Pulmonary Vein Reconnection Sites Research Articles

Causes for recurrence after personalized radiofrequency catheter ablation for paroxysmal atrial fibrillation and pulmonary vein reconnection site characteristics

Abstract Funding Acknowledgements Type of funding sources: None. Background Personalized pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF), tailoring the ablation index (AI) to the left atrial wall thickness (LAWT), has proven to be a highly efficient method with excellent arrhythmia free survival rates. However, the number and location of pulmonary vein (PV) reconnection sites in patients with arrhythmic recurrences after personalized PVI is not known. Purpose We aimed to analyze the PV reconnection sites and the probable causes responsible for these PV reconnections during REDO procedures after personalized atrial fibrillation (AF) ablation. Methods Consecutive patients referred for a REDO procedure, after a personalized ablation protocol for PAF, were included in the analysis. During the index procedure and using ADAS 3DTM imaging platform for segmentation, the LAWT maps were obtained from multidetector computerized tomography (MDCT) and, thereafter, imported into CARTO 3 navigation system. If reconnection of a PV was confirmed, the LAWT of the reconnection site was analyzed. Patients who lost follow-up were excluded. Results Among 251 consecutive patients who underwent personalized PVI from April 2019 to July 2021, 45 (17,9%) had recurrence of atrial tachyarrhythmias after a mean follow-up of 1,4 ± 0,8 years. Of them, 28 underwent a REDO AF ablation procedure. 26 patients (93%) had PV reconnections [17 (60%) had both right and left reconnected PVs, 5 (18%) isolated right PV reconnection and 4 (14%) isolated left PV reconnection]. Overall, there were 76 reconnection points (40 in right PVs and 36 in left PVs). Mean LAWT in right and left PV reconnection sites was 2 ± 0,8 mm and 3,1 ± 1,2 mm, respectively. Most frequent sites of PV reconnections were anterosuperior and anterior carina for RPV (accounting for 55% of reconnection points) and anterosuperior, anterior ridge and anteroinferior for LPV (75%). Only 2 PV reconnections (3%) occurred in areas with LAWT < 1 mm. Analyzing the possible causes for PV reconnections, we found a causal relationship in 20 reconnected points (26%): gaps in the ablation line (distance between two adjacent VISITAG™ > 6 mm) in 5, lower ablation index than pre-specified in the personalized ablation protocol at a given point in 15, and absence of right carina ablation line in 5 cases. Catheter instability and misinterpretation of the color-coded LAWT were the main causes of these suboptimal (under target RF dosing) ablation lesions. Conversely, among 6 patients with no gaps and optimal ablation lesions according to the pre-specified protocol, only 1 had PVs isolated during the REDO procedure. Conclusion Most of the patients with AF recurrence after a personalized AF ablation had PV reconnections. Reconnection points were more frequently present in thicker segments of both PVs. GAPS in the ablation line, suboptimal ablation lesions and catheter instability are associated with PV reconnections.

In Atrial Fibrillation, Omnipolar Voltage Maps More Accurately Delineate Scar Than Bipolar Voltage Maps

BackgroundOptimal method for voltage assessment in AF remains unclear. ObjectivesThis study evaluated different methods for assessing atrial voltage and their accuracy in identifying pulmonary vein reconnection sites (PVRSs) in atrial fibrillation (AF). MethodsPatients with persistent AF undergoing ablation were included. De novo procedures: voltage assessment in AF with omnipolar voltage (OV) and bipolar voltage (BV) methodology and BV assessment in sinus rhythm (SR). Activation vector and fractionation maps were reviewed at voltage discrepancy sites on OV and BV maps in AF. AF voltage maps were compared with SR BV maps. Repeat ablation procedures: OV and BV maps in AF were compared to detect gaps in wide area circumferential ablation (WACA) lines that correlated with PVRS. ResultsForty patients were included: 20 de novo and 20 repeat procedures. De novo procedure: OV vs BV maps in AF; average voltage 0.55 ± 0.18 mV vs 0.38 ± 0.12 mV; P = 0.002, voltage difference of 0.20 ± 0.07 mV; P = 0.003 at coregistered points and proportion of left atrium (LA) area occupied by low-voltage zones (LVZs) was smaller on OV maps (42.4% ± 12.8% OV vs 66.7% ± 12.7% BV; P < 0.001). LVZs identified on BV maps and not on OV maps correlated frequently to wavefront collision and fractionation sites (94.7%). OV AF maps agreed better with BV SR maps (voltage difference at coregistered points 0.09 ± 0.03 mV; P = 0.24) unlike BV AF maps (0.17 ± 0.07 mV, P = 0.002). Repeat ablation procedure: OV was superior in identifying WACA line gaps that correlated with PVRS than BV maps (area under the curve = 0.89, P < 0.001). ConclusionsOV AF maps improve voltage assessment by overcoming the impact of wavefront collision and fractionation. OV AF maps correlate better with BV maps in SR and more accurately delineate gaps on WACA lines at PVRS.

