Radiofrequency Ablation of Persistent Atrial Fibrillation: Diagnosis-to-Ablation Time, Markers of Pathways of Atrial Remodeling, and Outcomes

The Relationship Between Cardiac CT-based Left Atrial Structure and Epicardial Adipose Tissue and Postablation Atrial Fibrillation Recurrence Within 2 Years

PURPOSE

The aim of this study was to explore the association of cardiac CT-based left atrium (LA) structural and functional parameters and left atrial epicardial adipose tissue (LA-EAT) parameters with postablation atrial fibrillation (AF) recurrence within 2 years.

MATERIALS AND METHODS

Contrast-enhanced cardiac CT images of 286 consecutive AF patients (median age: 65 y; 97 females) who underwent initial ablation between June 2018 and June 2020 were retrospectively analyzed. Structural and functional parameters of LA, including maximum and minimum volume and ejection fraction of LA and left atrial appendage (LAA), and LA-EAT volume, were measured. The body surface area indexed maximum and minimum volume of LA (LAVImax, LAVImin) and LAA (LAAVImax, LAAVImin), and LA-EAT volume index (LA-EATVI) were calculated. Independent predictors of AF recurrence were determined using Cox regression analysis. The clinical predictors were added to the imaging predictors to build a combined model (clinical+imaging). The predictive performance of the clinical, imaging, and combined models was assessed using the area under the receiver operating characteristics curve (AUC).

RESULTS

A total of 108 (37.8%) patients recurred AF within 2 years after ablation at a median follow-up of 24 months (IQR=11, 32). LA and LAA size and LA-EAT volume were significantly increased in patients with AF recurrence (P<0.05). After the multivariable regression analysis, LA-EATVI, LAAVImax, female sex, AF duration, and stroke history were independent predictors for AF recurrence. The combined model exhibited superior predictive performance compare to the clinical model (AUC=0.712 vs. 0.641, P=0.023) and the imaging model (AUC=0.712 vs. 0.663, P=0.018).

CONCLUSION

Cardiac CT-based LA-EATVI and LAAVImax are independent predictors for postablation AF recurrence within 2 years and may provide a complementary value for AF recurrence risk assessment.

Repeat catheter ablation after very late recurrence of atrial fibrillation after pulmonary vein isolation

AIMS

Atrial fibrillation (AF) recurs in about one-third of patients after catheter ablation (CA), mostly in the first year. Little is known about the electrophysiological findings and the effect of re-ablation in very late AF recurrences (VLR) after more than 1 year. The aim of this study was to determine the characteristics and outcomes of the first repeat CA after VLR of AF after index CA.

METHODS AND RESULTS

We analysed patients from a prospective Swiss registry that underwent a first repeat ablation procedure. Patients were stratified depending on the time to recurrence after index procedure: early recurrence (ER) for recurrences within the first year and late recurrence (LR) if the recurrence was later. The primary endpoint was freedom from AF in the first year after repeat ablation. Out of 1864 patients included in the registry, 426 patients undergoing a repeat ablation were included in the analysis (28% female, age 63 ± 9.8 years, 46% persistent AF). Two hundred and ninety-one patients (68%) were stratified in the ER group and 135 patients (32%) in the LR group. Pulmonary vein reconnections were a common finding in both groups, with 93% in the ER group compared to 86% in the LR group (P = 0.052). In the LR group, 40 of 135 patients (30%) had a recurrence of AF compared to 90 of 291 patients (31%) in the ER group (log-rank P = 0.72).

CONCLUSION

There was no association between the time to recurrence of AF after initial CA and the characteristics and outcomes of the repeat procedure.

Early ablation of newly diagnosed paroxysmal atrial fibrillation (NEWPaAF) versus newly diagnosed persistent atrial fibrillation (NEWPeAF): Comparison of patient populations and ablation outcomes

INTRODUCTION

Little is known about very early atrial fibrillation (AF) ablation after first AF detection.

METHODS

We evaluated patients with AF ablation <4 months from newly diagnosed paroxysmal AF (NEWPaAF) and newly diagnosed persistent AF (NEWPeAF). We compared the two patient populations and compared ablation outcomes to those undergoing later ablation.

RESULTS

Ablation was done <4 months from AF diagnosis in 353 patients (135 = paroxysmal, 218 = persistent). Early ablation outcome was best for NEWPaAF versus NEWPeAF for initial (p = 0.030) but not final (p = 0.102) ablation. Despite recent AF diagnosis in both groups, they were clinically quite different. NEWPaAF patients were younger (64.3 ± 13.0 vs. 67.3 ± 10.9, p = 0.0020), failed fewer drugs (0.39 vs. 0.60, p = 0.007), had smaller LA size (4.12 ± 0.58 vs. 4.48 ± 0.59 cm, p < 0.0001), lower BMI (28.8 ± 5.0 vs. 30.3 ± 6.0, p = 0.016), and less CAD (3.7% vs. 11.5%, p = 0.007), cardiomyopathies (2.2% vs. 22.9%, p = 0.0001), hypertension (46.7% vs. 67.4%, p < 0.0001), diabetes (8.1% vs. 17.4%, p = 0.011) and sleep apnea (20.0% vs. 30.3%, p = 0.031). For NEWPaAF, early ablation AF-free outcome was no better than later ablation (p = 0.314). For NEWPeAF, AF-free outcomes were better for early ablation than later ablation (p < 0.0001). Delaying ablation allowed more strokes/TIAs in both AF types (paroxysmal p = 0.014, persistent p < 0.0001).

