Volume 13 Supplement 1
Non-invasive cardiac magnetic resonance and electrical myocardial imaging assessment of CRT in patients with heart failure and left bundle branch block
© Dawoud et al; licensee BioMed Central Ltd. 2011
Published: 2 February 2011
CRT is an effective treatment for patients with heart failure and intraventricular conduction delay. However, clinical non-response rates remain unacceptably high; emphasizing the need for improved selection criteria. Central to the underlying mechanism of resynchronization is the relationship between mechanical and electrical activation. The purpose of this study was to demonstrate that mechanical and electrical activation can be quantified in patients with CRT devices combining cardiovascular magnetic resonance (CMR) and electrical myocardial imaging (EMI).
Non-invasively characterize mechanical and electrical activation patterns in patients undergoing cardiac resynchronization therapy (CRT)
Patients implanted with biventricular CRT for greater than 9 months (N=10) were mapped with 120 body surface electrodes during both intrinsic activation (device off) and CRT pacing. CMR tagging was also acquired with pacing on/off to perform strain analysis. The circumferential uniformity ratio (CURE) was computed to characterize temporal-spatial mechanical dyssynchrony (value ranging from 0 to 1 where 1 represents perfect synchronous contraction). CMR images of the torso and heart were then used to reconstruct electrical epicardial activation maps using a novel EMI technique. Electrical synchrony was indexed by the mean total activation difference time (ΔMTA, negative values indicate RV activating before LV, on average). Only 2 patients underwent full analysis.
CMR and non-invasive EMI are feasible in patients with CRT devices. This ability to quantify mechanical and electrical synchrony before and after CRT may provide insights into mechanisms of resynchronization and lead to robust dyssynchrony metrics that will identify appropriate candidates for CRT.
This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.