Prior Failed Catheter Ablation
Posterior wall isolation is part of the complex strategy of managing advanced AF, in addition to PVI, however it is often difficult to achieve safely with only endocardial catheter ablation. This is due to the thickness of the roof of the posterior wall of the left atrium and because of the need for long connection lines between the roof and the floor of the atrium, to create the conduction block without a gap. The lower linear lesion line at the floor of the posterior wall is more difficult to create due to the proximity of the esophagus and risk of esophageal damage.48 In a study of patients undergoing left atrial posterior wall isolation concomitant with pulmonary vein reisolation, feasibility of isolating the LAPW with endocardial ablation was successfully demonstrated, despite no outcome differences in improvement of freedom from atrial arrhythymias compared to pulmonary vein reisolation alone. Of the 196 AF patients in the study, 103 were in the LAPW plus PV reisolation group and 36 patients (35%) required additional ablation within the center “box” of the LAPW.49This brings increased risk to endocardial catheter ablation but has potential to be easier and safer utilizing a Hybrid ablation approach such as those with advanced AF presenting for repeat ablation treatment. In patients with advanced AF and a need to isolate the posterior wall, a hybrid ablation approach may have the advantage of better access to completely and safely isolate it primarily through epicardial ablation applying energy towards the heart followed by endocardial touchup to address any gaps particularly near the pericardial reflections. This provides a more comprehensive treatment to prevent recurrence resulting from multiple triggers, including the pulmonary vein, left posterior wall, and endocardial tissue.
While the CONVERGE trial excluded patients with prior ablations, in routine clinical practice many patients with advanced AF have undergone prior catheter ablation attempts yet are still experiencing AF recurrences. A recent meta-analysis of Hybrid Convergent ablation studies included three studies in which one-third of the total patients had prior catheter ablation. Mannakkarra et al. recently reported their single-center experience with Hybrid Convergent ablation, including 38% of patients who had received prior catheter ablation at baseline.20 However, to date, only one study has directly compared outcomes of patients who received Hybrid Convergent as a de novo versus previous catheter ablation, finding there was no difference in arrhythmia recurrence.22Additionally, there may be a cumulative benefit in that those with prior ablations require less endocardial PV isolation and were more likely to convert to sinus rhythm during the Hybrid procedure compared to those with no prior ablation history.22 Kress et al. reported 75.0% of patients with prior ablation needed endocardial PV isolation, which was significantly less than 97.9% of patients who received hybrid ablation as a first ablation procedure (p<0.001). Additionally, fewer patients who had prior ablation needed cardioversions (26.7%) to achieve sinus rhythm intraprocedurally compared to those receiving hybrid ablation as a first ablation procedure (45.8%, p=0.038). With few comparative studies or studies exclusively looking at hybrid convergent ablation after previous catheter ablation patients, more research as well as additional cumulative real-world evidence is necessary to determine whether there are any significant differences in procedural and treatment outcomes.19