Investigation of the atrial conduction time measured by tissue Doppler imaging at the left atrial appendage and the actual electrical conduction time: consideration of left atrial remodeling in atrial fibrillation patients

Purpose The atrial conduction time measured by echocardiography using tissue Doppler imaging (TDI) has been reported as a predictive factor of left atrial (LA) remodeling. We investigated the P wave to LA appendage (LAA) conduction time defined by transthoracic echocardiography using TDI (P-LAA TDI), and directly compared the actual LA electrical conduction time determined by the electrophysiological data. Additionally, we confirmed the clinical utility of the P-LAA TDI by examining the relationship to the electroanatomical LA remodeling data. Methods Sixty-three AF patients (22 paroxysmal AF, 41 persistent AF) underwent ablation and electroanatomical LA mapping. The P-LAA TDI was measured after the ablation and was compared with the electrophysiological data during sinus rhythm, including the actual electrical conduction time. Results A strong linear correlation ( r = 0.776, p < 0.001, y = 1.28x + 49) was observed between the P-LAA TDI (161 ± 24 ms) and electrophysiological P-LAA time (87 ± 15 ms). The P-LAA TDI was also strongly correlated with the LA volume (173 ± 52 ml, r = 0.632, p < 0.001) and LA conduction velocity index (1.07 ± 0.19 mm/ms, r = −0.735, p < 0.001), but less to the focal anterior-LVA region surface area (2.2 [0.4-5.0] cm 2 , r = 0.380, p = 0.002). Additionally, a stepwise multiple linear regression demonstrated that both the LA volume and LA conduction velocity index were strongly associated with the value of the P-LAA TDI ( p < 0.001). Conclusions The P-LAA TDI was useful for estimating the actual electrophysiological conduction time and represented both electrical and anatomical LA remodeling.