Arrhythmia Recurrence Research Articles

Direct Current Cardioversion in Pregnancy: A Multicenter Study

(BJOG. 2023;130(10):1269–1274) The physiological changes that occur in pregnancy have been associated with new onset and recurrent cardiac arrhythmias. It is common for pregnant patients to experience palpitations in pregnancy, and most of these do not require treatment. However, some arrhythmias require treatment including medications and/or direct current cardioversion (DCCV) to restore the patient’s rhythm. In a recent inquiry into maternal deaths in the United Kingdom (UK), DCCV was not applied consistently and may have resulted in maternal deaths. This study aimed to understand practice surrounding DCCV in the UK, assessing which arrhythmias occurred and how they were treated. In addition, they evaluated outcomes associated with obstetric and neonatal health, including the use of fetal monitoring and whether there were cases where DCCV caused harm to the fetus.

Cardiac magnetic resonance to predict appropriate therapies in secondary prevention

Abstract Introduction Implantable cardioverter-defibrillator (ICD) therapy plays a pivotal role in the management of patient’s survivors of life-threatening ventricular arrhythmias (secondary prevention). Risk of recurrence may be related to presence of myocardial scar and its components (including core mass, border zone (BZ) mass, and BZ channels) assessed with late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Purpose Our study aims to analyze the role of imaging in predicting the risk of recurrent ventricular arrhythmias and improving the risk stratification for appropriate ICD therapy in patients receiving an ICD for secondary prevention. Methods From 2015 to 2020, a total of 111 patients with LGE-CMR before ICD implantation for secondary prevention. Scar tissue including core, BZ and BZ channels were automatically detected by specialized investigational software in patients with LGE-CMR. Patients were followed until a new event was detected. Results The mean age was 65.4 ± 11.4 years; 87% were men; 55% had ischemic cardiomyopathy. The mean left ventricular ejection fraction was 37.8 % ± 14.31%. Patients were followed for a median of 3.26 years (IQR 1.4-4.9). Within the first year of follow-up 22% of patients had received an appropriate therapy, 39% within 3 years and 53% within 6 years. Chronic kidney disease and New York Heart Association (NYHA) class were associated with the primary endpoint [HR 1.94(1.06-3.55), P-value 0.032)] and [HR 1.86 (1.19-2.91), P-value 0.006)], respectively. Regarding CMR characteristics, BZ percentage was also associated with appropriate ICD therapy in the follow up [HR 1.04(1-1.08), P-value 0.048)]. Other CMR parameter, such as BZ mass, BZ core %, BZ core mass and core mass showed a trend to predict ICD therapies during follow-up. ROC curve analysis with Youden’s index defined an optimal BZ percentage cutoff value for recurrence prediction of 9.5% [HR 0.49 (0.28-0.85)]. Conclusion In patients receiving an ICD for secondary prevention, chronic kidney disease, NYHA class and BZ percentage analyzed by LGE-CMR were predictors of recurrent ventricular arrhythmia. A cutoff of BZ of 9.5% could be used to select patients with high risk of recurrence.

Pulmonary vein isolation combined with a new protocol of linear ablation to treat persistent atrial fibrillation: a prospective cohort with 1 year follow-up

Abstract Background The clinical value of ablation strategies beyond pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (perFA) is not clearly established and the optimal strategy to cure perFA remains a challenge due to the high recurrence rate after PVI alone (up to 50% of patients during 1-year follow-up). Purpose To determine the additional therapeutic value of a new design of linear ablation in the left atrium (LA) added to PVI in patients with perFA. Methods In this prospective study consecutive patients with perFA were included and underwent PVI combined with a predefined homogeneous protocol of linear ablation in the LA: anterolateral line from the mitral annulus to the left superior pulmonary vein around the left atrial appendage, anteroseptal line and posterior wall isolation. Patients were followed during 12 months after ablation with daily 30 s single-lead ECG obtained with mobile applications. The main endpoint was the incidence of recurrences, defined as any documented, sustained (>30 s) episodes of atrial arrhythmia that occurred after a 3 months blanking period. Antiarrhythmic drugs were avoided after the blanking period. Results 59 patients were included (61 [IQR 53-69] years old, 76% male sex). Acutely successful PVI was achieved in all patients and the linear ablation protocol was performed in 52 (89,7%) patients. The linea ablation protocol was not completed in 6 patients due to the following reasons: repetitive AF triggering from the same PV in 2 patients, induction and successful focal ablation of left atrial flutter in 1 patient, respiratory failure in 1 patient with severe obstructive lung disease and excessively prolonged procedure time in 2 patients. 58 patients completed the 12 months follow-up period and 1 patient was lost due to end-stage heart failure. The survival free of atrial arrhythmia recurrences was 69.1% [95%CI 55.1-79.5] (Figure). No patient had recurrences of perAF (>7 days continuous AF). 9 (53%) patients had at least 1 episode of self-limited paroxysmal AF. In these patients the average paroxysmal AF burden during the follow-up was 24 hours/year [IQR 9-24 hours/year]. In another 8 (47%) patients the recurrent arrhythmia was atypical left atrial flutter exclusively The incidence of procedure-related complications was 6,9%: 1 pericardial bleeding, 1 acute pulmonary edema, 1 splenic infarction and 1 stroke); no patient died during the study period. Conclusions A combined strategy of PVI plus the specific linear ablation protocol used in this study is associated with a low rate of atrial arrhythmia recurrences and total absence of persistent AF after ablation. A randomized multicenter clinical trial is ongoing to validate these results.Ablation strategy.Kaplan-Meier curve: recurrences

Pulmonary vein isolation using pulsed field ablation versus high-power-short-duration radiofrequency ablation for paroxysmal atrial fibrillation: efficacy, safety, and long-term follow-up

