Catheter Ablation Research Articles

Artificial intelligence-estimated electrocardiographic age as a recurrence predictor after atrial fibrillation catheter ablations

Abstract Aims The application of artificial intelligence (AI) algorithms to 12-lead electrocardiogram (ECG) provides promising age prediction models. We explored whether the gap between the pre-procedural AI-ECG age and chronological age can predict atrial fibrillation (AF) recurrence after catheter ablation. Methods We validated a pre-trained residual network (ResNet)-based model for age prediction on four independent multinational datasets: CODE-15%, PTB-XL, UK Biobank, and SaMi-Trop cohorts. Then, we evaluated AI-estimated ECG (AI-ECG) age for AF recurrence in a single-center AF catheter ablation (AFCA) cohort, which included 4,794 patients with de-novo AFCA and pre-procedural sinus rhythm ECGs. We categorized the AI-ECG age gap into two groups: aged-ECG (>13 year) and normal age (≤13 year) groups based on the maximum log-likelihood for AF recurrence according to the difference between chronological age and AI-ECG age. Results The ResNet-based AI-ECG age model successfully reproduced the chronological age on the independent datasets (total ECG number=414,804): CODE-15% (r=0.83), PTB-XL (r=0.74), UK Biobank (r=0.53), and SaMi-Trop (r=0.60). During median 22 (9-47) months after AFCA, patients with aged-ECG had a significantly higher AF recurrence rate (adjusted hazard ratio 1.31, 95% confidence interval [1.17-1.48], p<0.001) than normal age group. In the sub-group analyses, the aged-ECG affected more in patients with paroxysmal AF than in non-paroxysmal AF (P for interactions <0.001) and after cryoballoon pulmonary vein isolation (Cryo-PVI) than radiofrequency PVI (P for interactions <0.001). Conclusions Pre-procedural AI- ECG age has a prognostic value for AF recurrence after AF catheter ablation.

Left atrial low-voltage area is associated with poor rhythm outcome and poor efficacy of left atrial additional ablation in patients with long-standing persistent atrial fibrillation ablation

Abstract Background Although left atrial additional ablation other than pulmonary vein (PV) isolation is often performed in order to modify arrhythmogenic substrate, rhythm outcome in patients with long-standing persistent atrial fibrillation (LS-PerAF) is still challenging. Left atrial low-voltage areas (LVAs) is correlated with degeneration of atrial myocardium, and atrial fibrillation (AF) recurrence following catheter ablation. However, in patients with LS-PerAF, the association between the prevalence of LVAs and rhythm outcome has not been clarified. We hypothesized that AF recurrence after AF ablation more frequently occurred in patients with LVAs than in those without, and that the prevalence of LVAs was associated with the efficacy of left atrial additional ablation. Purpose The purpose of this study was to investigate the association between the prevalence of LVAs and rhythm outcome or efficacy of left atrial additional ablation in patients with LS-PerAF ablation. Methods In total, 123 (age, 66 ± 9 years; female, 28 [23%]) consecutive patients who underwent initial ablation for LS-PerAF were included. Left atrial additional ablation was defined as an ablation for left atrium other than PV isolation and ablation for non-PV foci. The definition of LVAs was sites with a bipolar voltage of <0.5 mV covering ≥5 cm² of left atrium. Rhythm outcome after the catheter ablation was followed for 24 months. Results LVAs was found in 31 (25%) patients, and left atrial additional ablation was performed for 31 (25%) patients. Freedom from AF recurrence was significantly lower in patients with LVAs than in those without (Figure 1A). In contrast, freedom from AF recurrence was similar between patients with left atrial additional ablation and those without (Figure 1B). In patients without LVAs, freedom from AF recurrence was significantly higher in patients with left atrial additional ablation than in those without (Figure 2A). On the contrary, in patients with LVAs, freedom from AF recurrence during was similar between patients with left atrial additional ablation and those without (Figure 2B). Conclusions In patients undergoing LS-PerAF ablation, AF recurrence more frequently occurred in patients with LVAs than in those without. Only in patients without LVAs, freedom from AF recurrence was significantly higher in patients with left atrial additional ablation than in those without.Figure 1Figure 2

Acute impact of vein of marshall ethanol infusion combined with anatomical ablation validated by pacing in redo ablation of persistent atrial fibrillation

Abstract Background Catheter ablation with radiofrequency in persistent atrial fibrillation (PeAF) has limited success and a significant proportion of patients requires redo ablation. Several trials showed that addition of vein of Marshall ethanol infusion (Vom-EI) to catheter ablation, compared with catheter ablation alone, increases the possibilities of remaining free of AF. No data are available about the effect on VoM-EI in Pe-AF patients that undergo a redo ablation. Purpose We evaluated acute impact on lesion formation post-VoM-EI and the mitral line block validation after a methodical approach including VoM-EI and check of pulmonary vein isolation (PVI), roof-line, mitral line (ML) and cavo-tricuspid isthmus line in a population of PeAF patients undergone redo ablation. We aimed also the results of a short follow-up. Methods Consecutive patients undergoing redo ablation for PeAF were enrolled. All patients underwent check of PVI, left atrium (LA) roofline and cavotricuspid isthmus line and, if necessary, ablation was completed. In all patients, after a detailed electroanatomical map of the LA (filter at 0.05-0.5 mV if the patient was in sinus rhythm or 0.05-0.3 mV in the case of AF), we proceeded with the VoM-ETHO. LA map was thus repeated to assess the extension of the newly-formed low voltage area (LVA). According to the newly-formed LVAs, the validation of mitral line was obtained by the evidence of bidirectional block. In presence of conduction through the mitral line also after endocardial revision, we proceeded to mapping and ablating in the CS epicardial gaps in the "anchored wall" or in the "free-wall"of the great cardiac vein (GCV). Results Twenty consecutive patients (64±8 years and 65% male) undergone redo ablation for AF with VoM-EI were included in this study. All patients underwent PVI in the previous procedure but only in 11 roof line has been performed. In twenty patients (52%) reconnection of PV was observed (12/20 in right superior pulmonary vein). In 4/11 roof line was not complete. The medium value of basal LA-LVAs was 3.38土5.27 cmq and the newly-formed LVAs after the VoM-EI procedure was 9.21土5.63 cmq. All patients achieved bidirectional block validated across ML: in 8/20 after epicardial gaps ablations into the anchored wall of GCV and in 6/20 after epicardial gaps ablation in the free wall of GCV. The ML procedural time was 18.82土12.79 minutes. The number of radiofrequency irrigation was 20.11土10.56. No major complications occurred. Five patients had VOM dissection without consequences. During a short follow-up period (6土5 months), only one patient had AF recurrences after the blanking period of one month. Conclusions VoM ethanol ablation added to PVI and linear lesions in the context of a methodical and anatomical approach during redo ablation of PeAF patients seems to have promising results and to be safe. Longer follow-up is needed to understand the role of this technique in redo ablation.

