) for heart rate actually increases momentarily. The phenomenon of "QT stretching" is universal but is exaggerated in patients with LQTS, allowing for a simple but accurate diagnostic test. There is no data on the effects of quick standing on drug-associated form of the long QT syndrome. The investigators therefore propose the present study to better understand who these patients with drug-associated form of the long QT syndrome are and what the significance of their abnormal QT-response is.
The goal is to determine how lifestyle and exercise impact the well-being of individuals with hypertrophic cardiomyopathy (HCM) and long QT syndrome (LQTS). Ancillary study Aim: To understand how the coronavirus epidemic is impacting psychological health and quality of life in the LIVE population
Torsades de pointes (TdP) is a potentially fatal ventricular arrhythmia associated with corrected QT (QTc) interval prolongation. More than 50 commonly used drugs available on the US market may cause QTc interval prolongation and TdP. While TdP occurs more commonly in women, 33-45% of all cases of TdP have occurred in men. Older age is a risk factor for drug-induced TdP in men, possibly due to declining serum testosterone concentrations. Available evidence shows an inverse relationship between QTc intervals and serum testosterone concentrations. In addition, experimental data, including those from the investigators' laboratory, suggest that both exogenous testosterone or progesterone administration may be protective against prolongation of ventricular repolarization and TdP. Specific Aim: Establish the influence of transdermal testosterone administration and oral progesterone administration as preventive methods by which to diminish the degree of drug-induced QT interval prolongation in men 65 years of age or older. Hypothesis: Transdermal testosterone administration and oral progesterone administration both effectively attenuate drug-induced QT interval response in older men. To test this hypothesis, transdermal testosterone, oral progesterone or placebo will be administered in a 3-way crossover study to men 65 years of age or older. QTc interval response to low-dose ibutilide will be assessed. The primary endpoints will be Fridericia-corrected QT interval (QTF) response to ibutilide, in the presence and absence of testosterone, and in the presence or absence of progesterone: 1) Effect on pre-ibutilide QTF, 2) Effect on maximum post-ibutilide QTF, 3) Effect on % change in post-ibutilide QTF, and 2) Area under the QTF interval-time curves.
This study will evaluate the pharmacokinetics (PK), safety, and tolerability of a single oral dose of eleclazine and its metabolite, GS-623134, in participants with normal and impaired renal function. Participants in the healthy control group will be matched to participants with impaired renal function by age (± 5 years), gender, and body mass index (± 10%).
To assess the ability of common genetic variants in aggregate to predict drug-induced QT prolongation in patients being loaded with dofetilide or sotalol.
This is a registry to examine genetic and clinical predictors of torsade de pointes events.
The NLQTS Research Network team aims to build a Canadian collaboration of dedicated investigators that will create a new paradigm in the modern investigation of patients with LQTS and in the description of a new disease modifier. The project aims to describe the natural history of familial Long QT Syndrome to identify: 1. Low risk patients that do not require protective beta-blocker therapy 2. High-risk patients that require protective beta-blocker therapy and may benefit from a primary prevention ICD. This cohort would contain treated pre-symptomatic individuals effectively protected from harm.
Human induced pluripotent stem cells (hiPSCs) have driven a paradigm shift in the modeling of human disease; the ability to reprogram patient-specific cells holds the promise of an enhanced understanding of disease mechanisms and phenotypic variability, with applications in personalized predictive pharmacology/toxicology, cell therapy and regenerative medicine. This research will collect blood or skin biopsies from patients and healthy controls for the purpose of generating cell and tissue models of Mendelian heritable forms of heart disease focusing on cardiomyopathies, channelopathies and neuromuscular diseases. Cardiomyocytes derived from hiPSCs will provide a ready source of disease specific cells to study pathogenesis and therapeutics.
The purpose of this project is to test a new, very compact, 12-lead ECG device as a way to detect long QT syndrome (LQTS) in infants. The device -- called QTScreen -- was developed in Phase I of this project. In Phase II, the goals are to test the capacity of the device for LQTS screening in newborns and to obtain prevalence data on LQTS in California. The 4 main objectives are: 1. To validate the capacity of QTScreen for LQTS screening in newborns. 2. To determine the extent to which parents are able to use QTScreen on their babies at home. 3. To survey end-user experience and opinions. 4. To estimate the LQTS prevalence in California.