Areas of minimal generator impedance drop during the index atrial fibrillation ablation correlate with pulmonary vein reconnection sites despite adopting the CLOSE protocol

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein (PV) isolation is the cornerstone of atrial fibrillation (AF) management. However, AF recurrence is extremely common after a single procedure. The CLOSE protocol, which is the standardisation of radiofrequency catheter ablation by delivering a point-by-point lesion set defined by ablation index (AI), has demonstrated 80% freedom of AF. Yet PV reconnection is still up to 38% in these patients (1). A small decrease in generator impedance (GI), which is not part of the AI algorithm, has been associated with recovery of PV conduction. Purpose The study aimed to identify whether lesions having a poor impedance drop (PID) after wide area circumferential ablation (WACA) are associated with PV reconnection, despite adopting to the CLOSE protocol. Methods 120 consecutive patients who had both the index (i-AFA) and redo AF ablations (r-AFA) due to AF recurrence at our centre from Jan 2018 to Jun 2021 were screened. 18 patients who had WACA around PVs using high power (40 to 50W) with a minimum AI of 400, whilst adhering the CLOSE protocol during the i-AFA, and who had evidence of PV reconnection during r-AFA, were included in the study. Ones who had left atrial (LA) substrate or cryoablation were excluded. GI was measured between the skin patch and ablation catheter. CARTO® system was used to create LA electroanatomical maps (EAMs) and register ablation lesions. Each WACA around PVs was divided into eight anatomical segments (Figure). PID was defined as an impedance change of &amp;lt;8Ω, based on previous studies (2). These lesions were identified and categorised to the relevant anatomical segment in the i-AFA. Locations of the discrete ablation lesions that re-isolated PVs during the r-AFA, were used as a surrogate to denote areas of PV reconnection. These were also spatially matched to the relevant anatomical segment. Each EAM was reviewed by two electrophysiologists. Results 30 out of the 36 WACAs (83%) and on average, at least 2 segments per WACA (2.6; 95% confidence interval (CI): 2.2-3.1) had reconnected. 54% of the reconnected segments had at least one lesion with PID. Having a lesion with PID in a PV segment in the i-AFA was significantly associated with evidence of PV reconnection in the same segment in the r-AFA (odds ratio: 2.1 [95% CI: 1.3-3.6; p&amp;lt;0.01]). Right posterior/inferior (56%) and left anterior/superior (50%) PV segments were the most common areas to reconnect and these areas were also associated with a higher incidence of PID lesions in the i-AFA (94% and 67%, respectively). Conversely, 80% of segments with all lesions having an impedance drop of ≥8Ω had no PV reconnection. Conclusion Lesions with PID in the i-AFA could impact PV reconnection, despite lesion contiguity and an adequate AI. Identifying and targeting these areas of PID, in addition to the CLOSE protocol, could potentially reduce AF recurrence. Prospective studies are needed to validate this hypothesis and its safety.

Left atrial wall thickness and its relationship with reconnection after pulmonary vein isolation in patients with atrial fibrillation evaluated using a three-dimensional wall thickness map

