Endpoint Of Ablation Research Articles

Feasibility and efficacy assessment of a novel size-adjustable cryoballoon for ablation of atrial fibrillation in a multicenter clinical setting

Abstract Background The POLARx-FIT cryoballoon (CB) system introduces a unique feature, allowing the selection of two distinct balloon sizes within a single catheter. This innovation holds promise for treating larger pulmonary veins (PV), providing increased flexibility to achieve optimal occlusions. However, there is a scarcity of clinical data supporting its application in this context. Purpose To compare the benefits and safety of the new POLARx-FIT system to those of the existing POLARx system currently in use for PV isolation (PVI) in patients with atrial fibrillation (AF). Methods The first 140 consecutive patients who underwent CB-based PVI with the POLARx-FIT system were retrospectively compared with 300 consecutive patients treated with the POLARx system. Protocol-directed cryoablation was delivered for 180 sec or 240 sec according to operator’s preference for isolation achieved in ≤60 sec, or 240 sec if isolation occurred >60 sec or when time to isolation was not available. The ablation endpoint was PVI as assessed by entrance and exit block. In the POLARx-FIT group the choice of balloon size (28 or 31 mm) was determined during the procedure while attempting to occlude each vein. Results Two-thousand one-hundred fifty-five cryo-applications (CBA) from 440 patients were analysed (300, 68.2% POLARx; 140, 31.8% POLARx-FIT). PVI was achieved with cryoablation only in all patients. The mean number of freeze applications per patient was similar between groups (5.0±1.4 in the POLARx-FIT vs 5.3±1.8 in the POLARx group, p=0.207) whereas the number of PVs treated in a single-shot fashion was higher in the POLARx-FIT group (444, 80.7% with one shot; 75, 13.7% with 2 shots; 31, 5.6% with more than 2 shots) than in the POLARx one (1168, 70.2% with one shot, p=0.0002; 294, 17.7% with two shots and 143, 8.6% with more than two shots). Among the POLARx-FIT cases, in 54.2% (n=298) of applications, the 31-mm diameter was employed as a first choice, while in the remaining 45.8% (n=252) of applications, the 28-mm diameter was adopted. A switch to a different balloon diameter was applied in 11.6% of cases. The first pass isolation (i.e. a single shot CBA to achieve PVI) was slightly higher when using a 31 mm diameter (n=250, 83.9%) than a 28 mm diameter (n=194, 77.0%, p=0.05). Three (0.7%) transient phrenic nerve palsy were observed (all in the POLARx group, 0.9%, p=0.554), with full recovery in the 48-h post procedure; no major procedure-related adverse events were reported at 30 days post-procedure. Conclusion In this first multicentric experience in a clinical practice setting, this novel cryo-balloon system proved to be safe and effective and resulted in a high proportion of successful single-freeze isolation. The intraprocedural flexibility of balloon size contributed to its versatility, leading to a variation in balloon diameter in about 12% of freeze applications.

Advanced mapping and ablation technologies to target pulmonary veins gaps and residual antral potentials during repeat paroxysmal AF ablation: acute and long-term follow-up

Abstract Background A comprehensive understanding of pulmonary vein (PV) reconnection and residual potentials (RAP) within the antral scar during repeat atrial fibrillation (AF) ablation, facilitated by advanced mapping and ablation technologies, is currently lacking. Optimizing radiofrequency (RF) deliveries after failed PV isolation (PVI) may enhance ablation efficiency. Purpose This study aims to assess both the acute and long-term outcomes focusing on PV gaps (PVGs) and RAPs, utilizing advanced mapping and ablation technologies during repeat PV ablation in patients (pts) with paroxysmal AF. Methods Repeat AF-CHARISMA study, a prospective, single-arm cohort study, included consecutive pts from 13 centers undergoing repeat ablation of paroxysmal AF. The Lumipoint (Boston Scientific) map-analysis tool was used sequentially on each PV component. All patients were followed-up for at least 12 months after the procedure. The ablation endpoint was PVI and electrical quiescence in the antral region. Long-term outcome was the recurrence of AT/AF over follow-up. Results One-hundred pts were included (69% after failed RF procedure, 31% after failed cryoablation procedure). A total of 276 PVGs (192 after RF ablation, 2.8±1.8/pt; 84 after cryoablation, 2.7±1.9/pt, p=0.665 vs RF) and 44 RAPs (43 after RF ablation, 0.6±1.1/pt; 1 after cryoablation, 0.03±0.2/pt, p=0.002 vs RF) were detected. In the majority of cases (75%), only PVGs were present whereas, in 21%, both PVGs and RAPs were detected (2 pts had only RAPs). In 2 pts no PVG nor RAP were identified. PVGs were most common at anterior sites (103, 37.3%), followed by posterior sites (75, 27.2%) and carina sites (49, 17.8%). PVG location sites did not differ between prior ablation approach. Only 1 pt after cryoablation showed a RAP (at carina site), whereas the 44 RAPs after RF were fairly distributed across different sites. Acute procedural success was 100%, with all PVs successfully isolated and RAPs completely abolished in all study pts. After the blanking period, over a follow-up of 480±211 days, 18 pts (18%) suffered an AT/AF recurrence (time to recurrence: 245±80 days). Previous ablation approach (HR=0.66, 95%CI: 0.2 to 2.0 for previous cryoablation, p=0.46), number of PVGs (1.05, 0.8 to 1.3, p=0.67) or number of RAPs (0.41, 0.1 to 1.2, p=0.12) were not associated to AT/AF recurrence. No major complications or adverse events occurred. Conclusion A structured ablation workflow for repeat catheter ablation, incorporating consistent high-density mapping and improved diagnostic tools to guide the procedure, demonstrated safety and efficacy in treating paroxysmal AF irrespectively of previous ablation approach. Residual potentials within the antral scar were more frequently detected after RF ablation compared to cryoablation.