Abstract Background Pulsed field ablation (PFA) is a novel, nonthermal, cardiac tissue selective ablation modality. To date, radio-frequency (RF) guided high-power-short-duration (HPSD) ablation represents the gold standard for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). This study investigated the efficacy of PFA-PVI versus HPSD-PVI in terms of single-procedure arrhythmia-free outcome and safety. Methods Consecutive, paroxysmal AF patients who underwent PVI using PFA or HPSD were enrolled. In group PFA, PVI was performed using a 31/35-mm pentaspline PFA catheter. The ablation procedure in group HPSD was performed with HPSD-RF energy (45 watts), using Ablation Index (AI) and the CLOSE protocol. The CLOSE protocol combines AI and ≤6 mm interlesion distance using a 4-mm surround flow catheter. Results A total of 420 patients (group PFA: 211; group HPSD: 209) were included (55% men; age 67 ± 10 years). There was no difference between both groups with regard to age, gender and CHA2DS2-VASc-Score. Complete isolation of all PVs was achieved in 100% of patients. Procedure time was significantly shorter in group PFA (74 ± 41 min vs. 127 ± 34 min; p < 0.001); fluoroscopy time and dose area product were significantly longer in group PFA (18 ± 7 min vs. 4 ± 3 min; p < 0.01 and 555 ± 460 uGym2 vs. 213 ± 273 uGym2; p <0.01). Overall procedural complications were 1,4% in group PFA and 5,2 % in group HPSD (p < 0.01), driven by a higher tamponade rate in group HPSD. During a mean follow-up of 12 months after a single procedure, 170 (81%) patients of group PFA were free of arrhythmia recurrence versus 160 (76%) patients in group HPSD (p = 0.798) (Figure 1). Conclusions PVI using PFA compared to PVI using HPSD shows a similar acute efficacy but a significantly reduced complication rate and a shorter procedure time. One-year clinical success rates are favorable, but not different between groups.Figure 1

One-year freedom from arrhythmia following radiofrequency ablation using proactive oesophageal cooling

Abstract Background Proactive esophageal cooling is increasingly being utilized, and is now FDA cleared, to reduce the likelihood of ablation-related esophageal injury resulting from radiofrequency (RF) cardiac ablation of atrial fibrillation (AF). One-year follow-up from the largest randomized controlled study, the IMPACT trial, showed a trend towards improvement in long-term efficacy versus luminal esophageal temperature (LET) monitoring. With larger data sets now available for analysis, we sought to determine 1-year freedom from atrial arrhythmia associated with the use of proactive esophageal cooling. Methods Data from 2 trials comparing freedom from atrial arrhythmia after RF ablation using proactive esophageal cooling to LET monitoring were combined. Data were analyzed using a stratified Cox proportional hazards model to compare arrhythmia recurrence rates, with R statistical analysis software. Results Data from 631 patients across two studies comparing arrhythmia outcomes for proactive oesophageal cooling versus LET monitoring were analysed. Mean patient age was 66.4±9.8 years, and 37.4% were female. Arrhythmias were 56.3% paroxysmal AF and 43.7% persistent or long-standing persistent AF. Freedom from atrial arrhythmia at one year was 77.2% for patients receiving proactive oesophageal cooling and 64.4% for patients receiving LET monitoring (Figure 1), with a hazard ratio for cooling of 0.65 (95% CI 0.43 to 0.99, P = 0.044). Conclusions Proactive oesophageal cooling was associated with significantly greater freedom from atrial arrhythmia at one year when compared to LET monitoring during RF ablation.

Localization of critical isthmus in left atrial macroreentrant tachycardias: insights from peak frequency mapping during sinus rhythm and coronary sinus pacing

Abstract Background Successful ablation of left atrium macroreentrant tachycardia (LAMRT) has advanced significantly, benefiting from an enhanced understanding of reentrant mechanisms and technological innovations. However, challenges like difficult inductions and the presence of multiple coexistent LAMRTs can complicate tachycardia mapping, potentially resulting in recurrences during follow-up. Consequently, there is a growing need for strategies that focus on pinpointing the critical isthmus of conduction (CIC) in LAMRT circuits outside of tachycardia episodes. Peak frequency (PF) mapping, with its ability to discern near-field (NF) from far-field (FF) electrograms (EGMs) in low voltage areas, emerges as a valuable tool for precisely identifying these critical isthmuses. Purpose This study aims to investigate whether the accurate identification of the CIC in LAMRT circuits is achievable through PF mapping during sinus rhythm or coronary sinus pacing. Methods Patients with sustained LAMRT undergoing radiofrequency (RF) ablation were enrolled. Utilizing a 16-pole grid catheter (HD-Grid), bipolar voltage and activation maps were generated during LAMRT. PF maps were retrospectively computed. Voltage, activation, and PF maps were also created during sinus rhythm and coronary sinus pacing (500 ms). Potential CICs (P-CICs) were defined as areas with low voltage (<0.2 mV) and high PF (>250 Hz), covering a surface area of <2 cm2 by adjusting the PF threshold above 250 Hz. Only instances of LAMRT terminated by focal RF lesions (boundary <1.5 cm diameter) were included. Confirmed CICs (C-CICs) were identified at sites where LAMRT termination occurred due to RF application. The localization of P-CICs found during LAMRT, sinus rhythm (SR), and coronary sinus pacing (CSP) mapping, in relation to that of CIC, was analyzed, considering them matching if separated by <10 mm. Results Twenty-four consecutive patients with 26 atrial tachycardias (ATs) were prospectively enrolled, including 18 LAMRTs (270±63 ms) terminated by 2.2±2.9 focal RF lesions after 9.4±8.2 sec of energy delivery. A P-CIC was consistently identified at the tachycardia termination site during LAMRT mapping, with a visual cutoffs discrimination score (1-5) of 4.1±0.7, a mean P-P voltage cutoff <0.22±0.09 mV, and a mean PF cutoff >330±67 Hz in all patients. Importantly, P-CICs found during SR and CSP mapping matched those found during LAMRT mapping in all patients (figure). Conclusion PF mapping demonstrates precision in identifying the critical isthmus in LAMRT circuits during actual tachycardia episodes. Notably, the consistent identification of the CIC through PF mapping during sinus rhythm or coronary sinus pacing exhibits a high correlation with findings during LAMRT mapping. This approach holds promising potential for reducing arrhythmia recurrences, especially in scenarios involving multiple or unmappable LAMRTs.

