ated with the development of Fontan-associated liver disease, 2 and with supraventricular arrhythmia in adolescent patients with congenital single ventricle. 3 We hypothesized that mechanical dyssynchrony causes VF to disrupt efficient output; therefore, CRT response may be associated with the occurrence of LV VF. The aims of the present study were to investigate the relationship between efficient LV ejection and VF, and whether CRT response could be predicted on VFM analysis in patients with dilated cardiomyopathy (DCM). Methods Patients This retrospective cohort study was approved by the institutional research ethics board and involved 20 HF patients with LVEF ≥40% and 25 DCM patients with LVEF <40% who were scheduled for CRT between January 2010 and December 2016. All patients underwent CMR, cardiac catheterization, transthoracic echocardiography, 12-lead electrocardiogram (ECG), and clinical examination at the same