Percutaneous left atrial appendage closure improves left atrial mechanical function through Frank–Starling mechanism

Background Modifications in left atrial (LA) flow velocities after left atrial appendage (LAA) exclusion have been shown in animal and ex vivo models. In a substudy of PROTECT AF (Percutaneous Closure of the Left Atrial Appendage Versus Warfarin Therapy for Prevention of Stroke in Patients With Atrial Fibrillation), an objective improvement in quality of life was observed after LAA closure. Objective The purpose of this study was to investigate the impact of LAA closure on LA transport function. Methods Comprehensive transthoracic echocardiography evaluation (2-dimensional [2D]/3-dimensional [3D], 2D speckle tracking) was prospectively performed before and after LAA closure (at discharge and 45 days after procedure) in 33 patients. Results LAA closure was associated with a significant improvement in LA reservoir function at discharge and 45 days after the procedure with (1) increased maximum LA volume index, (2) increased 2D–LA reservoir volume and expansion index, and (3) increased 2D speckle tracking–derived peak atrial longitudinal strain (PALS) (27.9 ± 14 and 26 ± 12.6 vs 21.7 ± 10.7%, P P  = .0006). Conversely, the slope of the relation between PACS and PALS remained unchanged (0.5 ± 0.27 and 0.53 ± 0.3 vs 0.5 ± 0.25, P = .99), thus arguing for an improvement in LA contractile function secondary to a Frank–Starling effect rather than a modification in its intrinsic contractility. Conclusion LAA closure was associated with an improvement in LA mechanical function. These changes appeared to be related to a modification in loading conditions, that is, a Frank–Starling effect.