Pulmonary vein isolation with the radiofrequency balloon catheter: long-term results and predictors of ablation success

Abstract Background The novel multielectrode radiofrequency balloon catheter (RFB) has been demonstrated to achieve safe and effective pulmonary vein isolation (PVI). However, data on long-term ablation outcomes is lacking. Purpose This single-centre study aimed to evaluate the efficacy of the RFB beyond 1-year follow-up and define predictors of arrhythmia recurrence. Methods All consecutive patients with symptomatic paroxysmal atrial fibrillation (AF) undergoing first-time PVI with the RFB between January 2021 and November 2022 were prospectively included. Post-ablation remapping was systematically employed to confirm PVI at the end of the procedure. Procedural failure was defined as any atrial tachyarrhythmias (ATas) lasting >30 s occurring during the follow-up after a 3-month blanking period (BP). Patient characteristics, procedural parameters, and ATas recurrence during BP were analysed with respect to ablation outcome. Results A total of 120 consecutive patients (50 female, 42%; mean age 65±12 years) were enrolled. After a mean follow-up of 16.1±7.9 months, ATas recurrence occurred in 30 patients (25%). ATas were adjudicated as AF in 25 patients (83.3%) and as atrial tachycardia/atrial flutter in 5 patients (16.7%). The mean time from the index procedure to ATas recurrence was 203±130 days. A redo procedure was performed in 17 patients (56.7%) and at least one PV reconnection was observed in 12 patients (70.6%). Patients with ATas recurrence presented higher values of body mass index (31.0 ±5.7 vs. 28.1±4.9 kg/m2, p=0.048), larger left atria (43±11 vs. 35±9 ml/m2, p=0.003), and increased rates of ATas recurrence during the BP (53.3% vs. 2.2 %, p<0.001) compared to patients with persistent sinus rhythm. At multivariable Cox regression analysis, left atrial end-systolic volume index and ATas recurrence during the BP were independently associated with procedural failure (HR 1.05, 95%CI 1.00-1.11, p=0.048 and HR 23.88, 95%CI 7.71-73.99, p<0.001, respectively). Conclusion At 16 months follow-up, PVI with the RFB resulted in freedom from arrhythmia relapse in 75% of patients. Left atrial end-systolic volume index and ATas recurrence during the BP were independent predictors of arrhythmia recurrence.ATas-free survivalPredictors of ATas recurrence

Characterisation of ablation strategies at redo catheter ablation for atrial fibrillation and predictors of arrhythmia recurrence: results from the AFREDO registry

Abstract Background Patients who have undergone prior pulmonary vein isolation (PVI) for atrial fibrillation (AF) often require a repeat ablation for AF recurrence. The optimal ablative strategy for the redo procedure and predictors of AF recurrence thereafter remain largely unknown. Purpose We aimed to characterise the ablation strategies applied at re-PVI and identify possible predictors of AF recurrence. Methods Our single-centre, retrospective study included all consecutive patients who underwent first redo PVI at our centre from 2017 to 2022. Inclusion criteria required at least one available follow-up visit within the first 12 months after the redo procedure. Ablation strategies of the initial and redo procedure were captured. Kaplan-Meier curves were used to illustrate time of AF recurrence, as classified by predictors of outcome determined by multivariable regression analyses. Results We included 215 patients (39.1% female) with a median age of 66.6 years (IQR 58.6-73.2) at the time of redo procedure. The initial PVI was cryoablation in 39.9%, RFA in 57.7% and surgical ablation in 2.4%. After the initial procedure, 55.8% had paroxysmal AF and 44.2% had persistent AF. At the redo procedure, 25.1% of patients were found to have no PV reconnection, whereas 20.5% had a single reconnected PV, and 54.4% had two or more reconnected PVs. A left-sided flutter ablation was performed in 18.8%, a left atrial (LA) roof line in 16.9%, a posterior mitral isthmus line in 5.2%, an anterior mitral isthmus line in 27.9%, and a posterior box lesion in 8.4%. Overall, 34.4% of patients showed areas of low-voltages in the redo procedure. Patients with areas of low voltages were less likely to have any reconnected PVs in the redo-procedure (p<0.001). After the second ablation procedure, 54.0% experienced AF recurrence. Univariable regression analysis revealed moderate (p=0.006) or severe (p= 0.015) LA dilatation, persistent AF (p=0.005), and posterior LA low voltage areas (p=0.011) as significant predictors of AF recurrence after the redo procedure. The number of reconnected PVs at the re-PVI did not predict AF recurrence (p=0.1090). As illustrated in Fig. 1 and 2, patients with paroxysmal AF experienced less AF recurrence compared to those with persistent AF (log-rank p=0.0025). Moreover, moderate or severe LA dilatation at baseline was associated with more frequent AF recurrences (log-rank p=0.0279). Conclusion A significant proportion of patients undergoing re-PVI experienced AF recurrence. We found that persistent AF and moderate or severe LA enlargement emerged as significant predictors of AF recurrence after the redo procedure. Although PV reconnection was observed in more than two thirds of patients at the re-PVI, it did not predict AF recurrence thereafter. However, patients without PV reconnection had significantly more low-voltage areas, which may be indicative of a different AF recurrence mechanism in this subgroup.Figure 1:Type of AFFigure 2:LA dilatation

