Previous Ablation Research Articles

Abstract 13210: A Hidden Right Atrial Lipoma in a Patient With Recurrent Sustained Supraventricular Tachycardias

Introduction: Cardiac lipomas, known for their benign nature, compose 8 percent of primary cardiac tumors. Advanced imaging modalities allow improved diagnosis, yet little of their potential complications involving the heart's conduction system is known. Case: A 65-year-old male presented to the Emergency Department with palpitations. History was significant for recurrent sustained orthodromic atrioventricular reentrant tachycardia using a concealed left posterior accessory pathway from a prior EP study. He was treated with ablation twice in the past. The patient was hemodynamically stable on evaluation. ECG showed supraventricular tachycardia (SVT) involving orthodromic re-entry with a ventricular rate of 227 bpm. Computer tomography (CT) of the chest revealed a large, low-attenuated lesion with -102 Hounsfield unit (HU) attached to the right atrial roof, extending to both SVC and IVC. No sparing of foramen ovale was seen. Findings suggest right atrial lipoma. A transthoracic echocardiogram (TTE) visualized the same echo-dense structure without increased vascularity. The patient responded to intravenous Adenosine. We discussed the case with the Cardiothoracic surgery team. Outpatient cardiac MRI and elective surgery were planned. Discussion: The case presented clinically significant atrial arrhythmia in a patient with a massive right atrial lipoma. Although most cardiac lipomas remain asymptomatic, arrhythmias coinciding with the location of involved chambers have been reported. In addition, the recurrence of orthodromic tachycardia despite previous ablation suggests the potential benefit of surgical intervention.

Box Lesion Isolation of the Left Atrial Posterior Wall with Radiofrequency Ablation Restricted in Predetermined Lines for the Treatment of Persistent Atrial Fibrillation: The Prognostic Role of Acute Interventional Outcome and Trigger Identification.

The left atrial posterior wall (PW) is known to be a critical substrate for the initiation and perpetuation of atrial fibrillation (AF) and has been explored as a target for catheter ablation, particularly in persistent AF (PerAF). In this retrospective study, we investigate the clinical outcome of patients with PerAF who underwent PW isolation (PWI) restricted in predetermined lines in addition to pulmonary vein isolation (PVI). One hundred consecutive patients (64 ± 9.1 years, 66% male, 20% with previous PVI ablation) underwent PWI in a box lesion setting for PerAF lasting >3 months (34% long-standing PerAF). PW triggers were defined as either foci from the PW that repeatedly induced AF or as isolated AF or atrial tachycardia (AT) within the PW. After a mean follow-up period of 25.6 ± 6.7 months, 61% of the patients remained in sinus rhythm after the last procedure. In 79 patients, the PW was successfully isolated, while, in 21 patients, complete isolation was not possible due to failure in completion of the roof line (n = 16), the floor line (n = 7), or both (n = 2). Patients with incomplete isolation had similar AF/AT recurrence rates compared to those with complete PWI. In 12 patients, PW triggers were identified, and PWI in these patients was shown to have a significantly better prognosis in terms of sinus rhythm maintenance (P = .031). Failure of complete PWI does not predispose a patient to an inferior outcome nor is it responsible for iatrogenic ATs. The presence of AF triggers within the PW leads to a particularly favorable result after box lesion isolation.

From ablation to operation: Unraveling the surgical outcomes and complications of thyroidectomy after radiofrequency ablation

BackgroundRadiofrequency ablation is a minimally invasive treatment for thyroid nodules; however, concerns exist regarding its impact on subsequent thyroid surgery. We compared surgical outcomes and complications between patients undergoing thyroidectomy after radiofrequency ablation (post-radiofrequency ablation thyroidectomy group) and those without prior radiofrequency ablation (non-radiofrequency ablation thyroidectomy group). MethodsWe retrospectively analyzed thyroidectomy patients, comparing post-radiofrequency ablation thyroidectomy and non-radiofrequency ablation thyroidectomy groups, examining demographics, nodule characteristics, surgical techniques, and complications. ResultsThe study included 96 patients (73 in the non-radiofrequency ablation thyroidectomy group and 23 in the post-radiofrequency ablation thyroidectomy group). The mean age was 53.3 ± 14.4 years, with 78.1% female patients and 36.5% African American patients. Median operative time was similar between the post-radiofrequency ablation thyroidectomy (110 minutes) and the non-radiofrequency ablation thyroidectomy (92 minutes) cohorts (P = .40). Complications were reported in 13 patients, without significant differences between groups (P = .54). No permanent complications, including nerve injury or hypoparathyroidism, were reported in either cohort. Prior radiofrequency ablation treatment did not increase the risk of complications (odds ratio = 3.48, 95% confidence interval = 0.70–17.43, P = .16). ConclusionOur work found no differences in outcomes or safety in patients undergoing thyroidectomy with or without previous radiofrequency ablation treatment, potentiating the post-radiofrequency ablation thyroidectomy group as a safe management option. Accordingly, this may reassure both clinicians and patients of the safety of radiofrequency ablation in treating patients with thyroid nodules.

