Assessment of left atrial myocardial function and blood flow energy loss in atrial fibrillation patients using ultrasonic vector flow mapping combined with two-dimensional tissue tracking / 中国医学影像技术

ABSTRACT

Objective: To assess left atrial myocardial function and blood flow energy loss (EL) in patients with different types of atrial fibrillation (AF) using vector flow mapping (VFM) combined with two-dimensional tissue tracking (2DTT). Methods: Routine structural and functional parameters of left atrium of 45 patients with continuous AF (CAF group), 30 patients with paroxysmal AF (PAF group) and 41 healthy volunteers (control group) were measured. The left atrial systolic peak strain (SLAs) and left atrial systolic peak strain rate (SRLAs), left atrial early diastolic peak strain (SLAed) and left atrial early diastolic peak strain rate (SRLAed), left atrial late diastolic peak strain (SLAac) and left atrial late diastolic peak strain rate (SRLAac) were derived from 2DTT images, while the total EL of left atrium, including systolic EL (EL-S) and diastolic EL (EL-D) were acquired from VFM images. All parameters were compared among 3 groups, and the correlations of EL and left atrial structural and functional parameters were analyzed. Results: ① SLAs and SRLAs in CAF group and all strain and strain rate parameters in PAF group were lower than those in control group (all P<0.05). SLAs and SRLAs in CAF group were lower than those in PAF group (both P<0.01). ②EL-S and EL-D in CAF and PAF group were lower than those in control group (all P<0.01). ③EL-S was positively correlated with the left atrial total emptying fraction (LATEF), SLAs and SRLAs (r=0.26, 0.33, 0.19; all P<0.05), EL-S was negatively correlated with the left atrial anteroposterior diameter (LAD), left atrial maximum volume index (LAVImax) and left atrial minimum volume index (LAVImin) (r=-0.34, -0.25, -0.29; all P<0.01). In addition, EL-D was positively correlated with the LATEF, SLAs and SRLAs (r=0.30, 0.38, 0.25; all P<0.01); EL-D was negatively correlated with LAD, LAVImax and LAVImin (r=-0.46, -0.36, -0.37; all P<0.01). Conclusion: All types of AF could damage the left atrial myocardial function and increase the cost of blood flow EL. VFM combined with 2DTT can be used to simultaneously and quantitatively evaluate left atrial myocardial function and EL in patients with different types of AF.