Repeat pulmonary vein isolation and anterior line ablation using a novel point-by-point pulsed-field ablation system

BACKGROUND

Pulsed-field ablation (PFA) is a nonthermal energy source for ablation of cardiac arrhythmias. This study investigated the prospective outcomes of a novel PFA generator in conjunction with a commercially available, contact force-sensing, focal ablation catheter.

OBJECTIVE

The purpose of this study was to assess the feasibility, safety, and lesion characteristics of point-by-point PFA in consecutive patients undergoing repeat ablation of atrial fibrillation (AF).

METHODS

The study involved reisolation of pulmonary veins (PVs) with electrical reconnection and the creation of an anterior line (AL) in patients with anterior substrate or durable pulmonary vein isolation (PVI).

RESULTS

In 24 patients (46% female; mean age 67 ± 10 years; 67% persistent AF), successful reisolation of 27 of 27 reconnected PVs (100%) was performed. In 19 patients, AL ablation was performed, with bidirectional block in 16 (84%), median ablation time 26 [21, 33] minutes, and first-pass bidirectional block in 13 patients (68%). Acute AL reconduction occurred in 8 of 19 patients (42%). Among these 8 patients, a subsequent sustained block of the AL was achieved in 5 (63%). Ultra-high-density electroanatomic mapping revealed homogeneous but relatively large low-voltage areas in the ablated regions. Median procedural, left atrial dwell, and fluoroscopy times were 100 [90, 109] minutes, 83 [75, 98] minutes, and 10 [8, 13] minutes, respectively. No major or minor complications occurred.

CONCLUSION

This study demonstrated feasibility, acute efficacy, and safety of point-by-point PFA for repeat PVI and AL ablation. Further studies are warranted to assess the long-term durability and comparison with established ablation methods.

Acute lesion extension following pulmonary vein isolation with two novel single shot devices: Pulsed field ablation versus multielectrode radiofrequency balloon

INTRODUCTION

Pulsed-field ablation (PFA) and the multielectrode radiofrequency balloon (RFB) are two novel ablation technologies to perform pulmonary vein isolation (PVI). It is currently unknown whether these technologies differ in lesion formation and lesion extent. We compared the acute lesion extent after PVI induced by PFA and RFB by measuring low-voltage area in high-density maps and the release of biomolecules reflecting cardiac injury.

METHODS

PVI was performed with a pentaspline catheter (FARAPULSE) applying PFA or with the compliant multielectrode RFB (HELIOSTAR). Before and after PVI high-density mapping with CARTO 3 was performed. In addition, blood samples were taken before transseptal puncture and after post-PVI remapping and serum concentrations of high-sensitive Troponin I were quantified by immunoassay.

RESULTS

Sixty patients undergoing PVI by PFA (n = 28, age 69 ± 12 year, 60% males, 39.3% persistent atrial fibrillation [AF]) or RFB (n = 32, age 65 ± 13 year, 53% males, 21.9% persistent AF) were evaluated. Acute PVI was achieved in all patients in both groups. Mean number of PFA pulses was 34.2 ± 4.5 and mean number RFB applications was 8.5 ± 3 per patient. Total posterior ablation area was significantly larger in PFA (20.7 ± 7.7 cm²) than in RFB (7.1 ± 2.09 cm²; p < .001). Accordingly, posterior ablation area for each PV resulted in larger lesions after PFA versus RFB (LSPV 5.2 ± 2.7 vs. 1.9 ± 0.8 cm², LIPV 5.5 ± 2.3 vs. 1.9 ± 0.8 cm², RSPV 4.7 ± 1.9 vs. 1.6 ± 0.5 cm², RIPV 5.3 ± 2.1 vs. 1.6 ± 0.7 cm,² respectively; p < .001). In a subset of 38 patients, increase of hsTropI was higher after PFA (625 ± 138 pg/mL, n = 28) versus RFB (148 ± 36 pg/mL, n = 10; p = .049) supporting the evidence of larger lesion extent by PFA.

CONCLUSION

PFA delivers larger acute lesion areas and higher troponin release upon successful PVI than multielectrode RFB-based PVI in this single-center series.

Perioperative Arrhythmias

BACKGROUND

Perioperative arrhythmias are common depending on the type of the operation and can increase morbidity and mortality.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed, as well as the relevant European guidelines.

RESULTS

Arrhythmias are seen in more than 90% of cardiac operations; they are usually transient and often asymptomatic. The risk factors for arrhythmia include ion channel diseases, old age, structural heart disease, cardiac surgery, noncardiac surgery with major fluid shifts, and pulmonary resection. The full spectrum of supraventricular and ventricular arrhythmias can arise perioperatively. Correct ECG interpretation, consideration of the arrhythmia in the overall clinical context, and an understanding of its causes, pathophysiology, and options for effective treatment are critically important. According to a meta-analysis, betablockers lower the risk of perioperative atrial fibrillation (OR = 0.56; 95% confidence interval: [0.35; 0.91]). If anticoagulant treatment is not interrupted for surgery, there is less bleeding with direct oral anticoagulants than with vitamin K antagonists (relative risk: 0.62 [0.47; 0.82]). Moreover, clinical follow-up is important, especially for patients with new-onset atrial fibrillation or heart failure.

CONCLUSION

The identification of high-risk patients and the provision of individualized perioperative monitoring are essential aspects of patient safety. Outpatient cardiological follow-up can improve outcomes.

Association of genetic risk and outcomes in patients with atrial fibrillation: interactions with early rhythm control in the EAST-AFNET4 trial

AIMS

The randomized Early Treatment of Atrial Fibrillation for Stroke Prevention Trial found that early rhythm control reduces cardiovascular events in patients with recently diagnosed atrial fibrillation (AF) compared with usual care. How genetic predisposition to AF and stroke interacts with early rhythm-control therapy is not known.

METHODS AND RESULTS

Array genotyping and imputation for common genetic variants were performed. Polygenic risk scores (PRS) were calculated for AF (PRS-AF) and ischaemic stroke risk (PRS-stroke). The effects of PRS-AF and PRS-stroke on the primary outcome (composite of cardiovascular death, stroke, and hospitalization for acute coronary syndrome or worsening heart failure), its components, and recurrent AF were determined.A total of 1567 of the 2789 trial patients were analysed [793 randomized to early rhythm control; 774 to usual care, median age 71 years (65-75), 704 (44%) women]. Baseline characteristics were similar between randomized groups. Early rhythm control reduced the primary outcome compared with usual care [HR 0.67, 95% CI: (0.53, 0.84), P < 0.001]. The randomized intervention, early rhythm control, did not interact with PRS-AF (interaction P = 0.806) or PRS-stroke (interaction P = 0.765). PRS-AF was associated with recurrent AF [HR 1.08 (01.0, 1.16), P = 0.047]. PRS-stroke showed an association with the primary outcome [HR 1.13 (1.0, 1.27), P = 0.048], driven by more heart failure events [HR 1.23 (1.05-1.43), P = 0.010] without differences in stroke [HR 1.0 (0.75, 1.34), P = 0.973] in this well-anticoagulated cohort. In a replication analysis, PRS-stroke was associated with incident AF [HR 1.16 (1.14, 1.67), P < 0.001] and with incident heart failure in the UK Biobank [HR 1.08 (1.06, 1.10), P < 0.001]. The association with heart failure was weakened when excluding AF patients [HR 1.03 (1.01, 1.05), P = 0.001].

CONCLUSIONS

Early rhythm control is effective across the spectrum of genetic AF and stroke risk. The association between genetic stroke risk and heart failure calls for research to understand the interactions between polygenic risk and treatment.

REGISTRATION

ISRCTN04708680, NCT01288352, EudraCT2010-021258-20, www.easttrial.org.

Novel Radiofrequency Balloon Catheter - Impact of Ablation Parameters on Single-Shot Isolation

BACKGROUND

A novel multielectrode radiofrequency balloon (RFB) catheter has been released for pulmonary vein isolation (PVI).Methods and Results: In this observational study consecutive patients with drug-refractory paroxysmal or persistent atrial fibrillation (AF) undergoing first-time PVI were enrolled in 2 high-volume ablation centers. All procedures were conducted in conjunction with a 3D-mapping system. Clinical, procedural and ablation parameters were systematically analyzed. 105 patients (58% male; 52% paroxysmal AF, 68±11.3 years mean age, left atrial volume index 38.6±14.8 mL/m²) were included. 241/412 (58.5%) PVs were successfully isolated with a single shot (SS), with a time-to-isolation of 11.6±8 s. Total number of radiofrequency applications was 892 (mean 2.2/PV), resulting in successful isolation of 408/412 (99%) PVs at the end of the procedure. Mean electrodes' impedance drop was significantly higher in the SS-PVI compared with non-SS applications (21.5±6.6 vs. 18.6±6.5 Ohm). Concordantly, higher temperature rise was observed in the SS vs. non-SS applications (10.9±4.9℃ vs. 9.6±4.7℃).

