Effect of QRS area reduction and myocardial scar on the hemodynamic response to cardiac resynchronization therapy

Background Vectorcardiographic QRS area (QRSarea) predicts clinical outcomes after cardiac resynchronization therapy (CRT). Myocardial scar adversely affects clinical outcomes after CRT. Objective The purpose of this study in patients with an ideally deployed quadripolar left ventricular (LV) lead (QUAD) was to determine whether reducing QRSarea leads to an acute hemodynamic response (AHR) and whether scar affects this interaction. Methods Patients (n = 26; age 69.2 ± 9.12 years [mean ± SD]) underwent assessment of the maximum rate of change of LV pressure (ΔLV dP/dtmax) during CRT using various left ventricular pacing locations (LVPLs). Cardiac magnetic resonance (CMR) scan was used to localize LV myocardial scar. Results Interindividually, ΔQRSarea (area under the receiver operating characteristic curve [AUC] 0.81; P Conclusion Reducing QRSarea improves the AHR to CRT. Myocardial scar adversely affects ΔQRSarea and the AHR. These findings may support the use of ΔQRSarea and CMR in optimizing CRT using QUAD.