Catheter Ablation Research Articles

AV nodal ablation in atrial fibrillation: long term outcomes

Abstract Background Ablation of the atrioventricular (AV) node, following the insertion of a permanent pacemaker, is a treatment option for symptomatic atrial fibrillation (AF) where rate control is poor, despite maximally tolerated pharmacological intervention or percutaneous AF ablation [1], and yet there is limited data on long-term outcomes. Purpose The purpose of this study is to investigate post AV node ablation follow up outcomes, including the incidence and timeframe of conversion of paroxysmal to persistent AF; incidence and timeframe of upgrade to biventricular pacemakers; and mortality. Methods This observational descriptive study looked at the post-procedure follow-up outcomes of patients who underwent AV node ablation at our centre between March 2015 and June 2019. Retrospective analysis of prospectively collected data was analysed. The demographics of the patients, including their age, gender, co-morbidities, pre-ablation left ventricular ejection fraction (LVEF) and medications were recorded. The follow up outcomes investigated included the change in LVEF, the proportion of patients whose AF converted from paroxysmal to persistent, the proportion of patients requiring upgrade to biventricular devices, and deaths within 6 months of ablation. Outcomes were compared between those who had a biventricular pacemaker pre-ablation and those who had single/dual chamber pacemakers. Results 296 patients with a mean age of 72.7± 8.5 years and a female to male ratio of 54.1% : 45.9% were included. 94 patients (31.8%) had paroxysmal AF pre- ablation. 51.6% of those who had paroxysmal AF pre-ablation converted to persistent AF over a median period of 3 years (interquartile range, 3 years). Among those who had a biventricular pacemaker pre-ablation, 56.5% of those with paroxysmal AF converted to persistent, compared to 47.4% of those with a dual pacemaker pre-ablation p=ns Among patients with dual chamber pacemakers, those who remained in paroxysmal AF post-ablation had a mean CHADVASC score of 3.2 (range of 1-6) compared to 3.7 (range of 2-6) in those whose AF converted to persistent (p=0.19). 9 patients (3%) died within less than 6 months of the procedure, with 1 patient dying within 6 days. 13% of the patients originally having a single or dual chamber pacemaker required an upgrade to a biventricular pacemaker over a median period of 1.25 years (interquartile range 1.1 years). All the patients who required an upgrade to a biventricular pacemaker had normal LVEF pre-ablation except for one patient who had mild LV impairment. Conclusions A significant proportion of patients with paroxysmal AF converted to persistent AF following AV node ablation and having a biventricular pacemaker did not offer benefit in keeping people in paroxysmal AF.A considerable number of people required an upgrade to biventricular pacemaker over a short time frame even though they had normal LVEF pre AV nodal ablation.

Improved procedural workflow for catheter ablation of paroxysmal AF with high density mapping system and advanced technology: insights from a multicenter, international study

Abstract Background A high incidence of pulmonary vein (PV) reconnection has been reported in patients with clinical recurrences of AF. Low-voltage activity beyond PVs (e.g. antral activity potentials, RAP) likely represent vulnerabilities in antral lesion sets and they may contribute to ablation failures. Purpose The aim of this study is to validate a structured application of an approach that includes the complete abolition of any antral potential achieving electrical quiescence in antral regions. Methods DELETE AF is a prospective, single-arm, international post-market cohort study. Consecutive patients from 10 centers who were undergoing radiofrequency ablation of paroxysmal AF were included. The Lumipoint map-analysis tool was used sequentially on each PV component. Post-ablation, all patients were monitored with ambulatory event monitoring, starting within 30 days post-ablation to proactively detect and manage any recurrences within the 90-day blanking period, as well as Holter monitoring at 3, 6, 9, and 12 months post-ablation. Additional ECG monitoring were performed as indicated by patient symptoms. The ablation endpoint was PV isolation (PVI). Long-term outcome was the recurrence of AF over follow-up. Data are reported as median [IQ range]. Results One-hundred ten cases of AF ablation were analyzed: 28 (25.5%) females, age=63[56-69] years, 24 (21.8%) patients with a history of AT/AFL. The procedure duration was 58[24-76] min (RF delivery time=18[12-28] min, number of ablation spots=77[44-101]) and the fluoroscopy time was 13[9-19] min. Thirty-eight (34.5%) were repeat ablation: in these patients after initial mapping a total of 114 PV gaps (PVGs) in 29 (76.3%) patients and 69 RAPs in 15 patients (39.5%) were found. After ablation, a total of 5 early PVGs in 2 (1.8%) patients (all in de novo procedures) and a total of 10 RAPs in 7 (6.3%) patients (3 out 38 -7.9%- of repeat ablations vs 4 out 72 -5.6%- of de novo cases, p=0.690) were detected after first remapping. Each residual PVG was first targeted and additional focal ablations were performed at any low-voltage propagation suspected within the region of previous antral ablation. Acute procedural success was 100%, with all PVs successfully isolated and RAPs completely abolished in all study patients except for one that still exhibited a residual low-voltage antral signal after adenosine infusion with no PV conduction. Eighty-six (78.2%) patients had complete follow-up information. During the 90-day blanking period, 8 (9.2%) patients experienced an early recurrence. After the blanking period, over a follow-up of 357[190-380] days, 13 patients (15.1%) suffered an AF recurrence (time to recurrence: 207[144-300] days). No major complications or adverse events occurred. Conclusion A structured ablation workflow for catheter ablation, with consistent high-density mapping and improved diagnostic tools to guide the ablation, proved to be safe and effective in paroxysmal AF.