CONCLUSIONS

Patients presenting for early ablation after newly diagnosed persistent AF have more pre-existing comorbidities and worse initial ablation outcomes than patients with NEWPaAF. For NEWPaAF, there was no advantage to early ablation, as long as the AF remained paroxysmal. For NEWPeAF, early ablation gave better outcomes than later ablation and they should undergo early ablation. For both AF types, waiting was associated with more neurologic events, suggesting all patients should consider earlier ablation.

Lower Recurrence Rates of Atrial Fibrillation and MACE Events After Early Compared to Late Ablation: A Danish Nationwide Register Study

BACKGROUND

Guidelines recommend prioritizing treatment with antiarrhythmic drugs before referral of patients with atrial fibrillation to ablation, delaying a potential subsequent ablation. However, delaying ablation may affect ablation outcomes. We sought to investigate the impact of duration from diagnosis to ablation on the risk of atrial fibrillation recurrence and adverse events.

METHODS AND RESULTS

Using Danish nationwide registries, all patients with first-time ablation for atrial fibrillation were identified and included from 2010 to 2018. Patients were divided into 4 groups by diagnosis-to-ablation time: <1.0 year (early ablation), 1.0 to 1.9 years, 2.0 to 2.9 years, and >2.9 years (late ablation). The primary end point was atrial fibrillation recurrence after the 90-day blanking period, defined by admission for atrial fibrillation, cardioversions, use of antiarrhythmic drugs, or repeat atrial fibrillation ablations. The secondary end point was a composite end point of heart failure, ischemic stroke, or death, and each event individually. The study cohort consisted of 7705 patients. The 5-year cumulative incidence of atrial fibrillation recurrence in the 4 groups was 42.9%, 54.8%, 55.9%, and 58.4%, respectively. Hazard ratios were 1.20 (95% CI, 1.07-1.35), 1.29 (95% CI, 1.13-1.47), and 1.40 (95% CI, 1.28-1.53), respectively, with the early ablation group as reference. The hazard ratio for the combined secondary end point was 1.22 (95% CI, 1.04-1.44) in the late ablation group compared with the early ablation group.

CONCLUSIONS

In patients undergoing ablation for atrial fibrillation, early ablation was associated with a significantly lower risk of atrial fibrillation recurrence. Furthermore, the associated risk of heart failure, ischemic stroke, or death was significantly lower in early-compared with late-ablation patients.

The Association between Diagnosis-to-Ablation Time and the Recurrence of Atrial Fibrillation: A Retrospective Cohort Study

BACKGROUND

Catheter ablation (CA) for atrial fibrillation (AF) is superior to antiarrhythmic drugs in maintaining sinus rhythm. Novel evidence suggests that increasing the time between the first diagnosis of AF and ablation, or diagnosis-to-ablation time (DAT), is a predictor for AF recurrence post-ablation.

PURPOSE

Our primary objective was to investigate the relationship between DAT and AF recurrence after a first ablation.

METHODS

Patients with AF who underwent CA in our center were enrolled consecutively, and a retrospective analysis was performed. DAT was treated as a continuous variable and reported as a median for the group with recurrence and the group without recurrence. DAT was also considered as a categorical variable and patients were stratified into three categories: DAT < 1 year, DAT < 2 years, and DAT < 4 years.

RESULTS

The cohort included 107 patients, with a mean age of 54.3 ± 11.7 years. Mean DAT was significantly longer in those with AF recurrence: 4.9(3.06) years versus 3.99(3.5) (p = 0.04). The Kaplan-Meier curve revealed a higher likelihood of AF-free status over time for patients with DAT < 2 years compared to those with DAT > 2 years (p = 0.04). Cox multivariate analysis indicated that left atrial volume index (LAVI), obstructive sleep apnoea (OSA), and DAT > 2 years were independently associated with AF recurrence after a single AF ablation procedure (p = 0.007, p = 0.02, and p = 0.03, respectively).

CONCLUSION

A shorter duration between the first AF diagnosis and AF ablation is associated with an increased likelihood of procedural success after a single AF ablation procedure.

Impact of Diagnosis-to-Ablation Time on AF Recurrence: Pronounced the First 3 Years, Irrelevant Thereafter

BACKGROUND

Diagnosis-to-ablation time (DAT) strongly predicts recurrence of atrial fibrillation (AF) after ablation. Whether this association holds with any lower and/or upper limits is unknown.

OBJECTIVES

The goal of this study was to assess the impact of DAT on AF recurrence in search of lower and upper DAT thresholds.