Radiofrequency lesion in atrial wall: how variable is it? 9 Tesla MRI analysis of RF lesion volume in a swine model

Abstract Background Little is known about radiofrequency (RF) lesion volume (rLV). Most of animal or ex-vivo studies quantify the size of RF lesions size using width and/or depth, while electrophysiologists use manufacturers’ indirect indices (such as Ablation Index or Lesion Size Index). Purpose We aimed to evaluate rLV by high resolution 9-Tesla magnetic resonance imaging (MRI), in ex-vivo swine model. We studied the variability of rLV and extra-cardiac effects in two groups of swine, one treated with low energy (LE)-long application RF (20W-50 sec) and another treated with high energy (HE)-short application RF (50 W-20 sec). Methods This was a prospective observational study on 18 piglets, that were anesthetized, mechanically ventilated, and divided into LE (n = 9) and HE (n = 9) groups (Figure 1). An irrigated contact force catheter was used to perform RF applications in 4 largely separated spots: 2 on right atrium and 2 on left atrium wall. RF parameters were monitored during RF. Each animal was sacrificed after 5-7 days, and RF lesion samples were excised and acquired by 9 MRI. Results 70 RF applications were performed (36 in LE group and 34 in HE group). MRI was performed on 26 samples of LE group and 28 of HE group (Figure 2). The median RF lesion volume was 89.3 mm3 (IQR 47.9-175.9). Regarding lesion volume, the HE groups showed 35% higher volume than LE group (mean lesion volume 86.2 mm3 vs 116.3 mm3, p = 0.119). HE group also showed more complications (0 vs 7, p=0.02) and more extracardiac lesion (14 vs 18, p=0.613). Conclusions There was a wide and unpredictable variability of RF lesion on atrial wall, even under controlled experimental conditions, which could explain arrhythmias recurrences. The variability seems greatest, although not statistically significant, during HE applications. The dose/effect relationship needs to be carefully studied for treatments of cardiac arrhythmias for both RF and other forms of energy available today.Study flow-chartComparison between groups

Post-ablation atrial arrhythmogenic channels predict atrial fibrillation recurrence - iatrogenic substrate revisited

Abstract Background Fibrosis is a hallmark of atrial fibrillation (AF) arrhythmogenic substrate, and the extent of atrial fibrosis, as determined by late gadolinium enhancement (LGE)-MRI, predicts AF recurrence after ablation. However, ablation fundamentally alters the individual composition of fibrotic tissue, and inhomogeneous ablation lesions may constitute an arrhythmogenic substrate themselves. From ventricular arrhythmias (VA) we know that it is not the extent of scar tissue that determines arrhythmogenicity, but rather the scar-pervading channels of surviving tissue with residual conduction. Purpose To investigate post-ablation arrhythmogenic substrate in terms of atrial scar channels using LGE-MRI. Methods Patients with PVI-only AF ablation were included. All patients received a systematic 12-months follow-up and an LGE-MRI 3 months post-ablation. Scar channels were defined as corridors of borderzone tissue (residual conduction), protected by dense scar. Channels were automatically identified using a software algorithm that has been extensively validated in the ventricle and was now adapted for the atrium. To differentiate healthy tissue, borderzone and dense scar, LGE was quantified based on the signal intensity ratios of each voxel relative to the blood pool. Signal intensity ratio thresholds defining dense scar and borderzone, were then empirically tested to enhance the predictive value of the identified channels. The algorithm was then applied to an independent validation cohort using the empirically determined thresholds. Results 150 patients were included. 10 different combinations of signal intensity ratio thresholds defining borderzone tissue and dense scar were empirically tested regarding the prediction of potentially arrhythmogenic channels in 50 patients (derivation cohort). For each of the threshold combinations, the number of predicted channels was linked to 12-months arrhythmia-free survival using logistic regression. The computed channels best predicted 12-months arrhythmia recurrence, when based on signal intensity ratios of 1.1-1.32 (borderzone) and >1.32 (dense scar). This threshold combination was then validated in an independent cohort of 100 patients. Patients with scar channels had significantly lower arrhythmia-free survival than those without (55% vs. 88%, p=0.016, Fig. 1). The number of detected scar channels was predictive of 12-months arrythmia recurrence (OR 4.9; p=0.012) – independent of other factors like LA diameter, AF type or the extent of native atrial fibrosis (pre-ablation LGE-MRI). Of note, the number of gaps in the PV-encircling lesions was not predictive of AF recurrence. Conclusions LGE-MRI-detected post-ablation scar channels predict recurrent AF after PVI and may be a surrogate of iatrogenic substrate. In light of large-area ablations with PFA and other single-shot devices fueling a trend towards more and more extensive lesions, the concept of iatrogenic arrhythmogenic substrate may have to be reconsidered.

