Left Atrial Appendage Isolation in Persistent AF Patients
Does empirical electrical isolation of the left atrial appendage (LAA) improve freedom from atrial arrhythmia in patients with longstanding persistent atrial fibrillation (AF) undergoing extensive catheter ablation?
Patients in the BELIEF (Effect of Empirical Left Atrial Appendage Isolation on Long-term Procedure Outcome in Patients With Persistent or Longstanding Persistent Atrial Fibrillation Undergoing Catheter Ablation) study were randomly assigned to undergo empirical LAA isolation, along with extensive ablation (group 1; n = 85) or extensive ablation alone (group 2; n = 88). Recurrence of atrial arrhythmias was the primary endpoint. Secondary endpoints included cardiac-related hospitalization, all-cause mortality, and stroke at follow-up.
At 12-month follow-up, 48 (56%) patients in group 1 and 25 (28%) in group 2 were recurrence-free after a single procedure (unadjusted hazard ratio [HR] for recurrence with standard ablation, 1.92; 95% confidence interval [CI], 1.3-2.9; log-rank p = 0.001). After adjusting for age, sex, and LA size, standard ablation was predictive of recurrence (HR, 2.22; 95% CI, 1.29-3.81; p = 0.004). During redo procedures, LAA isolation was performed in all patients. After an average of 1.3 procedures, cumulative success at 24-month follow-up was 65 (76%) in group 1 and 49 (56%) in group 2 (unadjusted HR, 2.24; 95% CI, 1.3-3.8; log-rank p = 0.003).
In patients with longstanding persistent AF, empirical electrical isolation of the LAA improved long-term freedom from atrial arrhythmias without increasing complications.
Pulmonary vein (PV) isolation has repeatedly been shown to be effective in most patients with paroxysmal AF and many patients with persistent AF, and it has become the cornerstone of the AF ablation procedure. Beyond that, the field is replete with seemingly contradictory reports on just how much ablation is necessary and reasonable. The STAR AF II trial (N Engl J Med 2015;372:1812-22) suggested that there was no benefit to ablation beyond PV isolation in patients with persistent AF. In the present study, BELIEF, all patients underwent extensive AF ablation (extended PV antrum ablation plus non-PV trigger ablation), and were randomized to either undergo empiric LAA isolation or not. The BELIEF trial suggests that AF ablation efficacy is improved with the additional ablation. If LAA isolation is indeed achieved, the LAA is rendered noncontractile, and the CHA2DS2-VASc score-derived stroke risk assessment is no longer applicable. Prior reports suggested high prevalence of thrombi in the isolated LAA. Safety and efficacy of AF LAA ablation should therefore be re-examined in future randomized trials.
Keywords: Arrhythmias, Cardiac, Atrial Appendage, Atrial Fibrillation, Catheter Ablation, Heart Conduction System, Primary Prevention, Risk Assessment, Stroke
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