The Dissimilar Impact in Atrial Substrate Modificationof Left and Right Pulmonary Veins Isolation after Catheter Ablation of Paroxysmal Atrial Fibrillation

Abstract

Since the discovery of pulmonary veins (PVs) as foci of atrial fibrillation (AF), the commonest cardiac arrhythmia, investigation revolves around PVs catheter ablation (CA) results. Notwithstanding, CA process itself is rather neglected. We aim to decompose crucial CA steps: coronary sinus (CS) catheterization and the impact of left and right PVs isolation (LPVI, RPVI), separately. We recruited 40 paroxysmal AF patients undergoing first-time CA and obtained five-minute lead II and bipolar CS recordings during sinus rhythm (SR) before CA (B), after LPVI (L) and after RPVI (R). Among others, duration, amplitude and atrial-rate variability (ARV) were calculated for P-waves and CS local activation waves (LAWs). LAWs features were compared among CS channels for reliability analysis. P-waves and LAWs features were compared after each ablation step (B, L, R). CS channels: amplitude and area were different between distal/medial (p≤0.0014) and distal/mid-proximal channels (p≤0.0025). Medial and distal showed the most and least coherent values, respectively. Correlation was higher in proximal (≥93%) than distal (≤91%) areas. P-waves: duration was significantly shortened after LPVI (after L: p=0.0012, −13.30%). LAWs: insignificant variations. ARV modification was more prominent in LAWs (L: >+73.12%, p≤0.0480, R: <−33.94%, p≤0.0642). Medial/mid-proximal channels are recommended during SR. CS LAWs are not significantly affected by CA but they describe more precisely CA-induced ARV modifications. LPVI provokes the highest impact in paroxysmal AF CA, significantly modifying P-wave duration.

The Relevance of Heart Rate Fluctuation When Evaluating Atrial Substrate Electrical Features in Catheter Ablation of Paroxysmal Atrial Fibrillation

“…This channel varied among patients, but was always the same for one patient at all three time points from which the recordings were obtained. In case all channels showed a high amplitude and clear signals, medial or mid-proximal channels were selected [ 13 ].…”

“…Since structural changes are connected with the anatomical alteration of the atria, a blanking period of 3 months is typically used in order to safely assess the structural substrate modification [ 7 , 10 ]. Although electrical and functional—related to freedom from AF—modification have been observed as early as one day after CA, electrical substrate modification can in fact be observed even earlier, immediately after the CA procedure [ 11 , 12 , 13 ].…”

“…Nevertheless, variable CS anatomy and vivid cardiac contraction can complicate the CS cannulation procedure, and the selection of the proper CS channel for analysis should be performed with caution and may differ for recordings in AF or in sinus rhythm (SR). Recently, a study alerted the risk of high noise prevalence in recordings from the distal tip of the CS catheter during SR [ 13 ].…”

Progressions in Cardiac Arrhythmia: Specific Populations and the Need for Precision Medicine

“…In brief, they showed that left PVI is the critical part of the CA of PVs for paroxysmal AF patients, significantly altering the P-wave duration, whereas the effect of the CA of PVs on the coronary sinus is less straightforward and is demonstrated to a lesser extent. The authors suggest that other atrial structures may be more indicative of the ablation outcome and should be assessed as alternative references [3].…”