Safety and Effectiveness of Pulsed Field Ablation for Atrial Fibrillation in Patients With Heart Failure.

BACKGROUND: Atrial fibrillation (AF) and heart failure (HF) coexist, increasing morbidity and mortality. Studies have demonstrated improved outcomes following AF ablation in HF patients with reduced ejection fraction (EF). OBJECTIVE: This study sought to assess the outcomes of pulsed field ablation (PFA) in HF. METHODS: MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-Approval Clinical Use of Pulsed Field Ablation) is a multicenter, patient-level registry of consecutive patients undergoing PFA for paroxysmal AF or persistent AF (PerAF). In this substudy, patients were stratified as no history of HF (no-HF), HF with preserved EF (HFpEF) (left ventricular EF of ≥50%) or HF with reduced/mildly reduced EF (HFmr/rEF) (left ventricular EF of <50%). The primary effectiveness and safety endpoints were freedom from documented atrial arrhythmias lasting ≥30 seconds and major adverse events, respectively. RESULTS: Of the 1,381 patients, 85% (n = 1,174) were no-HF, 6.2% (n = 87) were HFpEF, and 8.6% (n = 120) were HFmr/rEF. No-HF patients had less PerAF than patients with HF (P < 0.001), with no difference between HF subtypes (P = >0.99). The 1-year freedom from atrial arrhythmia was significantly higher in no-HF patients than in those with HFpEF or HFmr/rEF (79.9%, 71.3%, and 67.5%, respectively; P < 0.001) but similar between patients with HFmr/rEF and HFpEF (P = 0.26). However, there was no significant difference in freedom from atrial arrhythmia among patients with no-HF vs HFpEF vs HFmr/rEF for those with paroxysmal AF (82.8%, 82.4%, and 71.7%, respectively; P = 0.09) and PerAF (73.3%, 64.2%, and 64.9%, respectively; P = 0.14). Major adverse event rates were similar between the no-HF, HFpEF, and HFmr/rEF groups (1.9%, 0%, and 2.5%, respectively). CONCLUSIONS: PFA appears to be potentially safe and effective in AF patients with HF. Freedom from atrial arrhythmia post-PFA was higher in patients without a history of HF, with no significant difference between HF subtypes.

Safety and Effectiveness of Pulsed Field Ablation for Atrial Fibrillation in Patients with Heart Failure: A MANIFEST-PF Sub-analysis.

BACKGROUND: Atrial fibrillation (AF) and heart failure (HF) coexist, increasing morbidity and mortality. Studies have demonstrated improved outcomes following AF ablation in HF patients with reduced ejection fraction (EF). OBJECTIVE: To assess the outcomes of pulsed-field ablation (PFA) in HF. METHODS: MANIFEST-PF is a multicenter patient-level registry of consecutive patients undergoing PFA for paroxysmal (PAF) or persistent AF (PerAF). In this sub-study, patients were stratified as: no history of HF (no-HF), HF with preserved EF (HFPEF; LVEF≥50%) or HF with reduced/mildly-reduced EF (HFMR/REF; LVEF<50%). The primary effectiveness and safety endpoints were freedom from documented atrial arrhythmias lasting ≥30s and major adverse events (MAEs), respectively. RESULTS: Of the 1,381 patients, 85% (n=1,174) were no-HF, 6.2% (n=87) were HFPEF, and 8.6% (n=120) were HFMR/REF. No-HF patients had less PerAF than patients with HF (p<0.001), with no difference between HF subtypes (p=1.00). The 1-year freedom from atrial arrhythmia was significantly higher in no-HF than with HFPEF or HFMR/REF (79.9%, 71.3%, 67.5%, p<0.001), but similar between HFMR/REF and HFPEF (p=0.26). However, there was no significant difference in freedom from atrial arrhythmia among patients with no-HF vs HFPEF vs HFMR/REF for those with PAF (82.8%/82.4%/71.7%, p=0.09) and PerAF (73.3%, 64.2%, and 64.9%, p=0.14.MAE rates were similar between the no-HF, HFPEF and HFMR/REF groups (1.9%, 0%, and 2.5%, respectively). CONCLUSION: PFA appears to be potentially safe and effective in AF patients with HF. Freedom from atrial arrhythmia post-PFA was higher in patients without a history of HF, with no significant difference between HF subtypes.

Whole-heart computational modelling provides further mechanistic insights into ST-elevation in Brugada syndrome.