Two-year safety and effectiveness of hybrid ablation versus catheter ablation in patients with non-paroxysmal AF: mid-term results of the CEASE-AF trial

Abstract Background Hybrid Ablation for atrial fibrillation (AF) combines epicardial and endocardial ablation through a Heart Team approach to target durable, transmural isolation of the pulmonary veins (PV) and left atrial posterior wall (LAPW). While the primary efficacy endpoint at 12 months was met with a significant benefit increase for hybrid ablation, we now report the midterm durability of those results. Purpose To evaluate 24-months safety and effectiveness of Hybrid Ablation with left atrial appendage exclusion (LAAE) versus Catheter Ablation in patients with persistent AF/enlarged left atrium and longstanding persistent AF (LSPAF). Methods CEASE-AF is a prospective, multi-center, 2:1 randomized controlled trial. Eligible patients were 18-75 years of age, had symptomatic, drug-refractory persistent AF and enlarged left atrium (>4 cm) or LSPAF, and were undergoing a first ablation. Hybrid Ablation consisted of two stages: thoracoscopic epicardial radiofrequency (RF) ablation for PV and LAPW isolation and epicardial LAAE followed by endocardial ablation 91-180 days later. Catheter Ablation consisted of minimum PV isolation by endocardial RF ablation, and repeat ablation was allowed between 91-180 days. In both arms, additional lesions were permitted according to institutional practices. Effectiveness was freedom from AF/atrial flutter (AFL)/atrial tachycardia (AT) off anti-arrhythmic drugs (AAD) (except AADs not exceeding doses which previously failed) and was assessed through 48-h Holter monitoring reviewed by an independent core laboratory blinded to the study. Safety was major adverse events throughout the study, adjudicated by an independent Clinical Events Committee. Results There were 102 Hybrid Ablation and 52 Catheter Ablation patients; 26% were female, mean age was 60.7±7.9 years, mean LAD was 4.7±0.4 cm, and 19% had LSPAF with no differences between arms. The 12- and 24-month results are shown for comparison (Table). Through 24-months, effectiveness was 66.3% (63/95) in the Hybrid Arm and 33.3% (17/51) in the Catheter Arm (absolute difference 33.0% [95% CI 14.3%, 48.3%; p<0.001]). Major adverse event rates through 24-months were statistically similar at 10.8% (11/102) in the Hybrid Arm and 9.6% (5/52) in the Catheter Arm (p=1.0). Through 24-months, repeat ablations were performed in 7.4% (7/95) of the Hybrid Arm versus 37.3% (19/51) of the Catheter Arm (p<0.001), and cardioversions were performed in 14.7% (14/95) of the Hybrid Arm versus 29.4% (15/51) of the Catheter Arm (p=0.034) Conclusions: CEASE-AF demonstrated that superior effectiveness of Hybrid Ablation including LAAE versus Catheter Ablation was durable through 24-month follow-up, with 33% absolute improvement in freedom from AF/AFL/AT. Safety rates continued to be similar between arms. Three-year follow-up is ongoing.

Atrial fibrillation recurrence in oncocardiological patients treated with catheter ablation. A retrospective cohort study

Abstract Background The relationship between oncological events and cardiovascular pathologies is a subject still widely discussed. Certain chemotherapy drugs, including alkylating agents, anthracyclines, taxanes, and topoisomerase II inhibitors have proven to possess arrhythmic and cardiotoxic capabilities. There is enough evidence to suggest an association between oncological events and the appearance of newly onset AF, but there is little to no scientific literature about the management of these patients and the outcome of normal therapeutically procedures. Purpose This study assess if oncocardiological patients with AF should be considered a risk group when planning to undergo catheter ablation for the arrhythmia treatment. Methods The studied population was based on the data recollection from the electrophysiology department and consisted of patients with AF intervened by radiofrequency catheter ablation. All the procedures were conducted between January 1st 2019 and December 31st 2022. Among 138 participants enrolled for this study, 68 of them had either recent history of oncological events (maximum of 5 years cancer-free). The control group had no previous nor active history of cancer. The cohort with the desired exposure (cancer patients) was compared with a cancer-free group. Two primary outcomes were measured: procedure related complications, and first AF recurrence within the first 12 months. Complications were categorized according to two dichotomous variables: the existence of acute complications directly during the procedure or within the first 12 hours after the end of the procedure, and the occurrence of self-limited arrhythmic events during the blanking period. Results When compared as dichotomous variables (yes/no) with Fisher’s exact test, no statistical significance was observed between the studied cohort and control for complications and events during blanking. The proportion of patients free of sustained episodes of AF at 12 months was 52,9% in the oncologic group and 77,9% in the Control group (P = 0.003; RR of 3.14; 95% CI 1.5 - 6.6) for the oncologic group. When not adjusted by any other factor, association with Cancer was shown (HR 2.43; P =0.005; 95% CI 1.3 – 4.4) for recurrence of arrhythmic events. The regression model with Kaplan-Meier method shows the overall 12-month survival in two groups and the difference between the two survival curves was statistically significant (P=0.0016). Conclusion Oncocardiological patients have demonstrated a significantly higher incidence in post-ablational recurrence when compared with a similar cancer-free control group. Results found in acute and chronic procedural complications were similar in both cohorts.