CONCLUSIONS

In this multicenter real-world study, mean impedance drop and temperature rise were associated with successful SS-PVI applying the novel RFB catheter. These parameters may help to guide efficient usage of the new RF balloon.

Mechanisms of late arrhythmia recurrence after initially successful pulmonary vein isolation in patients with atrial fibrillation

BACKGROUND

Catheter ablation is an effective treatment for atrial fibrillation (AF,) but arrhythmia recurrence occurs in a relevant number of patients. Mechanisms of late occurring arrhythmias after ablation procedures are not fully understood. We analyzed electrophysiological mechanisms of early and late arrhythmia recurrences in patients who underwent radiofrequency-based catheter ablation of AF.

METHODS AND RESULTS

Consecutive patients who underwent repeat ablation procedures after initial pulmonary vein isolation (PVI) for symptomatic arrhythmia recurrence were analyzed. A total of 110 consecutive patients who underwent catheter ablation for paroxysmal (79%) or persistent AF (21%) were included. Forty-seven patients suffered from early arrhythmia recurrence (group #1: 3-24 months), 29 patients from mid-term arrhythmia recurrences (group #2: 2-5 years), and 34 patients from late arrhythmia recurrences (group #3: > 5 years). Electrical PV reconnection was found in 98% in group #1, 72% in group #2 and 56% in group #3 (p < .001). Mode of arrhythmia recurrence was organized tachycardia in 25%, 28%, and 65% of patients in groups #1, #2, and #3 (p = .001), respectively. Patients with late arrhythmia recurrence had more pronounced left atrial low voltage as compared to patients with early arrhythmia recurrence based on two published scoring system.

CONCLUSION

Electrical PV reconnection was found in the majority of patients with early AF recurrence after PVI. In patients with late arrhythmia recurrences this mechanism may play an inferior role, with many patients presenting without PV reconnection, but with LA structural alterations. Thus, early and late occurring arrhythmia recurrence after catheter ablation may be the same symptom of different diseases.

A novel saline-based occlusion tool allows for dye-less cryoballoon-based pulmonary vein isolation and fluoroscopy reduction

Background

Cryoballoon (CB)- based pulmonary vein isolation (PVI) remains guided by fluoroscopy and dye. The novel saline injection-based occlusion tool allows for pulmonary vein (PV)-occlusion assessment without the need for dye injection.

Aim

To compare KODEX-EPD guided CB-PVI using the novel saline injection-based workflow with conventional cryoablation for acute efficacy, fluoroscopy exposure and dye volume.

Methods

Consecutive atrial fibrillation (AF)- patients undergoing CB-PVI in conjunction with KODEX-EPD (Cryo^EPD group) were analyzed. Patients undergoing conventional CB-PVI (Cryo group) in the same time period acted as controls.

Results

One hundred forty patients [91/140 (65%) persistent AF] were studied. Seventy patients underwent Cryo^EPD procedures [64 ± 13 years, 21 (30%) female] and seventy patients underwent Cryo procedures [68 ± 10 years, 27 (39%) female].A total of 560 PVs were identified and successfully isolated. Mean procedure time was 66 ± 15 min for the Cryo^EPD group, and 65 ± 19 min for the Cryo group (p = 0.3). Fluoroscopy time (Cryo^EPD 6 ± 4 min; Cryo 13 ± 6 min, p < 0.001) and dose area product (Cryo^EPD 193 [111; 297] cGycm²; Cryo 381 [268; 614] cGycm², p < 0.001) were lower in patients undergoing Cryo^EPD compared with Cryo procedures. No dye was needed in the Cryo^EPD group while 53 ± 18 ml dye per patient were administered for the Cryo group (p < 0.001). The overall complication rate was comparable between both groups (p = 0.5).

Conclusion

KODEX-EPD guided AF-ablation enables dye-free CB-based PVI with reduced fluoroscopy exposure when compared to conventional CB-ablation, without differences in acute procedural outcomes or procedure duration.

Temperature-controlled ablation of the mitral isthmus line using the novel DiamondTemp ablation system

Background

The novel DiamondTemp™ (DT)-catheter (Medtronic^®) was designed for high-power, short-duration ablation in a temperature-controlled mode.

Aim

To evaluate the performance of the DT-catheter for ablation of the mitral isthmus line (MIL) using two different energy dosing strategies.

Materials and methods

Twenty patients with recurrence of atrial fibrillation (AF) and/or atrial tachycardia (AT) following pulmonary vein (PV) isolation were included. All patients underwent reisolation of PVs in case of electrical reconnection and ablation of a MIL using the DT-catheter. Application durations of 10 (group A, n = 10) or 20 s (group B, n = 10) were applied. If bidirectional block was not reached with endocardial ablation, additional ablation from within the coronary sinus (CS) was conducted.

Results

In 19/20 (95%) patients, DT ablation of the MIL resulted in bidirectional block. Mean procedure and fluoroscopy time, and dose area product did not differ significantly between the two groups. In group B, fewer radiofrequency applications were needed to achieve bidirectional block of the MIL when compared to group A (26 ± 12 vs. 42 ± 17, p = 0.04). Ablation from within the CS was performed in 8/10 patients (80%) of group A and in 5/10 (50%) patients of group B (p = 0.34). No major complication occurred.

Conclusion

Mitral isthmus line ablation with use of the DT-catheter is highly effective and safe. Longer radiofrequency-applications appear to be favorable without compromising safety.

Acute and long-term success of left atrial anterior line and mitral isthmus line ablation in patients after mitral valve surgery

Background

Perimitral flutter and atrial fibrillation may occur in patients with prior surgical mitral valve (MV) repair or replacement and can be challenging for percutaneous catheter ablation.

Objective

This study sought to determine the feasibility, acute success and durability of catheter ablation of atrial fibrillation or atrial tachycardia by way of a mitral isthmus line (MIL) or an anterior line (AL).

Methods

A total of 81 patients (49 males, mean age 62±11 years) with prior MV replacement (n=30) or repair (n=51) underwent creation of a MIL (n=34) and/or an AL (n=72). Control group patients without prior surgery were matched 1:1 with the valve group (MIL, n=34; AL, n=72).

Results

Acute bidirectional block of the MIL was successfully achieved in 24/34 cases and of the AL in 64/72 patients with prior MV surgery. In the control group, acute bidirectional block was achieved in 31/34 MIL patients and 65/72 AL patients. In terms of durability, the MIL valve subgroup showed the poorest results (probability of long-term failure 2.224, as opposed to 0.605 in the MIL control subgroup; hazard ratio [HR]=0.27, 95% confidence interval [CI], 0.11–0.65; p=0.004). In the AL subgroups, long-term outcomes were similar (probability of failure in AL valve subgroup 0.844 vs. AL control subgroup 1.03; HR=1.22, 95% CI, 0.66–2.26; p=0.523).

Conclusions

Percutaneous creation of MIL and AL is feasible and safe in patients with prior MV replacement/repair. Because of poor long-term outcomes, MIL creation appears not advisable in patient with prior MV surgery.

Funding Acknowledgement

Type of funding sources: None.

Pulsed-field ablation-based pulmonary vein isolation: acute safety, efficacy and short-term follow-up in a multi-center real world scenario

PURPOSE

Pulsed-field ablation (PFA) is a new energy source to achieve pulmonary vein isolation (PVI) by targeted electroporation of cardiomyocytes. Experimental and controlled clinical trial data suggest good efficacy of PFA-based PVI. We aimed to assess efficacy, safety and follow-up of PFA-based PVI in an early adopter routine care setting.

METHODS

Consecutive patients with symptomatic paroxysmal or persistent atrial fibrillation (AF) underwent PVI using the Farawave® PFA ablation catheter in conjunction with three-dimensional mapping at two German high-volume ablation centers. PVI was achieved by applying 8 PFA applications in each PV.

