Iatrogenic risks of left atrial appendage isolation: Targeting the bull’s eye or circling the drain?

The opinion on whether the left atrial appendage (LAA) is a friend or foe depends on whether it is considered a vestigial structure whose sole purpose is to serve as a potential source of arrhythmias or thrombus, or whether its important electromechanical and neurohumoral role is considered. The LAA is the most compliant part of the left atrium and therefore buffers against a sudden rise in pressure with increases in left atrial (LA) volume. It may contribute between 20% and 40% of left atrial systolic function and contains high amounts of atrial natriuretic peptide granules, released in response to stretch, that help to regulate volume homeostasis.