Background: Brugada syndrome (BrS) is characterized by dynamic ST-elevations in right precordial leads and increased risk of ventricular fibrillation and sudden cardiac death. As the mechanism underlying ST-elevation and malignant arrhythmias is controversial computational modeling can aid in exploring the disease mechanism. Thus we aim to test the main competing hypotheses ('delayed depolarization' vs. 'early repolarization') of BrS in a whole-heart computational model. Methods: In a 3D whole-heart computational model, delayed epicardial RVOT activation with local conduction delay was simulated by reducing conductivity in the epicardial RVOT. Early repolarization was simulated by instead increasing the transient outward potassium current (Ito) in the same region. Additionally, a reduction in the fast sodium current (INa) was incorporated in both models. Results: Delayed depolarization with local conduction delay in the computational model resulted in coved-type ST-elevation with negative T-waves in the precordial surface ECG leads. 'Saddleback'-shaped ST-elevation was obtained with reduced substrate extent or thickness. Increased Ito simulations showed early repolarization in the RVOT with a descending but not coved-type ST-elevation. Reduced INa did not show a significant effect on ECG morphology. Conclusions: In this whole-heart BrS computational model of both major hypotheses, realistic coved-type ECG resulted only from delayed epicardial RVOT depolarization with local conduction delay but not early repolarizing ion channel modifications. These simulations provide further support for the depolarization hypothesis as electrophysiological mechanism underlying BrS.

Impact of Left Atrial Posterior Wall Ablation During Pulsed-Field Ablation for Persistent Atrial Fibrillation.

BACKGROUND: Pulmonary vein isolation (PVI) alone is insufficient to treat many patients with persistent atrial fibrillation (PersAF). Adjunctive left atrial posterior wall (LAPW) ablation with thermal technologies has revealed lack of efficacy, perhaps limited by the difficulty in achieving lesion durability amid concerns of esophageal injury. OBJECTIVES: This study aims to compare the safety and effectiveness of PVI + LAPW ablation vs PVI in patients with PersAF using pulsed-field ablation (PFA). METHODS: In a retrospective analysis of the MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-approval Clinical Use of Pulsed Field Ablation) registry, we studied consecutive PersAF patients undergoing post-approval treatment with a pentaspline PFA catheter. The primary effectiveness outcome was freedom from any atrial arrhythmia of ≥30 seconds. Safety outcomes included the composite of acute and chronic major adverse events. RESULTS: Of the 547 patients with PersAF who underwent PFA, 131 (24%) received adjunctive LAPW ablation. Compared to PVI-alone, patients receiving adjunctive LAPW ablation were younger (65 vs 67 years of age, P = 0.08), had a lower CHA2DS2-VASc score (2.3 ± 1.6 vs 2.6 ± 1.6, P = 0.08), and were more likely to receive electroanatomical mapping (48.1% vs 39.0%, P = 0.07) and intracardiac echocardiography imaging (46.1% vs 17.1%, P < 0.001). The 1-year Kaplan-Meier estimate for freedom from atrial arrhythmias was not statistically different between groups in the full (PVI + LAPW: 66.4%; 95% CI: 57.6%-74.4% vs PVI: 73.1%; 95% CI: 68.5%-77.2%; P = 0.68) and propensity-matched cohorts (PVI + LAPW: 71.7% vs PVI: 68.5%; P = 0.34). There was also no significant difference in major adverse events between the groups (2.2% vs 1.4%, respectively, P = 0.51). CONCLUSIONS: In patients with PersAF undergoing PFA, as compared to PVI-alone, adjunctive LAPW ablation did not improve freedom from atrial arrhythmia at 12 months.

Epicardial ventricular tachycardia ablation: safety and efficacy of access and ablation using low-iodine content.

BACKGROUND: Epicardial ablation has become an integral part of the treatment of ventricular tachycardias (VT). This study reports the safety of epicardial access as well as the efficacy of epicardial ablation of structural heart disease in a tertiary single-center experience. METHODS: Between January 2016 and February 2022, consecutive patients undergoing an epicardial access for VT ablation were included. Different puncture techniques and occurrence of epicardial access-related complications as well as the safety of ablation using non-ionic 5% dextrose in water (D5W) compared to standard 0.9% normal saline (NS) irrigation were analyzed. VT recurrence rates during a mean follow-up of 37 ± 23 months were reported. RESULTS: In total, 197 patients undergoing a total of 239 procedures were included (59.8 ± 15.3 years, 86% males). A total of 154 patients (78%) had non-ischemic cardiomyopathies with a mean LVEF of 37 ± 14. Anterior-oriented epicardial access was aimed for in all cases and was successful in 217 (91%) of all procedures, whereas access was achieved in 19 procedures (8%) only using an inferior oriented access and in three procedures (1%) using surgical access due to severe adhesions or anatomical requirements. Overall epicardial puncture-related complications occurred in 18 (8%) of all procedures with minor pericardial bleeding in nine, pericardial tamponade in one, pneumothorax in five, pneumopericardium in one, and abdominal puncture in two cases. Presence of adhesions could be identified as the only independent predictor of epicardial access-related complications. D5W was used in 79 cases and regular 0.9% saline in 117 procedures. No differences were seen regarding acute ablation success or complications. During follow-up, 47% of all patients were free from any VTs (56% D5W vs. 40% NS; log-rank p = 0.747) and 92% of clinical VTs (98% D5W vs. 91% NS; log-rank p = 0.139). CONCLUSIONS: In this large single-centre experience, epicardial access and ablation were safe and feasible. Although long-term clinical VT recurrence rates were low, overall VT recurrences as well as mortality were high advocating for a highly experienced, interdisciplinary approach including intense management of underlying cardiac disease/heart failure. Routine usage of D5W was safe and associated with comparable short- or long-term clinical or overall VT freedom.

