Recurrent focal electrical activation (or ectopy) superseding sinus activation is the only mechanism proven to drive paroxysmal atrial fibrillation (AF). However, it has not been possible to show similar focal drivers during AF, owing to the limitations of mapping in persistent AF. RETRO-Mapping has been developed as a method to generate activation maps during AF to test the hypothesis that persistent AF is also maintained by focal drivers.
RETRO-Mapping is able to locate sites of focal activation that were isolated, intermittent, or recurrent during persistent AF. However, a 30-second segment of AF can have approximately 150 wavefronts in a small area of myocardium. Screening for focal activation and manually validating these prior to ablation was not feasible using current commercial systems.
RETRO-Mapping can automatically detect focal activation and a recording system that enables the intracardiac signals to be directly analysed by the RETRO-Mapping software. This will allow RETRO-Mapping to build a detailed classification of focal activation types and study the impact of ablation of these sites on the AF cycle length, to address the hypothesis that persistent AF is maintained by focal drivers.
Persistent atrial fibrillation with clinical indication for catheter ablation
Clinically suitable candidate for catheter ablation
Signed informed consent
Previous atrial fibrillation or other catheter ablation procedure
Clinical contraindication to catheter ablation or general anaesthetic, including history of adverse reaction to contrast media, or presence of intracardiac thrombus, or inadequate anticoagulation in the preceding 6 weeks
Valvular disease graded moderate or greater, or presence of a prosthetic valve
Moderate-to-severe heart failure, defined as left ventricular ejection fraction <35% and/or New York Heart Association class III-IV
Parallel
Pulmonary vein isolation
Procedure/SurgeryStandard clinical radio-frequency ablation isolation of pulmonary veins
RETRO-Mapping without adjunctive ablation
Diagnostic testRETRO-Mapping performed using research equipment and software, but without any adjunctive ablation
Adjunctive ablation guided by RETRO-Mapping
Procedure/SurgeryRadio-frequency ablation using a European conformity (CE)-marked ablation catheter of sites of focal activation identified by RETRO-Mapping
Atrial fibrillation cycle length in coronary sinus and left atrial appendage
Measurement of atrial fibrillation cycle length in coronary sinus and left atrial appendage, measured in miliseconds
Freedom from atrial fibrillation
Follow-up after a 3-month blanking period. Recurrence of atrial arrhythmia at 3, 6, 9, and 12 months with a 24-hour Holter monitor, or at any point over same period with an AliveCor KardiaMobile, will be recorded. Measurements across differing devices will be aggregated to give a single time-to-recurrence measurement, given in days.
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Imperial College London
Lead sponsor
Imperial College Healthcare NHS Trust
Collaborator
