Abstract 13090: Extremely Poor Prognosis after Cardiac Resynchronization Therapy is Predictable by Heterogeneous Multi-directional Left Ventricular Activation Sequence on Magnetocardiography
Backgrounds: Cardiac resynchronization therapy (CRT) provides no benefit in an approximately one third of the patients with advanced heart failure, that is not readily predictable by any clinical tool. We hypothesized that multi-channel magnetocardiography (MCG) capable of delineating ventricular activation sequence can identify heterogeneous (multi-directional) left ventricular (LV) intraventricular conduction, which would predict non-responders to CRT and poor outcomes after CRT implantation.
Methods: We analyzed 64-Ch MCGs (1kHz) in 56 patients with advanced HF (LVEF 24±8%) and QRS duration (146±30ms) on ECG before CRT implantation. According to the QRS current arrow mapping of MCG, they were divided into Group-U (n=35) with uni-directional homogeneous ventricular conduction (UDC) and Group-M (n=21) with multi-directional heterogeneous ventricular conduction (MDC). CRT responder was defined when LVESV decreased >15% or LVEF increased >15%.
Results: Baseline LVEF and NYHA class were comparable between the groups. After 6 months, responders were more frequently found in Group-U (29/35) than Group-M (2/21, p<0.01). UDC more accurately identified CRT responders with a sensitivity of 94% and a specificity of 76% than QRS duration ≥150ms and CLBBB morphology. Multivariate analysis revealed UDC on MCG as the strongest independent predictor of CRT response (OR 36.9, p<0.001), followed by QRS duration ≥150ms (OR 9.8, p=0.02). More importantly, during the mean follow-up of 786 (105-2042) days, Kaplan-Meier analysis revealed a marked difference in mortality (death and LVAD implant, 0/35 in Group-U vs. 10/21 in Group-M, p<0.001).
Conclusions: Our MCG analysis showed that prolonged but homogeneous LV conduction may represent a characteristic of the candidates highly prone to benefit from CRT, while the presence of multi-directional, heterogeneous conduction may negate the efficacy of CRT and predict extremely poor outcomes after CRT implantation.
- © 2013 by American Heart Association, Inc.