Clinical Outcomes by Sex After Pulsed Field Ablation of Atrial Fibrillation.

Importance: Previous studies evaluating the association of patient sex with clinical outcomes using conventional thermal ablative modalities for atrial fibrillation (AF) such as radiofrequency or cryoablation are controversial due to mixed results. Pulsed field ablation (PFA) is a novel AF ablation energy modality that has demonstrated preferential myocardial tissue ablation with a unique safety profile. Objective: To compare sex differences in patients undergoing PFA for AF in the Multinational Survey on the Methods, Efficacy, and Safety on the Postapproval Clinical Use of Pulsed Field Ablation (MANIFEST-PF) registry. Design, Setting, and Participants: This was a retrospective cohort study of MANIFEST-PF registry data, which included consecutive patients undergoing postregulatory approval treatment with PFA to treat AF between March 2021 and May 2022 with a median follow-up of 1 year. MANIFEST-PF is a multinational, retrospectively analyzed, prospectively enrolled patient-level registry including 24 European centers. The study included all consecutive registry patients (age ≥18 years) who underwent first-ever PFA for paroxysmal or persistent AF. Exposure: PFA was performed on patients with AF. All patients underwent pulmonary vein isolation and additional ablation, which was performed at the discretion of the operator. Main Outcomes and Measures: The primary effectiveness outcome was freedom from clinically documented atrial arrhythmia for 30 seconds or longer after a 3-month blanking period. The primary safety outcome was the composite of acute (<7 days postprocedure) and chronic (>7 days) major adverse events (MAEs). Results: Of 1568 patients (mean [SD] age, 64.5 [11.5] years; 1015 male [64.7%]) with AF who underwent PFA, female patients, as compared with male patients, were older (mean [SD] age, 68 [10] years vs 62 [12] years; P < .001), had more paroxysmal AF (70.2% [388 of 553] vs 62.4% [633 of 1015]; P = .002) but had fewer comorbidities such as coronary disease (9% [38 of 553] vs 15.9% [129 of 1015]; P < .001), heart failure (10.5% [58 of 553] vs 16.6% [168 of 1015]; P = .001), and sleep apnea (4.7% [18 of 553] vs 11.7% [84 of 1015]; P < .001). Pulmonary vein isolation was performed in 99.8% of female (552 of 553) and 98.9% of male (1004 of 1015; P = .90) patients. Additional ablation was performed in 22.4% of female (124 of 553) and 23.1% of male (235 of 1015; P = .79) patients. The 1-year Kaplan-Meier estimate for freedom from atrial arrhythmia was similar in male and female patients (79.0%; 95% CI, 76.3%-81.5% vs 76.3%; 95% CI, 72.5%-79.8%; P = .28). There was also no significant difference in acute major AEs between groups (male, 1.5% [16 of 1015] vs female, 2.5% [14 of 553]; P = .19). Conclusion and Relevance: Results of this cohort study suggest that after PFA for AF, there were no significant sex differences in clinical effectiveness or safety events.

Recurrent Atrial Fibrillation Ablation after Initial Successful Pulmonary Vein Isolation.

BACKGROUND: Pulmonary vein isolation (PVI) is an effective treatment option for patients with symptomatic atrial fibrillation (AF). However, the electrical recovery of pulmonary veins (PVs) is the main trigger for AF recurrences. This study investigates the characteristics of patients admitted for redo AF ablation, the PV reconnection rates depending on previous ablation modalities and the impact of different ablation strategies for redo procedures. METHODS: Consecutive patients undergoing first redo AF ablation were included. Patients were grouped according to the electrical recovery of at least one PV. The impacts of the technique for first AF ablation on PV reconnection rates and patients with and without PV reconnection were compared. Different ablation strategies for redo procedures were compared and its recurrence rates after a mean follow-up of 25 ± 20 months were investigated. RESULTS: A total of 389 patients (68 ± 10 years; 57% male; 39% paroxysmal AF) underwent a first redo. The median time between the first and redo procedure was 40 ± 39 months. Radiofrequency was used in 278 patients, cryoballoon was used in 85 patients and surgical AF ablation was performed on 26 patients. In total, 325 patients (84%) had at least one PV reconnected, and the mean number of reconnected PVs was 2.0 ± 1.3, with significant differences between ablation approaches (p for all = 0.002); this was mainly due to differences in the left inferior PV and right superior PV reconnections. The presence of PV reconnection during redo was not associated with better long-term success compared to completely isolated PVs (67% vs. 67%; log-rank p = 0.997). Overall, the different ablation strategies for redos were comparable regarding AF recurrences during follow-up (p = 0.079), with the ablation approach having no impact in the case of left atrial low voltage or without. CONCLUSIONS: PV reconnections after initial successful PVI are common among all techniques of AF ablation. Long-term rhythm control off antiarrhythmic drugs was possible in 2/3 of all patients after the redo procedure; however, different ablation strategies with extra-PV trigger ablation did not improve long-term success. Patients with recurrent AF after PVI constitute a challenging group of patients.