Prognostic value of non-invasive programmed ventricular stimulation after VT ablation to predict VT recurrences.

The prognostic value of (non)-invasive programmed ventricular stimulation (NIPS) to predict recurrences of ventricular tachycardia (VT) is under discussion. Optimal endpoints of VT ablation are not well defined, and optimal timepoint of NIPS is unknown. The goal of this study was to evaluate the ability of programmed ventricular stimulation at the end of the VT ablation procedure (PVS) and NIPS after VT ablation to identify patients at high risk for VT recurrence. Between January 2016 and February 2022, consecutive patients with VT and structural heart disease undergoing first VT ablation and consecutive NIPS were included. In total, 138 patients were included. All patients underwent NIPS through their implanted ICDs after a median of 3 (1-5) days after ablation (at least 2 drive cycle lengths (500 and 400ms) and up to four right ventricular extrastimuli until refractoriness). Clinical VT was defined by comparison with 12-lead electrocardiograms and stored ICD electrograms from spontaneous VT episodes. Patients were followed for a median of 37 (13-61) months. Of the 138 patients, 104 were non-inducible (75%), 27 were inducible for non-clinical VTs (20%), and 7 for clinical VT (5%). In 107 patients (78%), concordant results of PVS and NIPS were observed. After 37 ± 20months, the recurrence rate for any ventricular arrhythmia was 40% (normal NIPS 29% vs. inducible VT during NIPS 66%; log-rank p = 0.001) and for clinical VT was 3% (normal NIPS 1% vs. inducible VT during NIPS 9%; log-rank p = 0.045). Positive predictive value (PPV) and negative predictive value (NPV) of NIPS were higher compared to PVS (PPV: 65% vs. 46% and NPV: 68% vs. 61%). NIPS revealed the highest NPV among patients with ICM and LVEF > 35%. Patients with inducible VT during NIPS had the highest VT recurrences and overall mortality. Patients with both negative PVS and NIPS had the lowest any VT recurrence rates with 32%. Early re-ablation of patients with recurrent VTs during index hospitalization was feasible but did not reveal better long-term VT-free survival. In patients after VT ablation and structural heart disease, NIPS is superior to post-ablation PVS to stratify the risk of VT recurrences. The PPV and NPV of NIPS at day 3 were superior compared to PVS at the end of the procedure to predict recurrent VT, especially in patients with ICM.

Acute post-procedural inducibility is a poor predictor of clinical outcomes in high-risk patients (PAINESD > 17) undergoing scar-related ventricular tachycardia ablation.

Ventricular tachycardia (VT) non-inducibility in response to programmed ventricular stimulation (PVS) is a widely used procedural endpoint for VT ablation despite inconclusive evidence with respect to clinical outcomes in high-risk patients. The aim is to determine the utility of acute post-ablation VT inducibility as a predictor of VT recurrence, mortality, or mortality equivalent in high-risk patients. We conducted a retrospective analysis of high-risk patients (defined as PAINESD > 17) who underwent scar-related VT ablation at our institution between July 2010 and July 2022. Patients' response to PVS (post-procedure) was categorized into three groups: Group A, no clinical VT or VT with cycle length > 240 ms inducible; Group B, only non-clinical VT with cycle length > 240 ms induced; and Group C, all other outcomes (including cases where no PVS was performed). The combined primary endpoint included death, durable left ventricular assist device placement, and cardiac transplant (Cox analysis). Ventricular tachycardia recurrence was considered a secondary endpoint (competing risk analysis). Of the 1677 VT ablation cases, 123 cases met the inclusion criteria for analysis. During a 19-month median follow-up time (interquartile range 4-43 months), 82 (66.7%) patients experienced the composite primary endpoint. There was no difference between Groups A and C with respect to the primary [hazard ratio (HR) = 1.21 (0.94-1.57), P = 0.145] or secondary [HR = 1.18 (0.91-1.54), P = 0.210] outcomes. These findings persisted after multivariate adjustments. The size of Group B (n = 13) did not permit meaningful statistical analysis. The results of post-ablation PVS do not significantly correlate with long-term outcomes in high-risk (PAINESD > 17) VT ablation patients.

