This non-randomised, prospective trial will examine the feasibility and efficacy of VT ablation guided by activation mapping using the Octaray and Optrell catheters. Annotation algorithms within the CARTO3 electro-anatomical mapping system will be integrated with 3D scar segmentation data from cardiac MRI (ADAS-VT), and extrastimulus voltage mapping will identify sites of interest for focussed activation mapping. The investigators hypothesise that the examination of these data will identify critical target sites for ablation. Intra-procedural diagnostic performance of the Octaray and Optrell catheters will be assessed as the primary outcome, and will be compared with the standard of care. Secondary, clinical outcomes - primarily the need for ICD therapies at 12 months post ablation - will be compared with propensity-matched controls undergoing substrate-based ablation alone. Follow-up MRI scans will review the impact of ablation on the elimination of conduction channels.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
10
A high density diagnostic catheter used for substrate and activation mapping.
VT ablation guided by substrate-mapping alone.
St. Bartholomew's Hospital
London, United Kingdom
Correct identification of VT exit site
The site of VT origin suggested by activation mapping will be confirmed by either: i) Termination with ablation at this site ii) Entrainment of the tachycardia at this site (concealed fusion with PPI-TCL \<30ms and equivalent stimulus-QRS interval to EGM-QRS (30-70% TCL) interval) iii) Pace-mapping (average correlation coefficient \>90%)
Time frame: Intra-procedural
Completeness of diastolic pathway recording
The VT diastolic interval will be divided into temporal segments: i) First third: VT entrance ii) Middle third: VT isthmus iii) Final third: VT exit Completeness of diastolic pathway recording will be assessed according to the number of segments in which electrical activity is recorded
Time frame: Intra-procedural
Requirement for ICD therapies at 1 year
ICD devices will be interrogated at 3 and 12 months post ablation, or according to clinical need, and the requirement for appropriate anti-tachycardia pacing (ATP) or defibrillation recorded
Time frame: 12 months following VT ablation
VT burden
ICD devices will be interrogated at 3 and 12 months post ablation, or according to clinical need, and the number and duration of recorded VT episodes noted
Time frame: 12 months following VT ablation
Symptoms related to arrhythmia
The Arrhythmia-specific questionnaire in Tachycardia and Arrhythmia (ASTA) will be completed both before and 12 months following ablation to assess for quantitative change in arrhythmia-related symptomatology
Time frame: 12 months following VT ablation
Morphological changes on serial cardiac MRIs
Cardiac MRI (CMR) will be performed before and 3 months post ablation. Changes in functional, volumetric and scar-related data will be recorded
Time frame: 3 months following VT ablation
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