Ethanol Ablation for Benign Insulinoma: Intraoperative and Endoscopic Approaches

IntroductionEthanol ablation can be utilized to manage insulinoma. We aimed to analyze our outcomes of endoscopic ultrasound (EUS) and intraoperative ultrasound (IOUS) guided Ethanol ablation of insulinoma. MethodsA single institution retrospective review of adults undergoing Ethanol ablation of benign pancreatic insulinoma (2007-2022) was performed. Outcomes were categorized as resolution of hypoglycemia, improvement, or no change at last follow-up. ResultsA total of 16 patients underwent Ethanol ablation of benign insulinoma (N = 8 EUS, N = 8 IOUS): median age was 68 y, 8 (50%) were females, and 2 (12.5%) were associated with multiple endocrine neoplasia type-1. Median insulinoma size was 12 (range 7, 25) mm. Ethanol ablation was preferred over resection to avoid pancreaticoduodenectomy when it was not possible to enucleate the tumor in 10 (62.5%) patients while the rest underwent ablation due to being poor surgical candidates or because of a history of previous pancreatic resection. The median follow-up (interquartile range) was 43 (19.5, 81.5) mo. Resolution of hypoglycemia occurred in 11 patients (5 EUS, 6 IOUS), while the rest (3 EUS, 2 IOUS) experienced improvement in the severity and frequency of hypoglycemia. A single patient underwent resection following a previous ablation for symptomatic hypoglycemia 5 y after EUS guided ablation. ConclusionsEthanol ablation provides an alternative therapeutic option for patients with insulinoma. Both EUS and IOUS guided approaches are associated with a favorable resolution rate although EUS guided ablation may require multiple procedures to optimize outcomes.

Totally Thoracoscopic Ablation in Patients With Recurrent Atrial Fibrillation After Catheter Ablation.

The objective of this study was to evaluate the efficacy and safety of totally thoracoscopic ablation (TTA) in patients with recurrent atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). From February 2012 to May 2020, 460 patients who underwent TTA were classified into two groups: CA (presence of RFCA history, n = 74) and nCA groups (absence of RFCA history, n = 386). Inverse probability of treatment weighting (IPTW) analyses were used to adjust for confounders. The primary endpoint was freedom from the composite of AF, typical atrial flutter, atypical atrial flutter and any atrial tachyarrhythmia, lasting more than 30 seconds during the follow-up. All patients were followed up at 3, 6, and 12 months via electrocardiogram and 24-hour Holter monitoring. Bilateral pulmonary vein isolation (PVI) was conducted in all patients and the conduction block tests were confirmed. In the CA group, difficult PVI occasionally occurred due to structural changes, such as pericardial adhesion and fibrosis of the pulmonary venous structure, caused by a previous catheter ablation. Early complications such as stroke and pacemaker insertion were not different between the two groups. The normal sinus rhythm was maintained in 70.1% (317/460) patients after a median follow-up period of 38.1 months. The IPTW-weighted Kaplan-Meier curves revealed that freedom from AF events at 5 years was 68.4% (95% confidence interval, 62.8-74.5) in the nCA group and 31.2% (95% confidence interval, 16.9-57.5) in the CA group (P < 0.001). In IPTW-weighted Cox regression, preoperative left atrial diameter, persistent or long-standing AF, the presence of congestive heart failure and catheter ablation history were associated with AF events. Patients in the CA group showed a higher recurrence rate of AF than those in the nCA group, while TTA was safely performed in both the groups.

Prognostic implications of baseline rhythm during catheter ablation for atrial tachycardia.