METHODS

A total of 2,000 patients with AF from 2 cohorts of 1,000 patients each (69% male; age 62 ± 10 years) undergoing pulmonary vein isolation (PVI) between 2005-2014 and 2017-2019 were followed up for 3 years.

RESULTS

Clinical success was achieved in 61.7% of patients. Median DAT decreased over time from 36 months (Q1-Q3: 12-72 months) in the first cohort to 12 months (Q1-Q3: 5-48 months) in the second cohort (P < 0.001). A multivariable Cox proportional hazards fitted model of AF recurrence rate in relation to DAT (range: 0-288 months) showed a steep rise in AF recurrence, from 27% to 40% in the first 36 months (d%/dt = 0.36), with a first inflection point at 36 months, and a less steep rise to 45% until 90 months (d%/dt = 0.09), with flattening beyond 90 months (d%/dt = 0.026). Rise in AF recurrence rate in the first 36 months was higher in patients with persistent AF (from 40% to 54%; d%/dt = 0.39) than in patients with paroxysmal AF (19% to 29%; d%/dt = 0.28).

CONCLUSIONS

The association between DAT and AF recurrence has no lower limit ("the shorter the better"), whereas little gain is to be expected beyond 36 months ("the longer the more irrelevant"). Our data advocate for performing PVI as early as possible, certainly within 3 years of AF diagnosis, and even more so in persistent AF.

Short-term and long-term effects of cryoballoon ablation versus antiarrhythmic drug therapy as first-line treatment for paroxysmal atrial fibrillation: A systematic review and meta-analysis

Cryoballoon ablation (CBA) is an effective treatment for drug-refractory atrial fibrillation (AF) patients. Whether CBA as a first-line treatment is superior in the rhythm control of AF than antiarrhythmic drugs (AAD) remains unclear. CBA is superior to AAD as initial therapy for rhythm control of paroxysmal atrial fibrillation (PAF). A comprehensive database search was performed in PubMed, Embase, Cochrane, and Web of Science from inception to March 22, 2023. Treatment efficacy was pooled using risk ratio (RR) and standardized mean difference (SMD) with a 95% confidence interval (CI). This study was registered with Prospero (CRD42023401596). Five randomized-controlled trials involving 923 patients and an observational study were included in this study. The CBA group had a significantly lower overall recurrence rate than the AAD group (CBA vs. AAD: RR = 0.59, 95% CI = 0.49-0.71, p < .05, I2  = 0). The incidence of persistent AF could be better controlled in the CBA group than in the AAD (CBA vs. AAD: RR = 0.17, 95% CI = 0.06-0.49, p < .05, I2  = 0). CBA could improve the quality of life (QoL) of patients better than AAD (CBA vs. AAD: SMD = 0.40, 95% CI = 0.14-0.67, p < .05, I2  = 68.5%). CBA can reduce hospitalization rate significantly than AAD at 36-month follow-up (CBA vs. AAD: RR = 0.29, 95% CI = 0.15-0.58, p < .05, I2  = 0%). Compared to AAD, CBA as first-line therapy could reduce the recurrence rate of atrial arrhythmia and incidence of persistent AF and improve QoL in PAF patients with lower incidences of hospitalization.

The predictive value of left atrium epicardial adipose tissue on recurrence after catheter ablation in patients with different types of atrial fibrillation

BACKGROUND

A growing body of evidence supports that the left atrium epicardial adipose tissue (LA-EAT) is related to the occurrence and recurrence of atrial fibrillation (AF). The relationship between LA-EAT and the recurrence after radiofrequency catheter ablation (RFCA) in patients with different types of AF is still unclear. This study aims to evaluate the predictive value of LA-EAT on the recurrence of AF after RFCA in patients with different types of AF.

METHODS

301 AF patients who underwent RFCA for the first time were divided into the paroxysmal atrial fibrillation (PAF) group (n = 181) and the persistent atrial fibrillation (PersAF) group(n = 120), which were followed up at 3, 6, and 12 months. All patients underwent left atrial computed tomography angiography (CTA) examination before the operation, and LA-EAT was measured using software (Advantage Workstation4.6, GE, USA).

RESULTS

After a median follow-up of 10.7 months, 73/301 patients (24.25%) had a recurrence of AF, including 43 /120(35.83%) patients with PersAF and 30/181(16.57%) patients with PAF. In multivariable Cox regression analysis, LA-EAT volume (OR = 1.053;95%CI: 1.024-1.083, p < 0.001), attenuation (OR = 0.949;95%CI:0.911-0.988, p = 0.012) and left atrial diameter (LAD) (OR = 1.063;95%CI:1.002-1.127，p = 0.043) were independent risk factors for recurrence in patients with PersAF but not in patients with PAF.

CONCLUSION

LA-EAT volume and attenuation are independent risk factors for recurrence after RFCA in patients with PersAF.

Intrinsic Cardiac Neuromodulation in the Management of Atrial Fibrillation- A Potential Missing Link?

