RESUMEN
BACKGROUND: Reproducibility of Doppler echocardiography for assessment of inter-ventricular and intra-left ventricular (LV) dyssynchrony, and its clinical implications, have not been established. METHODS: Twenty-eight subjects (heart failure stages A-C, 61% with QRS ≥ 120 ms, ejection fraction (EF) ≤ 35%) underwent two consecutive echo-studies within 24h to evaluate test-re-test reproducibility of inter-ventricular electromechanical delay (VV delay, by traditional pulsed-Doppler), and intra-LV electromechanical delay between opposite LV walls by color-coded Doppler tissue-velocity (COLOR-DTI), and by pulsed-Doppler tissue spectrum (PW-DTI). Reproducibility of LV internal diastolic diameter (LVIDD) and of EF (by Simpson's method) assessments was evaluated contextually for reference. RESULTS: Intra-study and inter-study reproducibility of inter-ventricular and intra-LV electromechanical dyssynchrony was in general good, and comparable to the reproducibility of LVIDD and EF assessments. Between-study reproducibility of PW-TDI method was fair, but showed poor agreement with COLOR-TDI method. In repeated studies, agreement of significant electromechanical delay by COLOR-TDI was comparable to the agreement of EF ≤ 35%. In the 5 patients who had simultaneously large QRS, EF ≤ 35%, and significant inter- and intra-ventricular dyssynchrony at study #1, 3 had EF 36-40% and 1 showed no significant dyssynchrony by study #2. CONCLUSION: In serial echocardiographic studies, Doppler echocardiography showed a good test-re-test reproducibility for the identification of significant electromechanical delay. Planimetry for EF assessment was a source of variability as relevant as Doppler echocardiography, but COLOR-DTI may add meaningful and reproducible information to QRS duration for cardiac-resynchronization therapy.