Two-dimensional speckle-tracking echocardiography is more accurate than tissue Doppler imaging in assessing regional atrial deformation: A study in patients after transcatheter atrial septal defect closure

Abstract

There is currently no optimal method for quantifying left atrial (LA) mechanical function. Tissue Doppler (TD) and two-dimensional speckle-tracking (2DST) strains are 2 new echocardiographic tools for non-invasive assessment of LA global and regional deformation [1]. Although myocardial deformation indices measured by these 2 methods have been increasingly reported in studies, the precision of these measurements is largely unknown mainly due to the lack of a good reference standard. Amplatzer septal occluder (ASO) is a bulky device implanted at the inter-atrial septum in patient with a secundum-type atrial septal defect (ASD). It is non-contractile and only moves passively due to tethering effect of surrounding cardiac structures. These 2 characteristics can serve as an “ideal reference” to validate the accuracy of TD or 2DST strain in evaluating LA regional myocardial deformation. We prospectively studied 44 adult ASD patients 3 months after successful percutaneous implantation of ASO devices and 4 patients with atrial fibrillation or pacemaker, 5with poor 2D or TD image quality were excluded. Finally, the data of 35 patients (age 43±14 years, 25 females, heart rate 64±8 bpm) in sinus rhythm were analyzed. Thirty-five age-, genderand heart rate-matched normal controls (NC, age 48±7 years, 17 females, heart rate 67±9 bpm) were enrolled in the same period. Transthoracic echocardiography (Vivid 7, Vingmed-General Electric, Horten, Norway) was performed and both 2D (frame rate>50/min) and color TD (frame rate>100/min) images with 5 consecutive beats were digitally recorded. One optimal cardiac cycle was selected for quantitative off-line analysis using 2D strain software (EchoPac PC, version 7.0.0, Vingmed-General Electric) to obtain strain parameters. The size of the sample volume was set to 6×20 mm. It covered the whole atrial segment and can be positioned at the middle portion of the ASO compatible to 2D strain sample volume (Fig. 1). The total segmental longitudinal strain was measured at the peak points of both 2DSTor TD-derived strain curves during systolic phase. Categorical and continuous variableswere expressed as percentage andmean±SD, respectively. Chi-square test and independent/ paired t test were used for comparisons as appropriate. A p valueb0.05 was considered significant.