Differences in atrial substrate localization using late gadolinium enhancement-magnetic resonance imaging, electrogram voltage, and conduction velocity: a cohort study using a consistent anatomical reference frame in patients with persistent atrial fibrillation.

AIMS: Electro-anatomical voltage, conduction velocity (CV) mapping, and late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) have been correlated with atrial cardiomyopathy (ACM). However, the comparability between these modalities remains unclear. This study aims to (i) compare pathological substrate extent and location between current modalities, (ii) establish spatial histograms in a cohort, (iii) develop a new estimated optimized image intensity threshold (EOIIT) for LGE-MRI identifying patients with ACM, (iv) predict rhythm outcome after pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF). METHODS AND RESULTS: Thirty-six ablation-naive persistent AF patients underwent LGE-MRI and high-definition electro-anatomical mapping in sinus rhythm. Late gadolinium enhancement areas were classified using the UTAH, image intensity ratio (IIR >1.20), and new EOIIT method for comparison to low-voltage substrate (LVS) and slow conduction areas <0.2 m/s. Receiver operating characteristic analysis was used to determine LGE thresholds optimally matching LVS. Atrial cardiomyopathy was defined as LVS extent ≥5% of the left atrium (LA) surface at <0.5 mV. The degree and distribution of detected pathological substrate (percentage of individual LA surface are) varied significantly (P < 0.001) across the mapping modalities: 10% (interquartile range 0-14%) of the LA displayed LVS <0.5 mV vs. 7% (0-12%) slow conduction areas <0.2 m/s vs. 15% (8-23%) LGE with the UTAH method vs. 13% (2-23%) using IIR >1.20, with most discrepancies on the posterior LA. Optimized image intensity thresholds and each patient's mean blood pool intensity correlated linearly (R2 = 0.89, P < 0.001). Concordance between LGE-MRI-based and LVS-based ACM diagnosis improved with the novel EOIIT applied at the anterior LA [83% sensitivity, 79% specificity, area under the curve (AUC): 0.89] in comparison to the UTAH method (67% sensitivity, 75% specificity, AUC: 0.81) and IIR >1.20 (75% sensitivity, 62% specificity, AUC: 0.67). CONCLUSION: Discordances in detected pathological substrate exist between LVS, CV, and LGE-MRI in the LA, irrespective of the LGE detection method. The new EOIIT method improves concordance of LGE-MRI-based ACM diagnosis with LVS in ablation-naive AF patients but discrepancy remains particularly on the posterior wall. All methods may enable the prediction of rhythm outcomes after PVI in patients with persistent AF.

Practical guidance to reduce radiation exposure in electrophysiology applying ultra low-dose protocols: a European Heart Rhythm Association review.

Interventional electrophysiology offers a great variety of treatment options to patients suffering from symptomatic cardiac arrhythmia. Catheter ablation of supraventricular and ventricular tachycardia has globally evolved a cornerstone in modern arrhythmia management. Complex interventional electrophysiological procedures engaging multiple ablation tools have been developed over the past decades. Fluoroscopy enabled interventional electrophysiologist throughout the years to gain profound knowledge on intracardiac anatomy and catheter movement inside the cardiac cavities and hence develop specific ablation approaches. However, the application of X-ray technologies imposes serious health risks to patients and operators. To reduce the use of fluoroscopy during interventional electrophysiological procedures to the possibly lowest degree and to establish an optimal protection of patients and operators in cases of fluoroscopy is the main goal of modern radiation management. The present manuscript gives an overview of possible strategies of fluoroscopy reduction and specific radiation protection strategies.

Spatial correlation of left atrial low voltage substrate in sinus rhythm versus atrial fibrillation: The rhythm specificity of atrial low voltage substrate.

INTRODUCTION: Improved sinus rhythm (SR) maintenance rates have been achieved in patients with persistent atrial fibrillation (AF) undergoing pulmonary vein isolation plus additional ablation of low voltage substrate (LVS) during SR. However, voltage mapping during SR may be hindered in persistent and long-persistent AF patients by immediate AF recurrence after electrical cardioversion. We assess correlations between LVS extent and location during SR and AF, aiming to identify regional voltage thresholds for rhythm-independent delineation/detection of LVS areas. (1) Identification of voltage dissimilarities between mapping in SR and AF. (2) Identification of regional voltage thresholds that improve cross-rhythm substrate detection. (3) Comparison of LVS between SR and native versus induced AF. METHODS: Forty-one ablation-naive persistent AF patients underwent high-definition (1 mm electrodes; >1200 left atrial (LA) mapping sites per rhythm) voltage mapping in SR and AF. Global and regional voltage thresholds in AF were identified which best match LVS < 0.5 mV and <1.0 mV in SR. Additionally, the correlation between SR-LVS with induced versus native AF-LVS was assessed. RESULTS: Substantial voltage differences (median: 0.52, interquartile range: 0.33-0.69, maximum: 1.19 mV) with a predominance of the posterior/inferior LA wall exist between the rhythms. An AF threshold of 0.34 mV for the entire left atrium provides an accuracy, sensitivity and specificity of 69%, 67%, and 69% to identify SR-LVS < 0.5 mV, respectively. Lower thresholds for the posterior wall (0.27 mV) and inferior wall (0.3 mV) result in higher spatial concordance to SR-LVS (4% and 7% increase). Concordance with SR-LVS was higher for induced AF compared to native AF (area under the curve[AUC]: 0.80 vs. 0.73). AF-LVS < 0.5 mV corresponds to SR-LVS < 0.97 mV (AUC: 0.73). CONCLUSION: Although the proposed region-specific voltage thresholds during AF improve the consistency of LVS identification as determined during SR, the concordance in LVS between SR and AF remains moderate, with larger LVS detection during AF. Voltage-based substrate ablation should preferentially be performed during SR to limit the amount of ablated atrial myocardium.

