AF Substrate Mapping and Guided Ablation

In this study, the investigators aim to identify and characterize, by means of an EnSite Velocity Research Software, the electrophysiological characteristics of substrates that sustain AF in patients with persistent AF and to test whether ablation of such patient-specific substrates might improve the acute and long-term success of conventional catheter ablation therapy.

This study is a prospective, single center, randomized, single-blind, controlled, 2-arm parallel group trial in Milan, Italy. The total duration of the study is expected to be 24 months with ~12 months of enrollment. Approximately 80 subjects suffering from persistent AF will be randomized in a 1:1 fashion to the following investigation arms: Modified circumferential pulmonary vein ablation alone (mCPVA); Substrate-targeted ablation guided by AF substrate mapping, followed by completion of modified circumferential pulmonary vein ablation (Substrate+ mCPVA) Ablate the areas that have fast and regular electrical activities, starting from the fastest cycle length (defined by Mean CL in the range of 120-250 milliseconds, and SD CL in the range of 1-30 milliseconds Ablate the areas that have consistent rotational or focal propagation pattern (defined by conduction velocity vectors) Ablate the areas that comprises the slow conduction zone of possible arrhythmia circuits If AF terminates during RF ablation, stimulation protocol will be used to examine if AF is re-inducible. If AF sustains or is re-inducible and physician decides to remap, mapping will be performed again for substrate-targeted ablation. If AF is not re-inducible, mCPVA will be completed Subjects will be followed up at 3, 6, 12 months. The primary objective of the study is to assess acute and long-term outcome of patient-tailored substrate-targeted ablation (Substrate) plus modified circumferential pulmonary vein ablation (Substrate+mCPVA) versus modified circumferential pulmonary vein ablation alone (mCPVA). The secondary objective of the study is to map and characterize electrophysiological substrates during AF, including regular and fast activities, complex fractionated electrograms, wave front propagation directions, and fibrosis.

Subjects in the mCPVA arm will undergo intervention called "modified circumferential pulmonary vein ablation", which is considered to be the standard ablation treatment for AF.

Subjects in the Substrate+mCPVA arm will undergo intervention of substrate mapping and substrate-targeted ablation guided by the investigational device, followed by completion of modified circumferential pulmonary vein ablation.

The intervention in the experimental arm includes using a research software (investigational device) to map AF substrate and guide ablation.

The intervention in the active comparator arm includes using the commercially available EnSite Velocity mapping and ablation system for modified circumferential pulmonary vein ablation.

Freedom from symptomatic AF off antiarrhythmic drug therapy assessed from the end of the 3 months blanking period to 12 months following the ablation procedure, documented by implantable loop recorder (ILR) monitoring or trans-telephonic (TT) ECG monitoring.

Acute AF termination or significant AF cycle length slowing during RF application in ablation procedure

Inclusion Criteria: 18 - 85 years of age Persistent AF scheduled to undergo catheter ablation with approved standard indication by ESC/EHRA guidelines First or second time ablation for persistent AF Ability to provide written informed consent for study participation and be willing and able to comply with the study evaluations and follow up schedule Exclusion Criteria: Had two or more previous AF ablation procedures Secondary AF Hyperthyroidism Left ventricular ejection fraction <30% NYHA functional class IV Left atrial area > 35 cm2 Uncorrected severe valvular heart disease Contraindication to anticoagulation Presence of left atrial thrombus Recent (<6 Months) myocardial Infarction or unstable angina or coronary artery by-pass Thoracic surgery for congenital, valvular or aortic disease History of cerebrovascular accidents Pregnancy Significant comorbidities such as cancer, severe renal insufficiency requiring hemodialysis, severe obstructive lung disease, cirrhosis, with a life expectancy less than 2 years

Pappone C, Ciconte G, Vicedomini G, Mangual JO, Li W, Conti M, Giannelli L, Lipartiti F, McSpadden L, Ryu K, Guazzi M, Menicanti L, Santinelli V. Clinical Outcome of Electrophysiologically Guided Ablation for Nonparoxysmal Atrial Fibrillation Using a Novel Real-Time 3-Dimensional Mapping Technique: Results From a Prospective Randomized Trial. Circ Arrhythm Electrophysiol. 2018 Mar;11(3):e005904. doi: 10.1161/CIRCEP.117.005904.