RIPPLE-VT study: Multicenter prospective evaluation of ventricular tachycardia substrate ablation by targeting scar channels to eliminate latest scar potentials without direct ablation

BackgroundRecurrent ventricular tachycardia (VT) can be treated by substrate modification of the myocardial scar by catheter ablation during sinus rhythm without VT induction. Better defining this arrhythmic substrate could help improve outcome and reduce ablation burden. ObjectiveThe study aimed to limit ablation within postinfarction scar to conduction channels within the scar to reduce VT recurrence. MethodsPatients undergoing catheter ablation for recurrent implantable cardioverter-defibrillator therapy for postinfarction VT were recruited at 5 centers. Left ventricular maps were collected on CARTO using a Pentaray catheter. Ripple mapping was used to categorize infarct scar potentials (SPs) by timing. Earliest SPs were ablated sequentially until there was loss of the terminal SPs without their direct ablation. The primary outcome measure was sustained VT episodes as documented by device interrogations at 1 year, which was compared with VT episodes in the year before ablation. ResultsThe study recruited 50 patients (mean left ventricular ejection fraction, 33% ± 9%), and 37 patients (74%) met the channel ablation end point with successful loss of latest SPs without direct ablation. There were 16 recurrences during 1-year follow-up. There was a 90% reduction in VT burden from 30.2 ± 53.9 to 3.1 ± 7.5 (P < .01) per patient, with a concomitant 88% reduction in appropriate shocks from 2.1 ± 2.7 to 0.2 ± 0.9 (P < .01). There were 8 deaths during follow-up. Those who met the channel ablation end point had no significant difference in mortality, recurrence, or VT burden but had a significantly lower ablation burden of 25.7 ± 4.2 minutes vs 39.9 ± 6.1 minutes (P = .001). ConclusionScar channel ablation is feasible by ripple mapping and can be an alternative to more extensive substrate modification techniques.

Simplification of resetting response in slow/fast atrioventricular nodal reentrant tachycardia: the 3 catheters approach

Abstract Background The resetting response is a maneuver that helps identify the anterograde limb of slow/fast atrioventricular nodal reentrant tachycardia (AVNRT). The actual described maneuver involved a 5 catheters approach, and the related complications are poorly described.(1) Purpose We describe a simplified approach with 3 catheters and the related complications of the maneuver. Methods A quadripolar catheter was placed in the His bundle region; a decapolar catheter in the coronary sinus (CS) and a 4 mm tip non irrigated or irrigated catheter was used for pacing and ablation. An 8.5 French Sl0 sheath was used to ensure contact and stability. In confirmed slow/fast AVNRT using the fast pathway as the retrograde limb (earliest retrograde atrial activity located in the parahisian region), a single decremental atrial extrastimulus was delivered at the lower part of the triangle of Koch and 2-3 cm inside the CS on the roof. Pacing maneuver was started near the end of the QRS complex and decremented by 10 ms per interval. The higher atrial signal with the best A/V ratio on the CS catheter was used as sense reference for resetting response. The end point of ablation was non inducibility. Results Ten patients were included in a 4-month period, comprising 2 redo procedures. The maneuver was not performed in 4 patients (40%) due to non-sustained tachycardia. Atrial fibrillation was induced in 2 patients (20%) during the maneuver systematically due to an atrial extrastimulus preceding the H potential (negative HA interval). In the 4 remaining patients with successful resetting response, the HA interval in successful ablation spot varies between 31 to 82 ms. The involved anterograde limb was the right extension in 3 (75%) and the left extension in 1 (25%). Conclusion Resetting response can be performed with a 3 catheters approach, the main limitation is non sustained tachycardia, and atrial fibrillation induced by short coupled extrastimulus.Resseting response in LIE and RIE

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.

Impact of pulmonary vein variant anatomy during cryo-ablation in paroxysmal and persistent AF patients: 1-year outcome from a nationwide multicenter clinical setting

Abstract Background Complete electrical pulmonary vein isolation (PVI) by cryo-balloon approach is a well-established ablation strategy of atrial fibrillation (AF). While contrast findings exist regarding the influence of variant pulmonary vein (PV) anatomy on predicting AF recurrence, limited data are currently available specifically for cases involving the POLARx cryoablation system during PVI. Purpose We report the real-world experience of POLARx in the context of de novo AF ablation in a multicenter Italian registry. Methods Consecutive patients undergoing AF ablation from the CHARISMA registry at 10 Italian centres were included. Protocol-directed cryoablation was delivered for 180 sec or 240 sec according to operator’s preference for isolation achieved in ≤60 sec, or 240 sec if isolation occurred &amp;gt;60 sec or when time to isolation was not available. The ablation endpoint was PVI as assessed by entrance and exit block. All patients were followed-up for at least 12 months after the procedure. Results Four-hundred twenty-nine patients were included (n=358, 83.4% paroxysmal AF, n=71, 16.6% persistent AF, mean age 60.7±10 years, 28.3% female, mean LVEF 58±8%). PVI was achieved in all pts using only cryoablation. Twenty-eight (6.6%) patients exhibited an anatomical variant: 17 (4.0%) a common ostium and 11 (2.6%) an adjunctive PV. The mean number of freeze applications per patient was 5.1 (1.2 for LSPV, 1.3 for LIPV, 1.2 for RSPV and 1.3 for RIPV). Over a median of 398[370-461] days of follow-up, 14 (3.2%) patients experienced an early recurrence of AF during the 90-day blanking period. Overall, 63 patients (14.7%) suffered an AF recurrence after the 90-day blanking period (median time to recurrence 342[171-381] days). The proportion of patients exhibiting AF/AT recurrences was higher in the persistent AF group (17 out 71, 23.9%) than in the paroxysmal AF group (46 out 358, 12.8%, p=0.026), with a hazard ratio of 2.02 (95%CI: 1.2 to 3.5, p=0.0137) whereas patients with anatomy variant showed a similar AF/AT recurrence rate (5 out 28, 17.9%) than in the standard anatomy group (58 out of 401, 14.5%) with a hazard ratio of 1.43 (0.6 to 3.6, p=0.441). Four (0.9%) transient phrenic nerve palsy were observed, both with full recovery in the 48-h post procedure; no major procedure-related adverse events were reported. Conclusion In this multicenter study, the cryo-balloon system demonstrated safety and efficacy in treating both paroxysmal and persistent AF patients, yielding a low incidence of AF/AT recurrence during follow-up, regardless of the presence of variant PV anatomy.

