Conduction system pacing potential alternative for biventricular pacing in heart failure

Conduction system pacing (CSP) demonstrated non-inferiority to biventricular pacing (BiVP) in terms of cardiac resynchronisation and ventricular remodelling in patients with heart failure and wide QRS segments. Evidence from the randomised-controlled LEVEL-AT trial suggests that CSP may be an alternative to BiVP in these patients, but additional studies are warranted before changing guidelines.

CSP is an emerging technique to treat patients with an indication for cardiac resynchronisation therapy (CRT), but only a few randomised studies have compared the BiVP therapy with CSP. Dr Margarida Pujol-López (Institut Clínic Cardiovascular, Spain) and colleagues designed the non-inferiority LEVEL-AT trial (NCT04054895), in which patients with heart failure (a left ventricular ejection fracture ≤35%) and a wide QRS segment (≥130 ms in left bundle branch block/≥150 ms in non-left bundle branch block), or patients with atrioventricular block and cardiac dysfunction were randomised 1:1 to CSP or BiVP (n=35 per group) [1]. The primary endpoint was a change in left ventricular activation time (LVAT), assessed by electrocardiographic imaging at day 45.

In the CSP arm, 11% of the participants received His bundle pacing, and 89% received left bundle branch area pacing. The primary endpoint displayed that CSP (LVAT -28 ms) was non-inferior to BiVP (LVAT -21 ms; P_{non-inferiority}<0.001). The mean left ventricular end-systolic volume change was -37 mL for patients in the CSP arm and -30 mL for patients in the BiVP arm (P_{non-inferiority}=0.04). The mean QRS shortening times for patients in the CSP arm and patients in the BiVP arm were -53 ms and -48 ms, respectively (P_{non-inferiority}<0.001). Finally, the total procedure time (mean 125 vs 129 minutes) and the number of complications requiring re-intervention (11.4% for both) were comparable for the 2 treatment conditions.

Although CSP is a promising technique, study discussant Prof. Christophe Leclercq (University Hospital Rennes, France) argued that this study is not able to deliver solid conclusions on the safety, efficacy, and long-term results of CSP. “The results of the LEVEL-AT trial are encouraging. However, the assessed population was small, the inclusion criteria were wide and the crossover rate of CSP to BiVP was rather high (23%). Larger, randomised-controlled trials are needed before guideline recommendations should be considered regarding the application of CSP as a tool for left bundle branch pacing in patients with heart failure.”

1. Pujol-López M, et al. Conduction system pacing vs. biventricular pacing in Heart Failure and wide QRS patients: a randomized study. Late-breaking science 1, EHRA 2022, 3–5 April, Copenhagen, Denmark.

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Posted on 1 June, 202213 June, 2022