Electromechanical Profiling of the Long-QT Syndrome (LQTS)

Study Overview
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Brief Summary
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High-resolution, non-invasive electromechanical mapping in genotyped long-QT syndrome patients and healthy controls at baseline and during smart provocation.

Detailed Description
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Using simultaneous ECG-imaging, speckle-tracking analysis and tissue-phase mapping with MRI we will assess electromechanical dispersion at rest. Regional electromechanical elasticity will be investigated during adenosine and epinephrine, isoprenaline infusions and is postulated to increase sudden cardiac death risk prediction in the individual patient.

Official Title
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Electromechanical Profiling of Arrhythmogenic Substrates and Triggers in the Long-QT Syndrome

Conditions
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Long QT Syndrome, Sudden Cardiac Death, Ventricular Tachycardia

Intervention / Treatment
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* Diagnostic Test: Adenosine and epinephrine, isoprenaline provocation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: LQTS group (Group 1): Diagnosis of LQTS according to the ESC guidelines. Genetic testing either already performed or consent to genetic testing (at least 5 major LQTS-related genes tested: KCNQ1, KCNH2, SCN5A, KCNE1, KCNE2). Control group (Group 2): > Control subjects with structurally normal hearts. Exclusion Criteria: Pregnancy, nursing or planning to become pregnant. Known allergy or strong reaction to skin electrodes or contrast agent. Inability to give informed consent. Presence of metal objects in or attached to the body. Dialysis. Cardiomyopathy. Second-degree heart block or higher degrees of block. Sick sinus syndrome. Asthma. Chronic obstructive pulmonary disease. Left-main coronary artery disease. Unstable coronary artery disease.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Symptomatic LQTS patients<br>Pharmacological (adenosine, epinephrine, isoprenaline) provocation, ECG-imaging and tissue-phase mapping using magnetic resonance imaging (TPM-MRI). | Diagnostic Test: Adenosine and epinephrine, isoprenaline provocation<br>* High-resolution electromechanical mapping at baseline and after provocative measures.<br>* Other names: Tissue-phase mapping with MRI.;|
| Asymptomatic LQTS patients<br>Pharmacological (adenosine, epinephrine, isoprenaline) provocation, ECG-imaging and tissue-phase mapping using magnetic resonance imaging (TPM-MRI). | Diagnostic Test: Adenosine and epinephrine, isoprenaline provocation<br>* High-resolution electromechanical mapping at baseline and after provocative measures.<br>* Other names: Tissue-phase mapping with MRI.;|
| Healthy controls<br>Pharmacological (adenosine, epinephrine, isoprenaline) provocation, ECG-imaging and tissue-phase mapping using magnetic resonance imaging (TPM-MRI). | Diagnostic Test: Adenosine and epinephrine, isoprenaline provocation<br>* High-resolution electromechanical mapping at baseline and after provocative measures.<br>* Other names: Tissue-phase mapping with MRI.;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Differences in regional electromechanical dispersion between LQTS patients and controls | Electromechanical dispersion in milliseconds | At day of investigation | 
| Differences in regional electromechanical dispersion between symptomatic and asymptomatic LQTS patients | Electromechanical dispersion in milliseconds | At day of investigation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation of electromechanical dispersion between LQTS type 1, 2, and 3. | Electromechanical dispersion in milliseconds | At day of investigation | 
| Relation between global electromechanical window vs regional electromechanical dispersion in LQTS | Electromechanical dispersion in milliseconds | At day of investigation | 
| Correlation between mechanical dispersion using TPM-MRI and cine-MRI | Time-to-diastolic peak in milliseconds | At day of investigation | 
| Correlation between mechanical dispersion using TPM-MRI and speckle-tracking echocardiography | Time-to-peak in milliseconds | At day of investigation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Electromechanical Mapping, Risk Stratification