Pulsed-field ablation of atrial fibrillation in elderly and frail patients: procedural efficacy and safety from a single-center experience

Abstract Introduction The demographic data shows a growing population, mostly elderly and with multiple comorbidities, therefore becoming increasingly frail. In this context Atrial fibrillation (AF) is the predominant sustained arrhythmia, and over the years trans-catheter isolation of pulmonary veins (PVI) has become a crucial approach in AF treatment. Among the technologies and energy resources employed through the years to perform atrial fibrillation transcatheter ablation, a novel technique has recently begun to gain ground, specifically pulsed-field ablation (PFA). PFA employs sequential brief and high amplitude electrical pulses to induce selective and irreversible electroporation of the myocardium, leading to cell death. The high selectivity of the lesion, ensured by the lower electroporation threshold of myocardial tissue compared to adjacent anatomic structures, allows for a decrease in potential complications associated with conventional thermal ablation. Purpose To assess the efficacy and safety in the use of pulsed field ablation in a selected population of elderly and frail patients undergoing atrial fibrillation ablation. Method We conducted a retrospective study focusing on elderly and frail patients admitted to our centre for paroxysmal or persistent AF ablation. The inclusion criteria were: age greater than 75 years and a Clinical Frailty Scale ≥ 5. The study population consisted of 26 patients [male gender 18, mean age 78 ± 3 years] including 8 who were affected by an oncological or haematological disease at the time of admission. The majority of patients were affected by paroxysmal AF while two of them presented persistent AF (9%). The primary ablation endpoint was the pulmonary vein isolation (PVI) that was achieved by delivering an energy of 2 kV over 8 applications, employing an alternating approach between the two configurations of the basket and flower catheter for each individual vein. Results The short-term success, represented by the complete and verified electrical isolation of the veins was achieved in all 26 patients without any periprocedural complications. First-pass pulmonary vein isolation (FPI) was universally achieved among the patient in study, with a mean skin-to-skin procedural time of 70 ± 30 minutes. From the procedural data perspective, ablation was achieved using an average fluoroscopy time of 22 ± 8.4 minutes and an average dose area product (DAP) of 1320 cGy×cm2. Conclusions In elderly and frail patients, we assessed the efficacy and safety of ablative procedures using the PFA technique. Successful electrical PVI was achieved without additional touch-ups, thanks to a high FPI rate. This results in lower procedural times and shorter intra-operative radiation exposure. These data confer an augmented value within the elderly-frail population, wherein shorter procedural times contribute to a better postoperative course, characterized by reduced bed rest and shorter intra-hospitalization periods.

Recurrent episodes of atrioventricular nodal reentrant tachycardia: Sites of ablation success, ablation endpoint, and primary culprits for recurrence

AbstractBackgroundAtrioventricular nodal reentrant tachycardia (AVNRT) sometimes recurs even after anatomical slow pathway (SP) ablation targeting the rightward inferior extension (RIE). This multicenter study aimed to determine the reasons for AVNRT recurrence.Methods and ResultsForty‐six patients were treated successfully for recurrent AVNRT. Initial treatment was for 38 slow‐fast AVNRTs, 3 fast‐slow AVNRTs, 2 slow‐slow AVNRTs, 2 slow‐fast and fast‐slow AVNRTs, and 1 noninducible AVNRT. All initial treatments were of RF application to the RIE; SP elimination was achieved in 11, dual AVN physiology was seen in 29, and AVNRT remained inducible in 5. The recurrent AVNRTs included 34 slow‐fast AVNRTs, 6 fast‐slow AVNRTs, 3 slow‐slow AVNRTs, 2 slow‐fast and fast‐slow AVNRTs, and 1 slow‐fast and slow‐slow AVNRTs. Successful ablation site was within the RIE in 39 and left inferior extension in 7. In 30 of 39, the successful RIE site was in the same area or higher than that of the initial procedure.ConclusionFor a high majority (around 85%) of patients in whom AVNRT recurs after initial ablation success, the site of a second successful procedure will be within the RIE even though the RIE was originally targeted. Furthermore, a high majority (around 86%) of sites of successful ablation will be higher than those originally targeted.

