Atrial Fibrillation Recurrence Research Articles

Utilizing cluster analysis of biomarkers alongside echocardiographic deformation parameters to forecast the outcome of atrial fibrillation post-ablation

Abstract Background Atrial fibrillation (AF) management often involves catheter ablation, but its recurrence necessitates careful clinical management and potential adjustments in medication or further ablation procedures. This study aims to investigate the predictive value of biomarkers and echocardiographic parameters for early AF recurrence. Methods In the prospective study, we enrolled patients with symptomatic paroxysmal or persistent atrial fibrillation undergoing catheter ablation. Pulmonary vein isolation was performed in every index procedure, with additional ablation or substrate modification as per physician preference. Blood samples were collected from both the atrium and peripheral vein to assess levels of tumor endothelial marker 1 (TEM1), galectin 3, connective tissue growth factor (CTGF), transforming growth factor-beta (TGF-β), C-terminal propeptide of procollagen type I (PICP), and Smad3. Pre-procedural echocardiographic parameters, including the E/e’ ratio, peak atrial longitudinal strain (PALS), and peak atrial contractile strain (PACS), were recorded. Clustering models with sparse canonical association analysis (CCA) were employed to develop predictive models integrating biomarker and echocardiographic data for early atrial fibrillation recurrence. Results Out of 80 prospectively enrolled patients, 68 completed the study, with six cases of early atrial fibrillation recurrence observed. Following dimension reduction and clustering, we found that the combined use of biomarkers and echocardiography significantly predicted atrial fibrillation recurrence (HR: 9.44, p=0.05, 95% CI: 1.0-88.9). Notably, among these parameters, TEM1 biomarker sampled from the peripheral vein (p=0.02), left atrium dimension (p=0.07), and left ventricle dimension (p=0.02) exhibited the most significant predictive power. Conclusions Our study highlights the effectiveness of integrating biomarkers and echocardiography parameters in predicting early recurrence of atrial fibrillation post-ablation in patients undergoing catheter ablation.main_figure

Effects of mineralocorticoid receptor antagonists on new-onset or recurrent atrial fibrillation: a Bayesian and frequentist network meta-analysis of randomized trials

Abstract Aims Clinical and translational research suggests that mineralocorticoid receptor antagonists (MRAs) may prevent atrial fibrosis and electrical remodeling associated with atrial fibrillation (AF). This study aimed to consolidate existing evidence from randomized controlled trials (RCTs) evaluating the effect of MRAs on incident or recurrent AF. Methods Medline, Cochrane Library and Scopus were searched until February 12, 2024. Triple-independent study selection, data extraction and quality assessment were performed. Evidence was pooled using both pairwise and Bayesian and frequentist network meta-analyses. Results Twenty-three RCTs (13,358 participants) were identified. Based on the pairwise random effects meta-analysis, MRAs were associated with a significant reduction in AF events compared to placebo or usual care (risk ratio {RR}= 0.75; 95% confidence interval {CI}= [0.66, 0.87]; P< 0.001; I2= 3%). This protective effect was robust both for new-onset and recurrent AF episodes (subgroup p-value= 0.69), while the baseline HF status was not a significant effect modifier (subgroup p-value= 0.58). MRAs demonstrated a significantly higher reduction in AF events for patients with chronic renal disease compared to placebo (RR= 0.78; 95% CI= [0.62, 0.98]; P= 0.03; I2= 0%). The network meta-analyses revealed that only spironolactone was associated with a significant reduction in AF events (Bayesian RR= 0.76; 95% CI= [0.65, 0.89]; P< 0.001; level of evidence moderate; SUCRA 0.731), while eplerenone and finerenone showed a neutral effect. Conclusion MRAs confer a significant benefit in terms of reducing incident or recurrent AF episodes, irrespective of HF status. In this context, spironolactone may be preferable compared to eplerenone or finerenone.

Weight change does not impact long-term outcomes following cryoballoon pulmonary vein isolation

Abstract Background Weight loss has been suggested to reduce frequency and burden of atrial fibrillation (AF) in overweight patients (pts). However, there are limited data on weight loss impact on outcomes in pts with AF who have undergone pulmonary vein isolation (PVI). Purpose To understand the impact of weight change on long-term outcomes, as assessed by freedom from recurrent AF in pts undergoing cryoballoon (CB) PVI. Methods We enrolled consecutive pts with AF who underwent CB PVI; all had implantable loop recorders (ILR) for long-term ECG monitoring. The cohort was divided into 4 groups based on weight change 1-year post ablation: (1) optimal weight loss (OWL) – weight decrease ≥ 10%; (2) minimal weight loss (MWL) - weight loss (WL) 3-9% weight decrease; (3) no weight change (NWC) - weight change < 3%, (4) weight gain (WG) ≥ 3% weight increase. We assessed for AF recurrence after excluding a 3-month post-ablation blanking period. Results Out of a total of 322 pts who underwent ablation, 241 (75%) pts (69 ± 10 years; 159 (66%) male; 133 (55%) PAF; CHA2DS2-VASc 2.7 ± 1.5; BMI 30 ± 5) had weight information available at ablation and last follow-up. All were off antiarrhythmics by 1 year. There were no differences in the 4 cohorts with respect to baseline characteristics. During the first year, about ¼ of pts were able to lose ≥ 3% of weight but only 8 pts (3%) were able to lose ≥ 10%. AF recurred in 153 (63%); they were older, more likely to have persistent AF (PeAF), and a higher CHA2DS2-VASc score. However, weight change did not impact outcome (Figure). In a multivariate Cox Regression hazards analysis, PAF vs. PeAF at ablation was the only factor associated with any recurrence at follow-up (Figure). Conclusions Post CB PVI only about ¼ of pts are able to lose weight. Weight changes in the first-year post ablation in obese pts did not alter outcomes with respect to likelihood of recurrent AF. These data should be taken into account when considering catheter ablation.