Innovations in arrhythmia management in pregnant woman: catheter ablation without using fluoroscopy

Abstract Background The latest data of effectiveness and safety of catheter ablation without using fluoroscopy in general population suppose wide using of this technology. However, data on pregnant population is limited. Purpose To investigate efficacy and safety of catheter ablation without using fluoroscopy in pregnant women with analyzing obstetric and neonatal outcomes. Methods We studied 47 cases of catheter ablation in pregnant (mean age 25.3±3.9 years, mean gestation age 23.7 ±3.1 weeks) within 24 month follow-up. Ablation was performed under the guidance of CARTO (n=21; 44.7%) and Ensite Precision systems (n=26; 55.3%) without using fluoroscopy in all cases. Results The most common arrhythmia was atrioventricular nodal reentrant tachycardia (n=21; 44.7%), which was followed by Wolff–Parkinson–White syndrome (n=15; 31.9%). Cases of combination of accessory pathways with slow conduction ways (n=3, 6.4%), ventricular tachycardia (n=3, 6.4%) and premature ventricular contraction (n=5; 10.6%) were rare. Ablation without using fluoroscopy was successful in all cases, mean procedural time was 71.9±14.5 minutes. There was one case of complication after ablation procedure: ileofemoral thrombosis, which was treated successfully without termination of gestation (2.1%). We found increased uterine contractile activity and placental abruption in pregnant after ablation in 4.54% and 2.3% cases respectively. Cases of uterine blood flow violation was more frequent: in 15.9% cases. Obstetric outcomes characterized by prevalence of vaginal delivery and delivery in term: in 76.6% and 95.7% cases. There were live births in all pregnant women with normal range of fetal birth weight and Apgar score (3207.4±485 grams and 8.4±1.6 respectively). There were no incidence of mortality and arrhythmia recurrence at follow up. Conclusions Catheter ablation without using fluoroscopy can be effectively and safety performed during gestation with good neonatal and obstetric outcomes.

Low-dose dexmedetomidine sedation in patients undergoing electrophysiological study and ablation of supraventricular tachycardias in a same day setting

Abstract Background Catheter ablation for supraventricular tachycardias (SVT) can frequently cause patient discomfort, anxiety or pain. Through the years different drugs have been employed to provide an optimal sedation without interfere with inducibility of tachyarrhythmia. Moreover, the increasing number of patients with this clinical condition and the growing demand of catheter ablation, makes same day discharge mandatory. For this purpose, drugs that guarantee minimal sedation and reduce adverse events should be used. Dexedetomidine (DEX) is a selective alpha-2 agonist with analgesic and sedating effect without significant respiratory depression. Its electrophysiological effects include the sinus node and atrioventricular (AV) node depression and an increased atrial refractoriness. Albeit there is a reduction of side effects of most commonly used sedation drugs, data on the efficacy and safety profile of DEX during SVT ablation of adult patients are unclear and conflicting. Purpose The aim of this study was to assess whether optimal sedation and patient’s comfort can be achieved with a low-dose DEX without interfering with electrophysiological parameters during catheter ablation of SVT in adult population. Methods This is a single-center prospective study. Study population consisted of patients undergoing mapping and catheter ablation of SVT from January to September 2023 divided into DEX group (periprocedural infusion of Dexedetomidine 0.07-0.11 mcg/kg/h without loading dose) and non-DEX group (midazolam 1-2 mg periprocedural). Clinical and procedural data were recorded for all patients, as well as all measurements taken during electrophysiological study. Results The study population was predominantly female (60%) with a mean age of 56 ± 13.7 years. Hypotension occurred in only one patient, in the DEX group. No cases of desaturation were observed in both groups. Most of the induced tachyarrhythmias were the slow-fast type of atrioventricular nodal reentrant tachycardia (75%), whereas atrioventricular reentrant tachycardia and atrial tachycardia were less common (7.1% and 7.1%). No significant differences were recorded in relation to AV node refractoriness, atrial refractoriness, anterograde and retrograde conduction. (Table 1) Isoproterenol was required to induce tachyarrhythmia in both groups. Arrhythmia inducibility and aberrancy in tachycardia was not significantly influenced by DEX. The jump phenomenon was recorded more frequently in the DEX group (86.4% vs. 46.7%; p=0.004). The mean duration of the procedure did not differ between the two groups. All patients were discharged on the same day after 3 hours of observation. Conclusions The use of low-dose Dexedetomidine was succesful in improving periprocedural patient comfort, without reducing tachyarrhythmia inducibility or major electrophysiological parameters.

The best practices for safety and effectiveness in pregnant: zero-fluoroscopy arrhythmias catheter ablation

Abstract Background Arrhythmias are common during gestation. While the safety and effectiveness of zero-fluoroscopy arrhythmias catheter ablation has been studied, the effects of it in pregnant poorly understood. Purpose The aim of our single-center, prospectively study is explore feasibility, efficacy and safety of zero-fluoroscopy catheter ablation in pregnant. Methods Characteristic, obstetric and neonatal outcomes of 47 cases of zero-fluoroscopy catheter ablation during gestation (main group) within 24 month follow-up were compared with group of pregnant with antiarrhythmic therapy (control group, p=54). Ablation was performed under the guidance of CARTO (n=21; 44.7%) and Ensite Precision systems (n=26; 55.3%) and intracardiac echocardiography without using fluoroscopy in all cases. Results Mean age of pregnant and mean gestation age were comparable in both groups (25.3±3.9 vs. 27.3±3.9 years, p=0.093 and 23.7 ±3.1 vs. 23.8 ±3.2 weeks, p=0.123). Atrioventricular nodal reentrant tachycardia was the most common indications for ablation during gestation (n=21; 44.7%), which was followed by Wolff–Parkinson–White syndrome (n=15; 31.9%). Cases of combination of accessory pathways with slow conduction ways (n=3, 6.4%), ventricular tachycardia (n=3, 6.4%) and premature ventricular contraction (n=5; 10.6%) were rare. Acute procedural success of zero-fluoroscopy ablation was in 100% with mean procedural time 71.9±14.5 minutes. Complication (ileofemoral thrombosis) was in one pregnant (2.1%). Further course of pregnancy characterized by occurring increased uterine contractile activity and placental abruption only in main group (4.54%, p=0.464 and 2.3%, p=0.414 respectively), while uterine blood flow violation and preeclampsia were in both groups (15.9% vs. 13%, p=0.234 and 4.55% vs. 3.7%, p=0.730 respectively). Obstetric outcomes characterized by prevalence of vaginal delivery and delivery in term in both groups (76.6% vs.81.5%, p=0.241 and 95.7% vs. 96.3%, p=0.743). There were live births in all cases with normal range of fetal birth weight in both groups (3207.4±485 vs 3142.2±214.1 grams and 8.4±1.6 vs. 8.6±1.3 respectively). There were no incidence of mortality and arrhythmia recurrence at follow up. Conclusions Zero-fluoroscopy ablation is feasible and can be safety performed during gestation with good outcomes.

