Electrically vs. imaging-guided left ventricular lead placement in cardiac resynchronization therapy: a randomized controlled trial

Abstract

Aims To test in a double-blinded, randomized trial whether the combination of electrically guided left ventricular (LV) lead placement and post-implant interventricular pacing delay (VVd) optimization results in superior increase in LV ejection fraction (LVEF) in cardiac resynchronization therapy (CRT) recipients. Methods and results Stratified according to presence of ischaemic heart disease, 122 patients were randomized 1:1 to LV lead placement targeted towards the latest electrically activated segment identified by systematic mapping of the coronary sinus tributaries during CRT implantation combined with post-implant VVd optimization (intervention group) or imaging-guided LV lead implantation by cardiac computed tomography venography, 82Rubidium myocardial perfusion imaging and speckle tracking echocardiography targeting the LV lead towards the latest mechanically activated non-scarred myocardial segment (control group). Follow-up was 6 months. Primary endpoint was absolute increase in LVEF. Additional outcome measures were changes in New York Heart Association class, 6-minute walk test, and quality of life, LV reverse remodelling, and device related complications. Analysis was intention-to-treat. A larger increase in LVEF was observed in the intervention group (11 ± 10 vs. 7 ± 11%; 95% confidence interval 0.4–7.9%, P = 0.03); when adjusting for pre-specified baseline covariates this difference did not maintain statistical significance (P = 0.09). Clinical response, LV reverse remodelling, and complication rates did not differ between treatment groups. Conclusion Electrically guided CRT implantation appeared non-inferior to an imaging-guided strategy considering the outcomes of change in LVEF, LV reverse remodelling and clinical response. Larger long-term studies are warranted to investigate the effect of an electrically guided CRT strategy.

Reproducibility and repeatability of identifying the latest electrical activation during mapping of coronary sinus branches in CRT recipients

“…[11][12][13] We recently published a randomized controlled trial showing that targeted LV lead placement at the site of the latest electrically activated segment combined with programming the interventricular (VV) delay achieving the shortest QRS duration resulted in an additional increase in absolute LVEF as compared to standard treatment. 14 Furthermore, we have demonstrated an acceptable reproducibility and repeatability of determining the VV-delay resulting in the narrowest QRS complex. 15 The aim of this study is to determine reproducibility and repeatability of identifying the latest electrically activated area during mapping of all available CS branches in patients receiving CRT.…”

“…The importance of the LV pacing site for CRT outcome has been demonstrated in several observational and randomized studies. [6][7][8]11,13,14,20 Several parameters for targeting optimal pacing sites during CRT have been reported, and prior studies have especially been focusing on echocardiography for this purpose. Later, the influence of echocardiography for selecting candidates to CRT or tailoring implantation strategy has declined 9,10 and measures such as electrical delay and hemodynamic response have become more prominent.…”

“…Later, the influence of echocardiography for selecting candidates to CRT or tailoring implantation strategy has declined 9,10 and measures such as electrical delay and hemodynamic response have become more prominent. 14,21,22 For all methods used to target the optimal pacing sites in CRT recipients, the majority of preferred segments are in lateral or posterior segments combined with a basal or midventricular position, which reflects the activation pattern seen during LBBB or RV pacing. 23 The knowledge of this might of course have an influence on observers during variability testing and thereby improve reproducibility and repeatability.…”

“…A faster and more simples approach has been introduced using a guidewire with the ability to perform unipolar sensing and pacing. 14,24 A potential drawback could be that the recorded signal is different from the guidewire as compared to the LV lead since near and far activity reflects F I G U R E 3 Target segment for different observers with an arrow pointing at alternative targets segment in case of disagreement with assessment by other observer or same observer second time differently on the recorded EGMs. However, a recent study found a good correlation between two methods when measuring the activation delay.…”

“…A number of studies have shown an association between an LV lead placed at sites of late electrical activation and better outcome in CRT recipients 11–13 . We recently published a randomized controlled trial showing that targeted LV lead placement at the site of the latest electrically activated segment combined with programming the interventricular (VV) delay achieving the shortest QRS duration resulted in an additional increase in absolute LVEF as compared to standard treatment 14 . Furthermore, we have demonstrated an acceptable reproducibility and repeatability of determining the VV‐delay resulting in the narrowest QRS complex 15 …”