Abstract 9449: Dynamic Left Ventricular Dyssynchrony Assessed by Three Dimensional Speckle-Tracking Area Strain during Dobutamine Stress Has a Negative Impact on Cardiovascular Events in Patients with Idiopathic Dilated Cardiomyopathy

Abstract

Background: Left ventricular (LV) dyssynchrony is not a stable phenomenon, but rather, changes dynamically with changes in hemodynamic conditions. Since the prognostic impact of dynamic dyssynchrony has not yet been elucidated, our objective was to investigate, by using novel three-dimensional (3-D) speckle-tracking area strain, the clinical impact of dynamic dyssynchrony on patients with idiopathic dilated cardiomyopathy (DCM). Methods: Forty-eight DCM patients with ejection fractions of 33±9% (all <45%) were prospectively recruited, and 3-D speckle-tracking area strain was used to measure both contractile reserve and changes in dyssynchrony during dobutamine stress (20μ g/kg/min). The standard deviation of time-to-peak area strain from 16 LV segments was adopted as the LV dyssynchrony index. Event-free survival was then tracked over a 12-month period. Results: A ≥6.94% increase in the dyssynchrony index during dobutamine stress (Δdyssynchrony index) was the best predictor of cardiovascular events with 90% sensitivity and 82% specificity. Multivariate Cox analysis indicated that not only the absence of contractile reserve ([[Unable to Display Character: ∆]]global area strain ≤3.89%, p=0.03), but also the presence of dynamic dyssynchrony ([[Unable to Display Character: ∆]]LV dyssynchrony ≥6.94%, p=0.04) was an independent predictors of cardiovascular events. Patients with dynamic dyssynchrony had a significantly poorer prognosis than those without (log rank p<0.001). Importantly, absence of dynamic dyssynchrony and presence of contractile reserve during dobutamine stress were associated with the most favorable outcome (100%), whereas the reverse condition was associated with the worst outcome (20%, p<0.001). Conclusions: Dynamic dyssynchrony during dobutamine stress constitutes a potential predictor of cardiovascular events in patients with DCM, while assessment of dynamic dyssynchrony in combination with contractile reserve may further improve prognostic risk stratification.