Slow pathway ablation in pediatric patients: long-term outcomes in a high-volume center according to baseline electrophysiologic characteristics

Abstract Background Slow pathway ablation (SPA) in pediatric patients with documented paroxysmal supraventricular tachycardia (PSVT) has been proven safe and effective. Arrhythmia induction is often difficult in the pediatric population. Accordingly, empirical SPA is frequently adopted in this population. Real-world data about long-term outcomes of slow pathway ablation (SPA) in relation to tachycardia inducibility and electrophysiologic characteristics in pediatric patients with PSVT in a high-volume center are lacking. Purpose To compare long-term clinical outcomes of SPA in pediatric patients with and without intraprocedural documentation of DAVP and AV nodal reentrant tachycardia induction. Methods In this retrospective sigle-center study, all SPA procedures performed on pediatric patients (under 18 years) at our Institution since 2016 were considered. All patients had documented PSVT with short RP interval, no evidet ventricular pre-excitatio on surface ECG and normal echocardiography. Baseline EPS was performed to exclude the presence of concealed accessory pathway and isoproterenol infusion was used to exclude focal atrial tachycardias. According to intraprocedural EP characteristics, three group of patients were identified: Group 1 with AVNRT induction; Group 2 with dual atrioventricular nodal physiology (DAVP) and no tachycardia induction; Group 3 without DAVP. According to previous documentation of a short RP PSVT and after discussion with patients’ families, SPA was performed in all patients. The endpoint of the ablation was to eliminate slow pathway conduction and AV node re-entrant beat. Follow up visits were scheduled three and twelve months after ablation for all patients. Results 1734 patients underwent SPA since 2016 at our Institution. 1092 patients (73.4%) showed AVNRT induction during EPS (Group 1). 433 patients (14.2%) showed DAVP without tachycardia induction (Group 2). 209 patients (12.4%) didn’t show DAVP at EPS (Group 3). Age and gender were similar among the three groups. SPA was performed with acute procedural success in all patients. After 36-month median follow-up, freedom from palpitations was 98.5% in Group 1, 97.1% in Group 2 and 92.3% in Group 3. A survival analysis showed the best outcomes in group 1 and no significant difference in recurrence rate among the groups 2 and 3 (Figure 1). No permanent heart blocks, neither other major complication was observed. Conclusions When performed by experienced operators and in high-volume centers, SPA is a safe and effective procedure in pediatric patients with documented short RP PSVT. Success rate is highest with AVNRT induction and good without AVNRT induction, regardless of AV node dual conduction at baseline EPS. Such high success rate depends on careful exclusion of others arrhythmia mechanisms (i.e., focal atrial tachycardias, AV re-entrant tachycardias) that, although infrequent in children, are the main determinants of arrhythmia recurrences.

Spatiotemporal stability of digital twin-guided atrial fibrillation dominant frequency sites and the clinical outcome of catheter ablation

Abstract Background Although the dominant frequency (DF) may localize the reentrant drivers of atrial fibrillation (AF), its meandering nature makes it difficult to localize as an extra-pulmonary vein (extra-PV) target. Purpose We explored and quantified the spatiotemporal stability of DF by sophisticated digital-twin maps and the association with the rhythm outcome of clinical AF catheter ablation (AFCA). Methods We retrospectively examined the DF sites in the digital twin integrated by high-density electroanatomical maps (EAM) of 170 patients previously included in the CUVIA-AF2 trial (male 70.6%, 59.2±11.3 years old, 100% persistent AF). We monitored 34 seconds of virtual AF and analyzed DF sites in 10 different left atrial (LA) regions at 3 consecutive periods (6 seconds each after 16sec induction and blanking periods). The spatiotemporal stability index (STSI) was calculated to quantify mean DF's spatial and temporal variability. During protocol-based rhythm follow-up, we assessed the atrial arrhythmia recurrence rate by dividing patients into two groups based on STSI 0.75. Results During the simulation, 108 out of 170 (63.5%) patients obtained mean DF values in all three consecutive periods. There were 26 (24.1%) patients in the stable DF group (STSI ≥0.75, Stable group) and 82 (75.9%) patients in the unstable DF group (STSI <0.75, Unstable group). Although the proportion of patients with hypertension (73.1 vs. 47.6%, p=0.041) was higher and left ventricular end-diastole diameter (51.3±3.9 vs. 49.0±4.4 mm, p=0.020) was larger in the stable DF group than in the unstable DF group, other parameters, including LA size, LA voltage, or AF ablation targets, did not differ between two groups. During the median 19 [15-22] months follow-up, the atrial arrhythmia recurrence rate of the Stable group is higher than that of the Unstable group (log-rank p=0.031, HR = 2.06, CI [1.06-4.01]) Conclusions We found that the temporally stable DF in EAM-integrated virtual AF, the potential extra-PV AF drivers, is a surrogate marker of the adverse rhythm outcome of AFCA. A prospective clinical trial targeting the spatiotemporally stable DF will be warranted.

Pulsed field ablation versus very high power short duration radiofrequency ablation in atrial fibrillation: what is better?