Atrial fibrillation (AF) is the most common supraventricular arrhythmia that is linked with higher cardiovascular morbidity and mortality. Recent evidence has demonstrated that catheter-based pulmonary vein isolation (PVI) is not only a viable alternative but may be superior to antiarrhythmic drug therapy for long-term freedom from symptomatic AF episodes, a reduction in the arrhythmia burden, and healthcare resource utilization with a similar risk of adverse events. The intrinsic cardiac autonomic nervous system (ANS) has a significant influence on the structural and electrical milieu, and imbalances in the ANS may contribute to the arrhythmogenesis of AF in some individuals. There is now increasing scientific and clinical interest in various aspects of neuromodulation of intrinsic cardiac ANS, including mapping techniques, ablation methods, and patient selection. In the present review, we aimed to summarize and critically appraise the currently available evidence for the neuromodulation of intrinsic cardiac ANS in AF.

Metabolic activity of the left and right atria are differentially altered in patients with atrial fibrillation and LV dysfunction

BACKGROUND

Alterations in atrial metabolism may play a role in the perpetuation of atrial fibrillation (AF). This study sought to compare 18F-fluorodeoxyglucose (FDG) uptake on PET, in patients with LV dysfunction versus those without AF.

METHODS

Seventy-two patients who underwent myocardial viability assessment were evaluated. AF patients (36) had persistent or permanent AF based on history and ECG. Patients without AF (36) were matched to AF patients based on sex, diabetes, age, and LVEF. Maximum and mean FDG Standard Uptake Values (SUV) in the left atrial (LA) wall and right atrial (RA) wall were measured. Tissue-to-blood ratios (TBR) were calculated as atrial wall to blood-pool activity. Atrial volumes were measured by echocardiography.

RESULTS

Maximum and mean FDG SUV and TBRs were significantly increased in the RA (but not the LA) of patients with AF compared to those without (P < 0.01). When accounting for changes in atrial volume, the presence of AF remained a significant predictor of higher RAMAX, but not RAMEAN FDG uptake.

CONCLUSION

In patients with LV dysfunction from ischemic cardiomyopathy, LA and RA glucose metabolism are differentially altered in those with persistent atrial fibrillation. Further investigations should elucidate the temporal relationship between AF and glucose metabolic changes, as a potential target for therapy.

Mediastinal radiation therapy for breast cancer in female patients is an independent risk factor for atrial fibrillation recurrence post-catheter ablation

BACKGROUND

The aim of this study was to assess the safety, efficacy, and predictors of outcomes for atrial fibrillation (AF) ablation in patients with a history of breast cancer.

METHODS

Consecutive patients with a history of breast cancer undergoing AF ablation from January 2010 to December 2021 were propensity matched in a 1:1 ratio to patients without a history of any cancer. The primary outcome was procedural efficacy, defined by clinical AF recurrence and repeat catheter ablation. The secondary outcome was an assessment of safety looking at eight peri-procedural events.

RESULTS

Our cohort was comprised of 82 female patients, 41 patients with a history of breast cancer (mean age, 74.6 ± 7.4 years), and 41 patients with no history of cancer (76.7 ± 8.1 years). Both groups had similar echocardiographic, baseline, and arrhythmia characteristics. Breast cancer patients were at an increased risk of AF recurrence post-ablation compared to non-cancer patients (OR 2.68, 95% CI 1.05-6.86, p = 0.04). Multivariate analysis found prior mediastinal radiotherapy (OR 4.79, 95% CI 1.34-17.1) and AF diagnosis to ablation time (OR 1.2, 95% CI 1.03-1.29) were both independent predictors of AF recurrence post-ablation.

CONCLUSION

Our study suggests that female patients with a history of breast cancer are at a higher risk of developing AF recurrence after catheter ablation. Multivariate analysis showed that patients with a history of prior mediastinal radiation therapy and AF diagnosis to time to ablation were both independent risk factors.

Racial, ethnic, and sex disparities in atrial fibrillation management: rate and rhythm control

BACKGROUND

Atrial fibrillation (AF) affects around 6 million Americans. AF management involves pharmacologic therapy and/or interventional procedures to control rate and rhythm, as well as anticoagulation for stroke prevention. Different populations may respond differently to distinct management strategies. This review will describe disparities in rate and rhythm control and their impact on outcomes among women and historically underrepresented racial and/or ethnic groups.

METHODS

This is a narrative review exploring the topic of sex and racial and/or ethnic disparities in rate and rhythm management of AF. We describe basic terminology, summarize AF epidemiology, discuss diversity in clinical research, and review landmark clinical trials.

RESULTS

Despite having higher rates of traditional AF risk factors, Black and Hispanic adults have lower risk of AF than non-Hispanic White (NHW) patients, although those with AF experience more severe symptoms and report lower quality-of-life scores than NHW patients with AF. NHW patients receive antiarrhythmic drugs, cardioversions, and invasive therapies more frequently than Black and Hispanic patients. Women have lower rates of AF than men, but experience more severe symptoms, heart failure, stroke, and death after AF diagnosis. Women and people from diverse racial and ethnic backgrounds are inadequately represented in AF trials; prevalence findings may be a result of underdetection.

