Assessment of Atrial Synchrony in Paroxysmal Atrial Fibrillation and Impact of Pulmonary Vein Isolation for Atrial Dyssynchrony and Global Strain by Three-Dimensional Strain Echocardiography

Abstract

Atrial fibrillation (AF) is a risk factor for ischemic stroke and congestive heart failure. AF may cause left atrial (LA) dyssynchrony as well as electrical and mechanical remodeling. The aim of this study was to investigate LA dyssynchrony in patients with paroxysmal AF (PAF) and its recovery after pulmonary vein isolation (PVI), using a three-dimensional strain method. Thirty patients with PAF who underwent PVI were enrolled. Three-dimensional echocardiography was performed before and 3months after PVI. Twenty subjects in whom AF had never been detected served as controls. LA dyssynchrony was quantified by the standard deviation of time to peak strain (TP-SD) from end-diastole by area tracking. Serial changes in TP-SD, LA volume, and global strain in three-dimensional echocardiography were investigated. In the PAF group, TP-SD was significantly higher (9.19±4.98% vs 4.80±2.30% in controls, P<.02) and global strain significantly lower (48.2±20.2% vs 84.4±32.9% in controls, P=.0003) than in the control group. TP-SD, global strain, and LA volume all improved significantly from before to after PVI (TP-SD, from 9.19±4.98% to 6.31±2.94%, P=.005; global strain, from 48.2±20.2% to 58.1±21.2%, P=.018; LA volume index, 29.5±10.6 to 25.8±7.1 mL/m(2), P=.04). Despite the improvement after PVI, TP-SD was still significantly higher and global strain lower than in controls. In patients with PAF, impaired LA function was documented by three-dimensional echocardiography. Despite early LA structural reverse remodeling, LA dyssynchrony was still observed 3 months after PVI. These results may affect medical therapy after successful PVI.