Relationship between vectorcardiographic QRSarea, myocardial scar quantification, and response to cardiac resynchronization therapy

Purpose: To investigate the relationship between vectorcardiography (VCG) and myocardial scar on cardiac magnetic resonance (CMR) imaging, and whether combining these metrics may improve cardiac resynchronization therapy (CRT) response prediction. Methods: Thirty-three CRT patients were included. QRS(area), T-area and QRST(area) were derived from the ECG-synthesized VCG. CMR parameters reflecting focal scar core (Scar(2sD), Gray(2sD)) and diffuse fibrosis (pre-T1, extra cellular volume IECVD were assessed. CRT response was defined as >= 15% reduction in left ventricular end-systolic volume after six months' follow-up. Results: VCG QRS(area), T-area and QRST(area) inversely correlated with focal scar (R = 0.44-0.58 for Scar(2sD), p <= 0.010), but not with diffuse fibrosis. Scar(2SD), GraY(2SD) and QRS(area) predicted CRT response with ADCs of 0.692 (p = 0.063), 0.759 (p = 0.012) and 0.737 (p = 0.022) respectively. A combined ROC-derived threshold for Scar(2sD) and QRS(area) resulted in 92% CRT response rate for patients with large QRSarea and small Scar(2sD) or Gray(2sD). Conclusion: QRS(area) is inversely associated with focal scar on CMR. Incremental predictive value for CRT response is achieved by a combined CMR-QRS(area) analysis. (C) 2018 Elsevier Inc. All rights reserved.