BackgroundThe major cause of recurrence after pulmonary vein (PV) isolation for atrial fibrillation (AF) is PV reconnection, and thicker wall could be associated with reconnection.ObjectivesThis study aimed to evaluate the wall thickness of the PV antrum in reconnection sites using a three-dimensional (3D) wall thickness map.MethodsA total of 91 patients who underwent a second ablation procedure due to AF recurrence were evaluated. The locations of the PV reconnection sites were confirmed in electroanatomical maps. A 3D atrial wall thickness (AWT) map was created using computed tomography scan data. The AWT values of the ablation lines of the index procedure were graded in each segment of the PV antrum: grade 1, 0.5 < AWT ≤ 1.0 mm; grade 2, 1.0 < AWT ≤ 1.5 mm; grade 3, 1.5 < AWT ≤ 2.0 mm; grade 4, 2.0 < AWT ≤ 2.5 mm; grade 5, AWT > 2.5 mm.ResultsA total of 281 PV reconnection sites among 1256 segments of the PV antrum in 79 patients were detected. The average AWT grades were 2.7 ± 1.0 and 2.2 ± 1.0 in the reconnected and non-reconnected segments, respectively (P < 0.01). Higher AWT grades were observed in the reconnected superior segments of the left superior PV, carina and inferior segments of the left inferior PV, superior and posterior segments of the right superior PV, and posterior and inferior segments of the right inferior PV.ConclusionThe reconnected segments of the PV antrum showed thicker myocardium than the non-reconnected ones in patients with recurrent AF after catheter ablation. A wall thickness map for PV isolation could be considered for customized ablation in order to reduce PV reconnection.

The impact of mechanical oesophageal deviation on posterior wall pulmonary vein reconnection.

During atrial fibrillation ablation, oesophageal heating typically prompts reduction or termination of radiofrequency energy delivery. We previously demonstrated oesophageal temperature rises are associated with posterior left atrial pulmonary vein reconnection (PVR) during redo procedures. In this study, we assessed whether mechanical oesophageal deviation (MED) during an index procedure minimizes posterior wall PVRs during redo procedures. Patients in whom we performed a first-ever procedure followed by a clinically driven redo procedure were divided based on both the use of MED for oesophageal protection and the ablation catheter employed (force or non-force sensing) in the first procedure. The PVR sites were compared between MED using a force-sensing catheter (MEDForce), or no MED with a non-force (ControlNoForce) or force (ControlForce) sensing catheter. Despite similar clinical characteristics, the MEDForce redo procedure rate (9.2%, 26/282 patients) was significantly less than the ControlNoForce (17.2%, 126/734 patients; P = 0.002) and ControlForce (17.5%, 20/114 patients; P = 0.024) groups. During the redo procedure, the posterior PVR rate with MEDForce (2%, 1/50 PV pairs) was significantly less than with either ControlNoForce (17.7%, 44/249 PV pairs; P = 0.004) or ControlForce (22.5%, 9/40 PV pairs; P = 0.003), or aggregate Controls (18.3%, 53/289 PV pairs; P = 0.006). However, the anterior PVR rate with MEDForce (8%, 4/50 PV pairs) was not significantly different than Controls (aggregate Controls-3.5%, 10/289 PV pairs, P = 0.136; ControlNoForce-2.4%, 6/249 PV pairs, P = 0.067; ControlForce-10%, 4/40 PV pairs, P = 1.0). Oesophageal deviation improves the durability of the posterior wall ablation lesion set during AF ablation.

Characterization of pulmonary vein reconnection post Cryoballoon ablation

BackgroundThe Arctic Front Cryoballoon System is a technology in which substrate alterations in patients with atrial fibrillation (AF) recurrence have not been well characterized. In this study, we evaluated sites of pulmonary vein (PV) reconnections and the accuracy of the Achieve™ circular mapping catheter in detecting these reconnections after cryoablation. MethodsThis study included 15 patients undergoing redo AF ablation after a prior single cryoablation procedure. PV reconnection sites were determined by measuring PV signals and high output pacing from 4 vectors of the Achieve catheter. The results were compared with a roving mapping catheter guided by rotational intracardiac echocardiography (ICE) in the left atrium. ResultsAll patients had PV reconnections (2.1 ± 0.8 veins/patient). The left superior PV was most commonly reconnected (n = 11), whereas the right inferior PV was least likely (n = 3). Both carinas (left: n = 11; right: n = 7) and left atrial appendage ridge (n = 11) were also frequently reconnected. Mapping with the Achieve catheter showed a positive predictive value (PPV) 100% and negative predictive value (NPV) 96% when compared with ICE guided mapping. In 2 patients, right superior PV reconnection was not identified by the Achieve. ConclusionDuring redo AF ablation after index cryoablation, multiple PVs are usually reconnected, with both carinas and left atrial appendage ridge being common sites of reconnection. The Achieve mapping catheter was able to identify reconnection with high positive and negative predictive values.