A straightforward assessment of anterior mitral isthmus lines block

Abstract Background Complex atrial fibrillation (AF) and left atrial flutter (LAFL) ablation procedures often involve creating lines on the anterior wall of the left atrium, such as the anterior septal and lateral mitral isthmus lines. Purpose This study aims to evaluate the role of a simplified criteria to demonstrate the achievement of conduction block across the anterior wall of the left atrium ("anterior mitral isthmus") after linear ablation (LA). Methods Patients scheduled for persistent AF or LAFT ablation were prospectively recruited. The procedure employed a homogeneous LA strategy that included the anteromedial, anterolateral and roof lines. The following intervals were measured before and after LA, placing a multipolar catheter in the left atrial appendage (LAA) in order to register the earliest egm in a reproducible position: 1) P-LAA: conduction time from the sinus P wave onset to the LAA, 2) IASp-LAA: conduction time pacing at CL 500 ms from the interatrial septum to the LAA, 3) CSp-LAA: conduction time pacing at CL 500 ms from the distal CS to the LAA, 4) LAA-QRS onset. Patients with linear ablation were further divided according to the presence or block (BG) or non-block group (NBG) in the anterior at the end of the procedure, demonstrated with a high-density activation map. A parallel control group (CG) of patients with paroxysmal AF without LA was also included for comparison. Statistical analysis involved the Kruskal-Wallis and Mann-Whitney test with Bonferroni correction. Results 21 patients were enrolled in the study: mean age 66.67 years (± 8.48), 80% male sex. Among them, 16 had AF and AFL and underwent LA, while the remaining 5 constitute the CG. Baseline measures before LA did not exhibit significant differences compared to the CG with mean values for P-LAA at 93±20 ms (P=2.35), IASs-LAA at 82±27 ms (P=1.94), CSs-LAA at 52±17 ms (P=0.91), and LAA-QRS at 80±27 ms (P=1.82). However, upon comparing the BG and NBG, significant differences emerged in P-LAA (82±10 ms vs. 11±5 ms (P=0.002) and IAS-LAA (83±17 ms vs. 27±24 ms (P=0.004), while no significant differences were observed in the remaining intervals. In comparisons between the BG and the CG, significant differences were noted in P-LAA (82±10 ms vs. 16±10 ms (P=0.01) and IAS-LAA (83±17 ms vs. 1.2±17 ms (P=0.01), without differences in the other intervals. Conversely, when comparing NB to the CG, no significant differences were observed in any of the intervals. Finally, P-LAA >70 ms and the IASp-LAA >55 ms showed a sensitivity of 100 % and specifitity of 100 vs. 87% respectively to discriminate anterior wall block. Conclusion The simple measurement of the P-LAA and IAS-LAA interval proves highly valuable in evaluating anterior mitral isthmus lines block, serving as a complementary approach to conventional maneuvers. P-LAA >70 ms and IASp-LAA > 55 ms could be usefull to discriminate anterior wall block.Anterior linear ablation with block

Prevalence of diabetes mellitus diminished the efficacy of additional ablation following pulmonary vein isolation: a sub-analysis of the EARNEST-PVI trial

Abstract Introduction Diabetes mellitus (DM) is a well-known cause of atrial remodeling in patients with atrial fibrillation (AF). Although additional left atrial ablation following pulmonary vein isolation (PVI) is a strategy to modify AF substrate, its efficacy has not been well elucidated in patients with DM. We hypothesized that the efficacy of additional ablation was different in patients with DM and in those without. Purpose The purpose of this study was to investigate the efficacy of additional ablation following PVI in patients with or without DM. Methods The EARNEST-PVI was a multicenter, prospective, randomized controlled trial. In this sub-analysis, 493 consecutive patients of persistent AF (age, 65 ± 9 years; female, 120 [24%] patients) who underwent the initial radiofrequency catheter ablation were analyzed. Patients were randomized to be treated with PVI only (PVI-alone) or PVI plus linear and/or complex fractionated atrial electrogram ablation (PVI-plus). Primary outcome measure was defined as AF recurrence during the 12 months follow-up periods. Results In total, 84 (17%) patients had DM. Primary outcome occurred in 120 (24%) patients. In patients without DM, freedom from AF recurrence was significantly higher in PVI-plus group than in PVI-alone group (80.0% versus 71.1%, p=0.03) (Figure 1A). Conversely, in patients with DM, freedom from AF recurrence was similar between PVI-plus group and PVI-alone group (75.4% versus 72.9%, p=0.70) (Figure 1B). Conclusion Additional ablation following PVI reduced AF recurrence after radiofrequency catheter ablation only in patients without DM.Figure 1

Electrophysiological findings, incidence, and predictors for AF recurrence after pulsed field versus radiofrequency pulmonary vein isolation. A retrospective analysis

Abstract Background Pulsed field ablation (PFA) is an emerging method for catheter ablation of atrial fibrillation (AF). Data comparing efficacy and safety of PFA compared to thermal ablation is still scarce. In this study, we compared a cohort of patients who underwent PFA with those who received very high power short duration (vHPSD) radiofrequency catheter ablation at the University Hospital Graz. Methods We analysed baseline data from both cohorts (PFA: n=231; RF: n=243). Both procedures were performed under deep sedation, using propofol and fentanyl. The PFA procedure involved 2x2x2 pulses, with additional pulses as required. RF procedures were performed using the QDOT Micro catheter to deliver 90 watts of energy over 4 seconds. Statistical analysis was performed using IBM SPSS Statistics for Windows, version 29. The Kruskal-Wallis test was used for quantitative non-parametric data in the baseline analysis, and the Man-Whitney-U test was used for quantitative non-parametric procedural data. For qualitative variables the Chi-squared test was used. A p-value of less than 0,05 was considered significant. Results Both groups were similar, apart from chronic heart failure, which was more prevalent in the RF group (p=0.003). Mean age for both groups was 62±10 years and mean body mass index did not differ as well. CHADS-VASc score was 2±2 in the RF and 2±1 in the PFA group (p=0.7). The types of AF were distributed as follows: (RF vs.PFA): PAF: 64%/61%; persAF: 34/36%; long standing persAF: 2%/3%. As to this date performing a CTI line with PFA is off-label, a significantly higher number of patients with additional flutter were ablated in the RF group. In the RF-group, 91 patients underwent additional cavotricuspid isthmus ablation, compared to only 14 patients in the PFA group (p<0.001). Procedural time (RF:PFA 122±min:57±26min; p<0.001), fluoroscopy time (RF:PFA 15±9min:19±9min; p<0.001) and fluoroscopy dose (RF:PFA 17±40Gycm2:15±15Gycm2, p=0.026) showed significant differences, with procedural time and fluoroscopy dose presenting lower values in the PFA group. First pass isolation was achieved more frequently in the PFA group (85% vs. 57%; p<0,001). There was significant difference in recurrence rates between the vHPSD and PFA groups (RF: 56/242 (28%), PFA: 38/231 (17%); p=0.005). Additionally, time to recurrence in the RF group was 138±117 days, compared to 166±84min in the PFA group. We exclude operator dependence as the same operators performed both procedures. Conclusion Based on our findings, PFA could potentially become the standard procedure for many patients. However, randomized trials are needed to confirm these findings.

Radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique: 9-year outcome

Abstract Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory atrial fibrillation. Cryoablation has been shown to be a safe and effective technique for pulmonary vein isolation. However, there is a significant arrhythmia recurrence rate after cryoablation procedures and there are no established strategies for redo procedures in these patients. Therefore, we have summarized our experience with radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique (including an analysis of pulmonary vein conduction recovery patterns after procedures performed with the first or second generation cryoballoon). Methods Two hundred and twenty patients (paroxysmal AF: 140 patients, persistent AF: 80 patients) had to undergo a redo procedure after initially successful circumferential PV isolation with the cryoballoon technique (First generation: 110 patients (group A); second generation: 110 patients (group B)). The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy (three-dimensional mapping system) depending on the intra-procedural findings. Results During the redo procedure, a mean number of 1.6 re-conducting PVs were detected (using a circular mapping catheter; group A: 2.2 re-conducting PVs, group B: 1.0 re-conducting PVs). There was a slightly higher incidence of chronic PV reconnections related to the left-sided PV ostia than to the right-sided PVs in both groups. Furthermore, sites of chronic PV reconnection were found more frequently in the inferior parts of the PV ostia than in the superior parts. In 97 patients in group A, a segmental approach was sufficient to eliminate the residual PV conduction because there were only a few recovered PV fibers (1-3 reconnected PVs; group A1). In the remaining 13 patients in group A, a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction of all four pulmonary veins (group A2). In group B, a segmental approach was sufficient in nearly all patients (109/110) because there was only a minor reconnection of 1-2 PVs. All recovered PVs could be isolated sucessfully again. At 108-month follow-up, 69.1 % of all patients were free from an arrhythmia recurrence (152/220 patients; group A: 72/110 patients (65.5 %), group B: 80/110 patients (72.3 %)). There were no major complications in both groups. Conclusions In patients with an initial circumferential PVI using the cryoballoon technique, a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation. In most cases only a few re-conducting PV fibers were found and therefore, a segmental re-ablation approach seems to be sufficient in the majority of patients (especially in patients treated with the second generation cryoballoon).

First clinical experience using a novel 8-spline ultra high-resolution mapping catheter to guide atrial fibrillation ablation

Abstract Background Multielectrode mapping catheters improve the detection of scarred and fibrotic tissue in patients with atrial fibrillation (AF) Recently, a novel multispline mapping catheter with 48 closely spaced microelectrodes has been introduced enabling fast high-resolution electroanatomical mapping. Objective This study sought to report our initial clinical experience with the novel Octaray catheter in patients with AF undergoing index ablation and to compare its impact on mapping and ablation with the 5-spline Pentaray catheter. Methods The study included consecutive patients who underwent index AF ablation using a multipolar mapping catheter and very high-power-short-duration guided ablation (Q4U-AF workflow; QDot; Qmode+; Biosense Webster) in conjunction with a visualized sheath (Vizigo; Biosense Webster). Arrhythmia recurrence was defined as any atrial fibrillation (AF)/ atrial tachycardia (AT) episode lasting > 30 s after a blanking period of 3 months. Results A total number of 183 patients undergoing AF ablation using the Octaray and QDot catheter were compared to a group of 166 matched patients who underwent ablation using Pentary and QDot. Utilization of the Octaray catheter resulted in an increased identification of areas with bipolar low-voltage representing fibrosis/scar or atrial cardiomyopathy (mean amount of left atrial bipolar low-voltage: Octaray 31% vs. Pentaray 18%; p= 0.03) and a higher rate of first-pass isolation (FPI) for the left-sided pulmonary veins (Octaray: FPI rate 73% vs. FPI rate 64% for Pentaray). A significantly higher number of mapping points was acquired using the novel 8-spline mapping catheter (right atrium: Octaray 1936 points vs. Pentaray 903 points; p < 0.001 left atrium: Octaray 5337 points vs. Pentaray 2385 points; p < 0.001). Procedural parameter, radiation time/dosage and acute procedural success were comparable between the two groups. During a mean follow-up of 12 months, the overall procedural success was 86 in the Octaray group vs. 84% in the control group (p=0.9). Conclusion The utilization of the novel Octaray mapping catheter resulted in an improved detection of atrial fibrosis and scar as well as a higher rate of first-pass pulmonary vein isolation. Figure: Institutional Q4U-AF-workflow using a multipolar mapping catheter, the QDot ablation catheter and a visualized sheath. High resolution mapping using the Octaray (A+B) and PentaRay catheter (C+D).

Ultra-high density mapping for the evaluation of the antral scar extension after ablation with a radiofrequency balloon catheter in atrial fibrillation patients

Abstract Background The Heliostar radiofrequency (RF) balloon ablation catheter enables one-shot pulmonary veins isolation (PVI). The RF balloon by occluding the PV ostia creates an antral scar. Purpose We sought to investigate the extension of the antral scar by mean of ultra-high density mapping. Methods Paroxysmal and persistent atrial fibrillation (AF) patients undergoing first PVI ablation with the Heliostar catheter across 4 European centers were enrolled. Ultra-high density mapping of left atrium was performed with the Octaray catheter, a octa-spline mapping catheter before and after the ablation. All maps were acquired in sinus rhythm, patients in AF underwent electrical cardioversion before mapping. The bipolar voltage maps from each patients were analysed: the left atrial area < 0.2 mV was considered scar and was calculated before and after the ablation and the distance between left and right antral lesions at upper and inferior posterior wall were also calculated. Results Overall, 49 patients were enrolled, 82% were male, the mean age was 60±9 years, 66% had paroxysmal AF. PVI was achieved in 100% patients. The mean left atrial area was 209±44 cm2, the scar after the ablation was 9±4.6 %, with 49±11% of the posterior wall still viable (bipolar voltage > 0.5mV). The distance between left and right antral lesions at the upper posterior wall was 26.57 mm whereas at the inferior aspect was 29.59 mm. Conclusions The RF balloon catheter creates a wide antral scar during AF ablation although without compromising the integrity of the posterior wall.

