Utility of dual-source computed tomography in cardiac resynchronization therapy—DIRECT study

BACKGROUND: Dual-source computed tomography (CT) can evaluate left ventricular (LV) dyssynchrony, myocardial scar and coronary venous anatomy in patients undergoing cardiac resynchronization therapy (CRT). OBJECTIVE: We aim to determine if dual-source CT predicts clinical CRT outcomes and reduces intra-procedural time. METHODS: In this prospective study, 54 patients scheduled for CRT (age 63±11, 74% male) underwent pre-procedural CT to assess their venous anatomy as well as CT-derived dyssynchrony metrics and myocardial scar. Based on the 1:1 randomization, the implanting physician had pre-implant knowledge of the venous anatomy in half the patients. In blinded analyses, we measured time-to-maximal wall thickness and inward motion to determine 1) CT global and segmental dyssynchrony and 2) concordance of lead location to regional LV mechanical contraction. Endpoints were 6-month CRT response by Heart Failure Clinical Composite Score and 2-year major adverse cardiac events (MACE). RESULTS: There were 72% CRT responders and 17% with MACE. Two wall motion dyssynchrony indices (global and opposing anteroseptal-inferolateral walls) predicted MACE (p