Novel wall motion score-based method for estimating global left ventricular ejection fraction: validation by real-time 3D echocardiography and global longitudinal strain

To evaluate the reliability of a regional wall motion score index (WMSI)-based method for assessment of left ventricular (LV) ejection fraction (EF). Two-dimensional (2D) echocardiography was used to assess a LV 16-segment-based regional wall motion. Each segment received a score based on contractility status: 4, normal kinesis; 3, mild; 2.5, moderate; and 1.5, severe hypo-kinesis; 0, akinesis; -1, dyskinesis; 3.5 and 4.5 were used for low-normal and high-normal kinesis; 5 for hyper-kinesis. Hence, WMSI-based EF was derived by summing the score assigned to each segment. Contextually, EF was evaluated by real-time three-dimensional (3D) echocardiography and by traditional Simpson's method (2D). Global longitudinal strain (GLS) by speckle-tracking method was derived as a volume-independent indicator of LV chamber contractility sensitive to regional wall motion abnormalities. In 40 subjects with 3D-EF ranging from 14 to 80%, including clinically healthy hypertensive and patients with Stage B-D congestive heart failure with global or segmental wall motion abnormalities, on average, WMSI-EF did not differ from EF measured by 3D or 2D (all P > 0.5). By intraclass correlation coefficients, reliability of WMSI-EF vs. 3D method was as good as the reliability of 2D method vs. 3D method. GLS correlated with WMSI-EF as strongly as with 3D-EF (both r(2) = 0.90). Moderate-severe mitral regurgitation was associated with increased difference between WMSI-EF and 3D-EF, independent to potential confounders. Intra-observer and inter-observer reproducibility of WMSI-EF was comparable to the reproducibility of EF estimated by 3D echocardiography. Feasibility (WMSI, 3D, 2D, and GLS all available) was 78%; however, feasibility of WMSI per se was similar to 92% in clinical series. Trained readers may rapidly estimate EF by a novel WMSI system, which was found to be accurate compared with 3D method and GLS.