Advanced pulsed field ablation: comprehensive analysis of safety and efficacy in a real-world cohort

Abstract Background Pulsed field ablation (PFA) represents a novel energy modality for catheter ablation of atrial fibrillation (AF). Initial preclinical and clinical studies indicate a higher safety profile with promising efficacy outcomes as well as shorter procedure times. Real world data are sparce and methods to improve clinical success rates are under development. Methods In this observational study 124 patients underwent pulmonary vein isolation with PFA (Farapulse, Boston) for paroxysmal and persistent AF. For anatomical visualization and optimal positioning of the PFA catheter a 3D mapping system was used (Ensite X, Abbott). Patients were followed over a 15-month period to evaluate both efficacy and safety of PFA in a real-world cohort using an advanced mapping technology. Results The patient cohort had a mean age of 67 ± 11 years, 38% females (n= 47), paroxysmal AF 53% (n = 66), persistent AF 47% (n = 58). Acute pulmonary vein isolation (PVI) rate was 100%. After a median FU of 6 months, 17 patients (14%) had a recurrence of AF. In our study population no esophageal complications, pulmonary vein stenosis, or persistent phrenic palsy occurred. Major complications were observed in 2.4% of the cases (3/124), involving two pericardial tamponades (1.6%) and one vascular complication with intervention (0.8%). There were no stroke events and no occurrences of death. Noteworthy was the absence of complications such as coronary arterial spasm or hemolysis-related acute renal failure. The average dose-area product and average procedure time were 9.54 ± 7.68 µGym² and 57.94 ± 18 minutes, respectively. Conclusion PVI with PFA in a real world cohort demonstrates a high safety profile. Furthermore, high clinical success rates can be achieved also in mixed paroxysmal/persistent AF populations. The use of 3D mapping systems might even improve clinical outcomes of PVI with PFA and will also help to guide more complex ablation strategies in the future. These findings pave the way for further exploration into the long-term benefits and broader applicability of PFA in AF ablation.

Incidence, types, and predictors of AF recurrence after AF ablation with pulsed field ablation. A single-centre experience

Abstract Background Pulsed field ablation (PFA) is an emerging method for the ablation of atrial fibrillation (AF). As there are few data on incidence, types, and predictors of AF recurrence after PFA for AF ablation, we are continuously analysing our cohort. Methods We report our outcome data after PVI with PFA. Each procedure was performed under deep sedation with propofol and fentanyl. Before transeptal puncture, unfractionated heparin was administered to maintain an ACT level >300sec throughout the procedure. Isolation of pulmonary veins was started after administration of 1mg of atropine with 8 applications per vein (4 in basket, 4 in flower configuration). In recent months we have routinely performed 2 additional ablations in flower configuration with an anterior twist at both right pulmonary veins. All veins were checked for entrance- and exitblock to confirm isolation in sinus rhythm. An additional ablation was performed if necessary. Results In total, 231 patients were analysed. Mean age was 62±10 years, 38% were female. Mean CHADS-VASc score was 2±1. 61% had paroxysmal AF (PAF), 36% persistent AF, and 3% patients had long-standing persistent AF. In 85% (n=197) first-pass isolation of all veins was possible. Primary PV isolation was achieved in all patients at the end of the procedure. In addition to PVI, the cavo-tricuspid isthmus (CTI) was blocked in 6% (using radiofrequency ablation in case of previously or during the procedure documented typical flutter) and the posterior wall was isolated in another 6% during the first procedure. Mean procedure time was 60±20 minutes (24-175 minutes), mean X-ray time 19±9 minutes. In 231 procedures, only two catheter-associated complications were documented. 38 patients (16%) had arrhythmia recurrence after a blanking period of 3 months and a mean follow-up of 273±177 days. Mean time to recurrence was 171±84 days. Women were more likely to have recurrences [OR 2.042 (CI 95% 1.012-4.121), p<0,05]. Patients who had undergone any type of cardiac surgery prior to ablation were also significantly more likely to have recurrence [OR 0.517 (CI 95% 0.116-0.212); p<0.001]. Patients with no other comorbidities were more likely to remain free from arrhythmias [OR 0.792 (95% CI 0.736-0.853); p<0,01]. The type of AF did not make a significant difference according to the risk of recurrence in this cohort. To date, we have performed 18 re-do procedures in patients after PVI with PFA. The recurrent arrhythmia was AF in 39% (n=7), atypical AT in 50% (roof-dependent: 28%, n=5; mitral isthmus dependent: 22%, n=4), and CTI-dependent flutter in 39% (n=7). All but one patient had PV reconnections, and all were successfully reablated. Conclusion PFA success rate is similar to that of thermal techniques. Procedure time is shorter in experienced operators and the complication rate is low in our cohort. Results from RCTs are needed to further evaluate this new method compared to other ablation techniques.

Multicenter retrospective evaluation of a patient-tailored electrogram-based ablation strategy using an artificial intelligence software in repeat atrial fibrillation ablation procedures