RESULTS

A total of 138 patients undergoing a first PVI (67 ± 12 years, 66% male, 62% persistent AF) were treated. PVI was achieved in all patients by deploying 4563 applications in 546 PVs (8.4 ± 1.0/PV). Disappearance of PV signals after the first application was demonstrated in 544/546 PVs (99.6%). More than eight PFA applications were performed in 29/546 PVs (6%) following adapted catheter positioning or due to reconnection as assessed during remapping. Mean procedure time was 78 ± 22 min including pre- and post PVI high-density voltage mapping. PFA catheter LA dwell-time was 23 ± 9 min. Total fluoroscopy time and dose area product were 16 ± 7 min and 505 [275;747] cGy*cm². One pericardial tamponade (0.7%), one transient ST-elevation (0.7%) and three groin complications (2.2%) occurred. 1-year follow-up showed freedom of arrhythmia in 90% in patients with paroxysmal AF (n = 47) and 60% in patients with persistent AF (n = 82, p = 0.015).

CONCLUSIONS

PFA-based PVI is acutely highly effective and associated with a beneficial safety and low recurrence rate.

Cryoballoon ablation guided by a novel wide-band dielectric imaging system

Background and aim

To investigate the feasibility, acute efficacy, periprocedural safety, and procedural parameters of CB-based PVI guided by KODEX-EPD using different occlusion tool software versions.

Methods and results

A total of 173 patients (60/173 (35%) paroxysmal AF, 64 ± 12 years, 66/173 (38%) female), underwent CB-based PVI guided by KODEX-EPD between August 2019 and October 2021. Acute PVI was achieved in all the patients. Total fluoroscopy time and dye volume were 13.9 [10.6–19.4] min and 47.5 [20–70] ml. Periprocedural complications occurred in 3 (2%) of the 173 patients. As part of the continued development program, different software versions were used, including 1.4.6 on 38 (22%), 1.4.6a on 33 (19%), 1.4.7 on 41 (24%), and 1.4.8 on 61 (35%) of the patients. Outcomes were compared between software versions by a univariate analysis. Sensitivity analyses were performed to account for confounders. Median fluoroscopy time was decreased by 6.4 min (37.3%), and the median volume of dye was decreased by 32.5 ml (52%) from versions 1.4.6 to 1.4.8. Software version was a significant predictor of fluoroscopy time and dye volume, while reductions in procedure duration and dose area product were observed but mainly explained via confounders.

Conclusion

CB-based PVI guided by KODEX-EPD is feasible and safe. Progressive software improvements appear to be associated with lower fluoroscopy duration and dye use. Further studies are needed to evaluate the advantage of KODEX-EPD-guided compared to conventional CB-PVI.

Bipolar ablation of therapy-refractory ventricular arrhythmias: application of a dedicated approach

AIMS

Bipolar radiofrequency ablation (B-RFA) has been reported as a bail-out strategy for the treatment of therapy refractory ventricular arrhythmias (VA). Currently, existing setups have not been standardized for B-RFA, while the impact of conventional B-RFA approaches on lesion formation remains unclear.

METHODS AND RESULTS

(i) In a multicentre observational study, patients undergoing B-RFA for previously therapy-refractory VA using a dedicated B-RFA setup were retrospectively analysed. (ii) Additionally, in an ex vivo model lesion formation during B-RFA was evaluated using porcine hearts. In a total of 26 procedures (24 patients), acute success was achieved in all 14 ventricular tachycardia (VT) procedures and 7/12 procedures with premature ventricular contractions (PVC), with major complications occurring in 1 procedure (atrioventricular block). During a median follow-up of 211 days in 21 patients, 6/11 patients (VT) and 5/10 patients (PVC) remained arrhythmia-free. Lesion formation in the ex vivo model during energy titration from 30 to 50 W led to similar lesion volumes compared with initial high-power 50 W B-RFA. Lesion size significantly increased when combining sequential unipolar and B-RFA (1429 mm3 vs. titration 501 mm3 vs. B-RFA 50 W 423 mm3, P < 0.001), an approach used in overall 58% of procedures and more frequently applied in procedures without VA recurrence (92% vs. 36%, P = 0.009). Adipose tissue severely limited lesion formation during B-RFA.

CONCLUSION

Using a dedicated device for B-RFA for therapy-refractory VA appears feasible and safe. While some patients need repeat ablation, success rates were encouraging. Sequential unipolar and B-RFA may be favourable for lesion formation.

Revival of the Forgotten

Pulmonary vein (PV) isolation (PVI) by continuous, transmural and durable lesions is decisive for ensuring long-term freedom from atrial fibrillation (AF). AF ablation requires irrigated tip catheters to reduce thromboembolic complications. This precluded temperature-controlled delivery of radiofrequency (RF) energy.The aim of this study was to evaluate feasibility, acute efficacy, and safety of an irrigated, temperature-controlled ablation catheter [DiamondTemp™ (DT) Medtronic^®] for PVI.Consecutive patients with AF underwent PVI using the DT catheter combined with high-power short-duration RF applications. Ablation settings were (1) a catheter tip temperature limit of 60°C, (2) a temperature-controlled power of 50 W, and (3) application duration of 10 seconds. The primary endpoint was acute isolation of PVs, reassessed after a 30-minute waiting period. Secondary endpoints included procedural parameters (defined as a catheter tip temperature of 50°C > 3 seconds, an impedance drop of 5-10 Ω) and the occurrence of serious adverse events.Fifty consecutive patients [mean age 66 ± 12 years, 38 (76%) women, 24 patients with paroxysmal AF (48%)] were included. Median procedure and left atrial dwell time was 89 [68; 107] and 63 [52; 79] minutes, respectively. Mean number of RF applications was 59 ± 20, and mean total RF duration was 14 ± 6 minutes. Acute PVI was achieved in all patients solely using DT ablation. Acute PV reconnection within the waiting period occurred in five patients; all reconnected PVs were successfully reisolated. One major complication occurred.In this study, the DT ablation system demonstrated high acute efficacy for PVI. Temperature-controlled ablation in conjunction with high-power short-duration applications might be effectively supported.

Ablation of Outflow Tract Arrhythmias in Patients With and Without Structural Heart Disease—A Comparative Analysis

Introduction

Catheter ablation of ventricular arrhythmias emerging from the ventricular outflow tracts and adjacent structures is very effective and considered almost curative in patients without structural heart disease (SHD). Outcomes of patients with SHD undergoing ablation of outflow tract arrhythmias are not known.

Methods

Consecutive patients (2019–2021) undergoing catheter ablation of ventricular arrhythmias in a single high-volume center were retrospectively analyzed. Patients with ablation of outflow tract arrhythmias were identified and divided in individuals with and without SHD. Procedural parameters and acute outcome were compared.

Results

We identified 215 patients with outflow tract arrhythmias (35.3% female, mean age 58.3 ± 16.0 years). Of those, 93 (43.3%) had SHD. Patients with SHD and outflow tract arrhythmias were older (65.0 ± 12.8 vs. 53.3 ± 16.3 years; p < 0.001), more often male (82.8 vs. 50.0%; p < 0.001) and had more comorbidities than patients without SHD (arterial hypertension: 62.4 vs. 34.4%, p < 0.001; diabetes: 22.6 vs. 8.2%, p = 0.005; chronic lung disease: 20.4 vs. 7.4%, p = 0.007). Outflow tract arrhythmias in patients with SHD had their origin more often in the left ventricle (68.8 vs. 53.3%, p = 0.025). The acute success rate was similar in both patient groups (93.4 vs. 94.2%, p = 0.781). Patients with SHD were discharged later {median length of hospital stay with SHD 5 [6 (interquartile range)] days, without SHD 2 [4] days, p < 0.001}. Periprocedural complications were numerically more frequent in patients with SHD [with SHD 12 (12.9%), without SHD 8 (6.6%), p = 0.154].

Conclusion

Outflow tract arrhythmia ablation has a high success rate irrespective of the presence of SHD. Longer hospital stay and potentially a higher risk of periprocedural complications should be considered when discussing this treatment option with patients.

Why are redo AF ablations required and what does it take? Type of index PVI predicts pattern of redo ablations

Funding Acknowledgements

Type of funding sources: None.

Background

Catheter ablation targeting isolation of the pulmonary veins (PVI) is the most effective treatment for atrial fibrillation (AF). Despite its high overall effectiveness, repeat AF ablations (re-do procedures, RDP) are often required to maintain sinus rhythm.

Purpose

Determine predictors for multiple and/or complex RDP, evaluate reference values for procedure duration and radiation exposure during index PVI (iPVI) and nth RDP in a large cohort.