Atrial tachycardias (AT) occurring in patients after previous atrial fibrillation (AF) ablation are increasingly observed in clinical practice. Catheter ablation is the treatment of choice but an optimal workflow to improve patient outcome has not been defined. The purpose of this study was to assess procedural and clinical outcome depending on baseline rhythm at the beginning of AT ablation. A total of 380 patients (69 (61-75) years, 56.6% male) who underwent catheter ablation for consecutive AT after previous AF ablation were studied. At the beginning of the procedure, 140 patients (36.8%) presented in sinus rhythm (SR), 208 (54.7%) with AT and 32 (8.4%) with AF. Patients in SR or with AT underwent shorter procedures (173 (132-213) minutes vs. 161 (120-203) minutes vs. 226 (154-249) minutes; p = 0.002) with more frequent termination to SR (87.9% vs. 81.3% vs. 56.3%; p < 0.001) than patients with AF. Acute procedural success did not differ between patients in SR or with AT but was higher compared to those with AF (96.4% vs. 97.1% vs. 87.5%; p = 0.033). During a follow-up of 290 (181-680) days, patients in baseline SR experienced arrhythmia recurrences less often (36.4% vs. 49.5% vs. 68.8%; p = 0.002) than patients with AT or AF. Baseline rhythm during AT ablation predicts procedural and clinical outcome. Whereas acute procedural success does not differ between patients in SR or with AT, patients presenting in SR have a more favorable mid-term success rate.

Feasibility and safety of the direct current cardioversion at the time of left atrial appendage occlusion for patients with atrial fibrillation.

With an increasing number of patients undergoing left atrial appendage occlusion (LAAO), more attention is being paid to relieving clinical symptoms and improving the quality of life of these patients. For patients with atrial fibrillation (AF), direct current cardioversion (DCCV) is an alternate, nonpharmacological choice to restore sinus rhythm and relieve clinical symptoms. The purpose of this study was to assess the feasibility and safety of the DCCV at the time of LAAO for patients with AF. Forty patients were enrolled in the DCCV group undergoing the DCCV at the time of LAAO. The control group undergoing LAAO alone was formed by 1:1 matching. In the DCCV group, cardioversion was immediately successful in 30 (75%) patients, of which 12 (40%) had AF recurrence at the three-month follow-up. The failed-DCCV group was older (73.70 ± 4.74 vs. 62.20 ± 9.01 years old, P = 0.000), had a faster postcardioversion heart rate (88.80 ± 16.58 vs. 70.97 ± 14.73 times, P = 0.03), and had a higher mean HAS-BLED score (4.00 vs. 3.00, P = 0.01) than the successful-DCCV group. No patients experienced periprocedural pericardial effusion, occluder displacement, device embolism, or >5 mm peridevice leakage. One patient experienced a transient ischemic attack (TIA) in the DCCV group during the follow-up. The DCCV at the time of LAAO is feasible and safe for AF patients with contraindications for catheter ablation or AF recurrence after previous catheter ablation to restore the sinus rhythm and relieve clinical symptoms. The DCCV at the time of LAAO is more likely to succeed for younger patients and patients with lower HAS-BLED scores.

Cryothermal energy demonstrates shorter ablation time and lower complication rates compared with radiofrequency in surgical hybrid ablation for recurrent ventricular tachycardia

Recurrent ventricular tachycardia (VT) after prior endocardial catheter ablation(s) presents challenges in the setting of prior cardiac surgery where percutaneous epicardial access may not be feasible. The purpose of this study was to compare the outcomes of cryothermal vs radiofrequency ablation in direct surgical epicardial access procedures. We performed a retrospective study of consecutive surgical epicardial VT ablation cases. Surgical cases using cryothermal vs radiofrequency ablation were analyzed and outcomes were compared. Between 2009 and 2022, 43 patients underwent either a cryothermal (n = 17) or a radiofrequency (n = 26) hybrid epicardial ablation procedure with direct surgical access. Both groups were similarly matched for age, sex, etiology of VT, and comorbidities with a high burden of refractory VT despite previous endocardial and/or percutaneous epicardial ablation procedures. The surgical access site was lateral thoracotomy (76.5%) in the cryothermal ablation group compared with lateral thoracotomy (42.3%) and subxiphoid approach (38.5%) in the radiofrequency group, with the remainder in both groups performed via median sternotomy. The ablation time was significantly shorter in those undergoing cryothermal ablation vs radiofrequency ablation (11.54 ± 15.5 minutes vs 48.48 ± 23.6 minutes; P < .001). There were no complications in the cryothermal ablation group compared with 6 patients with complications in the radiofrequency group. Recurrent VT episodes and all-cause mortality were similar in both groups. Hybrid surgical VT ablation with cryothermal or radiofrequency energy demonstrated similar efficacy outcomes. Cryothermal ablation was more efficient and safer than radiofrequency in a surgical setting and should be considered when surgical access is required.

