Native QRS narrowing reflects electrical reversal and associates with anatomical reversal in cardiac resynchronization therapy

Abstract

Native QRS narrowing associated with beneficial response and greater improvements in echocardiography. Abbreviation in native QRS duration could reflect electrical reversal imposed by CRT.

Meta-Analysis of the Usefulness of Change in QRS Width to Predict Response to Cardiac Resynchronization Therapy

“…We showed that QRSd change was more pronounced in studies 8e12,18 having a follow-up period 6 months compared with studies 7,13e17 with a follow-up period >6 months, and in studies 8,10,12,13,17,18 with a prospective design compared with studies 7,9,11,13e16 with a retrospective. The heterogeneity test showed significant differences among the subgroups (80.5% and 73.4%, respectively).…”

“…15% in LVEF after CRT Rickard 2011 A reduction in LVESV ! 10% from baseline Rickard 2012 No deterioration in LV function (deterioration in LV function was defined as an absolute decrease of 5% or greater in ejection fraction from baseline) Rickard 2013 A reduction in LVESV !15% from baseline Yang 2014 An absolute improvement in LVEF by ! 10% from baseline Zhang 2015 Those patients exhibiting !…”

Improvement in left ventricular intrinsic dyssynchrony with cardiac resynchronization therapy

“…The electrocardiographic response defined as a reduction of at least 20 ms was found to be associated with a better clinical and echocardiographic response. Yang et al (20) showed that native QRS narrowing was associated with beneficial response and greater improvements in echocardiography. Similarly, Karaca et al (21) showed that reversed ER, by means of narrowing of the intrinsic electrocardiographic QRS duration after CRT, has clinical and prognostic implications.…”

Prognostic Implications of ‘Paced’ and ‘Native’ QRS Durations Following Cardiac Resynchronization Therapy

“…Restoration of dyssynchronous electrical conduction within the His-Purkinje system by means of biventricular pacing has been proposed as the mechanism of action that correlates with the clinical and echocardiographic improvements after CRT. 21,22 Reversal of electrical dyssynchrony with CRT is determined by the degree of narrowing of the native QRSd. Dizon et al showed that CRT-induced loss of LBBB on the native ECG reflected improved electrical conduction that was subsequently associated with super-response to CRT suggesting that reversal of electrical remodelling is the main target of biventricular pacing in heart failure.…”

“…23 Narrowing of the native QRS duration as a marker of reversed electrical remodelling (RER) after CRT has been shown to correlate with favourable structural changes and CRT response in previous studies. 22,24 Yang et al assessed native conduction during the follow-up of 74 CRT recipients by programming the device pacing-off mode to obtain the spontaneous ECG. 22 They observed that patients with a narrowed intrinsic QRSd compared to baseline value seemed to derive more benefit in terms of CRT response and improvement in left ventricular ejection fraction.…”