Optimization of catheter/tissue contact during pulmonary vein isolation: the impact of atrial rhythm

Aims. During pulmonary vein isolation (PVI), even if operators are aware of the contact force (CF), its values may greatly vary and the impact of cardiac rhythm has not been thoroughly investigated yet. This study aims at assessing the actual values of CF, the applications with suboptimal CF, and the impact of cardiac rhythm on CF during PVI. Methods. Twenty patients undergoing point-by-point PVI with a CF-sensing catheter were considered. CF target was between 6-40 g. The mean CF per application (mCF) was evaluated and considered suboptimal if ≤5 g. The real-time graphic of CF was also evaluated and classified as pulsatile if regular variations synchronous with the atrial rate were seen; otherwise it was irregular. Results. To achieve PVI, 1458 applications were delivered; 287 (19.68%) had suboptimal mCF. A great variability of mCF was seen according to anatomy, operators and patients. Compared to applications in atrial fibrillation (AF), those in sinus rhythm (SR) showed a higher median value of mCF (11 vs.9 g; p=0.0099) and a lower percentage of suboptimal mCF (17.95 vs. 25.15%; p=0.0051). Compared to the irregular, the pulsatile pattern, almost exclusively observed in SR, was associated with higher mCF (14.69±8.77 vs. 10.79±7.89 g; p<0.0001) and fewer suboptimal applications (8.02 vs. 27.73%; p<0.0001). Conclusion. During PVI, several factors influence CF, which, despite optimisation attempts, can be suboptimal in about 20% of the applications. However, CF is higher in SR than in AF and this is strictly associated with a pulsatile pattern of instant CF values.