Study on how catheter ablation affects atrial structures in patients with paroxysmal atrial fibrillation: The case of the coronary sinus

It has been shown that substrate modification due to catheter ablation (CA), the first-line treatment of paroxysmal atrial fibrillation (PAF), provokes alterations in P-wave features of the surface electrocardiogram. The absence of knowledge on whether invasive recordings acquired during CA can track similar modifications, creates nevertheless a significant void in the thorough understanding of CA effect on PAF. By analyzing 5-minute bipolar coronary sinus (CS) recordings from 26 PAF patients in sinus rhythm (SR) undergoing CA, this study aims to shed light on whether CA affects local activation waves (LAWs) features recorded in the CS, which is a widely used reference point to assess AF substrate. Recordings were obtained before and after CA. The analysis consisted of LAWs detection and processing of features such as duration, amplitude, positive and negative area, morphology variability (MV), dispersion and number of deflections and inflections (NODI). These features were defined similarly as with previous studies made with surface P-waves. Statistical analysis contained median calculation and comparison with Mann-Whitney U-test. Although some variations in line with previously reported results on P-wave analysis have been observed, none of them was statistically significant (p > 0.05). Duration, amplitude, positive and negative area marked a minor decrease (−1.4% to −14.3%). MV and dispersion showed a minor to moderate increase (+1.2% to +64.8%). NODI showed no alteration. CA in PAF does not lead to significant variations on LAWs features of bipolar CS recordings. The alterations reported by previous studies on the P-waves may be the product of substrate modification of other atrial regions or the superposition of less significant alterations occurring at each atrial site.