LIBS at high duty-cycles: effect of repetition rate and temporal width on the excitation laser pulses

Laser-induced breakdown spectroscopy (LIBS) is becoming a more mature technology every year with new variants such as laser ablation molecular isotopic spectrometry, reheating by various discharge techniques, and multiple pulse excitation schemes, in which sometimes lasers of different pulse lengths are used. However, lasers with inherent parameters like pulse length and repetition rate are still almost exclusively employed. Recent years have witnessed the advent of novel high-repetition-rate laser concepts for machining processes, like welding, milling, and engraving. Here, a comprehensive study of single-pulse LIBS spectra of a single aluminum target is presented to showcase the applicability of flexible high duty-cycle master oscillator power amplifier (MOPA) lasers. Although traditional flashlamp-pumped Fabry–Pérot lasers only permit a variation in the pulse energy and are operated at very low duty-cycles, MOPA lasers add repetition rate and pulse length as variable parameters. A thorough analysis of the temporal plasma behavior revealed the emission dynamic to closely match the excitation laser pulse pattern. An aluminum sample’s spectral response was shown to be significantly impacted by variations in both rate and length. Although the spectral emission strength of the elemental lines of Al, Sr, and Ca all peaked at slightly different parameter settings, the strongest impact was found on the relative abundance of molecular AlO bands. Unlike in previous laser ablation molecular isotopic spectrometry (LAMIS) publications, the latter could be readily detected with a good intensity and well-resolved spectral features without any temporal gating of the detector. This finding, together with the fact that MOPA lasers are both inexpensive and dependable, makes for a promising combination for future studies including the detection of diatomic band structures.

Wide-Complex Tachycardia in a Patient with Previous Accessory Pathway Ablation

Wide-Complex Tachycardia in a Patient with Previous Accessory Pathway Ablation

Magnetic resonance detection of advanced atrial cardiomyopathy increases the risk for atypical atrial flutter occurrence following atrial fibrillation ablation.

Recurrence of arrhythmia after catheter ablation of atrial fibrillation (AF) in the form of atypical atrial flutter (AFL) is common among a significant number of patients and often requires redo ablation with limited success rates. Identifying patients at high risk of AFL after AF ablation could aid in patient selection and personalized ablation approach. The study aims to assess the relationship between pre-existing atrial cardiomyopathy and the occurrence of AFL following AF ablation. We analysed a cohort of 1007 consecutive AF patients who underwent catheter ablation and were included in a prospective registry. Patients who did not have baseline cardiac magnetic resonance imaging and late gadolinium enhancement (LGE-CMR) or did not experience any recurrences were excluded. A total of 166 patients were included gathering 56 patients who underwent re-ablation due to AFL recurrences and 110 patients who underwent re-ablation due to AF recurrences (P = 0.11). A multiparametric assessment of atrial cardiomyopathy was based on basal LGE-CMR, including left atrial (LA) volume, LA sphericity, and global and segmental LA fibrosis using semiautomated post-processing software. Out of the initial cohort of 1007 patients, AFL and AF occurred in 56 and 110 patients, respectively. An age higher than 65 [odds ratio (OR) = 5.6, 95% confidence interval (CI): 2.2-14.4], the number of previous ablations (OR = 3.0, 95% CI: 1.2-7.8), and the management of ablation lines in the index procedure (OR = 2.5, 95% CI: 1.0-6.3) were independently associated with AFL occurrence. Furthermore, several characteristics assessed by LGE-CMR were identified as independent predictors of AFL recurrence after the index ablation for AF, such as enhanced LA sphericity (OR = 1.3, 95% CI: 1.1-1.6), LA global fibrosis (OR = 1.03, 95% CI: 1.01-1.07), and increased fibrosis in the lateral wall (OR = 1.03, 95% CI: 1.01-1.04). Advanced atrial cardiomyopathy assessed by LGE-CMR, such as increased LA sphericity, global LA fibrosis, and fibrosis in the lateral wall, is independently associated with arrhythmia recurrence in the form of AFL following AF ablation.