CONCLUSION

Race, ethnicity, and gender are social determinants of health that may impact the prevalence, evolution, and management of AF. This impact reflects differences in biology as well as disparities in treatment and representation in clinical trials.

Impact of a dedicated atrial fibrillation clinic on diagnosis-to-ablation time

Background

Outcomes following catheter ablation (CA) for atrial fibrillation (AF) improve as the diagnosis-to-ablation time (DAT) shortens. Use of a protocol-based integrated care model through a dedicated atrial fibrillation clinic (AFC) may serve to standardize treatment pathways and decrease DAT.

Objective

To evaluate the DAT and clinical characteristics of patients with AF referred from an AFC vs a conventional electrophysiology clinic (EC).

Methods

Retrospective analysis was completed in consecutive patients undergoing index AF ablation at Riverside Methodist Hospital in 2019 with minimum 1 year follow-up. Patients were categorized based off their CA referral source (AFC vs EC) and where the initial visit following index diagnosis of AF occurred (AFC vs EC).

Results

A total of 182 patients (mean age 65 years, 64% male) were reviewed. Patients referred from an AFC (21%) had a median DAT of 342 days (interquartile range [IQR], 125-855 days) compared to patients referred from EC (79%) with a median DAT of 813 days (IQR, 241-1444 days; P = .01). Patients with their index visit following AF diagnosis occurring in the AFC (9%) had significantly shorter median DAT (127 days [IQR, 95-188 days]) compared to EC (91%) (789 days [IQR, 253-1503 days]; P = .002). Patients with DAT <1 year had lower AF recurrence than patients with DAT >1 year (P = .04, hazard ratio = 0.58, 95% confidence interval 0.3418-1.000).

Conclusion

DAT is a modifiable factor that may affect CA outcomes. Significant reductions in DAT were observed in patients evaluated through a dedicated AF clinic.

Development and Validation of a Risk Nomogram Model for Predicting Recurrence in Patients with Atrial Fibrillation After Radiofrequency Catheter Ablation

Purpose

This study aimed to develop and validate a risk nomogram model for predicting the risk of atrial fibrillation recurrence after radiofrequency catheter ablation.

Patients and Methods

A retrospective observational study was conducted using data from 485 patients with atrial fibrillation who underwent the first radiofrequency ablation in our hospital from January 2018 to June 2021. All patients were randomized into training cohort (70%; n=340) and validation cohort (30%; n=145). Univariate and multivariate logistic regression analyses were used to identify independent risk factors. The predictive nomogram model was established by using R software. The nomogram was developed and evaluated based on differentiation, calibration, and clinical efficacy by concordance statistic (C-statistic), calibration plots, and decision curve analysis (DCA), respectively.

Results

The nomogram was established by four variables including left atrial diameter (OR 1.057, 95% CI 1.010–1.107, P=0.018), left ventricular ejection fraction (OR 0.943, 95% CI 0.905–0.982, P=0.005), type of atrial fibrillation (OR 2.164, 95% CI: 1.262–3.714), and systemic inflammation score (OR 1.905, 95% CI 1.408–2.577). The C-statistic of the nomogram was 0.741 (95% CI: 0.689–0.794) in the training cohort and 0.750 (95% CI: 0.670–0.831) in the validation cohort. The calibration plots showed good agreement between the predictions and observations in the training and validation cohorts. Decision curve analysis and clinical impact curves indicated the clinical utility of the predictive nomogram.

Conclusion

The nomogram model has good discrimination and accuracy, which can screen high-risk groups intuitively and individually, and has a certain predictive value for atrial fibrillation recurrence in patients after radiofrequency ablation.

Outcomes of atrial fibrillation ablation in patients with or without silent pulmonary veins from prior ablation procedure

INTRODUCTION

Pulmonary venous (PV) electrical recovery underlies most arrhythmia recurrences after atrial fibrillation (AF) ablation. Little is known about procedural profiles and outcomes of patients with electrically silent PVs upon redo ablation for AF.

METHODS

In a prospectively maintained registry, we enrolled 838 consecutive patients (2013-2016) undergoing redo ablation procedures. Ablation procedures targeted the PVs, the PV antra, and non-PV sites at operators' discretion. Procedural profiles and clinical outcomes were assessed. The primary outcome was freedom from AF after a 3-month blanking period. The secondary outcome was improvement in quality of life.

RESULTS

Most patients undergoing redo AF ablation (n = 684, 82%) had PV reconnection while the remaining 154 (18%) had electrically silent PVs. Patients with recurrent AF and electrically silent PVs were older (66 vs. 64 years, p = .02), had more prior ablation procedures (median 2 IQR 1-3 vs 1 IQR 1-2 p = .001), were more likely to have non-paroxysmal AF (62% vs. 49%, p = .004) and atrial flutter (48% vs. 29%, p = .001) and had significantly larger left atrial volumes (89 vs. 81 ml, p = .003). Patients with silent PVs underwent a more extensive non-PV ablation strategies with antral extension of prior ablation sets in addition to ablation of the roof, appendage, inferior to the right PVs, peri-mitral flutter lines, cavotricuspid isthmus lines and ablation in the coronary sinus. Upon one year of follow-up, patients with electrically silent PVs were less likely to remain free from recurrent atrial arrhythmias (64% vs. 76%, p = .008). Regardless of PV reconnection status, redo ablation resulted in improvement in quality of life.