Comparative Effectiveness of Partial Gland Cryoablation Versus Robotic Radical Prostatectomy for Cancer Control

Background and objectiveThere is an absence of high-level evidence comparing oncologic endpoints for partial gland ablation, and most series used prostate-specific antigen (PSA) rather than biopsy endpoints. Our aim was to compare oncologic outcomes between partial gland cryoablation (PGC) and radical prostatectomy (RP) for prostate cancer. MethodsThis was a retrospective, single-center analysis of subjects treated with PGC (n = 98) or RP (n = 536) between January 2017 and December 2022 as primary treatment for intermediate-risk (Gleason grade group [GG] 2–3) prostate cancer. Oncologic endpoints included protocol surveillance biopsies after PGC in comparison to serial PSA testing after RP. The primary outcome was treatment failure, defined as a need for any salvage treatment or development of metastatic disease. Treatment failure and survival analyses were conducted using Cox proportional-hazard regression and Kaplan Meier survival curves. Key findings and limitationsAfter applying the inclusion/exclusion criteria, the PGC (n = 75) and RP (n = 298) groups were compared. PGC patients were significantly older (71 vs 64 yr; p < 0.001) but there were no differences in PSA, biopsy GG, or treatment year between the groups. The PGC group had higher rates of treatment failures at 24 mo (33% vs 11%; p < 0.001) and 48 mo (43% vs 14%; p < 0.001). One PGC patient (2.1%) and one RP patient (0.7%) had developed metastases by 48-mo follow-up (p = 0.4). On adjusted analysis, PGC was associated with a higher risk of treatment failure (hazard ratio 4.6, 95% confidence interval 2.7–7.9; p < 0.001). Limitations include observational biases associated with the retrospective study design. ConclusionsThis is the first comparative effectiveness study of cancer control outcomes for PGC versus RP. The results demonstrate an almost fivefold higher risk of treatment failure with PGC during short-term follow-up. Patient summaryWe compared cancer control outcomes for patients with intermediate-risk prostate cancer treated with partial prostate gland cryoablation versus radical prostatectomy. We found that partial gland cryoablation had an almost fivefold higher risk of treatment failure. Men with prostate cancer should be counseled regarding this difference in treatment failure.

Practicality and Safety of Electrical Pulmonary Vein Isolation and Left Atrial Appendage Ligation in Lung Transplant Recipients With Pretransplant Atrial Fibrillation.

Lung transplant surgery creates surgical pulmonary vein isolation (PVI) as a routine part of the procedure. However, many patients with pretransplant atrial fibrillation continue to have atrial fibrillation at 1 y. We hypothesized that the addition of electrical PVI and left atrial appendage isolation/ligation (LAL) to the lung transplant procedure restores sinus rhythm at 1 y in patients with pretransplant atrial fibrillation. We retrospectively reviewed all adult lung transplant recipients at the University of California Los Angeles from April 2006 to August 2021. All patients with pretransplant atrial fibrillation underwent concomitant PVI/LAL and were compared with lung transplant recipients without preoperative atrial fibrillation. In-hospital outcomes; 1-y survival; and the incidence of stroke, cardiac readmissions, repeat ablations, and sinus rhythm (composite endpoint) were examined at 1 y for the PVI/LAL cohort. Sixty-one lung transplant recipients with pretransplant atrial fibrillation underwent concomitant PVI/LAL. No patient in the PVI/LAL cohort required cardiac-related readmission or catheter ablation for atrial fibrillation within 1 y of transplantation. Freedom from the composite endpoint of death, stroke, cardiac readmission, and repeat ablation for atrial fibrillation at 1 y was 85% (95% confidence interval, 73%-92%) for lung transplant recipients treated with PVI/LAL. The addition of PVI/LAI to the lung transplant operation in patients with pretransplant atrial fibrillation was safe and effective in maintaining sinus rhythm and baseline risk of stroke at 1 y.

Biomarkers of myocardial injury during cellular electroporation by means of pulsed-field ablation and radiofrequency of atrial fibrillation

Abstract Background Several authors implemented different biomarkers to evaluate and quantify the size of effective atrial fibrillation (AF) ablation lesions after pulmonary veins isolation (PVI) with thermal energy source. However, limited data have been reported on the effects of a new form of non-thermal energy such as electroporation obtained by means of a pulsed-field ablation (PFA, Farapulse) system. Purpose Our analysis aims to compare acute myocardial injury through different biomarkers variation after PVI performed with different technologies (PFA vs radiofrequency, RF). Methods All consecutive patients (pts) undergoing AF ablation with PFA at our center were included. A PFA protocol-directed PVI was applied using 2kV with 8 applications per vein. RF deliveries were deployed according to a wide antral lesion set around the PVs at 50W. Pre- and post-procedure samples of cardiac troponin I (hs-TnI, ng/l), creatinine kinase-MB (CK-MB, ng/dl), fibrinogen (FB, mg/dl), myoglobin (Myo, ng/ml), N-terminal (NT)-pro hormone B-type natriuretic peptide (NT-ProBNP, pg/ml) and C-reactive protein (CRP, mg/dl) values were collected before PVI and at 24h after ablation. Ablation endpoint was PVI. Results Fourty-nine pts were included (62±12 years, 63% male, 84% with paroxysmal AF). PFA cases were 35 (71.4%) whereas RF cases were 14 (28.6%). Evaluating the kinetic of each cardiac biomarker, no differences were found between baseline and 24h for both FB (363±93 at baseline vs 387±112 at 24h, p=0.4513) and NT-ProBNP (137[61-462] at baseline vs 227[157-423] at 24h, p=0.0544). On the contrary kinetics of remaining biomarkers differed and significantly increased from baseline to 24h: 61±22 to 112±101 for Myo level, p=0.0017; 0.38±0.2 to 1.45±2.2 for CRP values, p&amp;lt;0.0001; 1.5±0.7 to 19.4±14 for CK-MB level, p&amp;lt;0.0001 and 11.2±20 to 6177±5765 for hs-TnI level, p&amp;lt;0.0001. By looking at the effect of the ablation strategy on cardiac biomarkers, hs-TnI level, CRP level and CK-MB were significantly different between groups at 24h after PFA/RF (hs-TnI: 7556±6025 for PFA vs 2038±1257 for RF, p&amp;lt;0.0001; CRP: 1.6±2.3 for PFA vs 0.9±1.2 for RF, p=0.0297; CK-MB: 23.7±12 for PFA vs 6.3±9.6 for RF, p&amp;lt;0.0001). PVI was achieved in all patients (100%) using only RF or PFA. No major procedure-related adverse events were reported. Conclusion Our preliminary results showed that cardiac troponin I enzyme level, C-reactive protein and creatinine kinase-MB increased after PVI by means of both radiofrequency and pulsed-field ablation and were higher after cellular electroporation by PFA than RF.