Long-term outcomes of thoracoscopic ablation for atrial fibrillation

The aim of this work is to analyze the effectiveness of thoracoscopic ablation (TSA) of atrial fibrillation (AF) and to define the risk factors for the return of atrial tachyarrhythmias after TSA in the long-term follow-up period.Methods. From January 2019 to December 2021, 150 patients with symptomatic atrial fibrillation (persistent 29.3% monitoring at the control points of the study, the results of which evaluated the effectiveness of the procedure.Results. The overall efficiency of TSA in the long-term follow-up period was 72.5%. After off-antiarrhythmic drugs, freedom from any atrial tachyarrhythmias was 79.2%, 70.5% and 68.9% after 6, 12 and 24 months, respectively. Additional catheter ablations after 3 months increase the effectiveness of the procedure to 82.9%. Important risk factors for the return of arrhythmia after TSA should be considered the patient’s age, duration of AF, previous catheter ablations and the left atria diameter of more 40 mm.Conclusion. The hybrid approach significantly improves the effectiveness of TSA for patients with non-paroxysmal forms of AF. The results obtained require further study of this problem in order to improve the quality of TSA and determine the optimal set of ablation lines, considering the risk factors for the return of arrhythmia.

The First Brazilian Cardiovascular Registry of Atrial Fibrillation: Primary Results of the RECALL Study

It is estimated that atrial fibrillation (AF) affects approximately 1.5 million people in Brazil; however, epidemiological data are limited. We sought to evaluate the characteristics, treatment patterns, and clinical outcomes in patients with atrial fibrillation (AF) in Brazil by creating the first nationwide prospective registry. RECALL was a multicenter, prospective registry that included and followed for 1 year 4585 patients with AF at 89 sites across Brazil from April 2012 to August 2019. Patient characteristics, concomitant medication use, and clinical outcomes were analyzed using descriptive statistics and multivariable models. Of 4585 patients enrolled, the median age was 70 (61, 78) years, 46% were women, and 53.8% had permanent AF. Only 4.4% of patients had history of previous AF ablation and 25.2% had a previous cardioversion. The mean (SD) CHA2DS2-VASc score was 3.2 (1.6); median HAS-BLED score was 2 (2, 3). At baseline, 22.0% were not on anticoagulants. Of those taking anticoagulants, 62.6% were taking vitamin K antagonists and 37.4% were taking direct oral anticoagulants. The primary reasons for not using an oral anticoagulant were physician judgement (24.6%) and difficulty in controlling (14.7%) or performing (9.9%) INR. Mean (SD) TTR for the study period was 49.5% (27.5). During follow-up, the use of anticoagulants and INR in the therapeutic range increased to 87.1% and 59.1%, respectively. The rates/100 patient-years of death, hospitalization due to AF, AF ablation, cardioversion, stroke, systemic embolism, and major bleeding were 5.76 (5.12-6.47), 15.8 (14.6-17.0), 5.0 (4.4-5.7), 1.8 (1.4-2.2), 2.77 (2.32-3.32), 1.01 (0.75-1.36), and 2.21 (1.81-2.70). Older age, permanent AF, New York Heart Association class III/IV, chronic kidney disease, peripheral arterial disease, stroke, chronic obstructive pulmonary disease and dementia were independently associated with mortality while use of anticoagulant (mono or double therapy) was associated with lower risk of death. RECALL represents the largest prospective registry of patients with AF in Latin America. Our findings highlight important gaps in treatment, which can inform clinical practice and guide future interventions to improve the care of these patients.

Hybrid Laparoscopic and Ultrasound-Guided Thermal Ablation of Recurrent Renal Cell Carcinoma in a Patient with von Hippel-Lindau Disease and a Solitary Kidney

Abstractvon Hippel-Lindau disease is an inherited autosomal dominant multisystem cancer syndrome. Multiple malignancies including renal cell carcinoma (RCC) occur in approximately 40%. A 69-year-old female presented with recurrent RCC in a solitary kidney, after previous partial nephrectomy and ablation. The 19-mm lesion was anterior and adherent to the descending colon, obviating percutaneous hydrodissection. A combined urology-interventional radiology procedure was performed including laparoscopic division of adhesions and mobilization of the colon, followed by direct laparoscopic and ultrasound-guided radiofrequency ablation. This novel approach was technically and clinically successful, which highlights the advantages of working in a multidisciplinary environment.

