Active clinical trials for "Long QT Syndrome"

The purpose of the study is to provide comprehensive follow-up in patients with Long QT Syndrome (LQTS) and gain additional information regarding genotype-phenotype correlation and effective management and treatment options.

The purpose of this study is to learn what effect rapid atrial pacing (in patients with dual chamber pacemakers) will have on the electrocardiogram including the QT Interval. The investigators are also interested in the differences caused by genes.

Risk prediction in in inherited heart rhythm conditions that may cause sudden cardiac arrest or death is difficult. Sometimes the risks may be low but the loss of life in an otherwise healthy young individual is catastrophic. Clinicians often treat to the extreme to prevent this and so often those at unknown risk for a serious cardiac event are treated with an implanted cardioverter defibrillator (ICD) to protect against sudden death even though the risk is low or unknown. ICDs them selves are not without adverse events such as needing battery replacements, mechanical complications, inappropriate shocks and body image and self esteem issues for the patient. This study will use an inject able monitor that is less invasive to monitor inherited heart rhythm patients long term to help gather long term heart rhythm data (3 years) on patients with an inherited heart rhythm that will help to detect symptoms of dangerous heart rhythms so that the appropriate care can be provided.

Azithromycin (AZ) is used in the pediatric group in COVID-19 diseas. It has been reported to cause prolongation in the QT interval in adult age group. The aim of this study is to evaluate the effect of AZ on ventricular repolarization in COVID-19 positive pediatric patients. METHOD The study was conducted prospectively in July-August 2020. COVID-19 pediatric patients who received AZ treatment were included in the study. ECG was obtained before treatment and on the 1st, 3rd and 5th days after the treatment. Measurements were made with Image J program®. QTmax, QTmin, Tp-emax, Tp-emin intervals were measured. QTcmax, QTcmin, Tp-ecmax, Tp-ecmin, QTcd, Tp-ecd, and QTc / Tp-ec ratios were calculated with Bazett formula.

The postnatal diagnosis of Long QT Syndrome (LQTS) is suggested by a prolonged QT interval on 12 lead electrocardiogram (ECG), strengthened by a positive family history and/or characteristic arrhythmias and confirmed by genetic testing. However, for several reasons such LQTS testing cannot be performed successfully before birth. First, fetal ECG is not possible and direct measure of the fetal QT interval by magnetocardiography is limited to fewer than 10 sites world-wide. Second, while genetic testing can be performed in utero, there is risk to the pregnancy and the fetus. Third, although some fetuses present with arrhythmias easily recognized as LQTS (torsade des pointes (TdP) and/or 2° atrioventricular (AV) block, this is uncommon, occurring in <25% of fetal LQTS cases. Rather, the most common presentation of fetal LQTS is sinus bradycardia, a subtle rhythm disturbance that often is unappreciated to be abnormal. Consequently, the majority of LQTS cases are unsuspected and undiagnosed during fetal life, with dire consequences. For example, maternal medications commonly used during pregnancy can prolong the fetal QT interval and may provoke lethal fetal ventricular arrhythmias. But the most significant consequence is the missed opportunity for primary prevention of life threatening ventricular arrhythmias after birth because the infant is not suspected to have LQTS before birth. The over-arching goal of the study is to overcome the barriers to prenatal detection of LQTS. The investigators plan to do so by developing an algorithm using fetal heart rate (FHR) which will discriminate fetuses with or without LQTS. Immediate Goal: The investigators propose a multicenter pre-birth observational cohort study to develop a Fetal Heart Rate (FHR)/Gestational Age (GA) algorithm from a cohort of fetuses recruited from 13 national and international centers where one parent is known by prior genetic testing to have a mutation in one of the common LQTS genes: potassium voltage-gated channel subfamily Q member 1 (KCNQ1), potassium voltage-gated channel subfamily H member 2 (KCNH2), or sodium voltage-gated channel alpha subunit 5 (SCN5A). The investigators have chosen this population because 1) These mutations are the most common genetic causes of LQTS, and 2) Offspring will have high risk of LQTS as inheritance of these LQTS gene mutations is autosomal dominant. Thus, progeny of parents with a known mutation are at high (50%) risk of having the same parental LQTS mutation. The algorithm will be developed using FHR measured serially throughout pregnancy. All offspring will undergo postnatal genetic testing for the parental mutation as the gold standard for diagnosing the presence or absence of LQTS.

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: To validate the capacity of QTScreen for LQTS screening in newborns. To determine the extent to which parents are able to use QTScreen on their babies at home. To survey end-user experience and opinions. To estimate the LQTS prevalence in California.

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: Low risk patients that do not require protective beta-blocker therapy 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.

To investigate the clinical, genetic and cardiologic aspects of the Long QT Syndrome, a predominantly hereditary disease with episodic malignant arrhythmias and sudden death, and a demonstrated gene linkage in a large pedigree.

To conduct a cross-sectional epidemiologic study of the determinants of prolonged heart rate corrected QT interval (QTc) among 300 men and 300 woman in the population with the highest known risk of SUDS: Southeast Asian refugees in Thailand. .

The Long QT syndrome is associated with potentially life-threatening cardiac arrhythmias as ventricular tachycardia (Torsade de pointes) as well as ventricular fibrillation, and might lead to syncope as well as sudden cardiac death (1). Good results have been achieved by treating patient at risk with beta blockers and implantable cardiac defibrillator (ICD). It is therefore important to diagnose the condition as early as possible as the disease is treatable (2). Prolonged QT duration might also be induced by the intake of numerous pharmaceutical substances, as well as with electrolyte disturbances, which also increases the risk of life-threatening cardiac arrhythmias. Furthermore, congenital LQTS can arise from mutations in one of at least 13 different genes. Many of these genes encode proteins which are constituents of ion channels. The genetically defined long QT syndrome has autosomal dominant (Romano Ward Syndrome) or autosomal recessive (Jervell and Lange-Nielsen Syndrome) inheritance. In this study we are using the hospital ECG database obtained with the GE Marquette 12SL ECG Analysis Program® at Telemark Hospital Skien recorded between March 2004 and April 2014. This database stores approximately 200 000 ECG recordings from 60 000 unique patients. By using the search algorithm in the MUSE ECG database, 2398 recordings have been be identified from 1603 patients where the corrected QT time is longer than 500 ms, and QRS is less than 120 ms. ECG recordings with QT intervals longer than 500 ms represents less than 1% of the population (5). Individuals having these recordings are selected for extensive clinical follow up. The patients will be offered the opportunity to have genetic analysis performed in order to distinguish between inherited or acquired long QT syndrome. The appropriate treatment will be initiated according to guidelines for patients with inherited QT syndrome. For patients with aquired long QT syndrome substitution of unfavourable pharmacotherapy or correction of electrolytes shall be performed in order to reduce their risk of cardiac arrhythmias. A T wave morphology score gives independent prognostic information useful for risk stratification. The purpose of this substudy is to examine if the T wave morphology score applied on the 1531 patients ECGs with QTc >500 ms, has independent prognostic value in this cohort.