Intraprocedural Versus Initial Follow-up Minimal Ablative Margin Assessment After Colorectal Liver Metastasis Thermal Ablation: Which One Better Predicts Local Outcomes?

The aim of this study was to investigate the prognostic value of 3-dimensional minimal ablative margin (MAM) quantified by intraprocedural versus initial follow-up computed tomography (CT) in predicting local tumor progression (LTP) after colorectal liver metastasis (CLM) thermal ablation. This single-institution, patient-clustered, tumor-based retrospective study included patients undergoing microwave and radiofrequency ablation between 2016 and 2021. Patients without intraprocedural and initial follow-up contrast-enhanced CT, residual tumors, or with follow-up less than 1 year without LTP were excluded. Minimal ablative margin was quantified by a biomechanical deformable image registration method with segmentations of CLMs on intraprocedural preablation CT and ablation zones on intraprocedural postablation and initial follow-up CT. Prognostic value of MAM to predict LTP was tested using area under the curve and competing-risk regression model. A total of 68 patients (mean age ± standard deviation, 57 ± 12 years; 43 men) with 133 CLMs were included. During a median follow-up of 30.3 months, LTP rate was 17% (22/133). The median volume of ablation zone was 27 mL and 16 mL segmented on intraprocedural and initial follow-up CT, respectively ( P < 0.001), with corresponding median MAM of 4.7 mm and 0 mm, respectively ( P < 0.001). The area under the curve was higher for MAM quantified on intraprocedural CT (0.89; 95% confidence interval [CI], 0.83-0.94) compared with initial follow-up CT (0.66; 95% CI, 0.54-0.76) in predicting 1-year LTP ( P < 0.001). An MAM of 0 mm on intraprocedural CT was an independent predictor of LTP with a subdistribution hazards ratio of 11.9 (95% CI, 4.9-28.9; P < 0.001), compared with 2.4 (95% CI, 0.9-6.0; P = 0.07) on initial follow-up CT. Ablative margin quantified on intraprocedural CT significantly outperformed initial follow-up CT in predicting LTP and should be used for ablation endpoint assessment.

Utility of Very High-Output Pacing to Identify VT Circuits in Patients Manifesting Traditionally Inexcitable Scar

BackgroundEntrainment and pace mapping are used to identify critical components (CCs) of ventricular tachycardia (VT) circuits. In patients with dense myocardial scarring, VT circuits may elude capture at standard high pacing outputs (up to 10 mA at a 2-millisecond pulse width). ObjectivesThe purpose of this study was to assess the utility of very high–output pacing (V-HOP, 50 mA at 2 milliseconds) for identifying CCs of VT circuits after standard high pacing output failed to elicit capture in densely scarred myocardial tissue. MethodsOur standard VT ablation approach included electroanatomic mapping for substrate characterization and entrainment and/or pace mapping to identify CCs of VT circuits. Patients that required V-HOP to capture sites of interest comprised the study cohort. Ablation endpoints were VT termination and noninducibility. ResultsTwenty-five patients (71 ± 10 years of age, all males) undergoing 26 VT ablations met the inclusion criteria. The mean left ventricular ejection fraction was 30% ± 14%, and 85% had ischemic cardiomyopathy. V-HOP was used to successfully entrain VT in 17 patients, yielding central isthmus sites in 10 and entrance/exit sites in 4. VT terminated with radiofrequency ablation at these sites in 15 patients. In 9 patients, V-HOP identified scar locations with a delayed exit. Acute procedural success was achieved in 24 patients without any adverse events. Over a follow-up period of 16 ± 21 months, 2 patients experienced VT recurrence requiring repeat ablation during which the same location was targeted successfully in 1 patient. ConclusionsIn VT patients with a dense scar that is traditionally inexcitable, V-HOP can identify CCs of the re-entrant circuit and guide successful ablation.

Cardioneuroablation for Treating Vasovagal Syncope: Current Status and Future Directions.