Clinical findings from a large endo-epicardial atrial arrhythmia ablation registry

Abstract Background Despite advances, catheter ablation success rates for persistent AF remain at 50-60%. The approach for recurrent persistent AF, beyond pulmonary vein isolation, remains contentious. Surgical maze procedures have demonstrated superior outcomes compared to catheter ablation. Catheter-based linear lesions sets have failed to demonstrate efficacy, perhaps due to a lack of consistent transmurality with endocardial radiofrequency. Objective We report our safety and clinical data of an endo-epicardial approach using high-power radiofrequency ablation for atrial arrhythmias. Methods 126 patients (80% male; mean age 65 years [43-81]) underwent redo ablation, between August 2020 and February 2024, for recurrent symptomatic atrial arrhythmias using an endo-epicardial approach. We used a standardised linear lesion set (posterior wall isolation and anterior mitral line) for recurrent persistent AF. Results Utilising an intentional coronary sinus exit and C02 insufflation technique, we achieved epicardial access in 121 anti-coagulated patients. 5 patients were found to have pericardial adhesions, prohibiting access. There were 2 LIMA punctures which were coiled, 2 cases of excess pericardial bleeding (not access related), that settled conservatively, and no surgery or death. 92% of patients received epicardial ablation. 86 anterior mitral lines (95% acute block, 79% with epi ablation), 88 roof lines (92% blocked, 50% with epi ablation) and 81 floor lines (98% blocked, 36% with epi ablation) were undertaken. 106 posterior wall isolations were performed (94% isolated, 51% epi ablation). 75 patients had a standardised lesion set and were included for recurrence analysis. 49 had persistent AF (71% male, mean age 65 years, mean LAVI 38 ml/m2, 26 PVI at baseline and 23 PV reconnections) and 26 longstanding persistent AF (92% male, median age 64 years, mean LAVI 37.1 mls/m2, 16 PVI at baseline and 10 PV reconnections). 82% with persistent AF (median follow up time 11 months) and 38% with longstanding persistent AF (median follow up time 10.1 months) maintained sinus rhythm. The submitted image demonstrates the freedom from persistent AF, for the cohort who are beyond the 3-month blanking period, as per classification of atrial arrhythmia. Conclusion In one the largest cohorts to date, we have shown that endo-epicardial atrial ablation is feasible and safe with epicardial ablation allowing improved transmurality and thus acute linear block. Clinical outcomes, using a posterior wall isolation and anterior mitral line, were favourable for persistent but not longstanding persistent AF.

Severity of anemia is correlated with the prevalence of left atrial low-voltage areas in patients with atrial fibrillation ablation

Abstract Background Although left atrial low-voltage areas (LVAs) are well-known indicator of atrial fibrosis and atrial fibrillation (AF) recurrence after catheter ablation, the association between anemia and prevalence of LVAs has not been clarified. We hypothesized that LVAs were more frequently found in patients with anemia than in those with normal hemoglobin levels. Purpose The purpose of this study was to investigate the association between hemoglobin levels and the prevalence of LVAs in patients with AF ablation. Methods In total, 1,473 (age, 68±10 years; female, 492 [33%]; persistent AF, 895 [61%]; CHA2DS2-VASc score, 2.5±1.5 points) consecutive patients who underwent initial AF ablation were enrolled in this study. Hemoglobin levels were measured before the ablation procedure, and anemia was defined as hemoglobin levels < 13.5 g/dL in male and < 12.0 g/dL in female. LVAs was defined as areas with bipolar voltage of <0.5 mV covered ≥5 cm² of left atrial surface area. Results Of 1,473 patients, LVAs existed in 348 (24%) patients. Hemoglobin levels was significantly lower in patients with LVAs than those without (13.4 ± 1.7 vs. 14.2 ± 1.5 g/dL, p <0.001). On classification by gender, only in male, hemoglobin levels were significantly lower in patients with LVAs than those without (Figure 1). The prevalence of LVAs increased with decreasing hemoglobin levels (Figure 2). On multivariate analysis including gender as a variable, anemia was an independent predictor of LVAs (odds ratio, 1.6; 95% confidence interval: 1.1–2.3; p=0.03). Conclusions The prevalence of LVAs increased with decreasing hemoglobin levels in patients with AF ablation. In particular, hemoglobin levels < 13.5 g/dL in male and < 12.0 g/dL in female was an independent predictor of LVA presence.Hemoglobin levels and LVAs presenceHemoglobin and the prevalence of LVAs

Long-term prognosis in patients undergoing atrial fibrillation ablation

Abstract Aims The aim of the analysis was to assess the risk of atrial fibrillation (AF) recurrence in the long-term observation of contemporary patients undergoing pulmonary vein isolation (PVI), who did not have recurrence during the first year after catheter ablation. Methods Retrospective analysis has been performed. Inclusion criteria: (1) the patients undergoing their first PVI in years 2017–2022, (2) the electroanatomical system, contact force catheters and lesion indexes (Ablation Index or Lesion Size Index) were used, (3) no recurrences were observed during the first 12 months of follow-up, and (4) follow-up longer than 12 months was available. Demographic, clinical and echocardiographic data were collected. Follow-up was based on ambulatory visits with ECG/holter monitoring or implanted device interrogation, when available. Results A total of 247 patients were included. The median follow-up was 22 months (interquartile range, 16–31 months). After 24 months, ablation efficacy was 84%, and after 36 months, it was 72%. In the univariate Cox regression analysis, age, previous electrical cardioversion, glomerular filtration rate (eGFR) and the presence of coronary artery disease were linked to AF-free survival. Interestingly, nonparoxysmal AF, left atrial (LA) dimension, heart failure, hypertension or diabetes were not linked to the risk of long-term recurrences. In multivariate Cox regression analysis, presence of coronary artery disease and previous electrical cardioversion were independently linked to the risk of long-term recurrence. In 127 (51.4%) patients, information about the presence of low voltage areas (LVA) was available, and in 21 (16.5%) patients in this group, the presence of LVA was found. Survival of patients with LVA was strikingly worse than that of those without (Figure 1), log-rank test p <0.0001. Conclusions Patients who had no recurrences within one year after PVI, still have substantial risk of recurrence in the next 2 years. That concerns specially the patients who had LVA in the electroanatomical mapping.