Safety and Effectiveness of Pulsed Field Ablation to Treat Atrial Fibrillation: One-Year Outcomes From the MANIFEST-PF Registry.

BACKGROUND: Pulsed field ablation is a novel nonthermal cardiac ablation modality using ultra-rapid electrical pulses to cause cell death by a mechanism of irreversible electroporation. Unlike the traditional ablation energy sources, pulsed field ablation has demonstrated significant preferentiality to myocardial tissue ablation, and thus avoids certain thermally mediated complications. However, its safety and effectiveness remain unknown in usual clinical care. METHODS: MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-Approval Clinical Use of Pulsed Field Ablation) is a retrospective, multinational, patient-level registry wherein patients at each center were prospectively included in their respective center registries. The registry included all patients undergoing postapproval treatment with a multielectrode 5-spline pulsed field ablation catheter to treat atrial fibrillation (AF) between March 1, 2021, and May 30, 2022. The primary effectiveness outcome was freedom from clinical documented atrial arrhythmia (AF/atrial flutter/atrial tachycardia) of ≥30 seconds on the basis of electrocardiographic data after a 3-month blanking period (on or off antiarrhythmic drugs). Safety outcomes included the composite of acute (<7 days postprocedure) and latent (>7 days) major adverse events. RESULTS: At 24 European centers (77 operators) pulsed field ablation was performed in 1568 patients with AF: age 64.5±11.5 years, female 35%, paroxysmal/persistent AF 65%/32%, CHA2DS2-VASc 2.2±1.6, median left ventricular ejection fraction 60%, and left atrial diameter 42 mm. Pulmonary vein isolation was achieved in 99.2% of patients. After a median (interquartile range) follow-up of 367 (289-421) days, the 1-year Kaplan-Meier estimate for freedom from atrial arrhythmia was 78.1% (95% CI, 76.0%-80.0%); clinical effectiveness was more common in patients with paroxysmal AF versus persistent AF (81.6% versus 71.5%; P=0.001). Acute major adverse events occurred in 1.9% of patients. CONCLUSIONS: In this large observational registry of the postapproval clinical use of pulsed field technology to treat AF, catheter ablation using pulsed field energy was clinically effective in 78% of patients with AF.

Analysis of the amplified p-wave enables identification of patients with atrial fibrillation during sinus rhythm.

Aim: This study sought to develop and validate diagnostic models to identify individuals with atrial fibrillation (AF) using amplified sinus-p-wave analysis. Methods: A total of 1,492 patients (491 healthy controls, 499 with paroxysmal AF and 502 with persistent AF) underwent digital 12-lead-ECG recording during sinus rhythm. The patient cohort was divided into training and validation set in a 3:2 ratio. P-wave indices (PWI) including duration of standard p-wave (standard PWD; scale at 10 mm/mV, sweep speed at 25 mm/s) and amplified sinus-p-wave (APWD, scale at 60-120 mm/mV, sweep speed at 100 mm/s) and advanced inter-atrial block (aIAB) along with other clinical parameters were used to develop diagnostic models using logistic regression. Each model was developed from the training set and further tested in both training and validation sets for its diagnostic performance in identifying individuals with AF. Results: Compared to standard PWD (Reference model), which achieved an AUC of 0.637 and 0.632, for training and validation set, respectively, APWD (Basic model) importantly improved the accuracy to identify individuals with AF (AUC = 0.86 and 0.866). The PWI-based model combining APWD, aIAB and body surface area (BSA) further improved the diagnostic performance for AF (AUC = 0.892 and 0.885). The integrated model, which further combined left atrial diameter (LAD) with parameters of the PWI-based model, achieved optimal diagnostic performance (AUC = 0.916 and 0.902). Conclusion: Analysis of amplified p-wave during sinus rhythm allows identification of individuals with atrial fibrillation.

Feasibility and safety of a three-dimensional anatomic map-guided transseptal puncture for left-sided catheter ablation procedures.

