Impact of left ventricular size on tissue Doppler and longitudinal strain by speckle tracking for assessing wall motion and mechanical dyssynchrony in candidates for cardiac resynchronization therapy.

BACKGROUND: Myocardial dysfunction and left ventricular (LV) geometry deformation may reduce the accuracy of tissue Doppler imaging (TDI) in assessing myocardial contractility.
METHODS: In 92 patients with heart failure who underwent cardiac resynchronization therapy (CRT), we assessed the impact of LV end-diastolic volume on the accuracy of peak longitudinal velocity (TDI) and strain (epsilon(L) by speckle tracking) to assess regional wall motion and LV dyssynchrony.
RESULTS: Peak-epsilon correlated to normal (-13% +/- 6%, n = 259), hypokinetic (-10% +/- 5%, n = 347), and akinetic (-7% +/- 5%, n = 498, P < .0001) wall motion independent of LV size. In contrast, velocity failed to distinguish normal from dysfunctional segments in patients with severe LV dilatation (end-diastolic volume > 250 mL). The 12 standard deviation of time to peak systolic velocity and the opposing septal-lateral wall delay by strain and TDI failed to predict response to CRT, whereas the 12 segment standard deviation of time to peak epsilon correlated to end-systolic volume reduction (r = -0.39, P < .001).
CONCLUSION: Accuracy of TDI in assessing LV wall regional motion is limited in severely dilated ventricles and probably affects LV dyssynchrony measurement.