Cine DENSE MRI detects delayed mechanical activation of the left ventricular free wall in a canine model of heart failure with left bundle branch block

Background Cardiac resynchronization therapy (CRT) benefits selected heart failure patients; however, CRT has a nonresponse rate of approximately 30-40%. Important factors that contribute to lead placement decisions and overall CRT success include determination of mechanical dyssynchrony, presence and location of scar, and the identification of late-activated segments. Recent imaging studies have reported progress in the first two areas. Previously, myocardial tagging showed promise for mapping mechanical activation time [1], but analysis of tagged images is time consuming. We investigated the use of cine DENSE to detect regions of late mechanical activation.