Timing of early recurrence of atrial fibrillation during the blanking period after catheter ablation for persistent atrial fibrillation and implications for long-term success: a multicentre study

Abstract Background After catheter ablation (CA) for atrial fibrillation (AF), early recurrences of AF (ERAF) that occur within a 90-day post-ablation "blanking period" are considered to represent transient post-ablation pro-arrhythmia. Purpose To determine if the timing of early recurrence of AF during the traditional 90-day post-CA blanking period is associated with long-term AF recurrence after CA for persistent AF (PsAF). Methods We performed a multicentre retrospective study of patients undergoing first-time CA for PsAF between 2015-2018. All patients had undergone pre-CA DCCV. Incidences of ERAF during the post-CA blanking period were reviewed, and patients were categorised into three groups based on the timing of last episode of ERAF during the blanking period: (1) no ERAF (reference population); (2) last ERAF <30 days post-CA; (3) last ERAF 31-90 days post-CA. The primary outcome was long-term recurrence of atrial arrhythmia, i.e. time to first recurrence of atrial arrhythmia occurring beyond the first 90 days after CA. Patients who had ERAF and exited the blanking period in AF (i.e. those with immediate recurrence at 90 days) were excluded from this analysis. Results 331 patients were identified from five centres. 206 patients had no ERAF during follow-up, 124 patients had ERAF during the blanking period, and in one patient the presence of ERAF was not documented. Of the 124 patients experiencing ERAF during the 90-day post-CA blanking period, the timing of the last episode was known in 122 patients (Table 1). Of these, 58 patients exited the 90-day blanking period in AF and were excluded. Over median post-CA follow-up of 590 days, 147 patients (54%) experienced the primary outcome. Compared with Group 1 (no ERAF), ERAF within each of the time periods was associated with a statistically significant progressively increased risk of long-term recurrence (Group 2, last ERAF <30 days post-CA: hazard ratio [HR] 1.95 [95% CI 1.15-3.31]; Group 3, last ERAF 31-90 days post-CA: HR 4.86 [95% CI 2.13-11.08]; Figure 1). Conclusion ERAF during the traditional 90-day post-CA blanking period is associated with long-term AF recurrence, with later recurrence within the 90-day period conferring greater risk. Patients with ERAF during the blanking period may need to be considered for earlier repeat intervention where clinically appropriate.

Comparison of continuity index for drag versus point-by-point ablation with the use of proactive esophageal cooling

Abstract Background Proactive esophageal cooling was recently FDA cleared to reduce the likelihood of esophageal injury during radiofrequency (RF) ablation for treatment of atrial fibrillation (AF). Long-term follow-up data have also shown improved freedom from arrhythmia with proactive esophageal cooling compared to luminal esophageal temperature (LET) monitoring during pulmonary vein isolation (PVI). One hypothesized mechanism is the greater lesion continuity attainable with the use of cooling, which can be quantified by the Continuity Index (which increases as continuity decreases). Increasing the Continuity Index increases gap formation, reduces isolation, and leads to greater AF recurrence; however, the difference in Continuity Index between ablating in a point-by-point fashion versus a dragging fashion has not previously been analyzed. Purpose To prospectively measure the Continuity Index of PVI cases and compare the dragging technique to point-by-point technique when using proactive esophageal cooling or LET monitoring. Methods We determined the Continuity Index for 101 patients: 77 prospectively utilizing proactive esophageal cooling, 24 retrospectively recorded using LET monitoring. Cases were completed by four operators, three utilizing point-by-point technique, and one using the drag technique. The Continuity Index was calculated by incrementing one unit for each lesion that did not border the previous lesion during the PVI (simplifying the original description of the Continuity Index). Results For cases using esophageal cooling and performing RF ablation using the drag technique, the average Continuity Index was 8.5 (range: 1 to 14). For point-by-point operators using esophageal cooling, the average Continuity Index was 1.2 (range: 0 to 9), representing a difference of 7.3 between the dragging technique and point-by-point ablation (p < .001). Patients receiving LET monitoring and RF ablation using the drag technique had Continuity Indices of 23.8 (range 15 to 30). Patients receiving LET monitoring and RF ablation using point-by-point ablation had Continuity Indices of 28.4 (range 16 to 50). Figure 1 compares these findings. Only 4 patients (5%) in the esophageal cooling group had a Continuity Index above 6 on either side (all in the dragging group), versus 100% (24) of patients in the LET monitoring group. Conclusion Proactive esophageal cooling during PVI is associated with a high degree of lesion continuity, as represented by the low Continuity Index. The drag technique resulted in a higher index than the point-by-point technique, but both provided significantly lower Continuity Indices (greater lesion continuity) than cases using LET monitoring. This may offer a mechanism for the greater freedom from arrhythmia seen to date with proactive cooling in long-term follow-up.Figure 1.Comparison of Continuity Index

Impact of paroxysmal atrial fibrillation ablation on cardiac sympathetic nervous system: a prospective stratified randomized comparative study in patients with and without heart failure

