D. Sathianathan

Reproducibility of Regional and Global Longitudinal Strains Derived from Two-Dimensional Speckle-Tracking and Doppler Tissue Imaging between Expert and Novice Readers during Quantitative Dobutamine Stress Echocardiography

BACKGROUND Longitudinal strain (LS) is a quantitative parameter that adds incremental value to wall motion analysis. The aim of this study was to compare the reproducibility of LS derived from Doppler tissue imaging and speckle-tracking between an expert and a novice strain reader during dobutamine stress echocardiography (DSE). METHODS Forty-one patients (mean age, 65 ± 15 years; mean ejection fraction, 58 ± 11%) underwent DSE per clinical protocol. Global LS derived from speckle-tracking and regional LS derived from both speckle-tracking and Doppler tissue imaging were measured twice by an expert strain reader and also measured twice by a novice strain reader. Intraobserver and interobserver analyses were performed using intraclass correlation coefficients (ICC), Bland-Altman analysis, and absolute difference values (mean ± SD). RESULTS Global LS measured by the expert strain reader demonstrated high intraobserver measurement reproducibility (rest: ICC = 0.95, absolute difference = 5.5 ± 4.9%; low dose: ICC = 0.96, absolute difference = 5.7 ± 3.7%; peak dose: ICC = 0.87, absolute difference = 11.4 ± 8.4%). Global LS measured by the novice strain reader also demonstrated high intraobserver reproducibility (rest: ICC = 0.97, absolute difference = 4.1 ± 3.4%; low dose: ICC = 0.94, absolute difference = 5.4 ± 5.9%; peak dose: ICC = 0.94, absolute difference = 6.1 ± 4.8%). Global LS also showed high interobserver agreement between the expert and novice readers at all stages of DSE (rest: ICC = 0.90, absolute difference = 8.5 ± 7.5%; low dose: ICC = 0.90, absolute difference = 8.9 ± 7.1%; peak dose: ICC = 0.87, absolute difference = 10.8 ± 8.4%). Of all parameters studied, LS derived from Doppler tissue imaging had relatively low interobserver and intraobserver agreement. CONCLUSIONS Global LS is highly reproducible during all stages of DSE. This variable is a potentially reliable and reproducible measure of myocardial deformation.

The Utility of Three-dimensional Transoesophageal Echocardiography in the Assessment of Prosthetic Para-valvular Regurgitation

meanMV gradient before exercise was 1.35± 0.05mmHg and increased to 4.00± 0.16mmHg post-stress (p< 0.001). This represented a 196% increase in the gradients. In the last 40 patients, the left ventricular outflow tract (LVOT) velocity profiles were also measured, as an indicator of increased cardiac output with exertion. The LVOT mean gradient increased from 2.3± 0.74mmHg to 4.1± 1.72mm Hg (p< 0.001). This was only a 78% increase in these gradients. Conclusion: This study provides a normal range for the effect of exercise on normal mitral valve gradients. Additionally, trans-mitral valve gradients increased substantially more than the LVOT stroke volume (i.e. cardiac output). These data suggest that the mitral valve apparatus acts as a sphincter with exercise, becoming relatively stenotic, out of proportion to increases in cardiac output.