Comparison of echocardiographic indices of myocardial strain with invasive measurements of left ventricular systolic function in anesthetized healthy dogs

Abstract

Objective-To compare echocardiographic indices of myocardial strain with invasive measurements of left ventricular (LV) systolic function in anesthetized healthy dogs. Animals-7 healthy dogs. Procedures-In each anesthetized dog, preload and inotropic conditions were manipulated sequentially to induce 6 hemodynamic states; in each state, longitudinal, radial, and global strains and strain rate (SR), derived via 2-D speckle-tracking echocardiography, were evaluated along with conventional echocardiographic indices of LV function and maximum rate of rise (first derivative) of LV systolic pressure (LV+dp/dtmax). Catheter-derived and echocardio-graphic data were acquired simultaneously. Partial and semipartial correlation coefficients were calculated to determine the correlation between LV+dp/dtmax and each echocardio-graphic variable. Global longitudinal strain was compared with conventional echocardio-graphic indices via partial correlation analysis. Results-All myocardial segments could be analyzed in all dogs. Significant semipartial correlations were identified between conventional echocardiographic strain indices and LV+dp/dtmax. Correlation coefficients for longitudinal deformation and global strain, segmental longitudinal strain, and segmental SR were -0.773, -0.562 to -0.786, and -0.777 to -0.875, respectively. Correlation coefficients for radial segments and strain or SR were 0.654 to 0.811 and 0.748 to 0.775, respectively. Correlation coefficients for traditional echo-cardiographic indices and LV+dp/dtmax (-0.586 to 0.821) and semipartial correlation coefficients for global strain and echocardiographic indices of LV systolic function (-0.656 [shortening fraction], -0.726 [shortening area], and -0.744 [ejection fraction]) were also significant. Conclusions and Clinical Relevance-Results indicated that LV systolic function can be predicted by myocardial strain and SR derived via 2-D speckle-tracking echocardiographic analysis in anesthetized healthy dogs.