Long-term outcomes of catheter ablation for atrial fibrillation in octogenarians

Abstract Background Catheter ablation is superior to standard medical therapy in controlling atrial fibrillation (AF). There is limited data on the long-term outcomes of AF ablation in octogenarians. Purpose This study aims to rigorously evaluate the efficacy and safety of AF catheter ablation in octogenarians, compared to non-octogenarians. Methods In this retrospective, multicentre, international study in 13 centres in the United Kingdom, France, and Switzerland, the long-term outcomes of 473 consecutive octogenarian patients undergoing catheter ablation for AF were compared to 473 propensity-matched non-octogenarian controls (median age 81.3 [80.0, 83.0] vs 64.4 [56.5, 70.7] years, 54.3% vs 35.1% females; p-value for both <0.001). The primary endpoint was the recurrence of atrial arrhythmia during 365 days' follow-up after an initial blanking period of 90 days (median follow-up time 322 [153, 365] days. Results Acute success of the ablation was achieved in 97% of octogenarians. When comparing non-octogenarians vs octogenarians, there were more complications in the octogenarians group (11.4% vs 7.0%, p=0.018), with the most common adverse events being vascular complications (3.8% vs 2.7%). The median follow-up time was 322 [153, 365] days. Through day 365, 131 (27.7%) octogenarians had a recurrence of atrial arrhythmia as compared to 111 (23.5%) non-octogenarians (odds ratio 1.49; 95% confidence interval 1.16-1.92; p=0.002). In a multivariable regression model including gender, previous AF ablation, vascular disease, chronic kidney disease, CHA2DS2-VASc score, left atrial dilatation, and indwelling cardiac implantable electronic device, age above 80 remained an independent predictor of recurrence of atrial arrhythmias throughout 365 days' follow-up. Conclusion Age over 80 is associated with higher rates of recurrence of atrial arrhythmia on 365 days' follow-up post-catheter ablation for atrial fibrillation. Arrhythmia recurrence on follow-up

Left and right ventricular function measured by strain analysis predicts one-year mortality in ventricular tachycardia ablation patients with structural heart disease

Abstract Introduction Radiofrequency catheter ablation has become increasingly important in the management of scar-related ventricular tachycardia (VT). Wide range of clinical and procedural predictors of VT recurrence and mortality are described by previous studies. However, currently known echocardiographic predictors are mainly limited to conventional echo parameters. Speckle tracking echocardiography (STE) is a novel and promising method to evaluate systolic and diastolic function. STE derived parameters, such as global longitudinal strain (GLS), are proven predictors of mortality and arrhythmic events in heart diseases. Aims The aim of the present study was to assess whether STE derived parameters could be considered predictors of VT recurrence and mortality after catheter ablation of ventricular tachycardia in patients with structural heart disease. Methods We measured pre-ablation strain and strain rate parameters with speckle tracking. Left ventricular four-chamber longitudinal strain (LV4CLS), early diastolic strain rate (e’-sr), right ventricular free wall longitudinal strain (RVFWLS) and right ventricular four-chamber longitudinal strain (RV4CLS) were assessed in 73 cases. Patients were followed up for one year. Endpoints were VT recurrence, which was defined as either ICD recording of a sustained VT episode requiring therapy or an episode of sustained VT recorded on 12-lead ECG or CIED, and all-cause mortality. Results Univariate analysis using the Cox proportional hazard model revealed that only lower LVEF (HR: 0.52 [0.31-0.88], p=0.02) was associated with higher VT recurrence in the first year among the echocardiographic parameters. High LVEDD (HR: 3.9 [1.31-11.65], p=0.02), low TAPSE (HR: 0.52 [0.28-0.98], p=0.04), low LV4CLS (HR: 0.4 [0.19-0.83], p=0.01) and low RV4CLS (HR: 0.31 [0.13-0.72], p<0.01) were the predictors of 1-year mortality. Conclusion Strain parameters, especially right ventricular four-chamber longitudinal strain may supplement conventional echocardiographic parameters in the prediction of one-year mortality after catheter ablation in patients with structural heart disease. Further prospective clinical studies are necessary to verify the significance of strain parameters.

Efficacy of catheter ablation in patients with persistent atrial fibrillation on chronic ibrutinib therapy

