Impact of AV Block Duration and P-Wave Indices on Atrial Fibrillation Development in Patients With Dual-Chamber Pacemakers

INTRODUCTION: In complete atrioventricular (AV) block, atrial contraction against closed AV valves may induce atrial pressure overload and early electrical remodeling. P-wave indices, such as P-wave area and dispersion, reflect atrial electrical heterogeneity, but the joint impact of AV block duration and baseline P-wave abnormalities on new-onset atrial fibrillation (AF) after dual-chamber pacing is unknown.
METHODS: We retrospectively studied 80 patients who received dual-chamber DDDR pacemakers for complete AV block. AV block duration was defined as the interval from the first documented complete AV block on ECG to implantation and was quantified in hours. Baseline P-wave indices (area, dispersion, and duration) were measured on pre-implant 12-lead ECGs. Patients were followed for 3 years if incident AF was confirmed by device interrogation or surface ECG. Predictors of AF were evaluated using ROC analysis, Kaplan–Meier curves, and Cox regression.
RESULTS: During follow-up, 14 patients (17.5%) developed AF. These patients had longer AV block duration and higher P-wave area and dispersion than those who remained in sinus rhythm (all p < 0.001). Optimal cutoffs were 38.5 hours for AV block duration, 5.150 µV·ms for P-wave area, and 39.5 ms for dispersion. AV block duration and P-wave indices showed excellent discrimination for incident AF and remained independent predictors in multivariable Cox models.
DISCUSSION AND CONCLUSION: Prolonged exposure to a complete AV block is associated with adverse P-wave remodeling and a higher risk of incident AF. AV block duration may represent a modifiable determinant of AF after pacemaker implantation, suggesting that earlier pacing could reduce atrial stress and arrhythmic risk.

Keywords: Atrial fibrillation, Dual-chamber pacemaker, Atrioventricular block duration, P-wave indices