CONCLUSION

Rhythm control with extensive ablation allowed maintenance of sinus rhythm in about two thirds of patients with silent PVs during redo AF ablation procedures. Regardless of PV reconnection status, redo ablation resulted in improvement in quality of life. This remains a challenging group of patients, highlighting the need to better understand non-PV mediated AF.

Catheter Ablation for Atrial Fibrillation in the Elderly > 75 Years old: Systematic Review and Meta-Analysis

INTRODUCTION

Atrial fibrillation (AF) ablation is increasingly performed worldwide. As comfort with AF ablation increases, the procedure is increasingly used in patients that are older and in those with more comorbidities. However, it is not well established whether AF ablation in the elderly, especially those >75 years old, has comparable safety and efficacy to younger populations.

OBJECTIVE

To compare the efficacy and safety profiles in patients older than 75years undergoing AF ablation with younger patients.

METHODS

Databases from EMBASE, Medline, PubMed and Cochrane, were searched from inception through September 2021. Studies that compared the success rates in AF catheter ablation and all complications rates between patients who were older vs under 75 years were included. Effect estimates from the individual studies were extracted and combined using random effect, generic inverse variance method of DerSimonian and Laird.

RESULTS

Twenty-seven observational studies were included in the analysis consisting of 363,542 patients who underwent AF ablation. Comparing patients older than 75 years old to younger patients, there was no difference in the success of ablation rates between elderly and younger patients (pooled OR 0.85: 95% CI:0.69 - 1.05, p=0.131). On the other hand, AF ablation in the elderly was associated with higher complication rates (pooled OR 1.43: 95% CI:1.21 - 1.68, p<0.001) CONCLUSION: As AF ablation is expanded to elderly populations, our study found that AF ablation success rates were similar in both elderly and younger patients. However, older patients experience higher rates of complications that should be considered when offering the procedure and as a means to improve outcomes with future innovations. This article is protected by copyright. All rights reserved.

Cryoablation or Drug Therapy for Initial Treatment of Atrial Fibrillation

AF is a common chronic and progressive disorder. Without treatment, AF will recur in up to 75% of patients within a year of their index diagnosis. Antiarrhythmic drugs (AADs) have been proven to be more effective than placebo at maintaining sinus rhythm and remain the recommended initial therapeutic option for AF. However, the emergence of ‘single-shot’ AF ablation toolsets, which have enabled enhanced procedural standardisation and consistent outcomes with low rates of complications, has led to renewed interest in determining whether first-line catheter ablation may improve outcomes. The recently published EARLY-AF trial evaluated the role of initial cryoballoon ablation versus guideline-directed AAD therapy. Compared to AADs, an initial treatment cryoballoon ablation strategy resulted in greater freedom from atrial tachyarrhythmia, superior reduction in AF burden, greater improvement in quality of life and lower healthcare resource utilisation. These findings are relevant to patients, providers and healthcare systems when considering the initial treatment choice for rhythm-control therapy.

Patterns of Care for First-detected Atrial Fibrillation: Insights from the Get With The Guidelines Atrial Fibrillation Registry

BACKGROUND

Despite multiple trials comparing rate with rhythm control, there is no consensus on optimal management of first-detected atrial fibrillation (AF).

OBJECTIVE

We analyzed current patterns of care for first-detected AF in the nationwide Get With The Guidelines®- Atrial Fibrillation Registry METHODS: Patients hospitalized with first-detected AF from 2013-19 were included and a descriptive analysis was performed comparing planned rate vs rhythm control. Multivariable logistic regression analysis was performed to identify predictors for choosing rhythm over rate control.

RESULTS

Among 86,759 patients with AF, 17.8% (15,473) had first-detected AF, 11,685 patients were included from 126 sites. Overall, 51.3% of patients were treated with rate control, and 48.7% with rhythm control at admission. Patients with planned rhythm control had a shorter length of stay and were more likely to be discharged home than a facility. A higher percentage of patients with planned rhythm control were discharged on anticoagulation compared to planned rate control (75.6% vs 70.9%) despite a higher underlying stroke risk in the rate control group (higher median CHA2DS2VASc-score (4; Q1-Q3 2-5 vs 3; Q1-Q32-4; p<0.001). While Hispanic ethnicity, Medicaid insurance, age >70 years, and liver disease decreased the likelihood of rhythm control, factors like heart failure, stroke, or prior bleeding diathesis had no association with the chosen treatment strategy.

CONCLUSIONS

Less than half of the patients with first-detected AF receive rhythm control at admission. Given recent trial results, further studies should assess the long-term impact of rhythm control on patients' symptoms and quality of life, cardiovascular morbidity, and mortality.

