Background Little is known about the impact of QRS duration and aetiology of heart failure on the pattern of left ventricular long- and short-axis dyssynchrony.

Objective To investigate the impact of QRS duration and aetiology of heart failure on the pattern of left ventricular long- and short-axis dyssynchrony using tissue Doppler imaging (TDI) and two-dimensional (2D) speckle tracking imaging.

Methods 448 patients with heart failure (aged 65±12 years, 75% men) with ejection fraction ≤35% from two cardiac centres were examined for the occurrence of longitudinal dyssynchrony by TDI, and for radial dyssynchrony by 2D speckle tracking imaging. Region(s) of the latest mechanical contraction were also determined.

Results Longitudinal dyssynchrony was identified in 263 (59%) patients and radial dyssynchrony in 185 (41%). 125 (28%) patients had both longitudinal and radial dyssynchrony, 138 (31%) had only longitudinal, 60 (13%) had only radial, and 124 (28%) had neither form of dyssynchrony. TDI showed that the single most delayed segment was the septal, lateral, anterior, inferior, anteroseptal and posterior wall in 12%, 27%, 12%, 19%, 7% and 13% of patients, respectively, while multisegmental delay occurred in 10% of patients. These figures were 10%, 8%, 5%, 10%, 12%, 14% and 41%, respectively, using 2D speckle tracking. When compared between patients with wide and narrow QRS complexes, both longitudinal (63% vs 53%) and radial (49% vs 36%) dyssynchrony parameters were more frequently positive in the wide QRS group defined by QRS duration ≥120 ms (both p<0.05). When compared between non-ischaemic and ischaemic patients, the prevalence of longitudinal dyssynchrony was comparable (61% vs 57%, p=0.467), while radial dyssynchrony was marginally more common in the non-ischaemic group (47% vs 37%, p=0.049). However, the distributions of the most delayed segment between the subgroups were similar when assessed by the same echocardiographic method.

Conclusion In patients with advanced systolic heart failure, the patterns of longitudinal and radial dyssynchrony are heterogeneous, and mechanical dyssynchrony tends to be more prevalent in the wide QRS group and the non-ischaemic group.