AIMS: Transseptal puncture (TP) for left-sided catheter ablation procedures is routinely performed under fluoroscopic or echocardiographic guidance [transoesophageal echocardiography (TEE) or intracardiac echocardiography (ICE)], although three-dimensional (3D) mapping systems are readily available in most electrophysiology laboratories. Here, we sought to assess the feasibility and safety of a right atrial (RA) 3D map-guided TP. METHODS AND RESULTS: In 104 patients, 3D RA mapping was performed to identify the fossa ovalis (FO) using the protrusion technique. The radiofrequency transseptal needle was visualized and navigated to the desired potential FO-TP site. Thereafter, the interventionalist was unblinded to TEE and the potential FO-TP site was reassessed regarding its convenience and safety. After TP, the exact TP site was documented using a 17-segment-FO model. Reliable identification of the FO was feasible in 102 patients (98%). In these, 114 3D map-guided TP attempts were performed, of which 96 (84%) patients demonstrated a good position and 18 (16%) an adequate position after TEE unblinding. An out-of-FO or dangerous position did not occur. A successful 3D map-guided TP was performed in 110 attempts (97%). Four attempts (3%) with adequate positions were aborted in order to seek a more convenient TP site. The median time from RA mapping until the end of the TP process was 13 (12-17) min. No TP-related complications occurred. Ninety-eight TP sites (85.1%) were in the central portion or in the inner loop of the FO. CONCLUSION: A 3D map-guided TP is feasible and safe. It may assist to decrease radiation exposure and the need for TEE/ICE during left-sided catheter ablation procedures.

Predictive value of late gadolinium enhancement cardiovascular magnetic resonance in patients with persistent atrial fibrillation: dual-centre validation of a standardized method.

Aims: With recurrence rates up to 50% after pulmonary vein isolation (PVI) in persistent atrial fibrillation (AF), predictive tools to improve patient selection are needed. Patient selection based on left atrial late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) has been proposed previously (UTAH-classification). However, this approach has not been widely established, in part owed to the lack of standardization of the LGE quantification method. We have recently established a standardized LGE-CMR method enabling reproducible LGE-quantification. Here, the ability of this method to predict outcome after PVI was evaluated. Methods and results: This dual-centre study (n = 219) consists of a prospective derivation cohort (n = 37, all persistent AF) and an external validation cohort (n = 182; 66 persistent, 116 paroxysmal AF). All patients received an LGE-CMR prior to first-time PVI-only ablation. LGE was quantified based on the signal-intensity-ratio relative to the blood pool, applying a uniform LGE-defining threshold of >1.2.  In patients with persistent AF in the derivation cohort, left atrial LGE-extent above a cut-off value of 12% was found to best predict relevant low-voltage substrate (≥2 cm two with <0.5 mV during sinus rhythm) and arrhythmia-free survival 12 months post-PVI. When applied to the external validation cohort, this cut-off value was also predictive of arrhythmia-free survival for both, the total cohort and the subgroup with persistent AF (LGE < 12%: 80% and 76%; LGE > 12%: 55% and 44%; P = 0.007 and P = 0.029, respectively). Conclusion: This dual-centre study established and validated a standardized, reproducible LGE-CMR method discriminating PVI responders from non-responders, which may improve choice of therapeutic approach or ablation strategy for patients with persistent AF.

Characterization of circumferential antral pulmonary vein isolation areas resulting from pulsed-field catheter ablation.

AIMS: The cornerstone of pulmonary vein (PV) isolation (PVI) is a wide-area circumferential ablation (WACA) resulting in an antral PVI area. Pulsed-field ablation (PFA) is a new nonthermal 'single-shot' PVI technique resulting in well-characterized posterior isolation areas. However, information on circumferential PVI area is lacking. Thus, we sought to characterize the circumferential antral PVI areas after PFA-PVI. METHODS AND RESULTS: Atrial fibrillation (AF) patients underwent fluoroscopy-guided PVI with a pentaspline PFA catheter. Ultra-high-density voltage maps using a 20-polar circular mapping catheter were created before and immediately after PVI to identify and quantify (i) insufficient isolation areas per antral PV segment (10-segment model) and (ii) enlarged left atrial (LA) isolation areas (beyond the antral PV segments) per LA region (8-region model). The PFA-PVI with pre- (5469 ± 1822 points) and post-mapping (6809 ± 2769 points) was performed in 40 consecutive patients [age 62 ± 6 years, 25/40 (62.5%) paroxysmal AF]. Insufficient isolation areas were located most frequently in the anterior antral PV segments of the left PVs (62.5-77.5% of patients) with the largest extent (median ≥0.4 cm2) located in the same segments (segments 2/5/8). Enlarged LA isolation areas were located most frequently and most extensively on the posterior wall and roof region (89.5-100% of patients; median 1.1-2.7 cm2 per region). CONCLUSION: Fluoroscopy-guided PFA-PVI frequently results in insufficient isolation areas in the left anterior antral PV segments and enlarged LA isolation areas on the posterior wall/roof, which both may be extensive. To optimize the procedure, full integration of PFA catheter visualization into three-dimensional-mapping systems is needed.

3D mapping of phrenic nerve course for radiofrequency pulmonary vein isolation.