Baseline rhythm during catheter ablation for atrial tachycardia predicts procedural and clinical outcome

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial tachycardias (AT) occurring after previous ablation in patients with a history of atrial fibrillation (AF) are increasingly observed in clinical practice. Catheter ablation is the treatment of choice but an optimal workflow to improve patient outcome has not been defined. The prognostic implications of baseline rhythm at the beginning of AT ablation are unknown. Purpose The aim of this study was to assess procedural and clinical outcome depending on baseline rhythm during AT ablation. Methods A total of 380 patients with a history of AF who underwent catheter ablation for consecutive AT after previous ablation were analysed. Results In our study population (69 (61–75) years, 56.6% male), 140 patients (36.8%) presented in baseline sinus rhythm (SR), 208 (54.7%) with AT and 32 (8.4%) with AF at the beginning of the procedure. Patients in SR or with AT underwent shorter procedures (SR: 173 (132–213) minutes vs. AT: 161 (120–203) minutes vs. AF: 226 (154–249) minutes; P=0.002) with more frequent termination to SR (SR: 87.9% vs. AT: 81.3% vs. AF: 56.3%; P&amp;lt;0.001) than patients with AF. Periprocedural AT cycle length was longer in patients presenting in SR than in those with AT or AF (SR: 320 (265–370) ms vs. AT: 270 (240–310) ms vs. AF: 245 (193–278) ms; P&amp;lt;0.001). Acute procedural success did not differ between patients in SR or with AT but was higher compared to those with AF (SR: 96.4% vs. AT: 97.1% vs. AF: 87.5%; P=0.033). During a median follow-up of 290 (181–680) days, patients in baseline SR developed arrhythmia recurrences less often (SR: 36.4% vs. AT: 49.5% vs. AF: 68.8%; P=0.002) compared to patients with AT or AF. Conclusions Baseline rhythm during AT ablation predicts procedural and clinical outcome. Whereas acute procedural success does not differ between patients in SR or with AT, patients presenting in SR have a more favourable mid-term success rate. Restoration of SR prior to ablation might improve long-term outcome by reducing the risk for recurrent arrhythmia.

Epicardial ablation of left atrial flutter

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial flutter (LAFL) may have epicardial components not accessible to endocardial ablation by radiofrequency (RF) application. Subxiphoid access to the pericardial space has been reported in isolated cases. Purpose to prospectively evaluate the efficacy and safety of subxiphoid access to the pericardial space to map and ablate LAFL refractory to endocardial RF application. Methods Patients with LAFL confirmed by activation and entrainment mapping and refractory to endocardial RF application were consecutively enrolled. An epicardial component of the tachycardia circuit was suspected when parts of the AFL activation, channels of slow conduction or conduction gaps on previous ablation lines intersecting the AFL circuit were not found. Pericardial access was obtained by subxiphoid puncture performed conventionally or facilitated by saline infusion or CO2 insufflation into the pericardial space. Following pericardial access, epicardial mapping and ablation was performed with a conventional RF irrigated tip ablation catheter. All procedures were performed under oral anticoagulation and during following heparin infusion for 350 sec activation clotting time target. Results 15 patients with 18 LAFL were included (61.0 ± 8.8 years, 80% male). 14 patients have had a previous atrial fibrillation (AF) ablation. Epicardial ablation was attempted after a previous LAFL endocardial ablation procedure in 6 patients and during the same endocardial ablation procedure in the last 9 patients. Pericardial access was not achieved in 1 patient due to pericardial adhesions (after prior cardiac surgery). Ablation was successfully performed in 11 patients (73.33%) and failed in 4 patients with perimitral AFL (1 patient also had a peri-left appendage AFL). The successful ablation site was found in the transverse sinus of Theile over the Bachmann bundle in 14 patients with perimitral, septal and anterior-wall LAFL and in the oblique sinus in a posterior-wall LAFL. No patient presented relevant complications except for 2 patients who presented hemopericardium and 1 with delayed cardiac tamponade following accidental RV puncture and who required pericardiocentesis. No patient presented AFL recurrences at 19.8 months (range 6-34 months) follow-up except for 2 patients in whom ablation failed or pericardial access was not achieved. Conclusions Epicardial ablation of LAFL refractory to endocardial ablation is successful in most patients following successful pericardial access. This approach appears associated with low risk of significant complications.

Omnipolar mapping in ventricular tachycardia: will it be a game changer?

