Quick Dive: Conduction system pacing

What is the reason for and aim of the publication?

Conduction system pacing (CSP) is gaining rapid acceptance as a more physiological alternative to right ventricular pacing (RVP) in patients with atrioventricular (AV) block, and in selected heart failure (HF) patients with conduction disease, as a potential substitute for biventricular cardiac resynchronization therapy (BiV-CRT). Since the 2021 guidelines, CSP use has expanded significantly, particularly with left bundle branch area pacing (LBBAP). The latest Heart Rhythm Society (HRS) guidelines on physiological pacing have broadened CSP indications, reflecting both growing clinical evidence and international expert consensus. In Europe, practice has advanced rapidly, prompting the need to harmonize pacing and resynchronization recommendations with current practice.

This document is the product of a collaborative effort by the ESC and EHRA, together with EHRA’s partner organizations: the Asia Pacific Heart Rhythm Society (APHRS), Canadian Heart Rhythm Society (CHRS), HRS, and Latin American Heart Rhythm Society (LAHRS). Following ESC and EHRA standards for evidence assessment, it provides updated recommendations on when CSP should be considered. According to ESC standards, there cannot be a focused update of the current guidelines on pacing in the absence of new results of randomized trials. Therefore, the format of an expert consensus statement was used.

What are the most important take-home messages?

1. Training: CSP implantation should only be performed by physicians who have received dedicated training and developed the necessary skills to ensure the procedure is carried out safely and effectively.
2. AV block: In patients with AV block, it may be appropriate to use CSP regardless of left ventricular ejection fraction (LVEF) or the expected percentage of ventricular pacing.
3. Heart failure with LBBB: In patients with heart failure symptoms, left bundle branch block (QRS ≥130 ms), and LVEF ≤35%, CSP-CRT may be considered to improve LVEF, exercise tolerance, symptoms, and to reduce hospitalizations.
4. Pacing-induced cardiomyopathy or non-responders to BiV-CRT: For patients who develop pacing-induced cardiomyopathy or show no response to BiV-CRT, upgrading to CSP can help improve LVEF and heart failure symptoms.
5. Failed coronary sinus lead implantation: In candidates for BiV-CRT where coronary sinus lead implantation is unsuccessful, CSP should be considered as a rescue option.
6. Specific patient groups: In individuals where a simpler device strategy is desirable (e.g., frail patients, those with limited life expectancy, or those needing a smaller device/less leads), CSP may be preferred over BiV-CRT as a primary approach, provided the operator has sufficient expertise.

What are challenges in practical implementation – and possible solutions?

Training and experience: CSP requires specific technical skills that are not yet widespread available, increasing procedural difficulty and complication risk. Structured training, mentorship, simulation-based practice, and stepwise adoption – starting with simpler cases – can address this gap.

Patient selection: Identifying candidates who will benefit most, such as those with AV block, HF with LBBB, or pacing-induced cardiomyopathy, can be complex. Clear institutional protocols and multidisciplinary case discussions can improve selection.

What further developments on the topic are emerging?

As CSP continues to gain momentum, several randomized controlled trials (RCTs) are currently underway. Smaller to mid-sized studies are expected to report results soon, while larger trials with hard clinical endpoints are projected to conclude by the end of the decade. The findings from these studies could substantially shape future pacing guidelines and influence the broader adoption of CSP across diverse patient populations.

Despite its growing use, many aspects of CSP implantation remain areas for improvement. Current pacing leads were originally designed for conventional endocardial sites, raising questions about their long-term performance in CSP. Data on the safety and feasibility of extracting CSP leads, particularly those for LBBAP, with long dwell times, remain limited.

Furthermore, evidence on CSP in specific populations – such as children, patients with complex congenital heart disease, or those with genetic disorders or sarcoidosis – is scarce. Expanded data collection and dedicated studies in these groups will be essential to guide safe and effective CSP implementation in the future.

Clinical consensus statement: Indications for conduction system pacing

Glikson M, Burri H, Abdin A et al. uropean Society of Cardiology (ESC) clinical consensus statement on indications for conduction system pacing, with special contribution of the European Heart Rhythm Association of the ESC and endorsed by the Asia Pacific Heart Rhythm Society, the Canadian Heart Rhythm Society, the Heart Rhythm Society, and the Latin American Heart Rhythm Society, EP Europace, Volume 27, Issue 4, April 2025, euaf050, https://doi.org/10.1093/europace/euaf050

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