Methods and Results

Data mining identified 934 (mean age 62.6 ± 12.3 years, 346 females) out of 6848 total AF ablation patients from a large German AF ablation center between 09/2008 and 09/2021 with an index PVI and at least one RDP. Analysis included 2152 procedures (out of 8750 total AF-related ablations). At iPVI, AF pattern was classified as paroxysmal AF (PAF) in 387 patients (41%). All others (59%) were classified as non-paroxysmal AF (Non-PAF). Non-PAF was significantly more frequent in males (64% vs. 49%, p&lt;0.01). Median period between first PVI and RDP was 558 days (25th/75th percentiles 244.0/1175.5 days). Non-PAF patients had a significantly higher probability of multiple RDP compared to patients with PAF at iPVI (p&lt;0.01, Figure 1A). 18% (8%) of patients with non-PAF had 2 (3) or more RDP while only 13% (3%) of pat. with PAF had 2 (3) or more RDP.

iPVI was classified as PVI-only or PVI with additional substrate modification (SM). 724/934 patients (78%) received PVI-only as initial procedure. Of these, 572 (79%) had only 1 RDP, 116 (16%) had 2 RDP and 36 (5%) had 3 or more RDP. This distribution was 77%, 15% and 8% for 1, 2 and 3 or more RDP for patients with complex PVI as iPVI.

An algorithm based on regular expressions classified all RDP as repeat PVI (Re-PVI) due to reconduction (PV reconduction), ablation of atrial tachycardia (AT) or SM, e. g. defragmentation of fractionated signals, or combinations. The results were manually quality-controlled. 798/934 (85%) patients required PV re-isolation due to PV reconduction, 298/934 (32%) required ablation for atrial tachycardia (AT) at least once during FU (Figure 1B). Comparing PVI-only iPVI patients with patients who received substrate modification during iPVI, significantly less patients with PVI-only iPVI had RDP for AT compared to those with SM during iPVI (27% vs. 50%, p&lt;0.01). More PVI-only iPVI patients required PV-reisolation at any time during FU (87% vs 79%, p&lt;0.01). Considering PVI-only (+/- CTI) iPVIs only, dose-area product decreased in RDP compared to first PVI, while procedure duration slightly increased (Figure 1C). Data on periprocedural complications will be reported.

Conclusion

Redo AF ablations procedures are mainly required due to reconnected pulmonary veins or AT. Patients with PAF at iPVI are less likely to require more than one RDP which provides indirect support for early rhythm control in treatment of AF. SM at iPVI might be a predictor for occurrence of AT in the further course.

Comparison of left atrial lesion size and troponin release of two novel single shot devices for pulmonary vein isolation: pulsed field ablation vs. multi-electrode radiofrequency balloon

Funding Acknowledgements

Type of funding sources: None.

Introduction

Pulsed-field ablation (PFA) and the multi-electrode radiofrequency balloon (RFB) are two novel ablation technologies to perform pulmonary vein isolation (PVI). It is currently unknown whether these technologies differ in lesion formation and lesion extent.

Purpose

We compared the acute lesion extent after PVI induced by PFA and RFB by measuring low-voltage area in high-density maps and the release of biomolecules reflecting cardiac injury.

Methods

PVI was performed with a pentaspline catheter (FARAPULSE) applying PFA or with the compliant multi-electrode radiofrequency balloon (HELIOSTAR). Before and after PVI high-density mapping with CARTO3 was performed. In addition, blood samples were taken before transseptal puncture and after post-PVI remapping. Serum concentrations of high-sensitive Troponin I (hsTropI) were quantified by Immunoassay.

Results

50 patients undergoing PVI by PFA (n=26, age 71±10 y, 58% males, 58% persistent AF) or RFB (n=24; age 64±13 y, 54% males, 25% persistent AF) were evaluated. Acute PVI was achieved in all patients in both groups. Mean number of PFA pulses were n=34±5 and mean number RFB applications were n=8±3. Total posterior ablation area was bigger in PFA (19.0±6.2 cm²) than in RFB (9.0±2.2 cm²; p&lt;0.001). The posterior distance between septal and lateral lesions was shorter in PFA (23.7±10.5 mm) than in RFB (30.0±7.3 mm; p=0.021). In a total of 38 patients increase of hsTropI was higher after PFA (625±138 pg/ml, n=28) vs. RFB (148±36 pg/ml; n=10; p=0.049) supporting the evidence of larger lesion extent by PFA.

Conclusion

Pulse-field ablation delivers larger acute lesion areas and higher troponin release upon successful pulmonary vein isolation than multi-electrode array balloon-based pulmonary vein isolation in this single-center series.

Shortened fluoroscopy duration and reduced use of contrast dye in cryoballoon-based pulmonary vein isolation procedures using KODEX-EPD’s novel occlusion tool

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Study grant by EPD Solutions, Philips, Netherlands

Background

The occlusion tool was recently introduced for KODEX-EPD which is a novel dielectric high-resolution cardiac imaging system. The occlusion tool provides information about level of pulmonary vein occlusion by the cryoballoon (CB) in CB-based pulmonary vein isolation (PVI) ablation procedures for atrial fibrillation (AF).

Purpose

Assess effects of the introduction of the occlusion tool on procedural parameters during CB-PVI such as feasibility, acute efficacy and periprocedural safety of KODEX-EPD in different software versions.

Methods and Results

173 consecutive patients (60/173 (35%) paroxysmal AF, 64±12 years, 66/173 (38%) female) underwent CB-PVI with EPD imaging between 08/2019 and 10/2021. 38/173 (22%) of all patients were treated using software version 1.4.6, 33/173 (19%) patients with version 1.4.6a, 41/173 (24%) patients with version 1.4.7 and 61/173 (35%) patients with the latest version 1.4.8. Acute PVI was achieved in all patients. No major periprocedural complications were documented. Software version showed significant effects on procedure duration, fluoroscopy duration and dose area product in ANOVA testing (Figure 1A-C). The largest effect in post-hoc testing was observed for fluoroscopy duration (Figure 1B). Tobit regressions were fitted to model effects of software version on the censored variable contrast volume. All software versions predicted used contrast volume (p&lt;0.00748, Figure 1D). Modelling only effects of procedure date on contrast volume was less accurate than for software version (r²=0.057, p for procedure date = 0.0031) and also a Likelihood-Ratio-Test between different regression models underlined significant effects of software version (p&lt;0.0001).

Conclusion

CB-based PVI in combination with its PV-occlusion tool is feasible and safe. The present data strongly suggests a steady positive development of the novel wide-band dielectric imaging and mapping system towards a fluoroscopy- and dye-reduced CB-based AF-ablation. Software versions were introduced sequentially. Therefore time (procedure date) needs to be considered as the most relevant confounder of the described results (e.g. due to a learning curve using the system). However, differentiated statistical testing could show that the results are mainly explained by software version and only much weaker by procedure date.

Safety of pulsed-field ablation in patients with cardiac implantable electronic devices. A single-center pilot study

Funding Acknowledgements

Type of funding sources: None.

Introduction

Pulsed-field ablation (PFA) is a novel energy source to perform pulmonary vein isolation (PVI) in patients with atrial fibrillation or cavo-tricuspid isthmus ablation (CTI) in patients with atrial flutter. Whether strong electrical fields generated by PFA could change the function and integrity of cardiac implantable electronic devices (CIED) is not known.

Aim

To assess the function and integrity of implanted devices before and after pulsed-field ablation.

Methods

This study included consecutive patients with CIED undergoing PFA at a large single center. Real-time CIED electrograms were recorded during PFA applications. CIED were interrogated before and after PFA assessing function (threshold, sensing), integrity (impedance), and arrhythmia episodes.

Results

We performed PFA in six patients (age 69±12 years, 1/6 female, left atrial diameter was 44±3 mm, left-ventricular ejection fraction 40±14%) for PVI in five patients with atrial fibrillation and CTI ablation in one patient with atrial flutter. All patients had CIEDs (one cardiac resynchronization device, two implantable cardioverter-defibrillators, three two-chamber pacemakers). Each patient undergoing PVI received 32 PFA applications of 2.5 s. (4x basket configuration and 4x flower configuration at each pulmonary vein), amounting to a total ablation time of 80 s and resulting in complete PVI in all five patients. For CTI ablation we applied 8 PFA applications of 2.5 s (20 s total ablation time) resulting in CTI blockade. Real-time intracardiac electrograms (iEGM) during PFA applications revealed sensing of single PFA application impulses in three patients and blanking of the iEGM in three patients. Postinterventional device testing revealed no changes in impedance, stimulation threshold or sensing. No leads were dislocated or damaged. No other device malfunctions occurred during the procedure, as well as no other major periprocedural complications occurred.

