A Novel High-Resolution Surface Electrocardiographic Method to Identify and Characterize Myocardial Scar: A Proof-of-Concept Study

ABSTRACT Background . The placement of the left ventricular (LV) lead in an area free of myocardial scar is an important determinant of cardiac resynchronization therapy (CRT) response. We sought to develop and validate a simple, practical and novel electrocardiographic (ECG) based approach to intra-operatively identify the presence of LV scar. We hypothesized that there would be a reduction in the measured amplitude of the LV pacing stimulus on the skin surface using a high-resolution (HR) ECG when pacing from LV regions with scar compared to regions without scar. We term this the E CG A mplitude S ignal E valuation (EASE) method. Methods . Consecutive patients with ischemic LV systolic dysfunction and standard criteria for de novo CRT implantation were prospectively enrolled. All underwent a pre-implant enhanced cardiac magnetic resonance (CMR) study to assess for scar. The average amplitude of the LV pacing impulse was sampled on HR surface ECG intra-procedurally and then blindly compared to the CMR results. Results . A total of 38 LV pacing sites were assessed among 13 recipients. The median voltage measured on the surface HR ECG in regions with scar were reduced by 41% (interquartile range [IQR] 17% to 63%), while there was no measurable change in voltage (IQR 0 to 0%) in regions without scar as compared to the maximal amplitude (Wilcoxon p Conclusion . The EASE method appears to be of potential value as a novel intra-operative tool to guide LV lead placement to regions free of scar. Future work is required to validate the utility of this method in a larger patient cohort.