Electrical isolation of the left atrial appendage increases the risk of ischemic stroke and transient ischemic attack regardless of postisolation flow velocity.

BACKGROUND: Electrical isolation of the left atrial appendage (LAA) is associated with a lower rate of atrial fibrillation (AF) recurrence in patients undergoing radiofrequency catheter ablation. However, LAA isolation can significantly impair LAA contractility.
OBJECTIVE: This study was performed to evaluate whether electrical isolation of the LAA is associated with an increased risk of ischemic stroke or transient ischemic attack (TIA).
METHODS: Consecutive patients with AF undergoing radiofrequency catheter ablation at Korea University Medical Center Anam Hospital were analyzed.
RESULTS: Of 2352 patients, 39 (1.7%) had LAA isolation. Patients with LAA isolation had a significantly higher rate of ischemic stroke or TIA than did those without LAA isolation (log-rank, P < .001; hazard ratio 23.6; P < .001). There were significant differences in the baseline characteristics of the 2 groups, including type of AF (34 [87.2%] and 911 [39.4%] patients with and without LAA isolation had nonparoxysmal AF, respectively). After multivariate adjustment, LAA isolation was found to be a significant risk factor for ischemic stroke or TIA (adjusted hazard ratio 11.3; P < .001). Propensity score-matched analysis also revealed an increased risk of ischemic stroke or TIA in patients with LAA isolation compared with those without LAA isolation (log-rank, P = .001). The LAA flow velocity of post-LAA isolation status was not significantly different between patients who did and did not experience ischemic stroke or TIA (30.3 ± 17.7 cm/s vs 33.9 ± 17.9 cm/s; P = .608).
CONCLUSION: A significantly increased risk of ischemic stroke or TIA was observed in patients with electrical isolation of the LAA. In addition, postisolation LAA flow velocity is not a reliable marker to predict future ischemic events.