Rosner A, et al. - The authors examined the presence of classic-pattern dyssynchrony (CPD), characterized by typical early and late deformation of opposite walls. In addition, they aimed to investigate its relation to QRS duration and myocardial function in patients with single-ventricle physiology after Fontan palliation. Following Fontan palliation, CPD was present in a proportion of adolescent and adult patients. Compared with Fontan patients without CPD, the presence of CPD was correlated with reduced systolic and diastolic function. These findings could have important potential for prospective evaluation of cardiac resynchronization therapy in patients with univentricular circulation because the presence of CPD appeared to be a promising predictor for response to cardiac resynchronization therapy in patients with biventricular circulation.