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

J Electrocardiol. 2018 May-Jun;51(3):457-463. doi: 10.1016/j.jelectrocard.2018.01.009. Epub 2018 Feb 8.

Abstract

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. QRSarea, Tarea and QRSTarea were derived from the ECG-synthesized VCG. CMR parameters reflecting focal scar core (Scar2SD, Gray2SD) and diffuse fibrosis (pre-T1, extracellular volume [ECV]) were assessed. CRT response was defined as ≥15% reduction in left ventricular end-systolic volume after six months' follow-up.

Results: VCG QRSarea, Tarea and QRSTarea inversely correlated with focal scar (R = -0.44--0.58 for Scar2SD, p ≤ 0.010), but not with diffuse fibrosis. Scar2SD, Gray2SD and QRSarea predicted CRT response with AUCs of 0.692 (p = 0.063), 0.759 (p = 0.012) and 0.737 (p = 0.022) respectively. A combined ROC-derived threshold for Scar2SD and QRSarea resulted in 92% CRT response rate for patients with large QRSarea and small Scar2SD or Gray2SD.

Conclusion: QRSarea is inversely associated with focal scar on CMR. Incremental predictive value for CRT response is achieved by a combined CMR-QRSarea analysis.

Keywords: Cardiac magnetic resonance imaging; Cardiac resynchronization therapy; Myocardial scar; Vectorcardiography.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cardiac Resynchronization Therapy / methods*
  • Cicatrix / physiopathology*
  • Electrocardiography
  • Female
  • Heart Failure / diagnosis*
  • Heart Failure / therapy*
  • Humans
  • Imaging, Three-Dimensional
  • Magnetic Resonance Imaging / methods*
  • Male
  • Prospective Studies
  • Vectorcardiography / methods*