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 echocardiographic data were acquired simultaneously. Partial and semipartial correlation coefficients were calculated to determine the correlation between LV+dp/dtmax and each echocardiographic variable. Global longitudinal strain was compared with conventional echocardiographic 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 echocardiographic 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.