Abstract Funding Acknowledgements Type of funding sources: None. Background Ventricular tachycardias(VT) are life-theatening cardiac arrhythmias. Catheter ablation, the standard approach to VT is relying heavily on maps depicting intracardiac signals. The current mapping approach was based on bipolar electrograms, which are massively influenced by the direction of the underlying tissue activation. The omnipolar (OT) electrogram method was recently proposed to generate orientation-independent electrograms and has shown improved results in recent publications (1-2). We describe the first cohort of patients ablated for VT with the help of an OT-enabled catheter. Purpose To evaluate acute and mid-term follow-up of patients ablated for VT using an OT enabled mapping system. Methods Eighteen patients (age 65 ± 19; 2 females, 32% nonischemic, median ejection fraction 40), underwent catheter ablation for scar-related VT. 50% (9) n patients had previous ablation, 4 of which underwent epicardial access. High-density omnipolar maps were obtained with an HD-grid catheter after which ablation was performed with an irrigated-tip catheter. In all patients the ablation was primarily substrate-based with the support of CT scan scar visualization. In 18 patients local abnormal ventricular activities (LAVA) ablation was performed (3), while one patient showed no LAVA. In 7 patients VT mapping was possible due to stable blood pressure during the tachycardia. The median radiofrequency application duration was 36 min. While all patients except one were inducible at the beginning of the procedure, only 3 patients were inducible at the end with a protocol using up to 3 extrastimuli. Follow-up was available in 13 patients (7.1 ± 2.5 months) with 66% freedom from VT recurrence (60% in redo cases and 71% in first procedures). Conclusion OT is a reliable method to visualize signals and perform a substrate-based ablation in with good acute and mid-term outcomes. Future studies will evaluate the impact on long term outcomes.

Correlation of NT-proBNP and left atrial pressure in patients with atypical atrial flutter after cardiac surgery and previous catheter ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Atypical atrial flutter (AFL) is often associated with cardiac surgery or extensive catheter ablation (CA) for the treatment of atrial fibrillation (AF). Therefore, the increase in the number of cardiac surgery procedures leads to the development of substrates for atypical AFL onset. Described several prognostic factors for the development of AF in the long-term period after cardiac interventions. To our knowledge, the prognostic factors of atypical AFL in patients after cardiac surgery are not described. Objective the aim of our study was to determine the relationship between increased left atrial pressure and the NT-proBNP biomarker in patients after cardiac surgery and catheter ablation. Methods Sixty-five adult patients with AFL after cardiac surgery and catheter ablation were included in a single-center prospective study. The patients' age varied from 18 to 76 years, and the mean age was 57.1±12.2 years. Of these, 36 patients were male (55.4%) and 29 women (49.3%), respectively. Patients were observed for NT-proBNP before index radiofrequency ablation (RFA). All patients underwent RFA of atypical AFL in the left atrium (LA) and measurement of LA pressure. The patients were discharged safely and were monitored for 12 months. Results According to basic characteristics of patients with atypical AFL cardiac surgery for valvular heart disease was performed in 30 (46.1%) cases, for ischemic and congenital heart diseases occurred with the same frequency, 8 (12.3%). Atypical AFL occurred in 20 (30.8%) cases after cryoballoon pulmonary veins isolation (PVI), after RFA of a typical AFL in 14 (21.3%) cases, and radiofrequency PVI in 13 (20%) cases. The mean invasive LA pressure before index RFA was 22.3±5 mm. Hg, mean LA size on transthoracic echocardiography was 42.3±6.9mm. The parameters of the left ventricle: mean EDV 93.3±26.1ml, mean ESV 41.7±16.9ml, and mean EF 56±7.6%. Mean NT-proBNP was 974.8±440.5 pg/ml. In our cohort of patients, we identified a positive correlation between NT-proBNP and LA pressure (p&amp;lt;0.001, r=0.761), as well as a positive relationship between NT-proBNP and LA diameter (r=0.512, p&amp;lt;0.001), between LA pressure and LA diameter (r=0.438, p&amp;lt;0.001). Additionally, a correlation was found between the pulmonary artery systolic pressure and LA diameter (r=0.314, p=0.011). Conclusions Our study demonstrates a strong direct linear relationship of NT-proBNP with an increase of LA pressure in patients with atypical AFL in patients previously undergone cardiac surgery and catheter ablation. Thus, these parameters can serve as possible prognostic criteria for the development of complex cardiac arrhythmias such as atypical AFL.

