Electrogram Determinants of Acute Electrogram Attenuation During Pulmonary Vein Pulsed Field Ablation

BACKGROUND: Pulsed field ablation (PFA) is a nonthermal modality for pulmonary vein isolation in atrial fibrillation. Whether baseline intracardiac electrogram characteristics are associated with acute electrogram attenuation during PFA remains unclear. OBJECTIVES: To evaluate the individual and combined associations of baseline bipolar amplitude and peak frequency (PF) with acute electrogram attenuation during pulmonary vein PFA. METHODS: Thirty-four consecutive patients undergoing pulmonary vein PFA were retrospectively analyzed. Paired bipolar electrograms were recorded immediately before and after the first PFA application from the same electrode pair and catheter position. Logistic regression, receiver operating characteristic (ROC) analysis, and nonlinear Hill modeling were performed. Additional analyses accounted for within-patient clustering and evaluated alternative attenuation thresholds, pulmonary vein regional heterogeneity, and dynamic-range constraints. RESULTS: Among 687 electrograms analyzed, marked attenuation (≥ 80%) occurred in 59.1%. Both baseline amplitude and PF were significantly associated with marked attenuation. ROC analysis demonstrated strong discrimination for amplitude (AUC 0.894) and moderate discrimination for PF (AUC 0.722), with ROC-derived cutoffs of 0.58 mV and 206 Hz, respectively. Both parameters remained independently associated with attenuation in multivariable analysis. Nonlinear modeling demonstrated distinct response patterns, with amplitude showing a gradual, broad dynamic-range relationship and PF exhibiting a steeper, threshold-like transition. Integration of amplitude and PF enabled graded stratification of attenuation across combined electrogram domains. These associations were preserved after accounting for within-patient clustering and were directionally consistent across alternative attenuation thresholds. CONCLUSIONS: Baseline bipolar amplitude and PF were independently associated with acute electrogram attenuation during pulmonary vein PFA. Their integration provides complementary, non-redundant information and supports a structured electrogram-based framework for interpreting acute electrogram response. These findings are hypothesis-generating and require validation against durable pulmonary vein isolation, late reconnection, and clinical outcomes.