Abstract Background Ibrutinib represents a cornerstone in the management of B-Cells malignancies and chronic lymphatic leukaemia. This drug however was associated with a 5-fold increased risk of developing atrial fibrillation (AF). The consequences of AF in this category of frailty patients such as heart failure may lead to the need of Ibrutinib withdrawal, which is considered a disease modifying therapy. Purpose This study aims to evaluate the safety and efficacy of catheter ablation in managing AF in patients on chronic ibrutinib therapy. Methods this study evaluated 20 consecutive patients from two centres in Italy who developed persistent AF during chronic therapy with Ibrutinib for chronic lymphatic leukaemia or small lymphocytic lymphoma and underwent AF catheter ablation from 2016 to 2020. Antiarrhythmic drugs were withdrawn because of side effects and drug interaction. All receive pulmonary vein (PV) isolation + isolation of left atrial posterior wall (PW) and superior vena cava. A standardized protocol was performed to confirm persistent PVI and elicit any triggers originating from non-PV sites. Ablation of non-PV sites triggering runs of atrial tachyarrhythmias was left to operator's discretion. Exclusion criteria were age<18 years and history of AF before ibrutinib therapy. Patients were monitored for arrhythmia at quarterly office visits, ECGs, 7-day Holter monitoring and event recorders during the first year followed by biannual checkups during the remaining part of the follow-up period. Results 12 patients received PV+PW+SVC isolation plus ablation of non-PV trigger (Group 1) whereas 8 receive only PV+PW+SVC isolation (Group 2). 10 (83,3%) patients in group 1 remained arrhythmia-free without the need for additional antiarrhythmic drugs while only 3 (37,5%) in group 2 maintained sinus rhythms. Non pulmonary triggers were mostly found in left atrial appendage (5/12, 41,6%), coronary sinus (4/12, 33,3%) and crista terminalis (3/12 25%). More than one trigger was found in 4 (33.3) patients. After 22.3 ±3.6 months follow-up, patients with ablation of induced non-PV triggers had a significantly higher arrhythmia control than those whose triggers were not ablated (Chi – square p value: 0.035; Log rank p value: 0.014) (Fig.1). 5 patient that received left atrial appendage isolation underwent a left atrial appendage closure with Watchman device 3 months after atrial fibrillation ablation. Conclusion Catheter ablation in this category of patients seems to be a safe and effective tool for managing atrial fibrillation in patients with persistent AF on chronic ibrutinib therapy; an ablation strategy that includes as a first line therapy non pulmonary vein triggers appears to be an effective approach when compared to pulmonary vein plus posterior wall only. This approach will allow continuation of ibrutinib treatment, which markedly enhances the prognosis and diminishes the risk of adverse cardiovascular events in this patient population.Kaplan-Meier curve showing recurrence-fr

Volumetric quantification of epicardial fat using semiautomated atrial CT segmentation in patients with atrial fibrillation: the Prospective AFAT study

Abstract Background Epicardial fat or epicardial adipose tissue (EAT) is most commonly defined as adipose tissue between the myocardium and the visceral pericardium. Previous studies have suggested EAT to be an important contributor to the pathogenesis of atrial fibrillation (AF) as well as a plausible predictor for AF recurrences after ablation. However, data on EAT using precise volumetric quantification is limited. Methods and Results AFAT is a prospective observational study conducted at a heart centre in our city with 200 patients aimed to be included. We conducted an interim analysis of the first 75 patients enrolled in the AFAT study. All patients received delayed dual source cardiac computer tomography (CT) imaging which was analysed using semi-automated 3D segmentation (Figure 2) to quantify left atrial (LA) and right atrial (RA) EAT prior to ablation (52.5 % persistent AF). The mean age was 67 ± 8.7 years with 46.9 % (n=35) being female. Mean BMI was 28 ± 4.5. The Mean LA EAT was 33.1 ml ± 13.2 ml and RA EAT was 32.7 ml ± 12.2ml. Median follow up after AF catheter ablation was 163 days. The optimal cut point for the total atrial EAT was estimated at 50.2 ml. In patients with total atrial EAT ≤ 50 ml recurrence of any atrial arrythmia after catheter ablation occurred in 8% (6 patients) compared to 25.3% (19 patients) recurrence rates in patients with a total atrial EAT > 50 ml. Kaplan-Meyer estimates showed no statistical difference between groups (log rank p=0.063) as this analysis is under-powered with more patients being enrolled for the final results (Figure 1). Conclusion The use of semi-automated CT based atrial segmentation presents a novel highly accurate and reproducible method to reliably identify atrial EAT. Increased atrial EAT is likely to play an important role for arrythmia recurrences after catheter ablation. Final results of the AFAT study will provide further evidence to this important subject.Arrhythmia recurrences depending on EATBiatrial 3D Segmentation of EAT

Preprocedural atrial fibrillation burden is associated with recurrence in patients undergoing atrial fibrillation ablation: findings from the ISOLATION AF Ablation Cohort Study

Abstract Background Non-invasive quantification of electrophysiological properties of the atria is increasingly used for outcome prediction in atrial fibrillation (AF) patients. Data on the benefit of the current classification of AF compared to AF burden based on single lead ECG measurements to predict AF recurrences are scarce. Objective This study sought to assess the predictive performance of low versus high AF burden compared to the conventional AF classification for predicting recurrences after AF catheter ablation. Methods A cross-sectional analysis was conducted in AF patients scheduled for catheter ablation included in the prospective multicenter ISOLATION cohort study between July 2020 and November 2022. Clinical characteristics, routine tests, blood tests and rhythm monitoring through single lead ECGs were collected prior to ablation. ECGs were recorded three times daily for four weeks, with additional measurements in case of the onset or relief of symptoms. The primary endpoint was "ablation success" defined as freedom from documented arrhythmia after the blanking period. Of 650 included patients, pre-procedural rhythm monitoring was available in 580. 261 patients had at least 14 days of ECG measurements and completed 12 months of follow-up. In these patients, we compared the recurrences after 12 months between paroxysmal and persistent AF and high versus low AF burden through survival analysis. Maximally selected rank statistics were used to determine the best cut-off value for AF burden. Results In 261 patients, the mean age was 64 ± 9 years, and 33.7% were female. Physicians classified 170 patients (65.1%) as paroxysmal AF and 91 (34.9%) as persistent AF based on medical history. The AF burden is shown in Figure 1. The optimal calculated cut-off value for AF burden was 42%. Out of 170 patients with paroxysmal AF, 17 (10%) had a burden of > 42%. Of the 91 patients with persistent AF, 35 (38%) had a burden of < 42%. After 12 months, a significant difference in recurrences was observed between patients with paroxysmal AF versus persistent AF (p= 0.015). Patients with high AF burden, had more recurrences after 12 months, than patients with a low AF burden (p= 0.006) (Figure 2). Conclusion Our preliminary results suggest that the addition of a new classification of AF based on burden might provide additional benefit in predicting AF recurrences after catheter ablation compared to the current existing classification and may improve prognostication. Completion of patient follow-up is necessary to determine the predictive value of AF burden derived from single lead ECGs for the prediction of AF recurrence.Figure 2.

