Left Pulmonary Veins Isolation: The Cornerstone in Noninvasive Evaluation of Substrate Modification After Catheter Ablation of Paroxysmal Atrial Fibrillation

While pulmonary vein isolation (PVI) is the corner-stone of the paroxysmal atrial fibrillation (pAF) treatment, whether left (LPVI) and right PVI (RPVI) provoke equal atrial substrate modifications (ASMs), vastly assessed by P-waves, remains unexplored. Five-minute recordings from 40 pAF patients undergoing first-time PVI were extracted before PVI (B), after LPVI (L) and RPVI (R) at 1 kHz sampling rate. Signal-averaged P-wave features of duration, amplitude and area were calculated. Heartrate fluctuations (HRF) were mitigated for duration and area (HRDur,area). Results were compared between each transition (B-L: LPVI, L-R: RPVI) and between variations in values due to transitions with non-parametric tests. Duration $(\Delta_{B-L}:-13.3\%,p=0.001, \Delta_{L-R}: +2.40\%,p=0.558)$ and amplitude $\Delta_{B-L}:-17.29\%,p=0.055,\Delta_{L-R}:+5.65\%, p=0.319)$ got decreased after LPVI and slightly increased after RPVI. HRF mitigation mostly preserved these trends but lost statistical power (HRDur: $\Delta_{B-L}: -10.54\%,p=0.141,\Delta_{L-R}: -5.52\%,p=0.740)$. LPVI showed a significantly higher effect on duration than RPVI $(p < 0.0001)$. Variations observed in P-wave features after PVI stem principally from LPVI, which contributes significantly to the ASM. Studies focusing on ASM observation should implement and prioritize the analysis of LPVI recordings.