Abstract Background Catheter ablation of atrial fibrillation (AF) might influence the cardiac sympathetic nervous system (CSNS). We sought to investigate the impact of AF ablation with 2nd generation cryoballoon catheter (CB) and contact force sensing radiofrequency ablation catheter (RF) on CSNS and the association of this effect with early AF recurrence in patients with and without heart failure (HF), using cardiac iodine-123-metaiodobenzylguanidine (MIBG) scintigraphy. Methods and Results One hundred sixty-five paroxysmal AF patients who were scheduled for ablation were enrolled. All patients were categorized into two groups: one with HF (n=31), defined as left ventricular ejection fraction ≤ 40% or previous history of hospitalization for worsening HF, and the other without HF (n=134). They were then randomly assigned to CB (17 patients with HF and 68 without HF) or RF (14 with HF and 66 without HF). MIBG scintigraphy was performed at baseline and 3 months post-ablation and the washout rate (WR) was measured. There were no significant changes in WR from baseline to 3 months after RF and CB ablation (28.7±18.6% to 27.9±16.7% in RF and 29.4±16.7% to 30.5±16.4% in CB). WR decreased more in patients with HF at 3 months after ablation than without HF, while WR significantly increased in patients without HF and there was a significant interaction in WR change between with or without HF (interaction p<0.001). WR change from the baseline to 3 months after ablation (dWR) was not significantly different between CB and RF, irrespectively of the HF presence. In the blanking period of 3 months after ablation, early AF recurrence (EAR) was observed in 37 (22%) patients with no antiarrhythmic drugs (17(21%) patients in RF and 20(24%) in CB). dWR was significantly greater in patients with than without EAR (4.0±14.1% vs -0.9±11.0%, p=0.027). Higher dWR (≥ 6.9% (AUC 0.644, 95%CI [0.535-0.753]) by ROC curve analysis) was independently associated with EAR (adjusted odds ratio = 4.15, 95%CI [1.87-9.22], p<0.001, adjusted for age, sex, and left atrial diameter). Conclusions Irrespectively of CB and RF, AF ablation might reduce adrenergic tone in patients with HF, while it might induce more adrenergic tone in patients without HF. Excessive adrenergic tone might be associated with early AF recurrence.WR changes before and after ablationdWR in patients with or without HF

Verification of intra- and inter-atrial conduction during Bachmann's bundle pacing using longitudinal bi-atrial strain

Abstract Introduction Although atrial septal pacing has been reported to reduce atrial fibrillation (AF) burden, there is less evidence regarding its effect on the prevention of permanent AF and the improvement of long-term clinical outcomes. However, Bachmann's bundle pacing (BBp), which features P-wave morphology similar to sinus rhythm and shortened P-wave duration (PWD), was reported to significantly reduce permanent AF recurrences and occurrences compared with right atrial appendage pacing (RAAp) and non-specific right septal pacing. Purpose Possible mechanisms for AF suppression with BBp are that fast inter-atrial conduction through BB decreases global atrial activation time and the dispersion of the overall atrial refractoriness, and it prevents the decrease in left ventricular filling and increase in left atrial pressure associated with delayed left atrial contraction. Intra-and inter-atrial conduction during BBp was evaluated using longitudinal bi-atrial strain. Methods In patients with successful BBp implantation defined by electrocardiographic criteria using SelectSecure pacing lead and C315 delivery catheter (Medtronic, Inc), both left atrium (LA) and right atrium (RA) global longitudinal strain (GLS) in simultaneous phases were measured using Philips Ultrasound Workspace 2D Strain in apical 4-chamber view during atrial pacing to assess intra- and inter-atrial conduction delay. The atrial GLS were measured semi-automatically, and the strain rate was analyzed in the three segments of septal wall, lateral wall, and roof and their average. The negative peak of strain rate during atrial systole was the starting point of atrial contraction, and time to peak (TTP) was measured. The difference in TTP between septal and lateral walls in each atrium was measured as intra-atrial conduction delay and the difference in average TTP between LA and RA as inter-atrial conduction delay. Results Ten patients who underwent successful BBp were enrolled (Sick sinus syndrome: 3, advanced atrioventricular block: 2, complete atrioventricular block: 5). At implantation, bipolar atrial electrogram amplitude was 2.03±0.93 mV, atrial lead impedance was 632.7±157.6 Ω, and atrial pacing threshold was 0.7±0.2 V at 0.4 ms. The PWD during sinus rhythm on the 12-lead ECG was 132.8±10.6 ms, while during BBp it was 108.0±11.9 ms, which was significantly shorter in the BBp group (p<0.001). The intra-atrial conduction delay in RA and LA was 10.9 ± 12.1 ms and 12.1 ± 17.3 ms, respectively, and the inter-atrial conduction delay was 6.6 ± 8.6 ms. On the other hand, for the 10 RAAp and 10 sinus rhythm patients as control groups, the inter-atrial conduction delay was 29.7±13.8 ms and 8.5±9.5 ms, respectively. BBp had significantly less inter-atrial conduction delay than RAAp (p=0.005) and was comparable to sinus rhythm (p=0.719). Conclusion Longitudinal bi-atrial strain suggested that BBp significantly reduced inter-atrial delay and it might be effective in AF suppression.Longitudinal bi-atrial strain

Long-term efficacy and safety of ablation for atrial fibrillation in patients with hypertrophic cardiomyopathy

