Two-dimensional speckle tracking-derived global longitudinal strain in healthy Doberman Pinschers: method evaluation, variability, and reference values.

INTRODUCTION: Evaluation of two-dimensional speckle tracking (2D-ST)-derived global longitudinal strain (GLS) in healthy Doberman Pinschers (DP) is essential before it can be used in diseased DP to assess systolic function. To determine feasibility and observer related measurement variability of 2D-ST-derived GLS by use of AutoSTRAIN (AUTO) and 2D Cardiac Performance Analysis (TomTec Imaging Systems GmbH, Unterschleissheim, Germany).

ANIMALS, MATERIALS, AND METHODS: This prospective study included 120 healthy, client-owned DP presented for screening evaluation. Global longitudinal strain of the apical four- (GLSA4C ), two-, and three-chamber view as well as the average GLS of all three views combined (GLSAV ) were determined, compared, and reference values established. Measurement variability was assessed by using intra- and inter-observer coefficient of variation.

RESULTS: A small difference existed for GLSAV (mean + 0.23%; P=0.022) between the two software programs although the determined strain values were similar and positively correlated (r = 0.84; P<0.001). No difference could be found between GLSAV and GLSA4C for AUTO (mean + 0.16%; P=0.228), whereas a difference existed for Cardiac Performance Analysis (mean -0.89% (end-systolic strain) and -0.56% (peak strain), P<0.0001). Software specific reference values were established for GLSAV and GLSA4C . Intra- and inter-observer coefficient of variation revealed very low to low measurement variability, with better results for AUTO.

DISCUSSION AND CONCLUSIONS: 2D-ST derived GLS is a feasible technique to assess systolic function with low measurement variability. Whenever possible, GLSAV should be determined, although GLSA4C might be a potential alternative.