P401Comparison of longitudinal strain by m-mode and a combination of tissue Doppler and speckle tracking


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Abstract

Purpose: Longitudinal indices of left ventricular (LV) function have been shown sensitive to detect and quantify LV dysfunction. Mitral annular excursion (MAE) by m-mode is attractive as there is little need of post-processing compared to more advanced longitudinal LV strain. By indexing MAE (iMAE) by LV length a measure that corresponds to global strain is obtained. We aimed to compare the two methods of assessing LV longitudinal strain with respect to feasibility, variability and absolute values.Methods: Variability was tested in 10 healthy individuals (7 men, age 30±6 years). 2 physician echocardiographers did separate echocardiographic examinations. Variability was tested as test-retest (2 echocardiograms, 2 analysers), inter-observer (same echocardiogram, 2 analysers) and intra-analyser (1 analyser reanalysing his own echocardiograms). Comparison of percentage LV systolic longitudinal shortening by the iMAE and end-systolic strain obtained by a combination of tissue Doppler (TD) and speckle tracking (ST) was done in a random sample of 449 healthy individuals (20-89 years) which participated in the ‘Echocardiography in the HUNT 3 Study’. All included participants were free from known heart diseases, diabetes or hypertension. Analyses were done blinded to patients characteristics.MAE was measured by m-mode at the base of the septal, lateral, inferior and anterior walls and indexed according to length of each wall. Strain was assessed on TD recordings by segmentation of the myocardium and tracking regions of interest along the ultrasound beam with TD and with ST perpendicular to the ultrasound beam. A 16 segmental model was used.Results: >98 % had values accepted for global strain by both methods in both populations. The test-retest, inter-observer and intra-analyser coefficient of variation were 3.5 %, 2.4 % and 1.8 % for strain by iMAE and 3.0 %, 2.5 % and 2.8 % for strain by ST and TD. Overall, LV strain was 16.3 % (SD 2.2 %) and 16.6 % (SD 2.2 %) by iMAE and the combination of ST and TD, respectively. There was a small, but clinical not significant difference (absolute, 0.3 %) between the two methods, p=0.002.Conclusions: Indexed MAE was comparable to longitudinal strain assessed by a combination of speckle tracking and tissue Doppler with respect to assess the percentage systolic longitudinal shortening of LV. We suggest that indexing MAE for LV length is an attractive alternative to TD or speckle strain for assessment of global LV function due to the low demand of post-processing.

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