Pulsed Field Ablation for Atrial Fibrillation Using the VARIPULSE™ Catheter

Rationale: Effectiveness of thermal ablation techniques for pulmonary vein isolation, to treat atrial fibrillation (AF), are hampered by frequent pulmonary vein reconnection and risks of collateral tissue injury. Pulsed field ablation (PFA) offers a non-thermal, tissue-specific alternative that may provide more durable isolation while also reducing procedural risks. While early data for the CE-marked VARIPULSE™ PFA system are promising, long-term lesion durability remains mostly unquantified. To obtain a definitive estimate of PFA effectiveness, a systematic invasive re-mapping approach is required. Advanced cardiac magnetic resonance (CMR) imaging can quantify atrial fibrosis after PVI across different ablation modalities, but it is unknown how well these imaging findings correspond with invasive electrical mapping. In the current study, CMR serves as a complementary modality to explore whether imaging-based tissue changes align with invasively confirmed long-term isolation. Objective: The primary objective is to evaluate the long-term durability of pulmonary vein isolation (PVI) using the VARIPULSE™ Pro PFA system, as defined by the rate of electrical reconnection during systematic invasive re-mapping at three months. Study design: Prospective multicenter intervention study. Study population: Patients ≥ 18 years old, eligible for primary PVI according to ESC guidelines, without contraindications for gadolinium-based contrast-enhanced CMR imaging. Intervention: Patients will undergo PVI using PFA with the VARIPULSE™ catheter. After 3-4 months, a re-map procedure will be performed to assess lesion durability and to re-isolate any electrical reconnections. Main study parameters/endpoints: Primary outcome measure: Patient-level PV lesion durability. Secondary outcome measures: Percentage chronic isolation for each PV; Location of reconnection during re-map and lesion characteristics; Presence, location, size, volume and composition of acute (within 72 hours) and chronic (3 months) ablation lesions and collateral tissue damage on CMR (in the atrial wall and surrounding structure); Procedural fluoroscopy time and radiation dose; Percentage direct isolation for each pulmonary vein (PV); Acute PV reconnection for each PV; Percentage freedom from atrial achyarrhythmias at 12 months follow-up; Incidence of procedure related adverse events. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Participation involves standard PVI care with additional CMR imaging and an invasive re-map procedure. Early studies show that PFA with the VARIPULSE™ catheter is safe, and the extra imaging adds only minimal burden or risk. The re-map study carries the same risks as standard ablation. Overall, the study is expected to provide valuable insights that may further improve patient care and outcomes in atrial fibrillation.

Inclusion Criteria: * ≥18 years of age * AF and eligible for index PVI according to current ESC guidelines Exclusion Criteria: * Unwilling or unable to give written informed consent * Prior left atrial ablation * Other left atrial arrhythmias including atrial flutters * Prior left atrial surgery * Severe mitral valve regurgitation * Contraindication for gadolinium-based contrast agents * Contraindications for CMR (including metallic implants, cochlear implants, cardiac devices, neurostimulation systems, claustrophobia) * Renal insufficiency (eGFR \< 30 ml/min)