Syncope is defined by transient and spontaneous loss of consciousness with rapid recovery. Vasovagal syncope (VVS) is the most common form of syncope and is strongly associated with hypervagotonia. There is, however, a lack of effective therapies for VVS. Cardioneuroablation (CNA) is an emerging and promising intervention for VVS with favourable outcomes. CNA has been shown to suppress excessive excitation of vagal activity through ablating the cardiac ganglionated plexi. CNA in the management of VVS requires more structured and comprehensive studies and several issues concerning patient selection, selection of ablation targets, ablation endpoints and the long-term effect of CNA are yet to be determined. This review describes its clinical applications and future directions based on current research data and the authors' own experiences.

Sex differences in catheter ablation for ventricular tachycardia in structural heart disease: a single center 10-years experience

Abstract Funding Acknowledgements Type of funding sources: None. Background Women are underrepresented in studies concerning ventricular tachycardia (VT) catheter ablation (CA). Different etiologies and type of structural heart diseases (SHD) are well established in women; nonetheless conflicting results about efficacy and safety of CA in women have been reported. Purpose To evaluate acute and long-term outcome of VT CA in SHD in women compared to men in a high-volume tertiary Center. Methods All consecutive procedures were included from January 2010 to December 2021. Clinical characteristics, VT etiologies and procedure data of female patients were compared to male population. Catheter ablation was performed according to standard protocol in our center. In mappable VTs, the reentry circuit was characterized, and ablation aimed at VT interruption during radiofrequency (RF); otherwise, a substrate modification approach aiming at late potentials abolition or ablation at sites of slow conduction during sinus rhythm was performed. Following ablation, prevention of any VT inducibility and substrate modification was considered ablation endpoint. Acute results, complications, and VT recurrences during follow up were analyzed comparing the two groups. Results Among 1608 overall VT CA procedures, 141 procedures were performed in 117 women. Female were younger, with less comorbidities, less ischemic VT etiology and higher left ventricular ejection fraction (LVEF) as compared to men (Table 1). They were also less likely ICD carriers. No significant differences were found with regards to: epicardial approach (39.7% vs 35.3%, p=0.68); VT inducibility at baseline (57.4% vs 67.6%, p=0.14), VT termination during RF (87.6% vs 77.6%, p=0.51), and prevention of any VT inducibility at the programmed electrical stimulation (PES) after ablation (79.5% vs 78.1%, p=0.7). Major complications occurred in 4.9% of females as compared to 4.3% of male patients. At median follow-up of 25 months, VT recurrences occurred in 24.7% of female population and 27.5% of male group (p=0.42). Cumulative VT-free survival was comparable in both groups (Figure 2). Conclusions Women with SHD have favorable acute and long-term outcome of VT ablation, despite a high prevalence of non-ischemic etiologies. VT recurrence rate and procedure safety is comparable to male patients, suggesting that catheter ablation can be offered as an effective treatment to women with refractory ventricular arrhythmias.

Novel pulsed-field ablation technology for pulmonary vein isolation in patients with atrial fibrillation: preliminary experience from a large multicenter clinical practice

Abstract Funding Acknowledgements Type of funding sources: None. Background Complete electrical pulmonary vein isolation (PVI) by thermal energy sources is a well-established ablation strategy of atrial fibrillation (AF). Recently, a non-thermal ablation approach by means of irreversible cellular electroporation has been made available for clinical use. Purpose We report the preliminary experience of a new pulsed-field ablation (PFA) system in the context of AF ablation in a multicenter Italian setting. Methods All consecutive patients (pts) undergoing AF ablation with PFA at 7 Italian centres 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. Applications were delivered in pairs at any given catheter position, rotating by ≈30–40° after the first two applications in each configuration. Additional lesions were performed at the operator’s discretion. The ablation endpoint was PVI as assessed by entrance and exit block. Data are reported as median [IQ range]. Results With a median of 32[25-38] pts treated per center, a total of 205 cases were included (n=150 73.2%, paroxysmal AF, n=55, 26.9% persistent AF). Of them 187 (91.2%) were de novo cases, whereas 18 (8.8%) were redo cases. A mapping system was used in 55 (21.5%) procedures and an intracardiac echocardiography in 65 (31.7%) cases. The number of PFA applications to reach PVI was 32[32-36]. Procedural parameters were: fluoroscopy time = 16[12-22] min, skin-to-skin time = 60[55-85] min, support time (preparation plus skin-to-skin) =75[64-95] min, lab occupancy time was 97[75-120] min and PFA LA dwell time was 23[20-28] min. The first pass isolation (FPI) rate per vein was 99.6% resulting from 202 patients (98.5%) with FPI. At the end of the procedure, PVI was achieved in all pts (100%) using only PFA. Additional PFA delivery outside PVs was performed in 19% (n=39) of the cases, mostly at the posterior wall area only (n=34, 87%), requiring 16[12-24] PFA deliveries. All the additional lesion sets were validated through differential pacing and/or 3D mapping. The learning curve was extremely fast. After only 5 cases time to PVI and total support time have significantly improved, whereas we did not notice any additional improvement after 10 or 20 cases (LA dwell time: 27[22-32] min during the first 5 cases vs 23[19-27] min after the first 5 cases, p=0.0172; support time: 100[65-120] min vs 75[65-90] min, p=0.0181, respectively). In 13 (6.3%) cases a transient bradycardia or asystole occurred after the first PFA application requiring temporary high-output pacing. No major procedure-related adverse events were reported. Conclusion In this first multicentric experience, the novel PFA system proved to be safe and effective in both paroxysmal and persistent AF patients. The learning curve seems to be very fast according with procedural parameters.