Abstract Background The newly introduced non-thermal pulsed field ablation (PFA) is a promising technology for catheter ablation (CA) of atrial fibrillation (AF) with high acute success rates and good safety features. However studies have shown that very high power short duration (VHPSD) ablation is also highly effective and fast with potentially less arrhythmia recurrence compared to conventional radiofrequency ablation. Data comparing this two methods are lacking Objective The aim of this study is to compare two source of energy used for CA of AF in terms of procedural, clinical and outcome data Methods We conduced a retrospective observational study enrolling all patients (pts) from september 2021 to may 2023 who underwent CA of AF with PFA system and VHPSD. In the PFA group pulmonary veins isolation (PVI) was obtained using 2KV with eight application each vein, posterior wall isolation (PWI) of left atrium (LA) was obtained with application in the flower configuration of the catheter and then additional lesion were deployed at the operator’s discretion. In the VHPSD group the encircling of PV was obtained with 90W for 4 seconds radiofrequency pulses in posterior portions of the LA including LA PW, whereas 50W with ablation index target of 500 was used in the anterior portions of the PV and additional lesions. General anesthesia or deep sedation was carried out in all pts Results A total of 205 pts were included, n = 86 (42%) in the PFA group and N = 119 (58%) in the VHPSD group: paroxysmal (n = 62[72%], N = 64[54%]), persistent (n = 19[22%], N = 43[36%]), long standing persistent (n = 5[5%], N = 10[8%]). PVI was successful in all pts and additional lesions were delivered in n = 26 (30%) in PFA group and N = 76 (64%) in HVPSD group, mostly at the PW (n = 24[92%]; N = 50[66%]). The PFA group revealed a shorter procedura duration (80 ± 29 min vs 108 ± 39 min; p = 0,00001) but longer fluoroscopic time (21 ± 8 min vs 14 ± 10 min; p = 0,00001). The VHPSD group revealed more complications (N = 7[6%] vs n = 3[3%]) but without statistically significant difference (p = 0,43), the most frequent in the PFA group was vascular access complications instead in the VHPSD group was post-procedural pericarditis. Only one patient in VHPSD group had major complication with a post-procedural stroke but without residual neurological deficits. At follow-up after median of 14 (26-6) months, n = 61 pts in the PFA group (71%) and N = 91 in the VHPSD group (76%) were free from atrial arrhythmia (p = 0,79). In both group 7 pts recurrenced as atypical atrial flutter (n = 7[28%] PFA; N = 7[25%] VHPSD; p = 0,061) Conclusion PFA and VHPSD are effective and safe to CA of AF with comparable arrhythmia recurrenses. However procedure duration with PFA is significantly shorter and therefore may be of potential benefit in particular for elderly and frail pts. Further research, including randomized controlled trials, is needed to validate and compare these techniques more comprehensively

LINAC-Based STereotactic Arrhythmia Radioablation (STAR) for paroxysmal atrial fibrillation in elderly: a prospective phase II trial

Abstract Background and aims Stereotactic arrhythmia radioablation (STAR) is a novel therapeutic approach for cardiac arrhythmias. The aim of this trial is to investigate the feasibility of STAR for the treatment of paroxysmal atrial fibrillation (AF) in elderly patients. Method inclusion criteria were: age > 70 years, symptomatic AF, antiarrhythmic drugs failure or intolerance. All patients underwent to 4D cardiac Computed Tomography simulation. The clinical target volume was identified in the area around pulmonary veins (PV). STAR was performed with a total dose of 25 Gy (single fraction) delivered in 3 minutes. Results Twenty patients were enrolled and 18 underwent STAR. One patient withdrew informed consent before treatment and 1 patient was excluded due to unfavorable esophagus position. With a median follow-up (FU) of 16 months (range 12-23), no acute toxicity more than grade 3 was reported. Five patients had a grade 1 esophagitis 24 hours after STAR; eight patients had an asymptomatic grade 1 pericardial effusion, one patient had a torsade de pointes treated effectively by electrical cardioversion and subsequent cardiac ICD implantation. Most patients had a significant reduction in AF episodes. Five patients, due to arrhythmias recurrences after STAR, performed electrophysiological study documenting successful PV isolation. Finally, a significant improvement of quality of life was documented (48 ± 15 at enrollment vs 75 ± 15 at 12 months FU; p < 0.001). Conclusion The present phase II trial demonstrated the feasibility of STAR in paroxysmal AF elderly patients and its potential role in increasing the quality of life. Surely, more robust data are needed about safety and efficacy.

Impact of additional pulsed field ablation in unsuccessful radiofrequency linear lesions -acute and chronic data

Abstract Background Performing linear ablation such as roof line, inferior line in the posterior part of LA and posterior mitral isthmus (MI) line in addition to PVI is one of the strategies for treating persistent atrial fibrillation. However, remnant conduction or reconnection in the lines is linked with atrial arrhythmia recurrence, either AF or AT. Radiofrequency ablation (RFA) is often unsuccessful achieving durable linear ablation. It is not yet well known whether using pulsed field ablation (PFA) would be superior in achieving complete linear lesions. Purpose We sought to evaluate the benefit of using PFA in unsuccessful RF ablation linear lesions. Methods We studied 17 patients that underwent redo procedures due to atrial arrhythmia recurrence. All of them underwent PFA (using a pentaspline PFA catheter) ablation lines due to previous unsuccessful RF ablation, either due to remnant conduction in the line or to reconnection of the line. Lines of block were evaluated based on activation mapping and differential pacing maneuvers close to the lines. Results We conducted 16 dome-posterior lines and 6 posterolateral mitral isthmus lines using PFA after unsuccessful RF ablation linear lesions. PFA was performed after several unsuccessful procedure, 1.3±0.4 for the roof line, 1.3±0.5 for the postero-inferior line and 1.7±0.9 for the MI line. In 4 out of 6 pts with MI isthmus ablation using PFA ethanol injection within vein of Marshall (Et-VOM) was conducted in a previous procedure and in 4 out of 6 patients with MI isthmus RF ablation within coronary sinus (CS) was performed in a previous procedure. Specifically, for the dome-posterior line, 2 patients underwent PFA deliveries only at the gap region in the posterior LA and in other 14 cases, PFA deliveries were performed at 3.2±0.8 sites of the posterior wall between LPV and RPV. We used a total of 15.5±4.6 PFA deliveries to complete the dome-posterior line. Dome-posterior line bidirectional block based on activation mapping and differential pacing maneuvers was achieved in all cases (16/16, 100%) after PFA. For the MI line, we performed a total of 11.8±2.3 application deliveries at 2.5±0.5 sites in the MI region. Posterior MI line bidirectional block based on activation mapping and differential pacing maneuvers was achieved in 5 out of 6 patients (83.3%). In one case additional Et-VOM was needed to achieve MI block. There was no AT/AF recurrence in all these 17 patients. Conclusion PFA treatment seems promising to back-up RF failed linear lesions. But we cannot exclude that it is in fact the combination of the 2 energies that was successful in those resistant cases.