Initial experience and early outcomes of posterior wall ablation using pulsed-field ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background The success rate of pulmonary vein isolation (PVI) is lower in patients with persistent compared to paroxysmal atrial fibrillation (AF). In patients with persistent AF, additional isolation of the posterior wall is under investigation to improve ablation success. Pulsed field ablation (PFA) might be superior to conventional methods for posterior wall isolation due to its safety profile and might allow for posterior wall ablation (PWA) rather than posterior wall isolation (PWI) based on its efficiency. Purpose To report our initial experience with PWA using a multipolar PFA catheter. Methods Consecutive patients with PWA during their first PFA procedure for AF between May 2021 and October 2022 at our institution were included. For PWA, the multipolar PFA ablation catheter was used in flower configuration only. With the wire in each of the pulmonary veins and the sheath angulated posteriorly, we first performed 2 x 2 sets of anchor lesions with the catheter rotated by ~30° between sets. Next, with the wire retracted back into the device, single sets of two applications were delivered in an overlapping fashion and without catheter rotation between lesion sets to cover the entire posterior wall between the superior and inferior pulmonary veins. Finally, completeness of PWA was verified by 3D electro-anatomical mapping. Results PWA using PFA was performed in 163 patients (mean age 67 years, 71% male). In 55 patients (34%), PWA was added to PVI during the first AF ablation procedure and the remaining 108 patients (66%) had undergone a median of two (interquartile range 1-3) previous AF ablation procedures using either cryoablation and/or radiofrequency ablation. Of all patients, 45 (28%) had paroxysmal, 93 (57%) persistent AF, and 22 patients (15%) left atrial reentry tachycardia. Median procedure duration and fluoroscopy time were 120 (70-190) min, and 18 (9-36) min, respectively. 3D-EAM showed no residual electrical signal (&amp;gt;0.05 mV) on the posterior wall at the end of the procedure in any patient. No cardiac tamponade, stroke, phrenic nerve injuries, atrio-esophageal fistula, or clinically manifest coronary spasm occurred. A repeat ablation was performed in seven patients (4%) and 3D-EAM showed persisting posterior wall isolation in six (86%) and recurrent roof dependent atrial flutter in one patient. Despite PWA, low-voltage signals were found in four (67%) cases on the superior aspect of the posterior wall. Conclusions Left atrial PWA can be performed safely and efficiently using PFA. Early data on the durability of PWA are promising. The impact of PWA on arrhythmia-free outcome needs to be evaluated in larger, prospective randomized trials.

The Omnipolar Mapping Technology - a new mapping tool to overcome bipolar blindness resulting in true high-density maps

Abstract Funding Acknowledgements Type of funding sources: None. Background Mapping, using the novel omnipolar technology (OT) obtains omnipolar signals displaying true voltage, real-time wavefront direction and speed, independent of catheter orientation and external reference. Employment of OT potentially overcomes so called "bipolar blindness" (conventional bipolar electroanatomic mapping). Hence, OT potentially improves substrate assessment, comprehension of tachycardia mechanisms and gap detection after previous catheter ablation (CA). Purpose Purposes of our study was to analyze previously performed left atrial (LA) and left ventricular (LV) maps for differences using automated OT vs. SD vs. the previously published HD Wave (HDW) algorithm. Methods Maps of patients undergoing CA for atrial or ventricular arrhythmia were initially acquired using HDW settings in conjunction with the Advisor HD Grid mapping catheter. These maps were then analyzed retrospectively applying the automated OT algorithm vs. SD vs. HDW. to reveal differences in voltage and point density. Additionally, detection of pulmonary vein (PV) gaps and LV scar area was evaluated. Results In 45 consecutive patients 135 maps were analyzed. The study population undergoing CA consisted of: 30 (22.2%) patients undergoing repeated CA for recurrence of persistent atrial fibrillation (persAF)/left atrial tachycardia (AT) and 15 (11.1%) patients with ventricular tachycardia (VT) or premature ventricular contractions (PVC). Atrial maps revealed a significantly higher point density using OT (21471) vs. SD (6682) or HDW (12189, p&amp;lt;0.001). Mean voltage was significantly higher using OT (0.75mV) vs. SD (0.61mV) or HDW (0.64mV, p&amp;lt;0.001). OT maps detected significantly more PV gaps vs. SD (4 vs. 2, p=0.001). In LV maps, OT revealed a significantly higher point density (25951) vs. SD (8582) and HDW (17071), p&amp;lt;0.001. Mean voltage was significantly higher for OT (1.49mV) vs. SD (1.19mV) and HDW (1.2mV), p&amp;lt;0.001. Detected scar area was significantly smaller using OT (25.3%) vs. SD (33.9%, p&amp;lt;0.001). Conclusion Using OT results in a higher voltage and point density compared to SD and HDW. Therefore displayed scar extend is significantly smaller in atrial and ventricular maps. Also, more PV gaps were detected using OT. The OT algorithm potentially improves scar delineation, facilitates substrate characterization, and may improve procedural outcome.