Arrhythmias & electrophysiologyResearch article
Line of block: A simple pacing maneuver to distinguish AV nodal from accessory pathway ventriculoatrial conduction
- study
Authors' conclusion
Using the "line of block" concept by determining the ΔSA1-SA2 allows for easy determination to the presence or absence of an AP. Larger studies and sample sizes are required to allow for universal application in other EP labs.
Study context
- Population
- Patients undergoing an electrophysiology (EP) study in whom the presence of a septal AP was suspectedpatients undergoing an EP study who fulfilled the criteria for enrollment, between October 2023 and April 2025 · proven accessory pathways (APs) 10 · no AP 14
- Participants
- 24 patients
- Comparison
- Stimulus-to-atrial interval at basal right ventricle (SA1) vs 2-3 cm deeper toward the apex (SA2): SA1 > SA2 = nodal response vs SA1 < SA2 = AP response
- proven APsn = 10
- no APn = 14
Main finding
As reported in the abstract
Proven APs
Further findings
SA1-SA2
SA1-SA2
- All patients with AP demonstrated an SA1-SA2 less than 0 msec, whereas the reverse was true among patients with no demonstrable AP
Original publication
Line of block: A simple pacing maneuver to distinguish AV nodal from accessory pathway ventriculoatrial conduction. Heart Rhythm. Published 27 January 2026. doi:10.1016/j.hrthm.2026.01.027
Summarised from the published abstract; every number is checked against it