Abstract Background While pulmonary vein isolation (PVI) is the gold standard approach of treatment of atrial fibrillation (AF), the optimal strategy in case of AF recurrences for redo patients is not well established. Several studies described the usefulness of ablating in atrial regions exhibiting abnormal electrograms, i.e. spatio-temporal dispersion, during AF and an artificial intelligence (AI) electrograms (EGMs)-based software solution has been developed and validated to obtain real-time adjudications of multipolar electrograms in de novo patients. Purpose This study sought to evaluate the novel AI-EGMs-based software approach for redo-AF ablation procedures. Methods This study was a retrospective, multicentric, nonrandomized study. Patients with recurrent symptomatic AF were enrolled in 7 European centers. Redo ablation procedures were performed using the AI software and acute and long-term outcomes after ablation were evaluated. Results A total of 117 patients with refractory symptomatic AF admitted for redo procedure were included with 30% paroxysmal, 42% short-standing persistent and 28% long-standing persistent AF at the time of the redo procedure. During the index procedures, a previous PVI ablation was performed in all patients while additional ablation such as lines and EGM-based ablation was performed in 64 patients (55%). Out of 117 patients, 30 (26%) presented with structural heart disease, 61 (52%) with hypertension, 31 (26%) with a BMI >30, 16 (14%) a sleep apnea syndrome and 24 (20%) had an antiarrhythmic treatment at the time of the procedure. The average AF history was 6.54 ± 4.15 years with an average sustained duration equal to 25 ± 62 months. AI-EGMs-based AF ablation was performed in all patients and easily integrated in the physicians’ workflow during redo procedures. AF termination, i.e. AF regularization or sinus rhythm conversion, occurred in 82/117 patients (71%) with sinus rhythm conversion by ablation in 79/117 patients (68%). After a mean follow-up of 11 ± 5 months, 81% of patients were free from documented AF, with or without antiarrhythmic drugs (AADs) after one redo procedure and 60% of patients were free from any documented atrial arrhythmia, with or without AADs, after one redo procedure per patient. Furthermore, we observed that 77%, 84% and 82% of patients were free from documented AF with or without AADs in paroxysmal, short-standing and long-standing persistent AF patients respectively, and that 71%, 59% and 49% of patients were free from any documented atrial arrhythmia with or without AADs in paroxysmal, short-standing and long-standing persistent AF patients respectively. Conclusions This retrospective study reports that patient-tailored spatiotemporal dispersion ablation is a relevant and standardized approach for repeat AF ablation. This was obtained with an AI-EGMs-based software solution, which may be added to the operative workflow of redo AF procedures.

Quantitative and qualitative assessment of left atrial cardiomyopathy as well as prediction of atrial fibrillation recurrences upon PVI using machine learning

Abstract Introduction Atrial fibrillation (AF) is one of the most common heart pathologies in daily clinical practice and confers significant mortality and morbidity. However, AF ablation often proves ineffective - even after successful pulmonary vein isolation (PVI). The prediction of PVI failure for the long-term treatment of AF as well as the improved assessment of the underlying substrate appears pivotal. We hypothesize, that ML can be applied to better characterize the substrate and recurrence in AF patients upon PVI. Methods & Results We retrospectively evaluated data from 205 patients that underwent AF ablation between 2019 and 2023, including high-density 3D electroanatomic maps (sinus rhythm), LA rotational angiography, invasive LA hemodynamic measurements (after transseptal passage), echocardiography, 12-lead ECG and laboratory testing. A neuronal net was trained on selected features extracted from those datasets using supervised learning and employed to predict measures of atrial cardiomyopathy and AF recurrence. Patients were 66±1 years old and received first or second pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation with 18% documented recurrences upon a mean follow-up of 23±1months. First, we extensively refined or developed tools for automated P-wave analysis from 12-lead ECGs as well as local LA voltage and volume quantification. Next, LA hemodynamics and volumes were assessed: Mean LA volume as derived from rotational angiography significantly correlated with LA volume index as obtained using echocardiography. Interestingly, LA size showed no correlation with NT-proBNP, LA low voltage or LA hemodynamics. In addition, global (25±2% of total LA area) and local (i.e. anterior, posterior, roof) LA voltage was determined and shown to be an independent predictor of AF recurrence. In our first unselected subset of 136 patients with 2nd PVI for atrial fibrillation, our ML models predicted LA fibrosis (i.e. low voltage regions; Utah stage) from 12-lead ECGs with an accuracy of 90%. Accuracy was 87% for the prediction of AF recurrences from LA pressure and low-voltage regions. In addition, the algorithm predicted AF recurrences from 12-lead SR ECGs obtained before PVI with an accuracy of 91%. Conclusion Artificial neural networks allow to quantitatively and qualitatively predict measures of atrial cardiomyopathy and atrial fibrillation recurrence probability upon complete PVI with high accuracy.Figures

A multicenter evaluation of repeat ablation for atrial fibrillation in patients with isolated pulmonary veins: a Netherlands Heart Registration study

Abstract Background Of the 25-50% atrial fibrillation (AF) ablation patients who undergo repeat ablation, approximately 15-30% have all pulmonary veins (PVs) isolated at the repeat procedure. Currently, there is limited evidence and a lack of consensus on the appropriate treatment strategy for patients with isolated PVs. Purpose Our aim was to characterize and compare the effectiveness of repeat AF ablation strategies to reduce AF recurrences in patients with isolated PVs using a real-world multicenter registry. Methods All AF patients referred for repeat AF ablation with all PVs isolated at 8 hospitals in the Netherlands were included (Netherlands Heart Registration; 2016-2019). Medical record reviews were conducted for all patients referred for repeat AF ablation to determine study eligibility, the presence of PV reconnection, ablation strategy used, and the outcome of AF recurrence. Patients referred for repeat AF ablation, with PVI only conducted during previous ablations, and all PVs isolated were eligible. Effectiveness of repeat AF ablation strategies were assessed with multivariable Cox models comparing individual ablation strategies, number of ablation strategies performed, and presence of persistent AF. Results Of 2,311 repeat AF ablations performed, 274 (11.9%) were eligible and had all PVs isolated (Figure 1). Patients with isolated PVs were a median age of 66 (IQR 58-70) years, 44.2% were women, 45.6% had persistent or long-standing persistent AF, and the median CHA2DS2-Vasc score was 2 (IQR 1-3). Ablation was not performed in 33 (12.0%) patients with isolated PVs (Figure 2a). A single ablation strategy was performed most often (41.2%; Figure 2a). Posterior box ablation was the most frequent (58.4%) ablation strategy performed, followed by antralization of the PVs (26.3%). Over a median follow-up of 2.0 (1.0-3.3) years, 147 (59.8%) patients with isolated PVs had an AF recurrence >3 months after repeat ablation and 30 (12.7%) patients had another repeat AF ablation within 1 year of repeat procedure. After multivariable adjustment, no difference in AF recurrences was detected between ablation strategies [p>0.05 for all; Figure 2b]. Further, there was no difference detected in AF recurrences for the number of ablation strategies performed (Figure 2c), the individual ablation strategy conducted, and persistent AF (p>0.05 for all). Among patients with isolated PVs, patients with larger left atrial size had a higher risk of AF recurrences [adjusted HR 1.03 (95% CI 1.01-1.05)]. Conclusion Among the 2,311 repeat AF ablations performed, 11.9% had all PVs isolated. Despite multiple ablation strategies performed for isolated PVs, 59.8% of patients had an AF recurrence over follow-up and no difference in the incidence of AF recurrences was detected between repeat ablation strategies. Further evidence is warranted to determine an effective treatment strategy to reduce AF recurrences in AF patients with isolated PVs.