Very early versus early referral for ablation among young patients for newly diagnosed paroxysmal atrial fibrillation

BACKGROUND

Catheter ablation (CA) has emerged as an effective therapy for the treatment of paroxysmal atrial fibrillation, however it is unclear whether proceeding expeditiously to CA improves clinical outcomes in a real-world population. This study compares outcomes of catheter ablation for new atrial fibrillation (AF) within 6 months of diagnosis (very early) 6 to 12 months after diagnosis (early) and 12 to 24 months after diagnosis (later).

METHODS

A large nationally-representative sample of patients ages 18 to 64 who underwent CA from January 2011 to June 2019 was studied using the IBM MarketScan® Database. The primary outcome was a composite of healthcare utilization over the following 24 months. Propensity score-matching was used to match patients in each cohort. Risk difference in outcomes were compared between matched patients.

RESULTS

2,631 patients were identified post-matching, with 1,649 in the very early cohort and 982 in the early cohort. The very early referral group was less likely to experience the primary composite outcome post-ablation (Absolute risk difference [ARD]: -3.9%; 95% Confidence interval [CI]: -5.8%, -2.0%), with the difference driven by fewer cardioversions (ARD: -2.9%, 95% CI: -5.3%, -0.5%) and outpatient visits (ARD: -6.6%, 95% CI: -10.5%, -2.7%). There was no difference in outcomes between early and later referral groups, with only very early referral showing decreased healthcare utilization.

CONCLUSIONS

Patients who underwent ablation within 6 months of diagnosis had lower healthcare utilization in the ensuing 24 months, driven by fewer outpatient visits and cardioversions, supporting expeditious referral for ablation for symptomatic AF. This article is protected by copyright. All rights reserved.

Early rhythm-control ablation therapy to prevent atrial fibrillation recurrences: Insights from the CHARISMA Registry

BACKGROUND

An early, comprehensive rhythm-control therapy is needed in order to treat atrial fibrillation (AF) effectively and to improve ablation outcomes.

METHODS

A total of 153 consecutive patients from the CHARISMA registry undergoing AF ablation at eight centers were included. Patients with de novo PVI were classified as having undergone early treatment (ET) if the procedure was performed within 6 months after the first AF episode, and as having undergone delayed treatment (DT) if ablation was performed over 6 months after the first AF episode.

RESULTS

One-hundred fifty-three patients were enrolled (69.9% male, 59 ± 10 years, 61.4% paroxysmal AF, 38.6% persistent AF). The time from the first AF episode to the ablation procedure was 1034 ± 1483 days. The ET group comprised 36 patients (25.3%), the DT group 60 (39.2%) and Redo cases were 57 (37.3%). During a mean follow-up of 366 ± 130 days, 18 patients (11.8%) suffered an AF/AT recurrence. More DT patients than ET patients suffered recurrences (15.7% vs. 2.2%, p = 0.0452) and the time to AT/AF recurrence was shorter in the group of patients who received an ablation treatment after 6 months (HR = 6.19, 95% CI: 1.7 to 21.9; p = 0.0474). On multivariate Cox analysis, only hypertension (HR = 4.86, 95% CI: 1.6 to 14.98, p = 0.0062) was independently associated with recurrences. Beyond the hypertension risk factor, ET was associated with a low risk of recurrence; recurrence rate ranged from 0% (ET patients without hypertension) to 25.0% (DT patients with hypertension).

CONCLUSIONS

An early rhythm-control ablation therapy in the absence of common risk factors was associated with the lowest rate of recurrences.

The role of brain natriuretic peptide in atrial fibrillation: a substudy of the Substrate Modification with Aggressive Blood Pressure Control for Atrial Fibrillation (SMAC-AF) trial

BACKGROUND

Catheter ablation is an established therapy for atrial fibrillation but is limited by recurrence; efforts have been made to identify biomarkers that predict recurrence. We investigated the effect of baseline NT-proBNP on AF recurrence following catheter ablation in patients randomized to aggressive (< 120/80 mmHg) or standard blood pressure management (< 140/90 mmHg) in the Substrate Modification with Aggressive Blood Pressure Control trial (SMAC-AF).

METHODS

The SMAC-AF study included 173 patients resistant or intolerant to at least one class I or III antiarrhythmic drug. We studied the effect of baseline NT-proBNP on the primary outcome of AF recurrence > 3 months post-ablation.

RESULTS

Of the 173 patients, 88 were randomized to the aggressive cohort, and 85 into the standard group. The primary outcome occurred in 61.4% of those in the aggressive arm, versus 61.2% in the standard arm. In the aggressive group, logNT-proBNP predicted recurrence (HR 1.28, p = 0.04, adjusted HR 1.43, p = 0.03), while in the standard cohort, it did not (HR 0.94, p = 0.62, adjusted HR 0.83, p = 0.22). NT-proBNP ≥ 280 pg/mL also predicted occurrence in the aggressive (HR 1.98, p = 0.02) but not the standard cohort (HR 1.00, p = 1.00).

