Simplified Electrocardiogram Criteria to Guide Conduction System Pacing: Is it Possible to Democratize the Procedure?

Conduction system pacing (CSP) is recommended when high ventricular pacing burden is expected, and as an alternative to cardiac resynchronization. Multiple studies have demonstrated the importance of achieving CSP over deep septal pacing, with associated improved clinical outcomes. There are various currently accepted criteria to ascertain CSP lead placement, which all require an electrophysiology (EP) system. EP systems are not widely available, limiting CSP lead placement to tertiary hospitals and specialized centres. The purpose of this study was to identify electrocardiography (ECG)-only criteria capable of confirming CSP capture and thereby improve accessibility to this pacing strategy.

We retrospectively extracted all attempted CSP implantations at our centre. Established CSP criteria were assessed for each patient, alongside the presence of ECG-only features.

The presence of 3 ECG-only criteria was found to be highly predictive of CSP in patients without a previously paced rhythm: terminal S wave in V₅-V₆; isoelectric ST segment in V₆; and positive T wave in V₅-V₆. When applied to patients with unpaced baseline rhythms and a V₆-V₁ interpeak interval > 44 ms, these criteria demonstrated a predictive accuracy of 80.4%, with a sensitivity of 87.8% and a specificity of 76.5%.

The findings suggest that CSP capture may be reliably identified using a combination of simple ECG-based markers in patients without prior ventricular pacing. Implementation of these criteria may facilitate broader adoption of CSP by enabling reliable confirmation of capture without the need for EP systems, thereby expanding patient access to this physiologic pacing strategy.