Pulsed Field Ablation (PFA) and the Ongoing Need for Hybrid AF Therapy in Long-Standing Persistent Afib
Long-standing persistent atrial fibrillation (LSPAF) represents one of the most challenging forms of Afib to treat and accounts for approximately 45% of the atrial fibrillation (Afib) population. Patients with LSPAF often have complex atrial remodeling and substrate progression that extend beyond the pulmonary veins alone.1,2
Pulsed Field Ablation (PFA) has rapidly emerged as an important advancement in Afib treatment due to its favorable safety profile and effectiveness in achieving pulmonary vein isolation (PVI). However, questions remain regarding the role of adjunctive posterior wall ablation with PFA in patients with LSPAF. Current evidence has not established a clear clinical benefit for routine posterior wall PFA beyond PVI in this patient population.4,5
Why Might PFA Alone Not Be Enough for Some LSPAF Patients?
As Afib progresses, the underlying disease often becomes more complex and may involve both the endocardial (inside) and epicardial (outside) surfaces of the left atrium. Studies have demonstrated that LSPAF can be associated with endocardial-epicardial dissociation, asynchronous electrical activation, and conduction patterns that may not be fully addressed by endocardial ablation alone.6,7,8
Recent investigations utilizing simultaneous endocardial and epicardial mapping have shown that electrical activity may persist on the epicardial surface despite apparently successful endocardial lesion delivery. These findings suggest that durable endocardial lesions alone do not necessarily translate into complete electrical modification of the underlying Afib substrate in all patients.3,6
Clinical Experience: Two Cases Reviewed by Dr. Sood
In the accompanying video, Dr. Sood reviews two real-world cases that highlight the challenges of treating LSPAF.
Case 1: Persistent Epicardial Activity Despite Prior Ablation
Using active epicardial mapping, the patient demonstrated ongoing posterior wall electrical activity despite previous endocardial ablation using both cryo and PFA. The findings suggest that arrhythmogenic substrate may remain present on the epicardial surface even when endocardial treatment appears complete.
Case 2: Durable Endocardial Lesions with Continued Recurrence
Following a repeat PFA procedure, the patient experienced immediate recurrence of atrial arrhythmia despite evidence of durable endocardial lesion formation. Epicardial mapping identified persistent high-voltage activity, leading to treatment with Hybrid AF™ Therapy.
The Role of Hybrid AF Therapy
Hybrid AF Therapy was specifically developed to address the limitations of endocardial-only approaches in LSPAF. By combining minimally invasive epicardial ablation of the posterior left atrial wall with endocardial catheter ablation and pulmonary vein isolation, Hybrid AF Therapy enables physicians to treat both epicardial and endocardial components of the Afib substrate.1,2
Evidence from the CONVERGE randomized controlled trial demonstrated improved effectiveness of Hybrid AF Therapy compared with endocardial catheter ablation alone in patients with persistent and long-standing persistent Afib. In the LSPAF subgroup, Hybrid AF Therapy achieved significantly higher rates of freedom from atrial arrhythmias through 12 and 18 months compared with catheter ablation alone.2,3
Additionally, emerging Hybrid AF Therapy best-practice recommendations continue to identify patients with LSPAF, enlarged atria, or previous catheter ablation failures as populations that may particularly benefit from a combined epicardial-endocardial treatment strategy.9
Conclusion: LSPAF Patients Require More Comprehensive Treatment
PFA has become an important tool for Afib ablation and has demonstrated excellent procedural safety and effectiveness for pulmonary vein isolation. However, for patients with LSPAF, the available evidence does not yet demonstrate a clear incremental benefit of posterior wall PFA beyond PVI alone. Emerging data regarding epicardial-endocardial dissociation and persistent epicardial substrate suggest that some patients may require a more comprehensive treatment strategy. Hybrid AF Therapy remains a proven option designed to address these complexities by treating both the epicardial and endocardial contributors to LSPAF.