Electrophysiological characteristics of tachyarrhythmia and effects of catheter ablation in patients with Fontan circulation

Abstract Introduction Incidence of arrhythmia in complex congenital heart disease is higher than general population. Characteristics of arrhythmia in patients with functional single ventricle is not known. Methods Total 18 patients (age, 22.1 8.5 years, 9 men) with Fontan circulation who had undergone catheter ablation for tachyarrhythmia were retrospectively consecutively included. Characteristics of congenital heart disease, mechanisms of tachyarrhythmia, and efficacy and safety of catheter ablation were analyzed. Results Congenital heart diseases of the patients were as follows: double outlet right ventricle, 9; common atrioventricular septal defect, 5; and pulmonary atresia, 4. Fontan types were as follows: lateral tunnel Fontan, 9; extracardiac conduit Fontan 9. Fontan conduit puncture was successful in all patients. Mechanisms of tachyarrhythmia were as follows: intraatrial macroreentrant tachycardia, 8; focal atrial tachycardia, 4; atrioventricular nodal reentrant tachycardia, 3; twin atrioventricular nodal reciprocating tachycardia, 2; unknown, 2. Success rate of catheter ablation, recurrence rate, and complication rate were 16 of 18 patients, 2 of 18 patients, and 0 of 18 patients, respectively. Conclusion Intraatrial macroreentrant tachycardia is the most common tachycardia mechanism in patients with Fontan circulation. Catheter ablation for tachyarrhythmia is effective and safe in these population.

Arrhythmia during gestation: from diagnosis to follow-up

Abstract Background Although arrhythmia is common cardiac complication during gestation, data on perinatal and neonatal outcomes in pregnant women with different arrhythmia management is limited. Purpose To explore clinical characteristics and outcomes of different management strategies in pregnant women with arrhythmias. Methods In this single-center, prospectively study we consequently included 87 cases of arrhythmias in pregnant (mean age 26.7±3.5 years, mean gestation age 24.6 ±3.3 weeks). Clinical characteristics, obstetric and neonatal outcomes were compared due to different arrhythmia management strategies: dynamic observation (the 1st group), antiarrhythmic therapy (the 2nd group) and catheter ablation (the 3rd group) within 12 month follow-up. Results Supraventricular tachycardia (n=47; 54%) was the most common arrhythmia in pregnant. Premature contraction was detected in 34 cases (39%). Cases of ventricular tachycardia (n=6; 7%) was rare during gestation. Benign course of arrhythmia was in 15 cases (17.2%) and do not require drug therapy or intervention. Antiarrhythmic drug was used for symptomatic patients with haemodynamic instability (n=28, 32.2%). Catheter ablation performed in cases of drug refractory and severe arrhythmias (n=44, 50.5%). The procedure performed under the guidance of CARTO (n=21; 47.7%) and Ensite Precision systems (n=23; 52.3%) without fluoroscopy and were successful in all cases (100%). The further course of gestation characterized by occurring increased incidence of uterine contractile activity (n=2, 4.5%, p=0.464) and placental abruption (n=2, 4.5%, p=0.464) only after catheter ablation while other complications were in all groups: uterine blood flow violation (n=6, 40% vs. n=4, 14.3% vs. n=6, 13.6%, p=0.168) and preeclampsia (n=1, 6.7% vs. n=1, 3.6% vs. n=2, 4.5%, p=0.730). Obstetric outcomes characterized by prevalence of vaginal delivery in all groups (n=13, 86.7% vs. n=22, 78.6% vs. n=37, 84%, p=0.465). Neonatal outcomes characterized by normal range of fetal birth weight and 5 minute Apgar score in all groups (3140.7±321.2 vs. 3265,3±290,1 vs. 3312,3±209,8 grams, p=0.701 and 8,6±1,1 vs. 8,5±1,2 vs. 8,6±1,2, p=0.721 respectively). There was no incidence of maternal and fetal mortality and arrhythmia recurrence after ablation in follow-up. Conclusions Supraventricular tachycardia is common in pregnancy. Arrhythmias in pregnant characterized by benign gestation course and outcomes regardless different management.

Associations between stroke risk factors and left atrial low-voltage areas in patients with atrial fibrillation undergoing catheter ablation from the REAL-AF registry

Abstract Background Prior research indicates that increased left atrial low-voltage areas (LA LVA) are linked to comorbidities and CHA2DS2-VASc score in patients with persistent atrial fibrillation (PerAF) undergoing catheter ablation. However, given the heterogeneity of AF where patients may transition between paroxysmal AF (PAF) and PerAF types, it is biologically plausible that these associations span all forms of AF. Purpose To investigate the relationship of stroke demographics and comorbidities to LA LVA and AF type in a multicenter registry of patients undergoing catheter ablation. Methods The Real-world Experience of Catheter Ablation for the Treatment of Symptomatic PAF and PerAF Using Novel Contact Force Technologies registry (REAL-AF) is a prospective, observational multicenter registry of patients undergoing catheter ablation. We evaluated 6053 patients undergoing first-time catheter ablation for both PAF and PerAF to identify associations between stroke risk factors and LA LVA. LA LVA was determined in contact maps as bipolar voltage <0.50 mV. Mapping was completed using 5-spline high-density catheters before ablation. LA LVA was categorized into low (<5%) vs. high (≥5%) based on preliminary data. Analyses were conducted using independent samples t-test and Chi-square test. Results LA LVA was associated with greater CHA2DS2-VASc score (3.2 vs. 2.5, p <0.001). Age 75+ (Odds ratio (OR): 2.22, p<0.001), congestive heart failure (CHF) (OR: 2.01, p<0.001), female sex (OR): 1.51, p<0.001), vascular disease (OR: 1.50, p<0.001), age 65-74 (OR: 1.20, p=0.001), hypertension (OR: 1.38, p<0.001), history of stroke (OR: 1.29, p=0.004) and diabetes (OR: 1.25, p=0.001) were also associated with LA LVA (Table 1). These associations remained significant among a subgroup of those presenting in normal sinus rhythm (N = 3546). Patients with CHF (OR: 2.09, p<0.001), hypertension (OR: 1.89, p<0.001) and male sex (OR: 0.60, p<0.001) were more likely to have PerAF in the LVA ≥5% subgroup (n=1594) (Table 2). All other components of the CHA2DS2-VASc score were not significantly associated with AF type in this subgroup. While there was a significant association between AF type and CHA2DS2-VASc score (PAF: 3.15, PerAF: 3.42, p<0.001) in the LA LVA ≥5% subgroup, the effect size was small (Cohen’s d = -0.179). Conclusion LA LVA ≥5% was associated with all separate components and overall CHA2DS2-VASc score. In patients with LA LVA ≥5%, there were only associations between PerAF and CHF, hypertension, and male sex, implying a special role in substrate progression. Our findings suggest that LA LVA may represent a more sensitive clinical phenotyping tool of AF rather than current duration-based ones. This is the largest study to our knowledge in elucidating the relationship between increased LA LVA and stroke risk factors in the AF population.

