Long QT Syndrome

ELDORA is a non-interventional observational data-science study aiming to develop and validate clinical-grade artificial intelligence tools applied to electrocardiogram (ECG) data. The project will standardize heterogeneous ECGs, create the ECGInsight harmonized database, and train interpretable models for life-threatening arrhythmia risk prediction, especially Torsades-de-Pointes/long QT syndrome and immune checkpoint inhibitor (ICI)-induced myocarditis. The project uses existing and ongoing national and international ECG cohorts with de-identified clinical metadata; AI outputs are intended for research/model development and are not used to drive patient care during the study.

The main research question of this study is whether wearable devices have utility in monitoring patients with Long QT syndrome.

The goal of this observational study is to develop a registry of Brazilian patients with hereditary cardiovascular diseases, combining clinical and genomic data. The main questions it aims to answer are: Which genes are most commonly affected? What is the frequency of these genetic alterations in our population? Participants will be interviewed in routine medical care visits and their DNA will be sequenced.

An important aspect of successful genomic medicine implementation is developing effective approaches for screening at-risk family members after probands are identified, also known as cascade screening. Most cascade screening studies conducted to date have been conducted outside the US, and very few studies have used a rigorous approach involving a comparator group or randomized controlled design. A major question in the field is how to most effectively implement cascade screening, given commonly cited communication barriers, while respecting privacy among probands and family members. This study will conduct a randomized controlled trial to assess direct contact of relatives by study team members vs indirect, or proband-initiated, contact. We will assess efficacy of the cascade screening intervention, patient-centered outcomes regarding mental, physical, and psychosocial outcomes in probands and family members, and implementation evaluation outcomes. Individuals who are known to carry the KCNQ1 Met224Thr or APOB Arg3527Gln variant will be eligible to participate. After providing consent and being deemed eligible, individuals will be randomized in a 1:1 manner into the direct or indirect contact of family members arm of the study. The randomization will be stratified by variant to ensure equal representation of each variant in the study arms. Individuals in the indirect arm will be instructed to contact their first-degree family members about the opportunity to be screened. They will be provided with a disease-specific pamphlet and a family letter explaining the cascade screening. In the direct arm, probands will be advised that the study staff will be contacting their family members. They will be instructed to also contact their family members prior to the study team contacting them. Approximately two weeks after this meeting with the proband, the study staff will mail letters to eligible first-degree family members of the probands. If we do not hear back from individual family members, we will follow-up with another letter, telephone call, or home visit. The information contained in the letters will be the same information for both the direct and indirect arms of the study. All interested family members will receive pre-test counseling and free, in-home, saliva-based genetic testing, and post-test counseling.

Each year world-wide, 2.5 million fetuses die unexpectedly in the last half of pregnancy, 25,000 in the United States, making fetal demise ten-times more common than Sudden Infant Death Syndrome. This study will apply a novel type of non-invasive monitoring, called fetal magnetocardiography (fMCG) used thus far to successfully evaluate fetal arrhythmias, in order to discover potential hidden electrophysiologic abnormalities that could lead to fetal demise in five high-risk pregnancy conditions associated with fetal demise.

The purpose of this study is to validate the continuous patch monitoring system to evaluate cardiac arrhythmias in patients receiving drugs that can cause cardiac complications and compare the continuous patch system with standard electrocardiograms (ECGs).

The goal of this observational study is to evaluate exercise testing and daily physical activity in children and adolescents who are diagnosed with an inherited arrhythmia. The main question it aims to answer is: Does maximum heart rate during controlled exercise tolerance testing accurately reflect maximum heart rate and peak exercise levels during free living daily physical activity in children and adolescents diagnosed with an inherited arrhythmia? Participants will: * Complete routine exercise tolerance testing * Record daily physical activity and exercise over two weeks, while wearing an activity and heart rate monitor and digit diary. * Complete a physical activity questionnaire at the end of two weeks.

Cardiac channelopathies induce severe heart rhythm or conduction disorders. Mutations of the KCNH2 gene, that encodes the human (h) ERG channel, is responsible for 30-40% of all cases of long QT syndrome (inherited LQT2). Besides, hERG is frequently responsible for off-target effects of several pharmacological agents (acquired LQT2). With the advent of Next Generation Sequencing, hundreds of new KCNH2 variants are accumulating in regional databases including those developed by french centers of references. Worldwide, we estimate there are more than 1000 variants for hERG channel. Unfortunately, many of these new variants appear to be of unknown functional significance in spite of available clinical and genetic information. Little is known on whether they affect the channel biophysical properties, its expression at the cell surface and/or its structure. Yet, this information is crucial to determine the real degree of pathogenicity of these variants, and therefore to make the proper diagnosis on inherited LQT2, counsel the patient for his treatment and improve the management of the patient's life. Our ambition is therefore to tackle this issue of variant significance by (i) launching a large-scale multi-functional evaluation of hERG variants, (ii) introducing for the first time a formatted large-scale pathogenicity annotation score for all variants that have been functionally evaluated by this multi-parametric approach, and (iii) regrouping all the relevant information collected in every French Regional centers of reference into a single National database hosted by an infrastructure that possesses enough flexibility for continuous data implementation and cross-referencing. The database will integrate the latest International guidelines for functional pathogenicity annotation. This project will also include the pharmacological characterization of several drugs susceptible to produce acquired LQT2 with variable severities. We aim to understand whether there are structural regions within hERG channel in which the introduction of a variant is more prone to increase the risk of acquired LQT2 or if, on the contrary, a set of variants may relatively protect some patients against LQT2-inducing drugs.

The "Long-term Outcome and Predictors for Recurrence after Medical and Interventional Treatment of Arrhythmias at the University Heart Center Hamburg" (TRUST) study is an investor-initiated, single-center, prospective clinical cohort study including patients treated with cardiac arrhythmias or at high risk for cardiac arrhythmias. The design enables prospective, low-threshold, near complete inclusion of patients with arrhythmias treated at the UHZ. Collection of routine follow-up data, detailed procedural information and systematic biobanking will enable precise and robust phenotyping.