Impact of continuous positive airway pressure for severe sleep apnea on very late recurrence in patients receiving catheter ablation of atrial fibrillation

Abstract Background Sleep apnea (SA) represents a risk for arrhythmia recurrence following catheter ablation (CA) of atrial fibrillation (AF). Continuous positive airway pressure therapy (CPAP) is the established standard treatment for moderate to severe SA. While CPAP exhibits promise in reducing AF recurrences post-CA, the evidence is not entirely consistent. The impact of CPAP for severe SA on very late recurrence post-CA of AF has not been elucidated. Methods This study employed a retrospective, single-center, observational design. Data were derived from SA screening tests routinely performed in patients scheduled for CA of AF in our facility. We defined severe SA as an apnea-hypopnea index (AHI)≥30 by a home sleep apnea test or polysomnography. After excluding patients already diagnosed with sleep apnea before CA, we enrolled 466 consecutive severe SA patients. We divided them into two groups according to whether they had more than 1-year usage of continuous positive airway pressure after CA (CPAP group) or not (non-CPAP group). CPAP usage was monitored through telemonitoring and regular follow-up visits at our outpatient clinic every three months. Very late AF recurrence was defined as AF recurrence more than 1-year after the index CA. Results The age was 65±10 years, 17.4% were females, and 60.3% had non-paroxysmal AF. The mean AHI was 38.0±15.2. The CPAP group included 33.7% (n=157) and non-CPAP group 66.3% (n=309). The AF recurrence rates within 1-year post-CA were similar between the two groups (CPAP group vs. non-CPAP group, 16.6% vs. 16.2%, log-rank p=0.91). However, the very late AF recurrence rate was lower in the CPAP group than non-CPAP group (CPAP group vs. non-CPAP group, 7.6% vs. 21.6%, log-rank p=0.0002). Conclusion Among the untreated severe sleep apnea patients at the time of the catheter ablation of AF, CPAP treatment during 1-year post-CA was associated with fewer AF recurrences beyond 1-year post-CA.KM curve according to CPAP group

Safety and efficacy of pulse field ablation of atrial fibrillation in patients aged over 75 years

Abstract Introduction Pulse-field ablation (PFA) is an emerging atrial fibrillation (AF) ablation technology associated with a favorable safety profile and short procedural times. Elderly patients, in whom AF ablation indications are expanding, may be particularly suitable to PFA. However, in a recent large multicenter trial, patients older than 75 years were not included, so that data on PFA safety and efficacy in this population are scarce. Methods Consecutive patients who underwent PFA of AF at a single academic center were prospectively included in a local registry. Written informed consent was obtained. Clinical, imaging and procedural data was collected and routine care follow-up was performed locally. Results From 2022, out of 345 consecutive patients who underwent PFA of, 42 (13%) were aged ≥75 years. As compared to <75 years-old patients (mean age 61±3 years), elderly patients (mean age 78±4 years) were more frequently females (21 [51%] vs 121 [40%], P=0.02), had more frequently non-paroxysmal AF (27 [65%] vs 164 [54%], P=0.01), significant cardiac comorbidities (9 [21%] vs 33 [11%], P=0.01), and larger indexed left atrial volumes (65 mL/m2 [interquartile range (IQR) 54-76] vs 61 [IQR 54-68], P=0.04). With regards to procedural parameters, the total procedural length was comparable, while elderly patients received more frequently PFA applications outside the pulmonary veins. The rate of major complications was comparable, but 3 cardiac tamponades occurred in patients aged over 75 years, while none occurred in younger patients. After a median follow-up time of 185 days (IQR 65 – 202), the cumulative freedom from sustained atrial arrhythmia recurrence was not statistically different between patients aged over 75 years (75%, 95% confidence interval (CI) [62-84%]) and under 75 years (75%, 95% CI [62-84%], P=0.11). Conclusions PFA appear as a safe and effective technique for AF ablation in elderly patients, although there was an excess of cardiac tamponades in this group

An economic evaluation of first-line cryoballoon ablation versus antiarrhythmic drug therapy for the treatment of paroxysmal atrial fibrillation from a Danish healthcare perspective

Abstract Background As demonstrated in three randomized clinical trials (RCTs), initial rhythm control with first-line pulmonary vein isolation (PVI) using cryoballoon ablation decreases atrial arrhythmia recurrence compared to antiarrhythmic drug (AAD) therapy in patients with symptomatic paroxysmal atrial fibrillation (PAF). Purpose To assess the cost-effectiveness of first-line cryoablation versus first-line AADs in a Danish healthcare setting. Methods Data from 703 participants with symptomatic PAF enrolled into Cryo-FIRST, STOP AF First and EARLY-AF RCTs were used to estimate risk equations (rate of ablation, AF recurrence and resolution, AF-related hospital attendance in addition to health-related quality-of-life (HRQoL) utilities). These were then incorporated into a cost-effectiveness model (CEM) . The Danish cost data was derived from published Danish literature, DRG tariffs and pharmaceutical list prices in Denmark. Where parameters could not be derived, inputs were sourced from published literature or expert opinion. The CEM consisted of a decision tree (one-year time horizon) and a Markov model (three-month cycle length) hybrid, with a lifetime (40 years) time horizon. The CEM is from the perspective of the Danish healthcare system. Health benefits were expressed in quality-adjusted life-years (QALYs), and all costs and benefits were discounted at 3%. As there is no official cost-effectiveness threshold in Denmark, the UK threshold of £20,000 (~€23,200) was assumed. Input uncertainty within the CEM was explored using probabilistic sensitivity analysis. The results presented include data from the initial 12-week blanking period for all studies. Results The three-monthly rate of AF symptom recurrence had a reduction, on average, of 46.7% (p<0.001) in those treated with cryoablation. In addition, the cryoablation arm had a 72.8% (p<0.001) reduction in the monthly rate of receiving an ablation following initial treatment. The average cryoablation patient was also associated with a 4.3% (p=0.025) increase in their HRQoL. Finally, there was no difference in the rate of AF symptom resolution in those who failed initial treatment. Base case results per patient are presented in Table 1. Cryoablation was shown to be dominant when compared to AADs (0.159 more QALYs and €2,519 less costly), with a 99.96% probability of being cost-effective at a willingness-to-pay threshold of ~€23,200 per QALY gained. Individuals in both arms of the model were also expected to receive ~1.2 ablations over a lifetime horizon. Nonetheless, there was a 45% relative reduction in time spent in symptomatic AF states for individuals who were initially treated with cryoablation. Scenario analysis results are presented in Table 2. Cryoablation remained cost-effective over AADs in all scenarios conducted. Conclusions Initial rhythm control with cryoballoon ablation is cost-effective (dominant) when compared to AADs in the Danish healthcare system.Table 1:Key results (per patient)Table 2.Deterministic scenario analysis