Newly diagnosed heart failure in patients with atrial fibrillation referred for catheter ablation - identifying patients with arrhythmia-induced cardiomyopathy

Abstract Introduction Atrial tachyarrhythmias are primary drivers in the development of arrhythmia-induced cardiomyopathy (AiCM). The restoration of sinus rhythm in patients with an AF (atrial fibrillation) based AiCM results in enhancement of left ventricular ejection fraction (LV-EF). This study aims to assess the prevalence of undiagnosed and unexplained heart failure among patients with AF referred for catheter ablation and seeks to phenotype these patients. Methods Our registry, a prospective, observational clinical cohort that recruits patients with heart rhythm disorders at a large tertiary-care center since March 2021 was interrogated for AF patients. These patients underwent screening for heart failure based on clinical, laboratory, and imaging characteristics. Undiagnosed heart failure at baseline, lack of heart failure medication and absence of known structural heart disease were considered suspicious for AiCM. Results A total of 1225 patients were analyzed. 35.2% were female, median age 67 (IQR 59;75) years, median LV-EF 55.0 (IQR 50;60) % and median N-terminal pro B-type natriuretic peptide (NT-proBNP) 686 (IQR 210;1630) mg/dl. NYHA class I was reported in 28.3% cases, NYHA class II in 32.2%, NYHA class III in 20.2% and NYHA class IV in 2%. At baseline, 263 patients (17.6%) had an LV-EF < 50% of those 110/263 (42%) with suspected AiCM. Patients with suspected AiCM were 67 (IQR 58;76) years old, 40.9% were female, median LV-EF was 41.0 (IQR 35;41) % and NT-proBNP at admission was 1681 (IQR 775;2352) mg/dl. Patients with suspected AiCM had a significantly reduced TAPSE (19 vs. 22 mm; p<0.001), showed generic characteristics of heart failure (NTproBNP: p<0.001, NYHA class: p=0.049), while EHRA score was significantly lower (p=0.006). In contrast, patients with known cardiomyopathy of non-AiCM origin at baseline and EF < 50% (n=153) had significantly higher LAVI (44.8 vs. 38.8 ml/m2; p=0.002), were predominantly male (76.5 vs. 59.1 %; p=0.004) and had lower GFR (60.2 vs. 68.5 ml/min; p=0.002) compared to AiCM patients. Among 29/110 suspected AiCM patients with available TTE at follow-up (within 12 months post-catheter ablation), 26/29 exhibited an improved LV-EF (40% at baseline vs. 54% at FU; p<0.001). 3/3 patients without LV-EF improvement exhibited arrhythmia recurrence. Conclusion Primary AiCM was suspected in 42% of all AF patients with reduced LV function referred for catheter ablation. These patients exhibited a different phenotype compared to the remaining cohort. After catheter ablation, ejection fraction improved in 90% of AiCM patients. These findings call for structured HF screening in clinical routine in AF patients. In the future, validated scores are required to enable early rhythm control for these patients.Proportion of patients with HFrEFCourse of EF after catheter ablation

Bipolar catheter ablation of left ventricular summit PVC

Abstract Background Premature ventricular contractions (PVC) arising from the left ventricular summit are a challenging arrhythmia to manage, often refractory to conventional radiofrequency ablation. This study aimed to investigate the effectiveness of bipolar ablation as a therapeutic option for PVCs originating from this anatomically complex region. Methods We conducted a retrospective analysis of a prospective ablation registry to identify patients with recurrent, symptomatic PVCs originating from the left ventricular (LV) summit who underwent bipolar ablation. Bipolar ablation involved the use of two ablation catheters, delivering radiofrequency energy from opposite sides of the summit. The catheters were connected by a dedicated adapter, allowing to connect one ablation catheter in position of a return electrode. Procedural success was defined as the elimination of PVCs during the procedure and freedom from PVCs on follow-up monitoring. Results were compared to a similar patient group who had received unipolar ablation of summit-PVCs. Results A total of 12 pts received bipolar ablation between July 2022 and October 2023. Three pts underwent ablation for VT and were excluded. A total of 9 pts (mean age 57±18 years, n=7 [78%] male, BMI 28±5kg/m2) were included in the analysis. All but one had a history of a previous unsuccessful ablation attempt (median 1 [1-2]). In a group of 33 patients undergoing unipolar ablation 8 (32%) had received ≥ 1 previous ablation and were included in the analysis. Baseline parameters did not differ between groups. The acute procedural success rate for bipolar ablation was 89% in bipolar pts and 75% in unipolar pts, with a mean procedural time of 173±33 min, a mean fluoroscopy time of 14±9 min (158±55 min [p=0.478] and 14±12 min [p=0.995] for unipolar pts). Bipolar ablation was performed between the LVOT and RVOT in 6, and between LVOT and the distal CS in 6 pts with 25-35 W. No major complications were detected in bipolar pts while one non-fatal tamponade occurred in the unipolar pts group. Follow-up data at 97 [93-269] days revealed a sustained reduction in PVC burden in bipolar pts (from 18±13% to 7±9%; p=0.026) while unipolar ablation did not show a significant burden reduction (15±6% to 11±10%; p=0.382). The success rate of a relative burden reduction >50% did not differ significantly between the groups (bipolar: 6 pts [67%] 3 pts [38%]; p=0.347). Conclusion Bipolar ablation offers an effective and safe therapeutic approach for PVCs originating from the LV summit. It significantly reduced PVC burden in this analysis. The data suggest that a repeat procedure after a failed summit PVC ablation should only be performed if bipolar ablation is available during the second procedure. Larger studies are warranted to confirm efficacy and safety of this ablation method.

