SMART Identification of Ventricular Tachycardia Isthmus

Study Overview
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Brief Summary
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Context : Ventricular tachycardia (VT) are serious heart rhythm disorders which can lead to sudden death. A curative treatment for these abnormalities in the cardiac electrical conduction system is possible through an interventional electrophysiology procedure. A catheter is inserted, generally via a femoral access, and is introduced in the heart ventricles in order to collect various 3D electro-anatomical maps. The pace-mapping technique developed in Nancy (de Chillou et al, Heart Rhythm 2014) allows the reentrant circuit underlying the VT to be identified, as well as a definition of the target zones to be ablated, using radiofrequency energy with the catheter. The pace-mapping technique consists of stimulating the ventricle from various sites within its internal surface, in order to generate different activation pathways of the myocardium. When an activation pathway is similar to the VT pathway, this means that the stimulation site is located near the pathologic zone to be ablated. The surface electrocardiogram (ECG) is used to compare activation pathways. A 3D correlation ma is then generated: the zones with high correlation (>90%) indicated the exit of the reentrant circuit, while rapid transition zones (several %/mm) indicate the entrance of the VT circuit. The pace-mapping technique has several limitations: (i) it requires an ECG recording of the clinical VT of the patient (spontaneous or induced at the beginning of the procedure), however it is not always possible to induce it; (ii) sometimes several VT circuits may be present, rendering the procedure of identification and ablation non-exhaustive. The aim of this study is to analyze retrospectively electroanatomical data collected during the intervention, in order to develop a new method for identifying target zones to be ablated, and to compare the results with the conventionally used method. Hypothesis : The investigators hypothesize that alternative methods to analyze electroanatomical data (surface ECG and spatial coordinates of the pacing sites) could provide information equivalent to conventional methods (e.g. VT correlation map, VT activation maps etc…) without the need for a reference recording of the clinical VT of the patient.

Official Title
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SMART Identification of Ventricular Tachycardia Isthmus

Conditions
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Ventricular Tachycardia, Ischemic Cardiomyopathy

Intervention / Treatment
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* Procedure: Ventricular tachycardia ablation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ventricular tachycardia ablation between October 2014 and April 2021 Patient for whom electroanatomical data are available. Ischemic cardiomyopathy / previous myocardial infarction At least 30 points of pace-mapping during the VT procedure Exclusion Criteria: Incomplete data Poor quality ECG recordings Absence of ventricular tachycardia isthmus identified during the procedure

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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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Procedure: Ventricular tachycardia ablation|patients having undergone ventricular tachycardia radiofrequency ablation using of pace mapping strategy to identify the critical isthmus|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between reference-less gradients identified by the SMARTIS software and the ventricular tachycardia isthmus |  | through study completion, an average of 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Electrophysiological features associated with reference-less gradients identified by the SMARTIS software and the ventricular tachycardia isthmus |  | through study completion, an average of 1 year | 
| Ventricular tachycardia free survival according to the presence of unablated reference-less gradients after VT ablation |  | through study completion, an average of 1 year | 
| Correlation between reference-less gradients identified by the SMARTIS software and myocardial scar as assessed by cardiac MRI late gadolinium enhancement |  | through study completion, an average of 1 year |