Long-term impact of multiple freezes during cryoballoon pulmonary-vein isolation on atrial arrhythmia recurrence

Abstract Background Cryoballloon pulmonary vein isolation (CryoPVI) is well established for atrial fibrillation (AF) ablation. Nevertheless, it is still important to identify possible periprocedural factors influencing its efficacy. With difficult anatomical conditions it is currently unclear whether the number of cryoballoon applications needed to achieve complete vein isolation has an impact on the long-term effectiveness of CryoPVI. Methods We prospectively analyzed AF patients who underwent first-time CryoPVI in a single center cohort between 2018-2023. The group allocation depended on the number of cryo applications until complete isolation was achieved. CryoPVI was performed in a standardized procedure. Follow-up was performed after 3, 6, 12, 18, 24 and 36 months post CryoPVI. Efficacy endpoint was the occurrence of symptomatic atrial arrhythmia. Results A total of 1170 patients were included in the study. Of these, in 610 patients received only one cryoballoon application per pulmonary vein to achieve complete isolation. Gender distribution (56.7% male vs. 43.3% male p=0.09) and AF phenotype (38.5% persistent AF vs. 61.5% paroxysmal AF, p=0.23) did not differ significantly between the two groups, patients who received only cryoballoon application were older (70.1 vs. 68.5, p=0.006) and accordingly had higher CHADS-VASc (2.86 vs. 2.62, p=0.006). After 36 months no difference in the efficacy endpoint was observed between the two groups (47.6% vs. 43.2%, p=0.53). Complications included three major access complications (0.5% vs. 0.5%) and one stroke within the first 30 days after the procedure (0.2% vs. 0.2%) in each group. No pericardial tamponade occurred. Conclusion Multiple- freezes during CryoPVI have no influence on atrial arrhythmia recurrence.

Posterior wall isolation in patients with persistent atrial fibrillation: a single center comparative study between ablation index and very high power short duration radiofrequency ablation protocol

Abstract Background Circumferential pulmonary veins ablation (CPVA) with posterior wall isolation (PWI) using radiofrequency catheter ablation (RFCA) is gaining increasing interest in terms of safety and efficacy. Purpose To compare procedural data and efficacy between two radiofrequency ablation protocols for the treatment of persistent atrial fibrillation (PersAF): very high power-short duration (vHPSD) ablation using a novel temperature-controlled ablation catheter and Ablation Index (AI) guided RFCA using traditional contact-force catheter. Methods This single center prospective study enrolled 75 consecutive patients (Group 1) with symptomatic PersAF undergoing RFCA using a novel contact-force catheter optimized for temperature-controlled ablation with microelectrodes and 6 thermocouples for real-time temperature monitoring during ablation. The vHPSD algorithm modulates power to maintain target temperature during these lesions (90 Watts, 4 s) in the posterior wall. RF delivery in anterior regions was performed in a temperature guided setting (1-45W, 45°C) to achieve a 500-550 AI. These patients were compared to 75 propensity matched patients (Group 2) undergoing PersAF ablation with traditional AI-guided ablation. Procedural data were compared between the two groups (Table 1). Procedural outcome was considered as loop recorder documented atrial arrhythmias recurrences and compared between the two groups. Results Seventy-five patients (69% male, 63.1±11.2 years old) underwent ablation with vHPSD protocol (Group 1). CPVA and PWI was achieved in all patients with total procedure and fluoroscopy times of 67.5±28.8 min and 4.5±2.8 min, respectively. After 12-month median follow-up, 57/75 patients (76%) were free from AF. Seventy-five propensity matched patients (69% male, 60.7±9.9 years old) have undergone ablation with standard contact-force catheter. CPVA and PWI was achieved in all patients with total procedure and fluoroscopy times of 81.99±20.5 min and 5.7±2.1 min, respectively. After 12-month median follow-up, 55/75 patients (73%) were free from AF. Procedural and fluoroscopy times were significantly lower in in Group 1 than in Group 2 (Table 1). AF recurrencies were comparable between the two groups as assessed with survival analysis (Figure 1, log-rank 0.509). There were no deaths or other severe periprocedural complications. Conclusions PWI on top of CPVA is effective in limiting arrhythmic recurrences following RFCA of PersAF. Compared to standard AI guided ablation, vHPSD protocol significantly reduces procedural time and fluoroscopy exposure. Clinical outcomes between the two protocols are similar.Figure 1