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Atrial Effective Refractory Periods in Patients With Frequent Premature Atrial Complexes: Implications for Atrial
Satoshi Higuchi1, Gaku Hatayama2, Satoshi Miyazawa3
1Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan; Clinical Research Division for Heart Rhythm Management Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan; Department of Cardiology, Sendai Cardiovascular Center, Miyagi, Japan.
JACC. Clinical Electrophysiology
|April 23, 2026
Summary
Frequent premature atrial complexes (PACs) preserve atrial effective refractory period (AERP) in humans, unlike atrial fibrillation (AF). This suggests PACs may precede AF development by altering atrial electrophysiology.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Arrhythmias
Background:
- Animal models suggest frequent premature atrial complexes (PACs) cause atrial remodeling via conduction slowing, not atrial effective refractory period (AERP) changes.
- The effect of frequent PACs on human AERP remains undetermined, contrasting with known atrial fibrillation (AF) remodeling mechanisms.
Purpose of the Study:
- To compare AERP characteristics in patients with isolated frequent PACs versus those with atrial fibrillation (AF).
Main Methods:
- Prospective study of patients undergoing ablation for isolated frequent PACs, paroxysmal AF (PAF), or persistent AF.
- AERP measured using incremental S2 pacing; interatrial conduction time (IACT) also assessed.
- Measurements taken at pulmonary veins (PVs) and extra-PV sites.
Main Results:
- AERP was longest in PAC patients, intermediate in PAF, and shortest in persistent AF patients, particularly in PVs (p<0.001).
- Extra-PV AERPs were similar in PAC and PAF but shorter in persistent AF (p<0.001).
- IACT was comparable between PAC and PAF but prolonged in persistent AF (p=0.004).
Conclusions:
- Isolated frequent PACs are associated with preserved AERP in both PV and extra-PV regions.
- Progressive AERP shortening in PVs (PAF) and widespread shortening (persistent AF) may indicate a transition from PACs to AF.
- Arrhythmia type independently predicts AERP, highlighting distinct remodeling patterns.
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