INTRODUCTION: Phrenic nerve (PN) injury is a rare but severe complication of radiofrequency (RF) pulmonary vein isolation (PVI). The objective of this study was to characterize the typical intracardiac course of the PN with a three-dimensional electroanatomic mapping system, to quantify the need for modification of the ablation trajectory to avoid delivering an ablation lesion on sites with PN capture, and to identify very circumscribed areas of common PNC on the routine ablation trajectory of a RF-PVI, allowing fast and effective PN screening for everyday usage. METHODS: We enrolled 137 consecutive patients (63 ± 9 years, 64% men) undergoing PVI. A detailed high output (20 mA) pace-mapping protocol was performed in the right (RA) and left atrium (LA) and adjacent vasculature. RESULTS: The right PN was most commonly captured in the superior vena cava at a lateral (50%) or posterolateral (23%) position before descending along the RA either straight (29%) or with a posterolateral bend (20%). In the LA, beginning deep within the right superior pulmonary vein (RSPV), the right PN is most frequently detectable anterolateral (31%), then descends to the lateral proximal RSPV (23%), and further towards the lateral antral region (15%) onto the medial LA wall (12%). To avoid delivering an ablation lesion on sites with PN capture, modification of ablation trajectory was necessary in 23% of cases, most commonly in the lateral RSPV antrum (81%). No PN injury occurred. CONCLUSION: PN mapping frequently reveals the close proximity of the PN to the ablation trajectory during PVI, particularly in the lateral RSPV antrum. Routine PN pacing should be considered during RF PVI procedures.

Validating left atrial fractionation and low-voltage substrate during atrial fibrillation and sinus rhythm-A high-density mapping study in persistent atrial fibrillation.

Background: Low-voltage-substrate (LVS)-guided ablation for persistent atrial fibrillation (AF) has been described either in sinus rhythm (SR) or AF. Prolonged fractionated potentials (PFPs) may represent arrhythmogenic slow conduction substrate and potentially co-localize with LVS. We assess the spatial correlation of PFP identified in AF (PFP-AF) to those mapped in SR (PFP-SR). We further report the relationship between LVS and PFPs when mapped in AF or SR. Materials and methods: Thirty-eight patients with ablation naïve persistent AF underwent left atrial (LA) high-density mapping in AF and SR prior to catheter ablation. Areas presenting PFP-AF and PFP-SR were annotated during mapping on the LA geometry. Low-voltage areas (LVA) were quantified using a bipolar threshold of 0.5 mV during both AF and SR mapping. Concordance of fractionated potentials (CFP) (defined as the presence of PFPs in both rhythms within a radius of 6 mm) was quantified. Spatial distribution and correlation of PFP and CFP with LVA were assessed. The predictors for CFP were determined. Results: PFPs displayed low voltages both during AF (median 0.30 mV (Q1-Q3: 0.20-0.50 mV) and SR (median 0.35 mV (Q1-Q3: 0.20-0.56 mV). The duration of PFP-SR was measured at 61 ms (Q1-Q3: 51-76 ms). During SR, most PFP-SRs (89.4 and 97.2%) were located within LVA (<0.5 mV and <1.0 mV, respectively). Areas presenting PFP occurred more frequently in AF than in SR (median: 9.5 vs. 8.0, p = 0.005). Both PFP-AF and PFP-SR were predominantly located at anterior LA (>40%), followed by posterior LA (>20%) and septal LA (>15%). The extent of LVA < 0.5 mV was more extensive in AF (median: 25.2% of LA surface, Q1-Q3:16.6-50.5%) than in SR (median: 12.3%, Q1-Q3: 4.7-29.4%, p = 0.001). CFP in both rhythms occurred in 80% of PFP-SR and 59% of PFP-AF (p = 0.008). Notably, CFP was positively correlated to the extent of LVA in SR (p = 0.004), but not with LVA in AF (p = 0.226). Additionally, the extent of LVA < 0.5 mV in SR was the only significant predictor for CFP, with an optimal threshold of 16% predicting high (>80%) fractionation concordance in AF and SR. Conclusion: Substrate mapping in SR vs. AF reveals smaller areas of low voltage and fewer sites with PFP. PFP-SR are located within low-voltage areas in SR. There is a high degree of spatial agreement (80%) between PFP-AF and PFP-SR in patients with moderate LVA in SR (>16% of LA surface). These findings should be considered when substrate-based ablation strategies are applied in patients with the left atrial low-voltage substrate with recurrent persistent AF.

Initial Clinical Experience With a Novel 8-Spline High-Resolution Mapping Catheter.

