Changes in P wave duration (PWD) following atrial fibrillation (AF) ablation have been described and may have diagnostic value. PWD is usually assessed manually from ECG. This study aimed at exploring a novel method for automated modeling of the P-wave and assessment of PWD. Moreover, it aimed at investigating the effect of hybrid procedure (HP) for AF treatment on PWD. P-wave modeling is achieved by means of a concatenation of two half-Gaussian functions, to account for potential left and right asymmetries in the P-wave morphology. When compared with a single Gaussian model, the method showed better fitting in terms of normalized mean square error (NMSE; 0.14±0.07 vs. 0.28±0.11, p < 10−4). When investigating the effect of HP on PWD, results showed that PWD was significantly decreased after procedure (111.49±23.29 ms vs. 96.27±30.28 ms, p = 0.0319). PWD pre-procedure, was significantly higher in persistent patients than in paroxysmal patients (126.85±15.50 ms vs. 106.70±23.82, p < 0.0272). Automated analysis of P-wave from ECG to extract PWD is possible. Results at 9 month follow-up suggest that selection of patients may be possible before procedure to individualize AF therapy.