Conclusion

The function and integrity of pacemakers and defibrillators is not affected by PFA in our patient sample. Larger series are needed to confirm the apparent safety of PFA in patients with CIED.

Pulmonary vein isolation by pulsed-field ablation induces smaller neurocardiac damage than cryoballoon ablation

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): FARAPULSE, Inc.

Introduction

Thermal energy sources damage the entire atrial tissue during pulmonary vein isolation (PVI) including cardiac nerves and ganglia. This induces a postinterventional increase in heart rate. Pulsed-field ablation (PFA), a new non-thermal energy source for PVI, primarily damages cardiomyocytes by electroporation. Whether use of PFA reduces damage to cardiac nerves and ganglia and influences postinterventional increase of heart rate is not known.

Purpose

We compared the acute effects of PFA with a pentaspline catheter and cryoballoon ablation (CBA) on secretion of circulating biomolecules reflecting cardiomyocyte and neuronal injury and postinterventional increase in heart rate to estimate damage to the cardiac autonomic nervous system and autonomic dysfunction after PVI.

Methods

Blood samples were taken before and after PVI in consecutive patients undergoing PFA and CBA. All patients participated in the TRUST registry. Serum concentrations of high-sensitive Troponin I (hsTropI, Immunoassay) and S100b (ELISA), a surrogate marker for neuronal injury, were quantified in blood samples taken prior to PVI and directly after PVI. Pre- and postinterventional heart rates were measured in ECGs and Holter-ECGs.

Results

Fifty-six patients underwent PVI, either by PFA (n=28, age 63 [54; 75] y, 64% males, 57% persistent AF) or CBA (n=28, age 71 [62; 78] y, 61% males, 54% persistent AF). All 112 blood samples were analyzable. Acute success of PVI was 100% in both groups without major complications, especially, no TIA and no stroke. After CBA, one patient suffered from phrenic palsy, which reversed after 3 months. HsTropI increased 3.3-fold more after PFA compared to CBA (625±138 vs. 185±42 pg/ml; p=0.004) suggesting more damage to cardiomyocytyes. S100b increased 2.9-fold less after PFA compared to CBA (21.1±3.7 vs. 61.2±8.1 pg/ml; p&lt;0.001). The ratio of ∆S100b/∆hsTropI was five-fold smaller after PFA compared to CBA (0.19±0.1 vs. 0.98±0.3; p=0.007), suggesting a lower neurocardiac injury in comparison to lesion size. Concomitantly, increase in heart rate at the postinterventional day was smaller in PFA (-0.2±3.0 bpm; n=45) than in CBA (+6.1±2.7 bpm, n=15; p=0.024).

Conclusion

This study in patients validates the experimental concept that PFA-based AF ablation leads to more specific damage to cardiomyocytes than to cardiac nerves and ganglia, reflected by lower S100B concentrations and no post-interventional heart rate increase compared to CBA.

Catheter ablation of the mitral isthmus line using the novel DiamondTemp ablation system: first experience using two different ablation protocols

Funding Acknowledgements

Type of funding sources: None.

Background

Mitral ishmus ablation is an established approach to treat perimitral reentrant tachycardia, and is often performed as substrat modification in patients with persistent atrial fibrillation (AF). Bidirectional block of the mitral isthmus line (MIL) is still a great challenge using conventional ablation catheters, but is essential to prevent recurrence of atrial arrhythmia.

Recently, the novel DiamondTempTM (DT) ablation system was introduced and allows for high-power, short-duration ablation in a temperature-controlled mode. Its use during pulmonary vein isolation (PVI) using a recommended ablation setting with a catheter-tip temperature limit of 60°C, a temperature-controlled power of 50 W and an application duration of 10 sec has shown to be effective and safe. However, data on DT ablation settings for substrate modification, i.e., creation of linear lesions are lacking.

Aim

The aim of the present study was to evaluate acute efficacy and safety of the novel DT ablation system for bidirectional block of the MIL using two different protocols.

Methods

The study population comprised 14 patients [67±8 years, 10/14 male (71%)] suffering from persistent AF and/or atrial tachycardia who underwent catheter re-ablation with creation of a MIL using the DT ablation system. Ablation settings were a catheter-tip temperature limit of 60°C, a temperature-controlled power of 50 W with an application duration of either 10 sec (group A, n=7) or 20 sec (group B, n=7). Additional epicardial ablation from within the coronary sinus with a temperature limit of 60°C, a temperature-controlled power of 20 W and an application duration of 20 sec was performed, if bidirectional block could not be achieved with endocardial ablation only.

Results

Mean procedure and fluoroscopy time, and dose area product for group A and group B were 103±24 vs. 119±38 min, 12±5 vs. 13±4 min, and 572±270 vs. 537±202 cGycm, respectively. Bidirectional block of the MIL was achieved in 7/7 (100%) patients in group A and in 6/7 (86%) patients in group B. Additional epicardial ablation was required in 6/7 patients (86%) in group A and in 4/7 (57%) patients in group B. In group B, bidirectional block of the MIL required fewer endocardial (31±11 vs. 26±10 applications) as well as epicardial RF-applications (10±6 vs. 7±3 applications). Pericardial effusion without hemodynamic relevance occurred in 1/7 (14%) patients of group B. No further complications occurred.

Conclusion

Catheter ablation of the MIL using the novel DT ablation system is safe and associated with high acute efficacy. A lower number of RF-applications and a less frequent need for additional epicardial ablation was observed when applying longer RF-applications of 20 sec. Further analyses are warranted to confirm these findings.

Optimizing catheter ablation of atrial fibrillation by a novel wide-band dielectric imaging system: first experience on real-time wall thickness measurement

Funding Acknowledgements

Type of funding sources: None.

Background

Conventional mapping systems do not provide wall-thickness data, which is, however, known to be a determinant of radiofrequency ablation lesion transmurality. KODEX-EPD is a novel open-platform system, which uses dielectric tissue properties to provide real-time, high-resolution cardiac images, tissue characteristics and wall-thickness measurement to guide ablation procedures.

Aim

The aim of this case series was to report on our first experiences with KODEX-EPD regarding estimation of myocardial wall-thickness during catheter ablation of atrial fibrillation (AF).

Methods

We retrospectively analyzed consecutive patients undergoing radiofrequency AF-ablation in combination with KODEX-EPD. A high-resolution image from the left atrium (LA) and the pulmonary veins (PV) was obtained prior to ablation using a spiral mapping catheter in conjunction with KODEX-EPD. Wall-viewer points were collected within the LA, the PVs and the left atrial appendage (LAA) using a standard radiofrequency non-contact force ablation catheter and analyzed for wall-thickness applying the latest KODEX-EPD software version (1.5.0, not yet commercially released). Wall-viewer points were divided into a total of 10 segments (PV ostia, anterior wall, posterior wall, LA roof, LA floor, LAA and PV carina, details see Figure 1) in order to characterize wall-thickness in respective areas.

Results

A total of 570 wall-viewer points in 5 patients were analyzed. Most of the wall-viewer points were collected at the PV ostia as well as along the posterior and anterior wall (449/570, 79%). Actual myocardial atrial thickness ranged from 1.6 to 3.9 mm. Thickest myocardial LA-tissue was measured at the anterior wall (median 3.1 mm) and thinnest at the LA-roof (median 2.2 mm). Figure 2 gives a detailed distribution of wall-thickness measurements at different sites in the LA and PVs.

Conclusion

Atrial wall thickness can be estimated in patients during AF ablation procedures using dielectric tissue properties. Further evaluation and validation of the method are needed to study its reliability and utility for clinical practice.

The established and the challenger: A direct comparison of current cryoballoon technologies for pulmonary vein isolation

INTRODUCTION

Cryoballoon (CB) ablation for pulmonary vein isolation (PVI) is an effective treatment of atrial fibrillation (AF). Recently, a novel cryoablation system was introduced. The aim of the study was to compare the safety, efficacy and biophysical characteristics of a novel cryoablation system (POLARx™; Boston Scientific) to a commonly used and clinically well characterized system (Arctic Front Advance Pro™, AFA; Medtronic).