Advanced practice nurse-coordinated same-day-discharge after atrial fibrillation ablation

Abstract Background Catheter ablation is an effective atrial fibrillation (AF) therapy, but a complex, resource-intensive procedure. Same-day discharge (SDD) reduces utilization of health care resources including personell and hospital beds, and may help to accommodate the increasing demand for AF ablation. However, besides structural adaptations, SDD requires more efficient logistics and coordination. Purpose Against this background, we established and validated a streamlined SDD program fully coordinated by an advanced practice nurse. Methods As dedicated SDD coordinator the advanced practice nurse was in charge of the full SDD protocol, including patient eligibility, patient flow, in-hospital logistics, patient education, discharge and short-term follow-up. For inclusion, basic home support and accessibility of the hospital within 60 minutes had to be warranted. Patients with LVEF <35% were excluded. Ablation was performed at the operator’s discretion. Ultrasound-guided femoral puncture was at the operator’s discretion for the first 150 SDD patients but became mandatory per protocol for all subsequent patients. Discharge by the SDD coordinator followed a standardized protocol including supervised ambulation, patient education, femoral inspection and echo. On post-ablation days 1 and 3, patients were called by the SDD coordinator to ensure well-being and good aspect of the femoral access site (smartphone foto control). In addition, patients could consult the SDD coordinator via mobile phone any time during working hours. In-person follow-up visits were scheduled at 2 weeks and 3, 6 and 12 months post-ablation. Results 420 consecutive patients were evaluated by the SDD coordinator of whom 331 were eligible for SDD. Reasons for exclusion were lack of home support (4.5%), living remotely (6.9%), or LVEF <35% (4.0%). 300 of the eligible patients (91%) were successfully discharged the same day (Fig. 1). Rates of unplanned medical attention (4.0%) and 30d-readmission (1.6%) were extremely low. Importantly, there was no major post-SDD complication. Unplanned medical attention and hospital readmissions were largely driven by minor femoral access site complications. Of note, those were significantly reduced upon introduction of mandatory ultrasound-guided puncture after the first 150 SDD patients (p=0.0145, Fig. 2). SDD coordination by the advanced practice nurse streamlined patient flow and in-hospital logistics and significantly reduced the total workload of nursing and medical staff. This resulted in great acceptance of the SDD program and satisfaction both among staff and patients. Conclusions Advanced practice nurse-coordinated SDD after AF ablation is safe and efficient. In fact, the position of a dedicated coordinator may be a key in the forthcoming transition of hospitals to SDD. Importantly, ultrasound-guided femoral puncture virtually eliminated relevant femoral access site complications and should be a prerequisite for SDD.Figure 1Figure 2

Safety and efficacy outcomes in 100 consecutive cases of pulsed field ablation

Abstract Background Pulsed field ablation (PFA) an emerging technology for ablation of atrial fibrillation (AF). This non-thermal ablation modality uses ultrarapid electrical pulses to destabilise cell membranes and can selectively ablate myocardial tissue. Successful pulmonary vein isolation (PVI) and reductions in procedure times compared to other modalities have been observed in initial studies. Aim To report initial outcomes and fluoroscopic times in the first 100 consecutive cases using PFA in AF ablation. Methods The first 100 consecutive PFA cases carried out by a single operator in a single centre were examined. All cases were performed under general anaesthesia, using ultrasound-guided vascular access and TOE-guided transseptal puncture. Outcomes were recorded from the first case in June 2022 to the present day. Electroanatomic mapping (EAM) was carried out using two proprietary systems. Results Procedural information and follow-up was achieved in all 100 patients (see table). The majority (77) were male. Mean age 61. Cardiovascular comorbidities included: hypertension (41), heart failure (12), ischaemic heart disease (10), stroke (4), diabetes mellitus (3). Antiarrhythmic drugs were used by 45 patients (Amiodarone in 22, Dronedarone in 18, Flecainide in 10, Sotalol in 8, Mexiletine in 1) with 55 taking beta blockers only or no rhythm control drugs. Persistent AF accounted for 57 cases, and 91 patients had no prior ablation procedure. Median CHA2DS2VASC 1. Warfarin was used on 1 patient, the other 99 patients underwent ablation on uninterrupted DOAC, most commonly Apixaban. EAM was conducted in 59 patients. Stand-alone PVI was carried out in 68, while 30 underwent an additional posterior wall box isolation, and a mitral isthmus line was added in a further 2 who had atrial flutter (AFl) during the procedure following successful PVI. There were no serious peri-procedural complications. (vascular access complications, pericardial effusion, stroke or death). All 100 patients were discharged following a one-night stay. Clinical pericarditis without effusion occurred in 1 patient on day 2, and resolved with a short course of Colchicine. Mean fluoroscopy time was 9minutes, 12seconds, and reductions in fluoroscopy times correlated significantly with case number (see figure). Mean fluoroscopy time was 2mins, 30secs higher where EAM was used. Sinus rhythm was achieved in 100%. Atrial arrhythmia recurred in 12 patients, 7 with AF and 3 atrial flutter, 2 with typical symptoms which could not be documented. Two of the recurrences were within 24 hours of the procedure. Conclusions This registry data shows that PFA was used to achieve PVI safely, with effective additional substrate ablation also demonstrated. There were no serious peri-procedural complications, and procedural improvements in fluoroscopic times were observed throughout the 100 cases. Long term follow-up data is required to validate the safety and efficacy of this new technology.