Abstract Background Hypertrophic cardiomyopathy (HCM) is often accompanied by atrial fibrillation (AF) but data on safety and long-term outcomes after catheter ablation for AF in HCM are scarce. Purpose To investigate safety, long-term efficacy and clinical outcomes following AF ablation in patients with HCM and in matched controls. Methods Patients with HCM (n=76) undergoing a first catheter ablation for AF or atrial flutter between 1999 and 2022 at a University Hospital in Sweden were included (age 64±12 years, 43% female). Diagnosis of HCM was based on the European Society of Cardiology definition (left ventricular wall thickness ≥15 mm or ≥13 mm not solely explained by abnormal loading conditions, and combined with family history, genetic components and/or electrocardiogram abnormalities). Patients with HCM were matched with controls (n=152) based on age, gender, ablation type and intervention-year. Patients were followed for a mean of 5 years and study endpoints included heart failure hospitalization (HFH), stroke and mortality. Cox regression analyses were performed for the association between HCM and the endpoints. Results Among the overall population, 121 (53%) underwent pulmonary vein isolation (PVI), 62 (27%) isthmus ablation and 45 (20%) His-Bundle ablation. Patients with HCM had a shorter mean duration of AF before ablation (48 months vs. 66 months; p=0.047) and more severe symptoms as indicated by a higher EHRA class (EHRA class IV: 30% vs. 10%; p<0.01). Procedural success rate of PVI and isthmus ablation was lower in patients with versus without HCM (88% vs. 97%; p=0.02). Procedure related complications (vascular complications, tamponade) were overall similar in both groups (9% in HCM vs. 5% in controls, p=0.17) except for higher rates of pulmonary oedema in patients with HCM (7% vs 1%, p=0.03). There was a nearly two-fold increase in risk of AF recurrence after PVI or isthmus ablation in patients with HCM compared to controls (OR 1.95; 95% CI 1.06-3.58; p=0.03). During follow-up, patients with HCM had an increased risk of HFH (HR 2.55, 95% CI 1.21-5.36, p=0.01) but not of stroke or mortality (Figure 1). Conclusion AF ablation was overall safe in patients with HCM but less effective. Patients with HCM had an increased risk of the individual endpoint of HFH after AF ablation but not stroke or mortality during long-term follow-up.

Prediction of atrial fibrillation recurrence after ablation: the impact of machine learning and recurrence during the blanking period

Abstract Introduction Pulmonary vein isolation is superior to antiarrhythmic drugs for rhythm control in patients with atrial fibrillation (AF). Nevertheless, recurrences within the first year are still significant. Several clinical risk scores were developed to predict AF recurrence; however, despite good results in development cohorts, the results in external validation are usually poor, limiting the general applicability of these scores. Purpose We aimed to develop machine learning (ML) models to predict AF recurrences within the first year after catheter ablation and compare their performance with conventional risk scores. Methods We used a retrospective dataset of a tertiary hospital center, including all consecutive patients submitted to the first AF ablation between 2017 and 2021. The dataset included 76 features: patient characteristics, medical history, baseline echocardiography, calcium score, procedure variables, and early recurrence (ER) during the 90-day blanking period. The outcome was defined as the occurrence of an electrocardiographically documented late recurrence (LR) of atrial tachycardia/AF > 30s between 3-12 months. Three different supervised ML models (penalized logistic regression, random forests, and XGBoost) were developed on the training cohort, and hyperparameters were tuned using 10-fold cross-validation. A testing dataset was held out to estimate the final performance (25%). The following risk scores were calculated: APPLE, CAAP-AF, and BASE-AF2 (the last includes ER). Areas under the curve (AUC) of receiver operating characteristic curves were compared using DeLong’s test. Results 679 patients were included: 62.7% males, median age of 59±16 years, and 78.2% with paroxysmal AF. The median time from diagnosis to ablation was 2±4 years. 74.2% underwent radiofrequency ablation and the remaining cryoablation. ER occurred in 12.5%, and most of these patients also experienced LR (68.7 vs 19.6% in those without ER, p<0.001). LR was observed in 25.6%. The XGBoost model showed the best performance with an AUC 0.774, 95% confidence interval (CI) 0.688–0.844) outperforming existing scores (picture 1): APPLE score AUC 0.607, 95% CI 0.562–0.653, p-value<0.001; CAAP-AF score AUC 0.622, 95% CI 0.576–0.668, p-value=0.002; BASE-AF2 AUC 0.628, 95% CI 0.581–0.675, p-value= 0.003. Variable importance analysis showed a significant drop in the performance of the models when ER was not considered, indicating its high importance in predicting LR (picture 2). Conclusions Recurrence during the blanking period was the most important predictor of LR in our population. The ML model was superior to conventional risk scores. ML models might be an essential tool to improve the prediction of outcomes and clinical decision-making for optimal follow-up.ROC curvesFeature Importance

A nurse-led intervention improves quality of life and reduces arrhythmic recurrences in patients undergoing atrial fibrillation ablation. Results of the NURSECAT-AF randomized clinical trial