METHODS AND RESULTS

Fifty consecutive patients with symptomatic AF, who underwent CB-based ablation with the POLARx were compared to 50 consecutive patients treated with the AFA. Acute PVI was achieved in 99.8% (POLARx 99.5%, AFA 100%, p = 1.00). Time to isolation (TTI) was comparable in both groups (POLARx 35 [27, 48] s, AFA 30 [21, 43] s, p = 0.165). The POLARx showed a lower balloon temperature at TTI (POLARx -44 [-50, -36] °C, AFA -31 [-38, -21] °C, p < 0.001) and lower nadir temperature (POLARx -60 [-65, -55] °C, AFA -48 [-54, -45] °C, p < 0.001). Procedure time (POLARx 80 [60, 105] min, AFA 62 [42, 80] min, p < 0.001), fluoroscopy time (POLARx 17 [13, 22] min, AFA 11 [7, 16] min, p < 0.001) and freeze cycles per patient (POLARx 5 [4, 6], AFA 4.5 [4, 5], p = 0.002) were higher in the POLARx group. Two cerebral ischemic events occurred in the POLARx group, two patients in each group had phrenic nerve injury.

CONCLUSION

Both systems enable effective isolation of pulmonary veins. The POLARx required longer procedure and fluoroscopy times. Larger, prospective and randomized studies are needed to assess long-term efficacy and safety of this technology.

Accuracy and acute efficacy of a novel occlusion tool to guide cryoballoon-based pulmonary vein isolation

Background

Cryoballoon (CB)-based pulmonary vein isolation (PVI) currently requires to verify occlusion of each pulmonary vein (PV) using fluoroscopy and dye injection.

Objective

The current study evaluated whether the novel CB-occlusion tool integrated into the wide-band dielectric imaging system KODEX-EPD reliably verifies occlusion of PV according to a novel dye-injection based algorithm.

Methods

Consecutive patients suffering from symptomatic atrial fibrillation (AF) underwent CB-based PVI using the KODEX-EPD and the novel occlusion-tool (group I). To confirm accurate display of the PVs, selective PV-angiography was performed in the first half of the patients of group I (group Ia) in addition to a three-dimensional left atrial (LA) map using a spiral mapping catheter (Achieve, SMC1, Medtronic, MN, USA). PV-angiographies were waived for the following patients (group Ib). Procedural duration and radiation exposure were compared to a control group of patients undergoing conventional CB-based PVI.

Results

CB-based PVI was successful in 50/50 patients of group I (mean age 63±11 years, 18 paroxysmal (36%)) and 25/25 patients of group II (66±10 years, 9 paroxysmal (60%)). Concordance of PV-occlusion as assessed by either PV-occlusion-angiography or KODEX-EPD, was documented in 237/272 (87%) occlusion-analyses among 198 PVs (95% for left superior PV, 93% for left inferior PV, 86% for right inferior PV and 77% for right superior PV).

In the final evaluation phase (group Ib) LA fluoroscopy times and dose area products were comparable to the conventional CB-ablation group (10.5±5 vs 8.8±4 minutes (p=0.23) and 403±425 vs 321±202 cGycm2 (p=0.44), whereas the amount of dye could be significantly reduced (group Ib: 31±10 ml vs group II: 70±20 ml, p&lt;0.0001).

Conclusion

The novel KODEX-EPD PV-occlusion tool allows for accurate PV-occlusion assessment in the majority of PVs and a high acute success rate. The system has the potential to reduce dye and radiation exposure. This should be evaluated in controlled clinical trials.

Funding Acknowledgement

Type of funding sources: None.

The RACE to the EAST. In pursuit of rhythm control therapy for atrial fibrillation-a dedication to Harry Crijns

The RACE trial was one of the first landmark trials to establish whether restoring and maintaining sinus rhythm could reduce morbidity and mortality in patients with atrial fibrillation (AF). Its neutral outcome shaped clinical decision-making for almost 20 years. However, there were two important treatment-related factors associated with mortality of rhythm control therapy at that time: One was safety of antiarrhythmic drug therapy, and the other one withdrawal of anticoagulation after restoration of sinus rhythm. Both concerns have been overcome, and, moreover, important knowledge considering the importance of time for the treatment of AF has been gained. These insights led to the concept of the EAST-AFNET 4 trial, and after more than two decades in the pursuit of ongoing therapeutic improvement, early rhythm control therapy has demonstrated to reduce a composite of cardiovascular death, stroke, and hospitalization for worsening of HF or acute coronary syndrome, by 21% (first primary outcome, absolute reduction 1.1 per 100 patient-years). For this entire period, Harry Crijns characterized the treatment of AF patients, and contributed decisively to realizing the benefit of rhythm control therapy. It is almost easier to list the clinical trials without Harry's involvement than to list those which he co-designed and led.

High anatomical accuracy of a novel high-resolution wide-band dielectric imaging system in cryoballoon-based ablation

PURPOSE

Recently, a novel cardiac imaging system based on a wide-band dielectric technology (KODEX-EPD) was introduced to guide catheter ablation. The aim of the study was to evaluate this 3D wide-band dielectric imaging system (WDIS) during cryoballoon (CB)-based atrial fibrillation (AF) ablation focusing on accuracy of pulmonary vein (PV)-anatomy.

METHODS

In consecutive patients with symptomatic AF, CB-based ablation was performed in conjunction with the 3D WDIS. Selective PV-angiographies were performed, and 3D anatomy of the left atrium (LA) and PVs using the 3D WDIS was created. The ostial diameters of the ipsilateral right-sided and left-sided PVs and ostial diameters of the right-/left-sided upper/lower PVs demonstrated by selective angiographies were analyzed and compared to 3D WDIS-based PV visualization.

RESULTS

In 65 patients (42/65 (65%) male, age 65 ± 9 years, 29/65 (45%) paroxysmal AF) a total of 260 PVs were identified. Median ostial PV-diameters for the ipsilateral left- and right-sided PVs were 38 [34; 43] and 37 [34; 40.3] mm when assessed fluoroscopically and 40 [35.7; 43] and 39 [35.0; 43] mm as demonstrated by 3D WDIS. There was no statistically significant difference between both methods regarding PV-diameter measurements. KODEX-EPD overestimated fluoroscopy measurements by 1.08 mm (95% limits of agreement of -1.93 mm and 4.1 mm).

CONCLUSION

The novel wide-band dielectric 3D-imaging system is feasible to create high-resolution images of cardiac structures during CB ablation procedures and accurately visualizes PV-anatomy.

[Update atrial fibrillation: the 2020 ESC guidelines and recent data on early rhythm control]

Atrial fibrillation (AF) can be a significant burden for patients as well as the health care system. Every third 55-year-old will develop AF. Despite improvements of disease management, a significant risk for cardiovascular events remains. The current AF guidelines of the European Society of Cardiology focus on an integrative therapy approach. The new algorithm "CC to ABC" comprises recommendations for diagnosis ("confirm" and "characterise") and treatment ("avoid stroke", "better symptom control", "comorbidities") of AF. Direct oral anticoagulants administered according to the CHA2DS2-VASc score remain the corner stones of stroke prevention. Besides the concept of heart rate control, rhythm control therapy like antiarrhythmic drugs or catheter ablation is recommended to relieve symptoms and in certain patient groups for the improvement of prognosis. Therapy of comorbidities and reduction of risk factors like hypertension, diabetes mellitus, obesity and obstructive sleep apnoea should be part of any comprehensive treatment approach. The results of the randomized, prospective EAST-AFNET 4 trial were published in August 2020. The trial shows that an early rhythm control therapy can lead to a reduction of cardiovascular mortality and incidence of stroke additionally to guideline-based AF management. Given the safety profile and potential positive effects of antiarrhythmic drugs and catheter ablation, early initiation of rhythm control therapy should be considered in every patient during the first months after diagnosis of AF.

Genetics of atrial fibrillation-practical applications for clinical management: if not now, when and how?

The prevalence and economic burden of atrial fibrillation (AF) are predicted to more than double over the next few decades. In addition to anticoagulation and treatment of concomitant cardiovascular conditions, early and standardized rhythm control therapy reduces cardiovascular outcomes as compared with a rate control approach, favouring the restoration, and maintenance of sinus rhythm safely. Current therapies for rhythm control of AF include antiarrhythmic drugs (AADs) and catheter ablation (CA). However, response in an individual patient is highly variable with some remaining free of AF for long periods on antiarrhythmic therapy, while others require repeat AF ablation within weeks. The limited success of rhythm control therapy for AF is in part related to incomplete understanding of the pathophysiological mechanisms and our inability to predict responses in individual patients. Thus, a major knowledge gap is predicting which patients with AF are likely to respond to rhythm control approach. Over the last decade, tremendous progress has been made in defining the genetic architecture of AF with the identification of rare mutations in cardiac ion channels, signalling molecules, and myocardial structural proteins associated with familial (early-onset) AF. Conversely, genome-wide association studies have identified common variants at over 100 genetic loci and the development of polygenic risk scores has identified high-risk individuals. Although retrospective studies suggest that response to AADs and CA is modulated in part by common genetic variation, the development of a comprehensive clinical and genetic risk score may enable the translation of genetic data to the bedside care of AF patients. Given the economic impact of the AF epidemic, even small changes in therapeutic efficacy may lead to substantial improvements for patients and health care systems.