Ultra-short-term deceleration capacity and heart rate variability as indicators of vagal denervation before and after pulmonary vein isolation

Abstract Introduction Pulmonary vein isolation (PVI) is a well-established therapy of atrial fibrillation (AF). However, subtypes of AF can differ and exact mechanisms in which patients benefit from PVI remain not fully understood. Parasympathetic activity can play important role in pathogenesis of AF. Moreover, catheter ablation can impact vagal innervation of the heart, nevertheless methods of periprocedural assessment of such impact of PVI are lacking. Purpose Ultra-short-term deceleration capacity (UST-DC) and ultra-short-term heart rate variability (UST-HRV) were investigated to determine their potential function as indicators of parasympathetic activity before and after PVI. Methods 24 consecutive patients (8 females, age 54±11) with paroxysmal AF were included in the study. UST-DC and UST-HRV were calculated from 1-minute ECG recordings performed before and after PVI. Results There was a significant differences between UST-DC before PVI vs after PVI (7.6ms vs 2.8ms; p=0.0000018) and between UST-HRV parameters before and after PVI: standard deviation of normal-to-normal (UST-SDNN) (37.8ms vs 18.4ms; p=0.00005), root mean square of successive differences (UST-rMSSD) (25.3ms vs 12.2ms; p=0.00083) and proportion of success NN intervals differing more than 50ms divided by total number of NNs (UST-pNN50) (8.4% vs 2%; p=0.045). Heart rate (HR) increase was also statistically significant (pre-PVI vs post-PVI, 65.5bpm vs 73.7bpm; p=0.016). After 3-months patients with baseline UST-DC>7.5ms, were less likely to experience AF recurrence when compared to patients with baseline UST-DC<7.5ms (0% vs 31%, p=0.0496). In these groups difference in AF recurrences after 12-months of follow-up did not meet statistical significance (36% vs 38%, p=0.52). No correlation between UST-HRV parameters and AF recurrence during follow up was observed. Conclusions PVI leads to significant changes in UST-DC and UST-HRV and these parameters may serve as indicators of vagal denervation after AF ablation. Patients with more prominent baseline UST-DC are less likely to experience AF recurrence during 3-month blanking period after PVI.

Charge-density mapping to evaluate non-pulmonary vein substrate in patients with paroxysmal atrial fibrillation: the ACUPRED study

Abstract Background/introduction Pulmonary veins (PV) electrical isolation (PVI) is the main ablation strategy for the treatment of paroxysmal atrial fibrillation (AF), since the description of PV triggers. However, non-PV substrate and triggers in AF are not a negligible clinical issue. Indeed, in up to 22% of patients with AF recurrence after PVI, all PV are found isolated. Non-PV triggers can be demonstrated in up to 10-15% of non-selected patients at first AF ablation and non-PV substrate has been related to functional slow conduction and fibrosis also in paroxysmal AF. Purpose The aim of this study is to evaluate non-PV substrate (slow conduction) and triggers with charge-density (CD) mapping in patients with paroxysmal AF. Methods All patients, were prospectively enrolled in 2023. Inclusion criteria for the study were: 1) paroxysmal AF patients undergoing PVI procedure with a single-shot device and 2) CD mapping pre- and post- PVI. CD mapping was performed during CS proximal pacing at cycle length (CL) 600 ms and CS proximal pacing at CL 300 ms, pre- and post- PVI. Conduction velocity (CV) magnitude (in cm/s) and vector (direction and sense) were calculated offline for each CD map for all anatomical vertices. Reduction map was defined as the map of CV magnitude difference between CL 600 ms and CL 300 ms, Figure 1. Refraction map was defined as the map of CV direction difference between CL 600 ms and CL 300 ms, Figure 1. Non-PV substrate was defined at pre-PVI maps as: 1) slow conduction (<30 cm/s) at CL 600 ms or CL 300 ms, or 2) difference in CV magnitude (>25 cm/s) at reduction map, a marker of functional slow conduction (induced by fast pacing), or 3) difference in CV direction more than 90° between two neighboring vertices at refraction map, a marker of anisotropy, Figure 1. Non-PV triggers were defined as non-PV premature atrial contractions >10/min or inducing AF. Results A total of 43 patients (60.6 ± 11.2 years, 74.4% males) with paroxysmal AF undergoing first procedure PVI were analyzed. Non-PV substrate was found in 13 patients (30.2%). Non-PV triggers were found in 3 patients (6.9%), including one patient on the posterior wall near right PV antra and two patients on the posterior wall near the left PV antra. At a mean follow-up of 5.6 months, a total of 5 patients (11.6%) experienced a recurrence. Patients experiencing a recurrence had more frequently non-PV substrate (80.0% vs 23.7%, p=0.024) and lower CV magnitude at CL 600 ms pre-PVI (72.3 cm/s vs 83.1 cm/s, p=0.04). At survival analysis for 34 patients (79.1%) out of the 2 months blanking period, patients with non-PV substrate had lower freedom from AF recurrence (56% vs 90%, p=0.0028), Figure 2. Conclusion In patients with paroxysmal AF undergoing index PVI, non-PV substrate or triggers can be found in up to 37.1% of cases. Non-PV substrate is associated with worse arrhythmic prognosis.Figure 1Figure 2

Predictors of low-voltage areas in the left atrium in patients with atrial fibrillation

Abstract Background Low-voltage areas (LVA) in the left atrium (LA) electroanatomical map are potent predictors of the efficacy of atrial fibrillation (AF) ablation. Clinical factors predicting the presence of LVA have moderate accuracy. The aim of the study was to find clinical and echocardiographic factors predicting the presence of LVA in patients undergoing AF ablation. Methods Consecutive unselected patients undergoing AF ablation were included in the retrospective analysis. All patients underwent transthoracic (including LA strains) and transesophageal echocardiography, pulmonary vein isolation and LA electroanatomical mapping using multipolar catheter. LVA were defined as an area greater than 2cm2 with a voltage below 0.5mV (or 0.3mV when measured during AF). Results A total of 432 patients were included in the analysis, 107 (24.8%) had LVA. The mean age of the study population was 62.8 years, 185 patients had nonparoxysmal AF (42.8%). In the univariate logistic regression analysis numerous clinical parameters (age, female sex, presence of heart failure, diabetes, coronary artery disease, AF during examination), echocardiographic parameters (LA reservoir strain - LASr, LA emptying fraction, LA volume index, E/e’, LA appendage velocity - LAAV) and mean LA pressure (measured invasively) were significant predictors of the presence of LVA. In the multivariate logistic regression analysis age (HR 1.11 per 1 year increase, p<0.001), LASr (HR 0.89 per 1% increase, p=0.014) and LAAV (HR 0.93 per 1cm/s increase, p<0.001) were significant predictors of the presence of LVA. In receiver-operator curve (ROC) analysis LASr and LAAV were potent predictors of LVA in patients tested on sinus rhythm (AUC 0.86 and 0.87 respectively), while they had moderate predictive value in patients tested on AF (LASr AUC 0.67, LAAV AUC 0.77). Conclusions Age, LASr, and LAAV were significant predictors of LVA in patients undergoing AF ablation. The predictive value of LASr and LAAV was better in patients examined during sinus rhythm than in patients examined during AF.