Cardiac Troponin I kinetic after pulmonary vein isolation for atrial fibrillation ablation with pulsed-field ablation and cryo-energy

Abstract Funding Acknowledgements Type of funding sources: None. Background Previous studies have demonstrated that cardiac biomarkers elevate after both cryoballoon (CB) and radiofrequency atrial fibrillation (AF) ablation, depending on the amount of energy delivered and the site of ablation. To date no comparison has been made between these thermal energy source and a novel non-thermal pulsed-field ablation (PFA) technology based on cells electroporation. Purpose Our analysis aims to compare acute myocardial injury through cardiac troponin I variation after pulmonary vein isolation (PVI) performed with different technologies (PFA vs CB). Methods All consecutive patients undergoing paroxysmal AF ablation with CB and PFA at our center from July to November 2022 were included. Protocol-directed cryoablation (CBA) was delivered for 180 sec or 240 sec according to operator’s preference for isolation achieved in ≤60 sec, or 240 sec if isolation occurred &amp;gt;60 sec or when time to isolation was not available. A standard PFA protocol-directed PVI was applied using 2kV with eight applications per vein (four applications each in the basket and flower poses). The ablation endpoint was PVI as assessed by entrance and exit block. Pre- and post-procedure samples of cardiac troponin I (CTpI) were collected before CBA/PFA and at 24h after ablation. Only patients with normal baseline values for myocardial injury were included. Results A total of 71 patients met inclusion criteria and were included in this analysis. The CBA group consists of 50 (70%) patients and the PFA group comprises 21 (30%) patients. The number of CBA applications to reach PVI was 5.0±1.4 and the number of PFA applications to achieve PVI was 32±4. All (100%) patients were in sinus rhythm at the time of the procedure. Evaluating the kinetic of CTpI, baseline values were homogeneous between CBA and PFA groups (p=0.979) whereas CTpI values significantly rose from baseline (7±2 ng/L) to 24h (8979±3691 ng/L, p&amp;lt;0.0001) and were significantly different between groups after CBA/PFA (8148±3311 ng/L for CBA vs 11900±7143 ng/L for PFA, p=0.0056). PVI was achieved in all patients (100%) using only CB or PFA. No major procedure-related adverse events were reported. Conclusion Our preliminary results showed that cardiac troponin I enzyme level increased after PVI by means of both cryoballoon and pulsed-field ablation and were higher after cellular electroporation by PFA than cryoablation.

General anesthesia in spontaneous respiration with intravenous ketamine in patients undergoing pulsed-field ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Thermal ablation of atrial fibrillation (AF) by means of radiofrequency or cryo-balloon is usually performed under general anesthesia, deep sedation, or conscious sedation at operator’s discretion and based on the general condition of the patient. However, a standardized sedation protocol when performing a non-thermal ablation, such as pulsed-field ablation (PFA) through irreversible cellular electroporation, has not been well established. Purpose We report our preliminary experience of a general anesthesia in spontaneous respiration protocol with ketamine used at a high-volume center during ablation of AF with a new PFA system. Methods All consecutive patients (pts) undergoing AF ablation with PFA at our center were included. Our sedation protocol consists of intravenous administration of midazolam (1+1 mg), fentanyl (25+25+25+25 mcg/kg) at low doses before local anesthesia with lidocaine (200mg) administration. Patients underwent sedation under spontaneous respiration by administering oxygen (4-6 l/min) through a face mask with nasal cannula. Local anesthesia was performed before the percutaneous femoral venous access. Soon after the trans-septal puncture, heparin (1 mg/kg) and atropine (1 mg, to mitigate anticipated bradycardia) were injected, followed by a second bolus of midazolam (1 mg). Ketamine adjunct (1 mg/kg) was then injected about 5 minutes before the first PFA delivery which was titrated to effect based on patient’s condition, response and changes in vital signs (total ketamine adjunction of 2 mg/kg). For quantitative assessment the Numeric Rating Scale for Pain (NRS) was applied. For qualitative assessment a 3-levels satisfaction evaluation was retrieved. The ablation endpoint was PVI as assessed by entrance and exit block. Results Forty-two pts were included in this analysis (mean age of 66±9 years,72% were male, CHA2DS2VASc score=2 [IQR 1–3], median body mass index 24[20-48]kg/m2, 35% had respiratory diseases – e.g. asthma, OSAS, COPD –). At baseline, before sedation, mean systolic blood pressure was 140.5+20.1mmHg and mean oxygen saturation was 97.9+2.1%. PVI was achieved in all the patients. The number of PFA applications to reach PVI was 33.4+3 (time to PVI = 25+4min). In two cases additional PFA lesion sets were deployed outside the PVs. Lab occupancy time was 122±32min, skin-to-skin time was 78±35min and fluoroscopy time was 23±14min. All the patients achieved a NRS ≤ 3. Satisfaction level was found to be acceptable in all procedures by both the patient and the primary operator (Score equal to 0). No major procedure-related adverse events were reported. Conclusion The PFA procedure has a short execution time. The standardized anesthetic protocol with the administration of drugs with rapid onset and pharmacological offset at low doses was effective and safe with an optimal degree of patient and operator satisfaction.