Abstract Background/Introduction Atrial fibrillation (AF) is a prevalent condition that can lead to a decrease in quality of life and frequent re-hospitalizations. Some data suggest that integrated care nurse-led may blunt these consequences in unselected patients with AF, but not all studies support this. While AF ablation is becoming a cornerstone treatment for symptomatic patients with AF, it is unclear what impact a nurse-led intervention would have on these, quite likely, more receptive patients. Purpose To assess the impact of nurse-led intervention on quality of life among AF patients undergoing ablation. Methods We conducted a single-centre prospective randomised clinical trial to test the effect of an expert nurse-based intervention consisting of an educational programme on AF, support for the patient undergoing cardiac ablation to ensure its success, and management of risk factors associated with this arrhythmia. The control group underwent standard medical follow-up. Patient selection was based on chronological order. Only patients who underwent their first ablation and did not have heart failure were included. The primary endpoint was quality of life at 12 months post-ablation using the Arrhythmia-Specific Scale in Tachycardia and Arrhythmia (ASTA) questionnaire (higher values denote impaired quality of life). Secondary endpoints were AF knowledge and satisfaction at 15 days post-ablation using validated instruments, symptoms using the ASTA questionnaire as well, and readmissions rates, emergency room visits, and AF recurrence rates over a one-year period. Results 116 patients were screened (50 were excluded mostly because were re do). A total of 66 patients were eventually included and randomized (33 per arm; mean age [mean±SD] 63±10 years; 44 men [67%]). At 12 months, quality of life was significantly better in the intervention group than in the control group (4.5 ± 6.1 vs 0.57 ± 2.3, respectively, p=0.001)(Figure). Furthermore, satisfaction levels (17 ± 4.1 vs 12.7 ± 5.4, p>0.001) and disease knowledge (20.5 ± 5.1 vs 15.9 ± 4.5, p<0.001) were higher in the intervention group. Patients in the control group experienced a higher symptom burden during the first year (0.6 ± 1.5 vs 3.8 ± 4.5, p<0.001. Relevant clinical endpoints such as readmissions (3% vs 18.2%, p=0.046), emergency room visits (21.2% vs 57.5%, p=0.021), and arrhythmia recurrences (15.2% vs 45.5%, p=0.02) were all significantly lower in the intervention group. Conclusion(s) Nurse-led integrated care for patients undergoing AF ablation yields substantial improvements in quality of life and symptomatic relief at one year post-procedure. Additionally, it enhances patient knowledge of AF and satisfaction levels, and reduces readmissions, emergency room visits, and arrhythmia recurrences.

Long-term patient clinical benefits and healthcare utilization after pulsed field ablation in paroxysmal atrial fibrillation: sub-analyses from the multicenter inspIRE trial

Abstract Background/Introduction The treatment of atrial fibrillation (AF) with pulsed field ablation (PFA) aims to prevent AF recurrence while reducing complications from the ablation modality. Similar to thermal ablation, PFA has proven to be safe and effective for treatment of paroxysmal AF (PAF); however, there is scarce evidence on patient-related clinical benefits, including healthcare utilization, using this new energy modality. Purpose The objective of this study is to assess long-term clinical improvements in patient care, symptoms, and quality-of-life (QOL) after PFA ablation in PAF. Methods InspIRE was a multicentre study evaluating the safety and efficacy of variable loop PFA catheters integrated with a 3D mapping system for treatment of symptomatic PAF. Patients were followed for up to 12 months for the following QOL and healthcare utilization endpoints: Atrial Fibrillation Effect on Quality-of-Life (AFEQT) score, Class I/III AAD utilization, repeat ablation, incidence of direct current cardioversion (DCCV), and cardiovascular (CV) hospitalization. Post-hoc Kaplan-Meier estimates for clinical benefit success at 12 months were provided. Success was defined as composite freedom from occurrence of the following events post-blanking: repeat ablation, CV hospitalization, AAD utilization, and DCCV post-blanking. Predictors of clinical benefit success were explored via multivariate logistic regression analysis. Results A total of 186 enrolled patients (59±10 years; 70.0% male; CHA2DS2-VASC score 1.3±1.2) underwent PVI. Compared to baseline: 1) improvements in the AFEQT composite score were seen at 12 months (P<0.001); 2) Class I/III AAD use was reduced from 81.7% to 20.1% at 6-12 months (P<0.05); and 3) the proportion of subjects with DCCV decreased from 13.7% up to 12 months before the index procedure to 3.3% up to 12 months after the index procedure (P<0.001, Figure 1). Minimal clinically important difference in QoL (≥5 points improvement in AFEQT) was achieved in 85.2% of patients. Patients free from 12-month AF/AT/AFL recurrence (asymptomatic and symptomatic) had significantly greater improvements in AFEQT scores from baseline to 12 months versus those with recurrence (P=0.01). The clinical benefit success rate at 12 months was 87.5% (Figure 2). Patients who failed the clinical benefit endpoint were counted, including those with repeat ablation (7.5%), those on new or higher dose of AAD (6.5%), those hospitalized for CV (4.8%), and those who had DCCV post-blanking (1.6%). Multivariate logistic regression analysis showed that left ventricle ejection fraction <60% (OR: 0.22; 95% CI: 0.08-0.62; P<0.05) and incidence of diabetes (OR: 7.25; 95% CI: 2.00, 26.3; p<0.05) were associated with a higher risk of clinical benefit failure. Conclusions PFA ablation of PAF patients led to a clinical benefit success rate of 87.5%, with clinically meaningful improvement in QOL, as well as a reductions in AAD use, cardioversion, and hospitalization.Figure 1.Improvements in QoL and HealthFigure 2.Kaplan-Meier Analysis of Time

A multi-center retrospective cohort analysis of age and racial disparities in patients undergoing repeat ablation for recurrent atrial fibrillation

