Two-dimensional tissue tracking: a novel echocardiographic technique to measure left atrial volume: comparison with biplane area length method and real time three-dimensional echocardiography.

Enlargement of the left atrium is an independent predictor of adverse cardiovascular outcomes, and an accurate, convenient imaging modality is necessary for clinical practice. The objectives of this study were to evaluate the feasibility of a novel imaging technique, two-dimensional tissue tracking (2DTT), for assessment of left atrial (LA) volume and function and to compare its correlation and agreement with biplane area length (AL) method and real time three-dimensional echocardiography (RT3DE). A total of 105 patients prospectively underwent 2DTT, AL and RT3DE. The LA volume index (LAVI) and emptying fraction were measured. In addition, intra- and inter-observer agreement were calculated by using the intraclass correlation coefficient. There were no significant differences in LAVI and emptying fraction measured by 2DTT in comparison with those made by AL or RT3DE, furthermore Bland-Altman analysis showed that 2DTT had significantly better agreement for LAVI and emptying fraction with AL and RT3DE. 2DTT also exhibited smaller intra- and inter-observer variability as compared with AL or RT3DE. Furthermore, the time to measure LA volume and acquire time-volume curve was significantly less by 2DTT than that by RT3DE (U = 49.00, P < 0.001). These observations suggest that the 2DTT could provide valuable information which is consistent with the standard AL and RT3DE measurements for LAVI and function with potentially lower intra- and inter-observer variability.