Validation of predictive models for lesion transmurality and steam-pop using ex-vivo porcine bipolar ablation model

Abstract Introduction Bipolar ablation has been reported to create deeper myocardial ablation lesion as compared to unipolar ablation, however, there is currently no standardized strategy for bipolar ablation settings such as energy and ablation time. Purpose The aim of the present study is to test our hypothesis that both transmural lesion creation and steam-pop occurrence during bipolar ablation can be predicted by the settings of bipolar ablation and the myocardial tissue characteristics such as tissue thickness and initial impedance prior to RF. Methods Using porcine cardiac tissues, we conducted ex-vivo ablation experiments. Commercially available radiofrequency (RF) ablation catheters were utilized for the procedures. Each ablation catheter was positioned bilaterally on the myocardial slices at a 45-degree angle, maintaining a targeted contact force of 10g. We documented the occurrence of steam-pop under various conditions, modulating tissue thickness (5-20 mm), RF power (20, 30, 40, 50 Watt) and ablation duration (20 sec, 40 sec, 60 sec, 180 sec). Generalized linear models (GLM) were developed to forecast the creation of transmural lesion and steam-pop incidents, drawing on the bipolar ablation settings and myocardial tissue characteristics. Subsequently, we engaged in an additional series of experiments to validate the models. Results In total, 194 bipolar applications were utilized as training data. Transmural lesions and steam-pops were observed in 95 (49%), and 11 applications (5.7%), respectively. We constructed GLM using the RF energy (Watt), tissue thickness (mm), initial bipolar impedance (Ohm), impedance drop during the first 5 seconds of application (Ohm), and RF duration (seconds). For transmurality prediction the model validation was conducted with another independent 111 RF applications (102 transmural, and 25 steam-pops). The GLM, which utilized RF energy, tissue thickness, initial bipolar impedance, and RF duration, performed the best performance in predicting transmural lesion creation (AUC 0.94 [0.90-0.99], sensitivity 86 %, specificity 100 %). However, the exclusion of ‘tissue thickness’ from this model led to a significant decrease in its predictive performance (AUC 0.69 [0.48-0.89], sensitivity 47%, specificity 100%, P=0.0057). For pop prediction in validation data, the GLM utilizing RF energy, initial bipolar impedance and impedance drop showed the best performance (AUC 0.90 [0.83-0.97], sensitivity 76 %, specificity 92 %). Conclusion Our data show that accurate assessment of tissue thickness is pivotal for predicting transmural lesion creation. To predict lesion transmurality and steam-pop incidents through RF parameters and tissue characteristics within a beating heart, further research is warranted. This could facilitate the calibration of RF settings, potentially enhancing the safety of bipolar ablation procedures.

Vein of Marshall ethanol infusion related lesion durability. A randomized dual centre pilot study

Abstract Introduction Vein of Marshall ethanol infusion (VOM-EI) creates a local ablation which includes epicardial bridges, AF triggers, vein innervation and facilitates mitral isthmus (MI) ablation. Recent trials demonstrated that in persistent AF patients the addition of VOM-EI to RF catheter ablation (CA) increased success rate vs CA alone. Moreover, a novel CA strategy (VOM-EI, PVI, and specific linear lesions set) is associated with a high rate of freedom from AF. Nevertheless, in these studies VOM-EI and RFCA were performed as different step of the same procedure. We hypothesize that performing electro-anatomical mapping (EAM) right after the VOM-EI would lead to an overestimation of ethanol-induced scar because of a certain amount of reversible oedema. This could affect the durability of the lesion set and possibly the success rate. Aim We postulated that VOM-EI performed at least 1 month earlier than RFCA would show a significantly smaller EAM low voltage area as compared to the standard strategy. Methods Patients with recurrent persistent AF with no history of previous ablation were enrolled in this randomized, dual centre, pilot study. All included patients were randomized 1:1 to group 1 (experimental): VOM-EI and after at least one month later high-definition (HD)-EAM and RFCA (PVI, MI, LA dome, cavo-tricuspid isthmus). group 2 (control): to a standard procedure (VOM-EI then 5 minute later HD-EAM and RFCA). Primary endpoint was ethanol induced HD-EAM scar area. According to the endpoint patients with unsuccessful VOM-EI were excluded. Moreover patiets with or no branches morphology, VOM dissection, and mechanical leakage were also excluded because these are demonstrated to be related to a smaller VOM-EI related lesion. Clinical and procedure related data were also collected. Results Forty consecutive patients met the inclusion criteria. The two groups did not differ for baseline characteristics (see table 1). Mean ethanol-induced HD-EAM scar area was significantly smaller in 20 patients where VOM-EI was performed at least 1 month earlier as compared to the standard procedure group (2,5±2,4 vs 11,2±9,5 cm2, p=0,018). The set of linear lesions was successful achieved in all patients. Notably the two group did not differ for any procedural technical aspect of mitral isthmus block (table 1). Neither VOM-EI nor AF ablation procedure related complications were recorded. Conclusion This is the fist randomized pilot study to demonstrate that a consistent amount of ethanol-induced related lesion could be reversible at least in its endocardial aspect of the left atrium. This would possibly affect the long-term stability of the lesion set. Notably, we still had a high rate of block at first mitral line attempt which could possibly be related to a persistent effect of VEOM-EI on the epicardial aspect of the left atrium. Larger population, randomized trial is needed to confirm this preliminary result and if it would affect the procedure success.Table 1Picture 1