Abstract Introduction Atrial fibrillation (AF) is the most common type of cardiac arrhythmia, and its prevalence has been increasing worldwide. Current data shows that AF is more common in white males compared to blacks despite blacks having multiple cardiovascular comorbidities. There is paucity of data showing the recurrence of AF re-ablation after index ablation specifically as it pertains to race, gender, and age. We sought to explore the rates of recurrent AF re-ablation in this retrospective cohort analysis. Methods Using a multi-center database, we examined 23,558 encounters and 10,530 had readmission records i.e. readmitted within 3 years. The encounters included adults (18+) who had an ablation procedure for atrial fibrillation between 1/1/2018-06/30/2020. We used binary logistic regression models and Tukey-Kramer procedure to analyze pairwise comparisons among different subgroups of race, sex, and age group. The primary endpoint was recurrence of repeat ablation. Secondary endpoints included non-fatal stroke and myocardial infarction. Results Our sample size was 23,558 patients, 20,276 were white patients (86%) and 3,282 were non-white patients (14%). The average age was 66.29 years (SD 10.43) and average age at the time of repeat ablation was 65.97 years. The average BMI was 21.55. Out of the 23,558 patients, 14.30% (N= 3368) had re-ablation within 3 years of the index ablation. The odds ratio of re-ablation for patients in their 50s is 1.4229 (95% CI [1.1172, 1.8122]) compared to patients in their 80s. Similarly, the odds ratio is 1.4330 (95% CI [1.1466, 1.7909]) for the 60-69 group, 1.3075 (95%CI [1.0458, 1.6346]) for the 70-79 group and 1.3443 (95% CI [1.0088, 1.7914]) for patients below 50 compared to over 80 group. The LR for re-ablation was 0.8438 (p=0.3583) in females. The incidence of non-fatal stroke and MI were 0.27% (N= 63) and 0.19% (N= 45). Average length of time to re-ablation was 415.5 days. Discussion When controlling for age group and sex, race was not significantly associated with an increased likelihood of repeat ablation. When controlling for race and age group, sex was not significantly associated with an increased likelihood of repeat ablation. When controlling for race only, females were not at a higher risk of re-ablation. However, when controlling for race and sex, patients in their 50s are 42.3% more likely to have re-ablation when compared to patients in their 80s. In contrast, the age of patients at their first ablation increased, there appeared to be a rising trend indicating a higher chance of AF recurrence within 3 years when controlling for race and sex. Conclusion The incidence of repeat AF ablation is not higher in racial minorities when compared to whites. Interestingly, there appears to be an decreasing rate of AF re-ablation in older patients despite a higher rate of AF recurrence as age increases possibly owing to more conservative therapeutic approach such as medical management.

Ppulsed field ablation and ultra-high-density mapping for PVI: use of machine learning and data augmentation to guide procedure and identify recurrent tachycardia mechanisms at one-year follow-up

Abstract Background In managing atrial fibrillation (AF), radiofrequency and cryoablation have been cornerstone techniques for achieving pulmonary vein isolation (PVI). Recently, pulsed-field ablation (PFA) has introduced a novel method for PVI. There remains a gap in knowledge regarding the permanent efficacy of ablation, related explicitly to acute lesion characteristics following PVI. Purpose Our study delves into an in-depth examination of acute lesion characteristics following PFA-PVI through ultra-high-density mapping (UHDM). We aim to identify specific clinical, anatomical, and periprocedural lesion features independently related to 1) intraoperative identification of UHDM non-isolated gaps with electrical conduction after first isolation and 2) three months follow-up recurrency of specific arrhythmias. Methods Results The present study includes 204 patients submitted to PFA-PVI for AF. UHDM guided all procedures to identify non-isolated gaps with electrical conduction. Perioperative and 3-month follow-up data were collected prospectively and analyzed. To build our prediction model, avoiding biases related to the unbalanced nature of the data, data augmentation was performed with SMOTE (Synthetic Minority Over-sampling Technique). Two machine learning (ML) models have been built, using logistic regression as learner, to predict the presence of isolation gaps identified by UHDM and follow-up recurrence of arrhythmias. A 20-fold cross-validation has been performed to train and test the models. The non-isolated gap was detected and immediately corrected in 14 (6.9%) patients and was present more often in patients with larger left atria (LA) (p<0.0001) and those with persistent AF (p=0.02). The ML model achieved an AUC of 0.88 in the prediction of the non-isolated gap after PFA (Precision: 0.65; Sens.: 0.90; F1: 0.76; Spec.: 0.83; NPV: 0.96). At three months follow-up, no patient experienced recurrent AF; recurrent roof-dependent atrial tachycardia was present in 10 (4.9%). Patients with recurrent atrial tachycardia had a significantly narrower remaining atrial-roof conduction bridge (p=0.01) identified intra-procedurally by UHDM, significantly larger LA (p=0.03), and non-significant trend for older age (p=0.07). The ML model achieved an AUC of 0.86, predicting recurrent tachycardia after PFA (Precision: 0.63; Sens.: 0.86; F1: 0.72; Spec.: 0.82; NPV: 0.94). Conclusions Consistent use of UHDM can help identify non-isolated gaps with electrical conduction that may occur even after PVI with updated technologies, such as PFA. Non-isolated gaps should be expected, particularly in patients with larger LA, where UHDM could be of particular use. Moreover, UHDM can help predict the eventual recurrence of arrhythmias. Again, LA size plays an essential role in such recurrencies, together with the size of the remaining conducting tissue "bridges" within the LA roof, measure by UHDM.

Early repeat catheter ablation in patients with early recurrent arrhythmia

Abstract Background Repeat catheter ablation reduces adverse cardiovascular endpoints in patients with recurrent atrial tachyarrhythmia after index ablation. However, when to proceed with re-ablation in patients with early recurrent arrhythmia is unknow. Objective In this study, we aim to access the effectiveness of early repeat ablation on cardiovascular outcomes in early recurrent atrial tachycardia patients. Methods A total of 502 post-ablation patients, who experienced early atrial tachyarrhythmia recurrence within 6 months outside the blank period post index ablation and had undergone a repeat ablation, were consecutively enrolled from China AF registry from January 2012 to December 2018. Early repeated ablation (ERA) was defined as patients underwent a subsequent catheter ablation procedure within early recurrent period, then late repeated ablation (LRA) referred to a redo procedure that performed after 6 months since the de novel ablation. Cox proportional hazard models were used to estimate the effect of early re-ablation on primary endpoint (a composite of cardiovascular death, stroke and cardiovascular rehospitalization) and secondary endpoint (each component of primary outcome and AF/AT recurrence). Results The median follow-up time was 26 months after the redo-AF/AT ablation. First primary composite outcome occurred in 39 of the patients received early re-ablation (24.38 per 100 person-years) and in 136 of the patients performed with late re-ablation (39.77 per 100 person-years) (HR = 0.55, 95% CI = 0.38-0.79; P0.001). Cardiovascular re-hospitalization (hazard ratio 0.52 95% confidence interval [0.36; 0.73]) and AF recurrence occurred less often (hazard ratio 0.76, 95% confidence interval [0.58; 0.98]) in the ERA group. No significant difference between the two groups was found in terms of cardiovascular death, stroke and major bleeding events. Conclusion Early initiation of redo-ablation conveys better clinical benefit in patients with early arrhythmia recurrence.

