Left Atrial Appendage: Extending the Search for New Sources of Atrial Fibrillation Triggers.

Abstract

should be performed first after the PV isolation. Di Biase et al. performed LAA isolation in only patients in whom firing was documented in the LAA usually with administration of isoproterenol. In that study, LAA firing was documented in 27% of the patients with recurrences, which accounts for only 6.7% of all the patients that underwent AF ablation in their centers. More than a decade ago, we administered isoproterenol to induce triggers for PV focal ablation. Thus, we know isoproterenol is not always effective for the induction of arrhythmias. Even among the patients who did not exhibit any LAA firing, a cer tain number of those patients may benefit from LAA isolation. Another issue with the LAA isolation is the risk of future thromboembolisms. Almost half of the patients exhibited excellent LAA contraction at 6-months of follow-up. This may be due to passive blood flow or electrical reconnection. In the patients with depressed LAA contraction, however, the continuation of anticoagulation therapy or LAA occlusion needs to be considered. In patients with excellent LAA contraction at the midterm follow-up, it is unknown whether or not the LAA contraction will remain that way for the next 10 years. There remain issues to be solved concerning the LAA isolation; however, we recognized that the LAA is an important source of triggers in AF in addition to the thoracic veins.