BACKGROUND: The Octaray (Biosense Webster) is a novel, multispline mapping catheter with 48 closely spaced microelectrodes enabling high-resolution electroanatomical mapping. OBJECTIVES: This study sought to report the initial clinical mapping experience with this novel catheter in a variety of cardiac arrhythmias and to compare the mapping performance with the 5-spline Pentaray. METHODS: Fifty consecutive procedures among 46 patients were retrospectively analyzed regarding safety, efficacy, and acute procedural success defined as termination or noninducibility of clinical tachycardia, conduction block across an ablation line, or pulmonary vein isolation. In addition, another 10 patients with sustained atrial tachycardia mapped with the 5-spline catheter (2-5-2 spacing) or the novel 8-spline catheter (2-2-2-2-2 spacing) were analyzed. RESULTS: Left atrial and ventricular mapping by either transseptal (n = 41) or retroaortic (n = 2) access was feasible without any complications related to the multispline design of the novel catheter. The acute procedural success rate was 94%. In sustained atrial tachycardia compared with the 5-spline catheter, the novel 8-spline catheter recorded more electrograms per map (3,628 ± 714 vs 11,350 ± 1,203; P < 0.001) in a shorter mapping time (13 ± 2 vs 9 ± 1 minutes; P = 0.08) resulting in a higher point density (18 ± 4 vs 59 ± 10 electrograms/cm2; P < 0.01) and point acquisition rate (308 ± 69 vs 1,332 ± 208 electrograms/min.; P < 0.01). CONCLUSIONS: In this initial experience, mapping with the novel catheter was safe and efficient with a high electroanatomical resolution. In sustained atrial tachycardia the novel 8-spline catheter demonstrated a marked increase in point density and mapping speed compared with those of the 5-spline catheter. These initial results should be validated in a larger multicenter cohort with longer follow-up.

Multi-national survey on the methods, efficacy, and safety on the post-approval clinical use of pulsed field ablation (MANIFEST-PF).

AIMS: Pulsed field ablation (PFA) is a novel atrial fibrillation (AF) ablation modality that has demonstrated preferential tissue ablation, including no oesophageal damage, in first-in-human clinical trials. In the MANIFEST-PF survey, we investigated the 'real world' performance of the only approved PFA catheter, including acute effectiveness and safety-in particular, rare oesophageal effects and other unforeseen PFA-related complications. METHODS AND RESULTS: This retrospective survey included all 24 clinical centres using the pentaspline PFA catheter after regulatory approval. Institution-level data were obtained on patient characteristics, procedure parameters, acute efficacy, and adverse events. With an average of 73 patients treated per centre (range 7-291), full cohort included 1758 patients: mean age 61.6 years (range 19-92), female 34%, first-time ablation 94%, paroxysmal/persistent AF 58/35%. Most procedures employed deep sedation without intubation (82.1%), and 15.1% were discharged same day. Pulmonary vein isolation (PVI) was successful in 99.9% (range 98.9-100%). Procedure time was 65 min (38-215). There were no oesophageal complications or phrenic nerve injuries persisting past hospital discharge. Major complications (1.6%) were pericardial tamponade (0.97%) and stroke (0.4%); one stroke resulted in death (0.06%). Minor complications (3.9%) were primarily vascular (3.3%), but also included transient phrenic nerve paresis (0.46%), and TIA (0.11%). Rare complications included coronary artery spasm, haemoptysis, and dry cough persistent for 6 weeks (0.06% each). CONCLUSION: In a large cohort of unselected patients, PFA was efficacious for PVI, and expressed a safety profile consistent with preferential tissue ablation. However, the frequency of 'generic' catheter complications (tamponade, stroke) underscores the need for improvement.

Echocardiographic and Electrocardiographic Determinants of Atrial Cardiomyopathy Identify Patients with Atrial Fibrillation at Risk for Left Atrial Thrombogenesis.

Objective: Atrial cardiomyopathy (ACM) is associated with development of AF, left atrial (LA) thrombogenesis, and stroke. Diagnosis of ACM is feasible using both echocardiographic LA strain imaging and measurement of the amplified p-wave duration (APWD) in digital 12-lead-ECG. We sought to determine the thresholds of LA global longitudinal strain (LA-GLS) and APWD that identify patients with AF at risk for LA appendage (LAA) thrombogenesis. Methods: One hundred and twenty-eight patients with a history of AF were included. Left atrial appendage maximal flow velocity (LAA-Vel, in TEE), LA-GLS (TTE), and APWD (digital 12-lead-ECG) were measured in all patients. ROC analysis was performed for each method to determine the thresholds for LA-GLS and the APWD, enabling diagnosis of patients with LAA-thrombus. Results: Significant differences in LA-GLS were found during both rhythms (SR and AF) between the thrombus group and control group: LA-GLS in SR: 14.3 ± 7.4% vs. 24.6 ± 9.0%, p < 0.001 and in AF: 11.4 ± 4.2% vs. 16.1 ± 5.0%, p = 0.045. ROC analysis revealed a threshold of 17.45% for the entire cohort (AUC 0.82, sensitivity: 84.6%, specificity: 63.6%, Negative Predictive Value (NPV): 94.3%) with additional rhythm-specific thresholds: 19.1% in SR and 13.9% in AF, and a threshold of 165 ms for APWD (AUC 0.90, sensitivity: 88.5%, specificity: 75.5%, NPV: 96.2%) as optimal discriminators of LAA-thrombus. Moreover, both LA-GLS and APWD correlated well with the established contractile LA-parameter LAA-Vel in TEE (r = 0.39, p < 0.001 and r = −0.39, p < 0.001, respectively). Conclusion: LA-GLS and APWD are valuable diagnostic predictors of left atrial thrombogenesis in patients with AF.