Quantification of Left Atrial Fibrosis in Patients After Pulmonary Vein Isolation Using the Second-Generation Cryoballoon

Left atrial (LA) fibrosis is associated with a poor outcome after atrial fibrillation (AF) ablation. This study examined the extent of low-voltage areas in patients with recurrence of atrial tachyarrhythmia (ATA) after CB-based pulmonary vein isolation (PVI).Sixty patients (mean age 67 ± 10 years, n = 32 female; n = 34 paroxysmal AF) who received radiofrequency redo-procedure due to recurrence of ATA within 6 months after CB-based PVI were included. A point-by point 3D-map was performed, and low-voltage sites were delineated based on bipolar voltage < 0.5 mV. The extent of fibrosis was categorized as stage A (0-10% of the LA wall), stage B (10-30%), stage C (30-50%), and stage D (> 50%).The median area of LA low-voltage sites was 28.9 (9; 50.3) cm², corresponding to 17.4 (6; 30.6) % of the LA wall surface. 17/60 (28.3%) patients were categorized as fibrosis stage A, 21/60 (35%) as stage B, 18/60 (30%) as stage C, and 4/60 (6.7%) as stage D. Patient age and LA diameter were associated with more pronounced LA fibrosis; the extent of LA fibrosis was significantly higher in patients with LA tachycardia (LAT) during redo-procedures (P < 0.01), and ablation of linear lesions was more often performed (P < 0.01).In patients after CB2-based PVI, expanded LA tissue fibrosis was associated with the occurrence of LAT and more extensive LA ablation during redo-procedures.

[Management of acute complications during electrophysiological procedures]

Catheter ablation is an established treatment option in patients suffering from symptomatic cardiac arrhythmias. However, despite technical advances, catheter ablation is still associated with an incidence of severe complications of up to 5%. Therefore, electrophysiologists should be trained to prevent complications, maintain a high index of suspicion to recognize them quickly and implement necessary treatment strategies. This article reviews the incidence, risk factors, management and preventative strategies of the major complications associated with ablation procedures such as transseptal puncture-related risks, cardiac tamponade, aortic puncture and air embolism.

Atrial fibrillation ablation in patients with pulmonary lobectomy or pneumectomy: Procedural challenges and efficacy

BACKGROUND

Catheter ablation of atrial fibrillation (AF) in patients with pulmonary lobectomy or pneumectomy is challenging due to anatomical alterations. After lung resection, electrically active pulmonary vein (PV) stumps remain and need to be localized for PV isolation (PVI). The present study aims to describe clinical challenges of PVI in patients with pulmonary lobectomy or pneumectomy.

METHODS

We performed a retrospective study on 19 patients with previous pulmonary lobectomy or pneumectomy undergoing catheter ablation for AF in three German hospitals.

RESULTS

Nineteen patients with paroxysmal, persistent, or longstanding-persistent AF and history of pulmonary lobectomy (n = 11) or pneumectomy (n = 8) were enrolled. Catheter ablation was performed as radiofrequency (RF) ablation using 3D mapping, robotic RF ablation, or by using balloon devices. Decent anatomical changes were observed in patients with lobectomy while cardiac rotation and mediastinal shifting was dominant in patients with pneumectomy. Visualization of all PVs including PV stumps by PV angiography was possible in 10 of 19 patients (52.6%). PV spikes were observed in all identified PV remnants. In nine patients (47.4%), at least one PV remnant could not be identified and electrical isolation was not performed. During 24 months follow-up, patients with incomplete PVI had a significantly shorter arrhythmia-free survival than patients with complete PVI (76.2% [95% Confidence interval (CI) 47.2-100.0%] vs 40.0% [95% CI 5.6-74.1%], P = .043).

CONCLUSION

In patients with AF and previous lobectomy or pneumectomy, identification and isolation of all PVs are challenging but crucial for ablation success. Additional imaging techniques may be necessary to achieve complete PVI.

Management of thrombus formation after electrical isolation of the left atrial appendage in patients with atrial fibrillation

Aims

Left atrial appendage (LAA) electrical isolation (LAAEI) in addition to pulmonary vein isolation is an emerging catheter-based therapy to treat symptomatic atrial fibrillation. Previous studies found high incidences of LAA thrombus formation after LAAEI. This study sought to analyse therapeutic strategies aiming at the resolution of LAA thrombi and prevention of thromboembolism.

Methods and results

Left atrial appendage electrical isolation was conducted via creation of left atrial linear lesions or cryoballoon ablation. Follow-up including transoesophageal echocardiography was conducted. In patients with LAA thrombus, oral anticoagulation (OAC) was adjusted until thrombus resolution was documented. Percutaneous LAA closure (LAAC) under use of a cerebral protection device was conducted in case of medically refractory LAA thrombi. Left atrial appendage thrombus was documented in 54 of 239 analysed patients who had undergone LAAEI. Thrombus resolution was documented in 39/51 patients (72.2%) with available follow-up after adjustment of OAC. Twenty-nine patients underwent LAAC and 10 patients were kept on OAC after LAAEI. No thromboembolic events or further LAA thrombi were documented after 553 ± 443 days of follow-up in these patients. Persistent LAA thrombi despite adaption of OAC was documented in 12/51 patients. One patient remained on OAC until the end of follow-up, while LAAC with a cerebral protection device was performed in 11 patients in the presence of LAA thrombus without complications.

Conclusion

Left atrial appendage thrombus formation is common after LAAEI. Adjustment of OAC leads to LAA thrombus resolution in most patients. Left atrial appendage closure in the presence of LAA thrombi might be a feasible option in case of failed medical treatment.

Epicardial access for VT ablation: analysis of two different puncture techniques, incidence of adhesions and complication management

Introduction

Pericardial access for ablation of ventricular arrhythmias (VA) can be gained either by an anterior-oriented or inferior-oriented epicardial puncture under fluoroscopical guidance. We retrospectively sought to assess the safety of these two puncture techniques and the incidence of epicardial adhesions and introduce our algorithm for management of pericardial tamponade.

Methods and results

In 211 patients (61.4 ± 15.6 years, 179 males; 84.8%) 271 epicardial ablation procedures of VA were performed using either an anterior- or inferior-oriented approach for epicardial access. Puncture-related complications were systematically analyzed. Furthermore, the incidence of adhesions was evaluated during first and repeated procedures.

A total of 34/271 (12.5%) major complications occurred and 23/271 (8.5%) were directly related to epicardial puncture. The incidence of puncture-related major complications in the anterior and inferior group was 4/82 (4.9%) and 19/189 (10.1%), respectively. Pericardial tamponade was the most common major complication (15/271; 5.5%). Collateral damages of adjacent structures such as liver, colon, gastric vessels and coronary arteries occurred in 6/189 (3.2%) patients and only within the inferior epicardial access group. Adhesions were documented in 19/211 (9%) patients during the first procedure and in 47.1% if patients had 2 or more procedures involving epicardial access.

Conclusion

Anterior-oriented epicardial puncture shows an observed association to a reduced incidence of pericardial tamponades and overall puncture-related complications in epicardial ablation of VA. In cases of repeated epicardial access adhesions increase significantly and may lead to ablation failure.

Outcome of cardiac tamponades in interventional electrophysiology

Aims

The aim of this study was to analyse tamponades following electrophysiological procedures regarding frequency and mortality in a high-volume centre and to identify independent predictors for severe tamponades.

Methods and results

We performed a retrospective study on 34 982 consecutive patients undergoing diagnostic electrophysiological studies or catheter ablation of cardiac arrhythmias. The combined endpoint was defined as severe tamponade. Criteria for severe tamponade included surgical repair, repeat pericardiocentesis, cardiopulmonary resuscitation, intrahospital death or death during follow-up, and thrombo-embolic events or complications due to therapeutic management. Multivariate analysis was performed to identify independent predictors for severe tamponade. A total of 226 tamponades were identified. Overall frequency of tamponades was 0.6%. Procedures requiring epicardial approach had the highest rate of tamponades (9.4%). Twenty-nine patients with tamponade underwent surgery (12.8% of all tamponades and 21.4% of tamponades during epicardial procedures). Overall tamponade-related mortality was 0.03% (9 deaths). Fifty-six patients (24.8%) experienced severe tamponade. Independent risk factors for severe tamponades were endocardial ablation of ventricular tachycardia, epicardial approach, balloon device ablation, high aspiration volume during pericardiocentesis and structural heart disease.