Acute safety and efficacy of ablation for atrial fibrillation in elderly patients by means of pulsed field ablation

Abstract Background It is well known that age affects the efficacy of pharmacological treatment for atrial fibrillation (AF). Thermal ablation (radiofrequency or cryoballoon) is an established strategy for AF. However, there is no evidence evaluating efficiency, effectiveness, and safety outcomes in elderly patients in the context of the novel pulsed-field ablation (PFA) technology. Purpose We aimed to analyze the efficacy and safety of PFA in elderly (age≥75 years) patients with AF compared to non-elderly (age<75 years) patients with AF. Methods All consecutive patients undergoing AF ablation with the Farapulse system at 10 centers were included. Protocol-directed PVI was delivered using 2000 V with eight applications per vein, that is, four applications each in the basket and flower poses. Additional lesions were performed at the operator’s discretion. Results A total of 851 consecutive patients were included: 83 (9.8%) had ≥75 years (median of 77[75-78] years) whereas 768 (90.2%) had <75 years (median of 62[56-68] years, p<0.0001). Older patients had more comorbidities compared to younger patients (kidney disease: 9.6% vs 1.2%, p<0.0001; chronic obstructive pulmonary disease: 8.4% vs 3%, p=0.021; cancer history: 18.1% vs 6.1%, p=0.0004; hypertension: 61.4% vs 43.8%, p=0.002), whereas they exhibited a higher LVEF (60±6% vs 57±8%, p=0.0243). No differences between older and younger patients were found in terms of underlying AF type (paroxysmal AF: 66.3% vs 68.9%, p=0.62), procedure type (repeat ablation: 8.4% vs 13.4%, p=0.29), more extensive lesion set than PVI only (28.9% vs 22.5%, p=0.22) and the use of 3D mapping system (22.9% vs 21.1%, p=0.67). By looking at procedural metrics, no differences were also found between groups: 73±28 min vs 72±32 min for skin-to-skin time, p=0.41; 93±41 min vs 88±43 min for preparation plus skin-to-skin time, p=0.11; 18±9 min vs 17±9 min for fluoroscopy time, p=0.61 and 32[32-40] vs 32[32-38] PFA spots to achieve PVI, p=0.29. PVI was achieved in all patients. No major procedure-related adverse events were reported. Conclusion In our experience, the use of Farapulse PFA system for AF ablation in elderly patients was rapid, safe and effective, with no differences compared to the younger population.

Impact of iNAV and dNAV 3D LGE-CMR on the assessment of atrial fibrosis in atrial fibrillation patients

Abstract Background Late gadolinium enhanced (LGE) cardiac magnetic resonance (CMR) imaging serves as a valuable non-invasive tool for visualizing and quantifying left atrial (LA) fibrosis in atrial fibrillation (AF) patients. The extent of pre-procedural LA-LGE, indicative of native atrial fibrosis, has proven to be a predictor of AF recurrence risk following AF ablation. Consequently, assessing the LA fibrotic burden has emerged as a potential guide for personalized patient management. Currently, most centers engaged in LA-LGE image acquisition apply a scan protocol based on a diaphragmatic navigator-gated 3D image strategy (dNAV). Recently introduced image navigated (iNAV) 3D LGE strategies are proposed to outperform the dNAV strategy. This advancement involves the dynamic tracking of the heart's respiratory position with an image reconstruction algorithm, yielding motion-compensated images in significantly reduced and more consistent scan durations. We performed an evaluation of the novel image navigated (iNAV) 3D LGE-CMR imaging strategy in comparison to the conventional diaphragm navigated (dNAV) 3D LGE-CMR strategy. Methods In twenty-six consecutive AF patients, both imaging techniques (i.e. iNAV and dNAV) were performed subsequently, with equivalent spatial resolution and timing in the cardiac cycle. Patients were randomized in the acquisition order of iNAV and dNAV. LA fibrosis was quantified (percentage of atrial fibrosis using image intensity ratio threshold 1.2) and overlap in atrial fibrosis areas was tested between the two methods. Results Acquisition time of iNAV was significantly lower compared to dNAV (5±1 minutes vs. 12±4 minutes, p<0.001, respectively). There was a significant correlation between the iNAV and dNAV LA fibrotic burden (r=0.69, p<0.001). LA fibrosis scores were lower for iNAV compared to dNAV (12±8% vs. 20±12%, p<0.001, respectively). Spatial correspondence between the atrial fibrosis maps was modest (Dice similarity coefficient 0.43±0.15). Notably, 13/23 (56%) patients underwent a shift in their UTAH fibrosis stage classification, depending on the chosen imaging strategy. Conclusion iNAV acquisition was more than twice as fast as dNAV, and iNAV resulted in a lower atrial fibrosis score as compared to dNAV. More than half of the patients were reclassified into a different UTAH fibrosis stage depending on the employed imaging strategy. This underscores the critical importance of recognizing that the choice of imaging strategy significantly impacts the categorization of patients into their respective fibrosis stages. This distinction carries potential clinical implications when evaluating the utility of UTAH fibrosis stages in the context of AF management and therapeutic decision-making, as patients in lower fibrosis stages are generally regarded as more suitable candidates for ablation, while those categorized in higher fibrosis stages face an increased risk of arrhythmia recurrence following PVI.Figure 1Figure 2