No association between dormant conduction sites and pulmonary vein reconnection sites in late atrial fibrillation recurrence after catheter ablation

ObjectiveDespite use of provocation testing to unmask dormant left atrium (LA)-PV conduction after index pulmonary vein isolation (PVI) for atrial fibrillation (AF), AF recurrence still occurs, with PV reconnection as the main cause. In an effort to answer the question whether freedom from AF recurrence can be achieved by ablation that targets sites of dormant conduction, we compared sites of dormant conduction against sites of PV reconnection identified at the time of repeat ablation for AF recurrence. Materials and methodsThe study group comprised 46 patients (30 men/16 women, aged 58.7±10.3 years) with AF (paroxysmal: n=37, persistent: n=9) who underwent repeat ablation for AF recurrence 12.3 (7.4–29.7) months after the index ablation procedure. Ipsilateral PVs were divided into 8 segments each (736 total segments), and the relation between dormant conduction sites and PV reconnection sites was determined per segment. ResultsDormant LA-PV conduction was unmasked and ablated in 22 (47.8%) of the 46 patients at sites within 43 (5.8%) of the 736 PV segments. Late PV reconnection was found within 122 (17%) of the 736 PV segments at the time of re-ablation for AF recurrence. Only 22 (18%) of these 122 PV segments corresponded to dormant conduction sites identified during the index procedure. ConclusionAlthough additional ablation to eliminate dormant PV conduction unmasked during the index ablation procedure is performed, the majority of PVs that show reconduction at the time of treatment for clinical AF recurrence are PVs that have not shown dormant conduction.

Long Term Outcome and Pulmonary Vein Reconnection of Patients Undergoing Cryoablation and/or Radiofrequency Ablation: Results from The Cryo Versus RF Trial.

Long term prospective data comparing the efficacy of radiofrequency (RF) and cryoballoon ablation (CRYO) for paroxysmal atrial fibrillation (PAF) is lacking. We report the long-term outcomes of a randomized control trial comparing CRYO to RF ablation, or a novel COMBINED approach (RF followed by CRYO) for PAF. We studied the number and pattern of pulmonary vein (PV) reconnections in patients undergoing repeat procedure(s). The COMBINED approach had significantly higher single procedure success rate and is associated with the fewest reconnected PVs. 203 patients who underwent first time PAF ablation in a randomized clinical trial comparing CRYO (67), RF (67) and COMBINED (69) approaches were followed up. All patients with symptomatic recurrence of AF were offered a repeat procedure(s). Reconnected PV(s) at repeat procedure(s) were recorded. In a subset, the PV reconnection sites during the first repeat procedure were prospectively assessed and categorised into one of 8 segments. . At 5 years, 57% of COMBINED patients remained free of AF after a single procedure compared to 47% CRYO and 19% RF patients (p<0.001 COMBINED vs RF and CRYO vs RF, p=0.043 COMBINED vs CRYO). During the first repeat procedure, theCOMBINED group had less number of reconnected PVs (mean number of reconnected PVs in the COMBINED group 1.2 vs 2.3 CRYO and 2.4 RF, p=0.034). There was a different pattern of PV reconnection comparing the CRYO and RF groups. The COMBINED approach had a significantly higher single procedure success rate with fewer reconnected PVs and fewer reconnection sites compared to either CRYO or RF alone. CRYO in turn was superior to RF. PV reconnection pattern differed between CRYO and RF and the synergistic effect of the COMBINED approach may explain the improved single procedure efficacy.

Sites With Small Impedance Decrease During Catheter Ablation for Atrial Fibrillation Are Associated With Recovery of Pulmonary Vein Conduction.

To correlate impedance decrease during atrial fibrillation (AF) ablation with lesion durability and PV conduction recovery demonstrated during redo procedures. Markers of successful ablation beyond acute conduction block are needed to improve durability of pulmonary vein (PV) isolation (PVI). Local impedance decrease resulting from ablation is a real-time marker of tissue heating and is correlated with lesion creation. Impedance changes associated with point-by-point radiofrequency ablation in the PV antra were recorded during 167 consecutive first-time AF ablations. During clinically indicated redo procedures, sites of recovered PV conduction were identified, and were correlated with the impedance change achieved during ablation at these locations during the initial procedure. Redo procedures were performed in 28 patients, in whom 19 sites of recovered PV conduction were documented. Most sites of PV reconnection (58%) occurred along the posterior PV antra. Ablation resulting in impedance decrease <10 ohms during the initial procedure was present in 89% (17/19) of sites with conduction recovery. Regions with adjacent ablation resulting in impedance decrease <10 ohms were associated with a higher rate of conduction recovery (37% vs. 1.5%, P < 0.001). Likewise, patients with PV conduction recovery demonstrated during redo procedure (Group 1) had larger regions where ablation resulted in <10 ohm impedance decrease than patients without PV conduction recovery (Group 2) (21.9 ± 15.5 mm vs. 11.5 ± 2.1 mm, P < 0.01). Recovered PV conduction occurs predominantly in regions where adjacent ablation applications result in impedance decreases <10 ohms. Impedance-guided ablation strategies may improve durability of PVI.