Conclusion

The frequency of tamponades is strongly dependent on the type of procedure performed. Overall tamponade-related mortality was low but significantly higher in patients undergoing epicardial procedures. Surgical backup should be considered for patients undergoing complex ventricular tachycardia ablation and left atrial ablation procedures.

P1361Impact of radiation/chemotherapy for breast cancer on the electroanatomic features in patients receiving catheter ablation for left atrial arrhythmia

Background

Atrial fibrillation (AF) is a common cardiac arrhythmia and catheter ablation a viable treatment option for patients with AF. Extensive left atrial (LA) scars, frequently seen in patients with persistent AF, can limit its efficacy. Radiation for breast cancer treatment is known to have serious long-term effects (e.g. fibrosis) on the targeted tissue. At the same time, chemotherapy often leads to organ dysfunction. We sought to examine the effects of radiation and chemotherapy on the electroanatomic features of the LA in patients who received catheter ablation for left atrial arrhythmias with prior breast cancer treatment.

Methods and Results

We compared 38 patients (mean age 68.4 ± 7.1 years) who underwent catheter ablation for LA arrhythmia and had a previous diagnosis of breast cancer with 38 patients (mean age 65.4 ± 7.3 years) without breast cancer who formed our control group. LA scar area, as well as its distribution was measured during the electrophysiology (EP) study and graded according to the Utah classification.

The existence of LA scarring did not differ significantly between both groups (71.1% vs. 76.3%, p = 0.602). LA scar area (excluding PVs) was 107.5cm2 ± 19.0cm2 in the breast cancer group compared to 110.1cm2 ± 18.5cm2 in the control group (p = 0.536). The distribution of the scar area revealed no significant difference between both groups, however an involvement of the anterior wall was common (65.8% vs. 73.7%; p = 0.454). We further investigated whether the location of breast cancer had an impact on the LA scar development of the patients in our study cohort. Here, we found no significant difference in the amount of LA scarring when comparing patients with left-sided breast cancer to patients with right-sided breast cancer (66.7% vs. 73.9%). In a sub-analysis patients with breast cancer and persistent AF showed a non-significant trend towards greater LA scar areas (17.4cm2 vs. 6.8cm2) in comparison to patients of the control group with similar LA volumes.

The patient’s age (&gt;65 years) was the only independent predictor for greater LA scarring we could identify. Neither former radiotherapy, nor chemotherapy showed a positive correlation with greater LA scarring.

Conclusion

There is no change in the distribution as well as an increase of the extent of LA scars after thoracic irradiation and/or chemotherapy. A trend towards greater LA scar areas was seen in patients with breast cancer and persistent AF. The patient’s age was identified as an independent predictor for LA scar development.

Catheter Ablation of Atrial Fibrillation: State of the Art and Future Perspectives

PURPOSE OF REVIEW

Atrial fibrillation (AF), the most common sustained arrhythmia, is associated with high rates of morbidity and mortality. Maintenance of stable sinus rhythm (SR) is the intended treatment target in symptomatic patients, and catheter ablation aimed at isolating the pulmonary veins provides the most effective treatment option, supported by encouraging clinical outcome data. A variety of energy sources and devices have been developed and evaluated. In this review, we summarize the current state of the art of catheter ablation of AF and describe future perspectives.

RECENT FINDINGS

Catheter ablation is a well-established treatment option for patients with symptomatic AF and is more successful at maintaining SR than antiarrhythmic drugs. Antral pulmonary vein isolation (PVI) as a stand-alone ablation strategy results in beneficial clinical outcomes and is therefore recommended as first-line strategy for both paroxysmal and persistent AF. While radiofrequency-based PVI in conjunction with a three-dimensional mapping system was for many years considered to be the "gold standard", the cryoballoon has emerged as the most commonly used alternative AF ablation tool, especially in patients with paroxysmal AF. Patients with persistent or long-standing persistent AF and with arrhythmia recurrence after previous PVI may benefit from additional ablation strategies, such as substrate modification of various forms or left atrial appendage isolation. New technologies and techniques, such as identification of the AF sources and magnetic resonance imaging-guided substrate modification, are on the way to further improve the success rates of catheter ablation for selected patients and might help to further reduce arrhythmia recurrence.

CONCLUSIONS

Pulmonary vein isolation is the treatment of choice for symptomatic patients with paroxysmal and persistent drug-refractory AF. The reconnection of previously isolated pulmonary veins remains the major cause of AF recurrence. Novel ablation tools, such as balloon technologies or alternative energy sources, might help to overcome this limitation. Patients with non-paroxysmal AF and with AF recurrence might benefit from alternative ablation strategies. However, further studies are warranted to further improve our knowledge of the underlying mechanisms of AF and to obtain long-term clinical outcomes on new ablation techniques.

Left-lateral thoracotomy for catheter ablation of scar-related ventricular tachycardia in patients with inaccessible pericardial access

Objectives

We aimed to describe the feasibility of a surgical left thoracotomy for catheter ablation of scar-related ventricular tachycardia (VT) in patients with inaccessible pericardial access.

Background

Pericardial adhesion due to prior cardiac surgery or previous epicardial ablation procedures limits epicardial access in patients with drug-refractory VT originated from the epicardium.

Methods

Six patients who underwent a surgical left lateral thoracotomy epicardial access for catheter ablation of VT after failed subxiphoid percutaneous epicardial access were reviewed. Patients’ baseline characteristics and procedural characteristics including epicardial access, mapping, and ablation were described. Epicardial access was successfully obtained in all patients by a surgical left lateral thoracotomy.

Results

The reasons of pericardial adhesion were prior cardiac surgery (n = 3, 50%) and previous epicardial ablation procedures (n = 3, 50%). Epicardial mapping of the lateral and inferior left ventricle was acquired, and a total of 15 different VTs originated from those regions were abolished. Unless one patient with ST elevation myocardial infarction due to periprocedural occlusion of the posterior descending artery no further complications occurred. All patients were discharged 10.2 ± 4 days after the procedure. VT recurred in 1 patient (17%) and was controlled with oral amiodarone therapy during follow-up (median follow-up: 479 days).

Conclusions

A surgical left lateral thoracotomy is feasible and safe for selected patients. This approach provides epicardial ablation in patients with VT located at the infero-lateral left ventricle and pericardial adhesions due to previous cardiac surgery or previous ablation procedures.

Graphic abstract

Second-generation cryoballoon-based pulmonary vein isolation: Lessons from a five-year follow-up

BACKGROUND

Pulmonary vein isolation (PVI) using the second-generation cryoballoon (CB2) for atrial fibrillation (AF) treatment has demonstrated encouraging procedural success rates and mid-term results. However, long-term follow-up data on outcome is sparse. The current study is reporting on five-year clinical outcomes following CB2-based PVI in patients with paroxysmal AF (PAF) and persistent AF (PersAF).

METHODS

A total of 139 patients underwent index CB2-based PVI patients (PAF: n = 105, 76% and PersAF: n = 34, 34%) in two electrophysiology centers. Freeze-cycle duration was 240 s. After successful PVI a bonus freeze-cycle of the same duration was applied in the first 71 patients while the bonus-freeze was omitted in 68 following patients. Three patients (2.2%) were lost to follow-up.

RESULTS

After a median follow-up duration of 60 months (interquartile range: 46, 72 months) 74/136 (54.4%) patients remained in stable sinus rhythm (PAF: 62/104, 59.6%; PersAF: 15/32, 46.9%). Significant differences were observed concerning 5-year clinical outcome between PAF and PersAF patients (p = 0.0315). After a mean of 1.32 ± 0.6 procedures (2nd and 3rd procedure by radiofrequency ablation) and a median follow-up duration of 60 (37, 68) months 90/136 (66.2%) patients remained in stable sinus rhythm (PAF: 72/104 (69.2%), PersAF: 21/32 (65.6%), p = 0.0276). For the comparison of bonus-freeze vs no-bonus-freeze protocols no differences were observed (53.5% vs 57.4%, p = 0.650).

CONCLUSIONS

The five-year single-procedure success rate for CB2-based PVI was 54.4% and increased to 66.2% following repeat RF-based procedures. No differences were detected comparing bonus-freeze and no-bonus-freeze protocols.