Evaluation of Left Ventricular Diastolic Dysfunction with Early Systolic Dysfunction Using Two-Dimensional Speckle Tracking Echocardiography in Canine Heart Failure Model

Background: This study evaluated the role of two-dimensional speckle tracking echocardiography (2DSTE) for predicting left ventricular (LV) diastolic dysfunction in pacing-induced canine heart failure. Methods: Pacing systems were implanted in 8 adult mongrel dogs, and continuous rapid right ventricular pacing (RVP, 240 beats/min) was maintained for 2 weeks. The obtained measurements from 2DSTE included global strain rate during early diastole (SRe) and during late diastole (SRa) in the longitudinal (L-SRe, L-SRa), circumferential (C-SRe, C-SRa), and radial directions (R-SRe, R-SRa). Changes in heart morphology were observed by light microscopy and transmission electron microscopy at 2 weeks. Results: The onset of LV diastolic dysfunction with early systolic dysfunction occurred 3 days after RVP initiation. Most of the strain rate imaging indices were altered at 1 or 3 days after RVP onset and continued to worsen until heart failure developed. Light and transmission electron microscopy showed myocardial vacuolar degeneration and mitochondrial swelling in the left ventricular at 2 weeks after RVP onset. Pearson's correlation analysis revealed that parameters of conventional echocardiography and 2DSTE showed moderate correlation with LV pressure parameters, including E/E'(sep) (r = 0.58, P < 0.01), L-SRe (r = -0.58, P < 0.01), E/L-SRe (r = 0.65, P < 0.01), and R-SRe (r = 0.53, P < 0.01). ROC curves analysis showed that these indices of conventional echocardiography and strain rate imaging could effectively predict LV diastolic dysfunction (area under the curve: E/E'(sep) 0.78; L-SRe 0.84; E/L-SRe 0.80; R-SRe 0.80). Conclusion: 2DSTE was a sensitive and accurate technique that could be used for predicting LV diastolic dysfunction in canine heart failure model.