Background: Conventional noninvasive imaging methods have limitations for the assessment of hemodynamic status and prediction of symptoms in patients with left bundle branch block (LBBB). However, advancements in contrast echocardiography (CE) permit transthoracic imaging of LV vortex flow. The aim of this study was to evaluate whether LV vortex flow analysis by CE is superior to conventional echo-Doppler parameters to predict hemodynamic and symptomatic status in patients with LBBB. Methods: 22 patients with LBBB (10 with DOE and 12 without DOE) with normal LV systolic function underwent 2-D CE with Definity infusion. LV vorticity was estimated by PIV. We measured morphology parameters (vortex length, width, and sphericity index) and pulsatility parameters (Relative strength, RS) of vortex. We also measured minimal vortex size (min-VS,%) during diastasis. Results: There was no significant difference in LVEF between two groups (62짹10% vs 57짹9%, P=NS). There were no significant differences in vortex morphology parameters between two groups. However, RS was significantly higher in asymptomatic than symptomatic group (2.3짹0.6 vs 1.6짹0.7, P=0.01). Min-VS during diastasis was significantly larger in asymptomatic than symptomatic group (34짹13 vs 12짹11% P=0.001). RS and Min-VS were well correlated with LVEDP measured by invasive cath (RS, r = -0.727, p<0.01, min VS, r=-0.644, p<0.05). Conclusion: LV vortex flow parameters were well correlated with LV filling pressure in patients with LBBB with normal systolic function, Furthermore LV flow vortex parameters were incremental to conventional echo-Doppler measurements to predict symptomatic status in patients with LBBB.