Preventive VT Substrate Ablation in Ischemic Heart Disease

Study Overview
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Brief Summary
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The investigators hypothesize that preventive VT substrate ablation in patients with chronic ICM, previously selected based on imaging criteria (BZC mass) for their likely high arrhythmic risk, is safe and effective in preventing clinical VT events.

Detailed Description
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Fibrotic tissue is known to be the substrate for the appearance of scar-related reentrant ventricular arrhythmias (VA) in chronic ischemic cardiomyopathy (ICM). Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) has proven to be a useful technique in the non-invasive characterization of the scarred tissue and the underlying arrhythmogenic substrate. Previous studies identified the presence of significant scarring (>5% of the LV mass) is an independent predictor of adverse outcome (all-cause mortality or appropriate ICD discharge for ventricular tachycardia or fibrillation) in patients being considered for implantable cardioverter-defibrillator (ICD) placement. Parallelly, the presence of heterogeneous tissue channels, which correlate with voltage channels after endocardial voltage mapping of the scar, can be more frequently observed in patients suffering from SMVT than in matched controls for age, sex, infarct location, and LVEF. However, the lack of solid evidence and randomized trials make LVEF still the main decision parameter when assessing suitability for ICD implantation in primary prevention of SCD. (7,8) In a recent, case-control study, the investigators identified the BZC mass as the only independent predictor for VT occurrence, after matching for age, sex, LVEF and total scar mass. This BZC mass can be automatically calculated using a commercially available, post-processing imaging platform named ADAS 3D LV (ADAS3D Medical SL, Barcelona, Spain), with FDA 510(k) Clearance and CE Mark approval. Thus, CMR-derived BZC mass might be used as an automatically reproducible criterium to reclassify those patients with chronic ICM at highest risk for developing VA/SCD in a relatively short period of time (approx. 2 years). On the other hand, catheter ablation has become an essential tool in the treatment of ventricular arrhythmias in patients with structural heart disease (SHD). VT ablation techniques have evolved towards substrate-based approaches that permit to abolish multiple VT circuits irrespective of their inducibility or hemodynamic tolerability, improving outcomes with respect to clinical VT ablation. Moreover, VT substrate ablation procedures performed during sinus rhythm and CMR-guided have proven to be safe, with very low procedure related complications. The investigators hypothesize that preventive VT substrate ablation in patients with chronic ICM, previously selected based on imaging criteria (BZC mass) for their likely high arrhythmic risk, is safe and effective in preventing clinical VT events.

Official Title
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Preventive VT Substrate Ablation in Patients With Chronic Post-MI Scar Showing Arrhythmogenic Characteristics

Conditions
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Ventricular Tachycardia, Ventricular Arrythmia, Sudden Cardiac Death, Sudden Cardiac Death Due to Cardiac Arrhythmia, Ischemic Heart Disease, Myocardial Infarction, Magnetic Resonance Imaging

Intervention / Treatment
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* Procedure: Ventricular tachycardia substrate-based radiofrequency ablation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age > 18 years. Chronic, stable ischemic heart disease, irrespectively of the LVEF. Life expectancy of > 1 year with a good functional status. Documented scar AND a BZC mass > 5.15 g as measured per LGE-CMR and automatic post-processing using the ADAS-3D LV (ADAS 3D Medical SL, Barcelona, Spain). Signed informed consent. Exclusion Criteria: Age < 18 years. Pregnancy. Life expectancy of < 1 year, or bad functional status (NYHA IV functional class). Other concomitant structural heart diseases (e.g. congenital, non-ischemic, etc.) Previously documented sustained ventricular arrhythmias. Impossibility to perform a contrast-enhanced CMR study. Calculated BZC mass in the scarred tissue < 5.15 g using the ADAS-3D LV software. Concomitant investigation treatments. Medical, geographical and social factors that make study participation impractical, and inability to give written informed consent. Patient's refusal to participate in the study.

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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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ABLATE arm<br>Ventricular tachycardia substrate ablation intending to: i) eliminate all the potential arrhythmogenic substrate, aiming for complete electrical isolation/elimination of all the electrograms with delayed components or showing hidden slow conduction properties, and ii) non-inducibility or ventricular tachycardias at the end of the procedure. Standard medical treatment will also be given for these patients. | Procedure: Ventricular tachycardia substrate-based radiofrequency ablation<br>* The CARTO3 electroanatomic navigation system (Biosense Webster, Diamond Bar, CA, USA) will be used for ablation. An open irrigated 3.5-mm tip ablation catheter (ThermoCool SmartTouch, Biosense Webster, Diamond Bar, CA, USA) will be used for mapping and ablation. The first step of the procedure will be the acquisition of a fast-anatomical map (FAM) of the aorta. This FAM will be then used to integrate the multi-detector cardiac tomography (MDCT) reconstruction and cardiac magnetic resonance (CMR)-derived pixel-signal intensity (PSI) maps within the spatial reference coordinates of the CARTO3 system. RF will be delivered at the entrance of the border zone channels (BZCs) identified in the PSI maps (CMR-guided scar dechanneling technique). Programmed ventricular stimulation (PVS) will be always performed after substrate elimination to test for final inducibility.<br>|
| No Intervention: NO-TREAT arm<br>Only standard medical treatment will be offered for these patients. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of sudden cardiac death or sustained ventricular tachycardia | Composite outcome of sudden cardiac death or sustained ventricular tachycardia (either treated by an ICD or documented with continuous Holter monitoring) in patients undergoing preventive ventricular tachycardia (VT) substrate ablation vs. standard of care. | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Procedure time | Procedure time | 2 years | 
| Radiofrequency time | Radiofrequency time | 2 years | 
| Rate of achievement of complete substrate ablation | Rate of achievement of complete substrate ablation | 2 years | 
| VT inducibility rate | Final VT inducibility rate | 2 years | 
| Rate of complications | Rate of complications | 2 years | 
| Rate of need for anti-arrhythmic drugs | Rate of need for anti-arrhythmic drugs in both arms of the study | 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ventricular tachycardia, ventricular arrhythmia, sudden cardiac death, ischemic heart disease, cardiac magnetic resonance, border zone channels