Difference Between Dormant Conduction Sites Revealed by Adenosine Triphosphate Provocation and Unipolar Pace-Capture Sites Along the Ablation Line After Pulmonary Vein Isolation

Dormant pulmonary vein (PV) conduction revealed by adenosine/adenosine triphosphate (ATP) provocation test and exit block to the left atrium by pacing from the PV side of the ablation line ("pace and ablate" method) are used to ensure durable pulmonary vein isolation (PVI). However, the mechanistic relation between ATP-provoked PV reconnection and the unexcitable gap along the ablation line is unclear.Forty-five patients with atrial fibrillation (AF) (paroxysmal: 31 patients, persistent: 14 patients; age: 61.1 ± 9.7 years) underwent extensive encircling PVI (EEPVI, 179 PVs). After completion of EEPVI, an ATP provocation test (30 mg, bolus injection) and unipolar pacing (output, 10 mA; pulse width, 2 ms) were performed along the previous EEPVI ablation line to identify excitable gaps. Dormant conduction was revealed in 29 (34 sites) of 179 PVs (16.2%) after EEP-VI (22/45 patients). Pace capture was revealed in 59 (89 sites) of 179 PVs (33.0%) after EEPVI (39/45 patients), and overlapping sites, ie, sites showing both dormant conduction and pace capture, were observed in 22 of 179 (12.3%) PVs (17/45 patients).Some of the ATP-provoked dormant PV reconnection sites were identical to the sites with excitable gaps revealed by pace capture, but most of the PV sites were differently distributed, suggesting that the main underling mechanism differs between these two forms of reconnection. These findings also suggest that performance of the ATP provocation test followed by the "pace and ablate" method can reduce the occurrence of chronic PV reconnections.

Cryoballoon versus radiofrequency catheter ablation of paroxysmal atrial fibrillation: Biomarkers of myocardial injury, recurrence rates, and pulmonary vein reconnection patterns

Cryoballoon ablation has emerged as a novel treatment strategy for patients with atrial fibrillation (AF). The purpose of this study was to compare pulmonary vein isolation (PVI) using cryoballoon ablation versus RF ablation with regard to myocardial injury, pulmonary vein (PV) reconnection patterns, and outcome. Fifty patients (age 59 ± 9 years, ejection fraction 0.59 ± 0.06, left atrial size 41 ± 5 mm) with paroxysmal AF were studied. Twenty-five patients underwent PVI using a 28-mm cryoballoon. A control group of 25 patients underwent PVI using an open-irrigation RF ablation catheter. Myocardial injury was determined by measuring troponin T (TnT). PV reconnection patterns were studied in case of repeat procedures. Procedure duration was 166 ± 32 minutes in the cryoballoon group versus 197 ± 52 minutes in the RF group (P = .014), with similar ablation times (cryoballoon: 45 minutes [interquartile range 40-52.5 minutes]; RF: 47 minutes [interquartile range 44-65 minutes], P = .17). Postprocedural TnT in the RF group was 1.29 ± 0.41 μg/L versus 0.76 ± 0.55 μg/L in the cryoballoon group (P = .002). In 12 patients who underwent repeat ablation, 74% of PV reconnection sites were inferiorly located in the cryoballoon group compared to 17% in the RF group (P = .0004). With 1.2 ± 0.4 and 1.3 ± 0.6 procedures per patient, 88% of patients in the cryoballoon group and 92% in the RF group were in stable sinus rhythm after follow-up of 12 ± 3 months (P = NS). Differences in the extent of myocardial injury and patterns of PV reconnection were observed between cryoballoon ablation and RF ablation of paroxysmal AF.