Empirical Anatomy-Based Ablation vs Emphasize Map-Guided Substrate Ablation in Persistent Atrial Fibrillation : (COMPASS-AF)

Pulsed-field ablation (PFA) is increasingly being adopted in clinical practice due to its advantages in shortening procedure times and reducing the incidence of complications. While the majority of PFA-related research has focused on PVI-centric strategies, recent studies have reported that posterior wall isolation (PWI) using PFA can also be performed safely. However, sufficient clinical evidence regarding the efficacy of additional ablation strategies beyond PVI in patients with persistent atrial fibrillation (AF) has yet to be established.

The Emphasize mapping system, a software feature within the EnSite X platform, is designed to simultaneously visualize Voltage maps, Peak frequency, and CFAE-related information. Unlike the individual analysis of each parameter, this integrated approach allows for a more precise identification of electrophysiologically significant pathologic substrates by evaluating the complex characteristics of electrical signals holistically. Currently, however, Emphasize-guided ablation is technically limited to the use of radiofrequency (RF) energy.

Persistent AF is characterized by complex and heterogeneous mechanisms, meaning a single, uniform ablation strategy may not yield consistent clinical outcomes across all patients. Consequently, it is hypothesized that an individualized substrate ablation strategy guided by functional mapping may be more effective than a conventional, empirical anatomy-based approach.

Therefore, this study aims to compare the clinical efficacy and safety of an empirical anatomy-based ablation strategy using PFA versus an individualized Emphasize map-guided substrate ablation strategy in patients with persistent AF.

• Anatomy-based ablation (Procedure): In the empirical anatomy-based ablation strategy group, pulmonary vein isolation (PVI) will be performed using pulsed-field ablation (PFA) with a single-shot multielectrode catheter. For each pulmonary vein, approximately 4-10 pulse applications will be delivered depending on the catheter position, with each application consisting of several seconds of pulse delivery. The catheter will be positioned around the PV ostia, and electrical isolation will be achieved by utilizing various catheter configurations as necessary. The energy settings and application methods for PFA in this study will follow the manufacturer's recommended protocols and established methods from prior clinical studies. Additionally, the creation of supplementary lesion sets is permitted at the operator's discretion.
• Emphasize map-guided ablation (Procedure): In the Emphasize map-guided substrate ablation group, ablation will be performed using a contact force-sensing irrigated radiofrequency (RF) catheter. Following pulmonary vein isolation (PVI), an Emphasize map will be acquired during atrial fibrillation (AF) using the EnSite X mapping system. Based on this map, electrophysiologically significant pathologic substrates will be evaluated, and additional substrate ablation will be performed. Subsequently, electrical cardioversion will be conducted to restore sinus rhythm. If sinus rhythm is not maintained or if AF is re-induced, an additional Emphasize map may be acquired in the right atrium (RA), and RA substrate ablation can be performed if necessary.

Primary outcomes

• Recurrence of atrial tachyarrhythmia [From 3 months to 12 months after the index procedure]: Any documented atrial tachyarrhythmias excluding the initial 3-month blanking period. Documented atrial tachyarrhythmias (atrial fibrillation, atrial flutter, atrial tachycardia) were defined as follows: * Atrial tachyarrhythmias documented in 12 lead ECG * Atrial tachyarrhythmias of more than 30 seconds in Holter monitoring Recorded as a binary outcome (presence or absence of recurrence)

Secondary outcomes

• Atrial fibrillation burden [From 3 months to 12 months after the index procedure]: The proportion of time spent in atrial fibrillation or atrial flutter during rhythm monitoring .The burden will be assessed as percent(%) using Holter monitoring.
• Repeat ablation [From index procedure to 12 months]: Any additional catheter ablation procedure performed after the index procedure for documented recurrent atrial tachyarrhythmia during the follow-up period.
• Use of antiarrhythmic drug therapy [From 3 months to 12 months after the index procedure]: Percentage of patients prescribed any Class I or Class III antiarrhythmic Temporary use during the blanking period (first 3 months) will not be counted.
• Atrial Fibrillation Effect on Quality-of-life (AFEQT) questionnaire score [From index procedure to 12 months]: The AFEQT is outcome instrument designed to measure the impact of AF on a patient's health-related quality of life. Scores range from 0 to 100, with higher scores indicating a better health-related quality of life
• Stroke [From index procedure to 12 months]: Proportion of participants experiencing a new focal or global neurological deficit lasting ≥24 hours with imaging evidence of ischemic or hemorrhagic stroke. Transient ischemic attack will not be included.
• Cardiovascular hospitalization [From index procedure to 12 months]: Proportion of participants experiencing hospitalization primarily due to a cardiovascular cause, including: * Atrial tachyarrhythmia recurrence * Heart failure exacerbation * Acute coronary syndrome * Cardiovascular procedural complications
• Bleeding event [From index procedure to 12 months]: Proportion of participants experiencing bleeding events. Bleeding event will be classified according to the International Society on Thrombosis and Haemostasis(ISTH) criteria: * Major bleeding * Clinically relevant non-major bleeding
• All-cause mortality [From index procedure to 12 months]: Death due to any cause occurring during the follow-up period.
• Procedure-related complications [From index procedure to 30days]: Proportion of participants experiencing any complication occurring during or within 30 days after the index procedure, including: * Cardiac tamponade * Vascular access complication * Pulmonary vein stenosis * Esophageal injury * Phrenic nerve injury * Major bleeding.
• Procedure time [at the index procedure]: Total procedure time measured in minutes from vascular access puncture to removal of all catheters at the end of the procedure.
• Radiation time [at the index procedure]: Total fluoroscopy exposure time measured in minutes.
• Left atrial reservoir strain [From index procedure to 12 months]: Measured as percentage by echocardiography

Sex: All, ages: 19 Years to any

Inclusion Criteria:

* Adults aged 19 years or older who have voluntarily provided written informed consent to participate in the study
* Patients diagnosed with persistent atrial fibrillation (AF) who are scheduled to undergo catheter ablation for AF.

Exclusion Criteria:

* History of prior catheter ablation or MAZE surgery for atrial fibrillation.
* Left atrial (LA) diameter exceeding 60 mm.
* Patients with end-stage renal disease (ESRD).
* History of prior open-heart surgery.
* Women who are pregnant, lactating, or of childbearing potential.
* Heart failure corresponding to New York Heart Association (NYHA) functional class IV.
* Acute coronary syndrome (ACS) experienced within the past 3 months.
* Patients with terminal illness and a life expectancy of less than one year.
* Any other condition that the investigator deems inappropriate for participation in the study.

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