Catheter ablation vs medical management for atrial fibrillation in patients with heart failure: a systematic review and metanalysis

Abstract Background Current guidelines recommend a class IIa recommendation for catheter ablation in Atrial Fibrillation [AFIB]. Traditionally, catheter ablation has been known to be more effective in maintaining sinus rhythm than pharmacological management. However, there is sparse evidence to suggest that this translates to improved clinical outcomes in patients with heart failure. We did a systematic review and meta-analysis of randomized trials to compare the efficacy of ablation vs medical management for AFIB in heart failure. Methods A systematic search was conducted for randomized trials from inception to Jan 2024 for studies comparing the outcomes of catheter ablation vs medical management for AFIB in heart failure. The primary outcome was all-cause mortality. Secondary outcomes were cardiovascular (CV) mortality, heart failure hospitalizations, change in LV ejection fraction (LVEF), AF recurrence rate, 6-minute walk test (6MWT), change in MLHFQ scores and cerebrovascular events. Random-effects models were used to calculate the pooled incidence, mean difference (MD), and risk ratios (RRs) with 95% confidence intervals (CIs). Results A total of 10 RCTs with 2,348 patients were included in this study. Pulmonary vein isolation was the mainstay ablation strategy used. Compared with medical management, Ablation was associated with a significant reduction in all-cause mortality (RR- 0.61; 95% CI, 0.48-0.78; P<0.0001). Ablation was also associated with lower cardiovascular (CV) mortality (RR- 0.52; 95% CI, 0.36-0.75; P<0.0004), heart failure hospitalizations (RR- 0.67; 95% CI, 0.54-0.82; P<0.0001) and AF recurrence rate (RR- 0.43; 95% CI, 0.25-0.75; P<0.003). The study showed an improvement in LVEF (RR - 6.05; 95% CI, 3.35-8.75; P<0.0001), 6MWT (RR- 13.99; 95% CI, 4.18-23.81; P<0.005) and in MLHFQ score (RR -6.98; 95% CI, -12.03 to -1.93; P<0.007. There was a statistically significant difference between the 2 cohorts in the rates of cerebrovascular events (RR- 0.68; 95% CI, 0.35-1.30; P<0.24). Conclusion Randomized trials have shown clear benefits with catheter ablation compared to medical management for AFIB in heart failure. Ablation has demonstrated significantly lower all-cause mortality, reduced CV mortality, HF hospitalizations, AFIB recurrence rate, and improvement in LVEF. Patients who underwent catheter ablation showed improvement in functional outcomes like 6MWT and MLHFQ scores. There was no difference in the incidence of cerebrovascular events compared to medical management. This study adds to the growing evidence in the literature for ablation therapy; however, more trials are needed to identify patients for optimal benefits across the spectrum of heart failure patients.Forest PlotsForest Plots

A meta-analysis of the safety and efficacy of pulsed-field versus conventional thermal ablation for atrial fibrillation

Abstract Background Since pulsed-field ablation (PFA) specifically targets myocardial tissue, it has become a cutting-edge substitute for radiofrequency (RF) and cryoablation. Purpose We aim to compare the safety and efficacy of PFA vs thermal ablation for AF ablation. Methods We conducted a systematic review and meta-analysis synthesizing randomized controlled trials (RCTs) and observational comparative studies, which were retrieved by systematically searching: PubMed, EMBASE, Web of Science, SCOPUS, and Cochrane through September 2023. RevMan version 5.4 software was used to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD) with a 95% confidence interval (CI). Results Seventeen studies with a total of 2,255 patients were included. PFA was significantly associated with a decreased AF recurrence (RR: 0.65, 95% CI [0.51, 0.84], P= 0.0010) but not any arrhythmia recurrence (RR: 0.87, 95% CI [0.69, 1.09], P= 0.22). Also, PFA was significantly associated with decreased total procedure time (MD: -15.15, 95% CI [-20.23, -10.07], P< 0.00001) and heart rate (MD: -7.56, 95% CI [-12.78, -2.34], P= 0.005); however, there was no significant difference between PFA and thermal ablation in fluoroscopy time (MD: 2.83, 95% CI [-0.38, 6.04], P= 0.08). PFA decreased phrenic nerve palsy (RR: 0.38, 95% CI [0.15, 0.98], P= 0.05) and esophageal lesions (RR: 0.09, 95% CI [0.01, 0.69], P= 0.02); however, PFA was significantly associated with increased pericardial tamponade (RR: 6.14 with 95% CI [1.43, 26.33], P= 0.01). Conclusion PFA was significantly associated with decreased AF recurrence, heart rate, total procedure time, phrenic nerve palsy, esophageal lesion, and increased incidence of pericardial tamponade compared with thermal ablation. However, current evidence is mainly weighted by observational studies, requiring further large-scale randomized trials.Figure

Role of Steroid Therapy in Preventing Recurrence of Atrial Fibrillation After Ablation: A Systematic Review and Meta-Analysis

Role of Steroid Therapy in Preventing Recurrence of Atrial Fibrillation After Ablation: A Systematic Review and Meta-Analysis