The goal of the present study was to assess the effects of left ventricular (LV) pacing site (apex vs. free-wall) on radial synchrony and global LV performance in a canine model of contraction dyssynchrony. Ultrasound tissue Doppler imaging (TDI) and hemodynamic (LV pressure-volume) data were collected in 7 anesthetized, opened-chest dogs. Right atrial (RA) pacing served as control and contraction dyssynchrony was created by simultaneous RA and right ventricular (RV) pacing to induce a left bundle-branch block-like contraction pattern. Cardiac resynchronization therapy (CRT) was implemented by adding simultaneous LV pacing to the RV pacing mode at either the LV apex (CRTa) or free-wall (CRTf). A new index of synchrony was developed via pair-wise cross-correlation analysis of TD radial strain from six mid-myocardial cross-sectional regions, with a value of 15 indicating perfect synchrony. Compared to RA pacing, RV pacing significantly decreased radial synchrony [11.1±0.8 vs. 4.8±1.2; P<0.01] and global LV performance [cardiac output: 2.0±0.3 vs. 1.4±0.1 L·min^-1; stroke work: 137±22 vs. 60±14 mJ; P<0.05]. Although both CRTa and CRTf significantly improved radial synchrony, only CRTa markedly improved global function [cardiac output: 2.1±0.2 L·min^-1; stroke work: 113±13 mJ; P<0.01 vs. RV pacing]. Furthermore, CRTa decreased LV end-systolic volume compared to RV pacing without any change in LV end-systolic pressure, indicating augmented global LV contractile state. Thus, LV apical pacing appears to be a superior pacing site in the context of CRT. The dissociation between changes in synchrony and global LV performance with CRTf suggests that regional analysis from a single plane may not be sufficient to adequately characterize contraction synchrony.