Arrhythmias & electrophysiology
Unipolar Electrograms at the Pulmonary Vein Antrum: Spatial and Directional Heterogeneity with Distinct Postablation Morphologies
- Observational study of unipolar electrograms recorded before and after radiofrequency ablation
Authors' conclusion
Antral PV U-EGMs frequently represent composites of near- and far-field signals with spatial heterogeneity and direction-dependent variation. Postablation responses are diverse, including S-wave disappearance, residual negativity, often reflecting contributions from overlapping far-field components, and newly developed positive deflections. PV-antral U-EGMs should be interpreted in the context of their composite nature.
Study context
- Population
- Patients undergoing radiofrequency ablation for atrial fibrillationpatients, unipolar electrogram (U-EGMs) recorded at 116 antral pulmonary vein (PV) sites
- Participants
- 15 patients
- Exposure
- U-EGMs before vs after ablation, during sinus rhythm and distal coronary sinus (CS) pacing
Main finding
As reported in the abstract
- Spatial heterogeneity: small r and deep S in the right anterior PV antrum transitioning to a positive-dominant morphology (Rs) in the left-lower PV antra
Observational data: associations, not effects.
Further findings
| Outcome | Before ablation | After ablation |
|---|---|---|
| Overall S-wave amplitude · before vs after ablation | mean −0.94 (SD 0.70) mV | mean −0.08 (SD 0.55) mV |
- Overall S-wave amplitude: P<0.001
Effect of distal CS pacing
- Direction-dependent changes, most prominently in the right PV antrum
Residual negative deflections ≥0.5 mV · after ablation
- Recordings with residual negative deflections ≥0.5 mV
- 18.1% (21/116)
- Frequently in association with direction-dependent far-field activity
Newly developed positive deflections ≥1.0 mV · after ablation
- Sites with newly developed positive deflections ≥1.0 mV
- 17/116 sites (14.7%)
- Mean amplitude
- 1.42 ± 0.42 mV
- Predominantly in the right-sided antra
Original publication
Summarised from the published abstract; every number is checked against it