CONCLUSION

We conclude that pre-ablation NT-proBNP may be useful in predicting recurrence in hypertensive patients and identifying patients who benefit from aggressive blood control and upstream therapies.

TRIAL REGISTRATION

NCT00438113, registered February 21, 2007.

Catheter ablation vs. antiarrhythmic drugs as 'first-line' initial therapy for atrial fibrillation: a pooled analysis of randomized data

AIMS

Catheter ablation (CA) is recommended for patients with atrial fibrillation (AF) after failure of antiarrhythmic drugs (AADs). The role of CA as 'initial therapy' for AF is to be determined.

METHODS AND RESULTS

Following PRISMA guideline an up-to-date pooled analysis of randomized data comparing ablation vs. AADs as first-line therapy for symptomatic AF was performed. The primary outcome was recurrence of atrial tachyarrhythmia. The secondary outcomes were improvement in quality-of-life (QoL) and major adverse events. A total of 997 patients from five randomized trials were enrolled (mean age 57.4 years, 68.6% male patients, 98% paroxysmal AF, mean follow-up 1.4 years). The baseline characteristics were similar between the ablation and AADs group. Overall pooled analysis showed that, as compared with AADs, CA as first-line therapy was associated with significantly higher freedom from arrhythmia recurrence (69% vs. 48%, odds ratio: 0.36, 95% confidence interval: 0.27-0.48, P < 0.001). This significance was maintained in subgroup analyses of 1- and 2-year follow-up (P < 0.001). Catheter ablation was associated with significantly greater improvement in QoL regarding AFEQT score and 36-Item Short-Form Health Survey score. The incidence of serious adverse events between ablation and AADs group (5.6% vs. 4.9%, P = 0.62) was similar.

CONCLUSIONS

Catheter ablation as 'initial therapy' was superior to AADs in maintenance of sinus rhythm and improving QoL for patients with symptomatic paroxysmal AF, without increasing risk of serious adverse events.

Electrophysiological Characterization of Human Atria: The Understated Role of Temperature

Ambient temperature has a profound influence on cellular electrophysiology through direct control over the gating mechanisms of different ion channels. In the heart, low temperature is known to favor prolongation of the action potential. However, not much is known about the influence of temperature on other important characterization parameters such as the resting membrane potential (RMP), excitability, morphology and characteristics of the action potential (AP), restitution properties, conduction velocity (CV) of signal propagation, etc. Here we present the first, detailed, systematic in silico study of the electrophysiological characterization of cardiomyocytes from different regions of the normal human atria, based on the effects of ambient temperature (5-50°C). We observe that RMP decreases with increasing temperature. At ~ 48°C, the cells lose their excitability. Our studies show that different parts of the atria react differently to the same changes in temperature. In tissue simulations a drop in temperature correlated positively with a decrease in CV, but the decrease was region-dependent, as expected. In this article we show how this heterogeneous response can provide an explanation for the development of a proarrhythmic substrate during mild hypothermia. We use the above concept to propose a treatment strategy for atrial fibrillation that involves severe hypothermia in specific regions of the heart for a duration of only ~ 200 ms.

Catheter ablation as first-line treatment for paroxysmal atrial fibrillation: a systematic review and meta-analysis

OBJECTIVE

To assess the efficacy and safety of catheter ablation (CA) compared with antiarrhythmic drugs (AADs) as first-line treatment for symptomatic paroxysmal atrial fibrillation (AF).

METHODS

Systematic review and meta-analysis of randomised controlled trials identified using MEDLINE, Cochrane Library and Embase published between 01/01/2000 and 19/03/2021. The primary efficacy endpoint was the first documented recurrence of atrial arrhythmias following the blanking period. The primary safety endpoint was a composite of all serious adverse events (SAEs).

RESULTS

From 441 records, 6 studies met the inclusion criteria. 609 patients received CA, while 603 received AAD therapy. 212/609 patients in the CA group had a recurrence of atrial arrhythmias as compared with 318/603 in the AADs group resulting in a 36% relative risk reduction (risk ratio: 0.64, 95% CI 0.51 to 0.80, p<0.01). The risk of all SAEs was not statistically different between CA and AAD (0.87, 0.58 to 1.30, p=0.49); 107/609 SAE in the CA group vs 126/603 in the AAD group. Both recurrence of symptomatic atrial arrhythmias (109/505 vs 186/504) and healthcare utilisation (126/397 vs 185/394) were significantly lower in the CA group (0.53, 0.35 to 0.79 and 0.65, 0.48 to 0.89, respectively). There was a 79% reduction in the crossover rate during follow-up among patients randomised to CA compared with AAD (0.21, 0.13 to 0.32, p<0.01).

CONCLUSIONS

First-line treatment with CA is superior to AAD therapy in patients with symptomatic paroxysmal AF, as it significantly reduces the recurrence of any atrial arrhythmias and symptomatic atrial arrhythmias, and healthcare resource utilisation with comparable safety profile.

Atrial Remodeling in Atrial Fibrillation. Comorbidities and Markers of Disease Progression Predict Catheter Ablation Outcome

Atrial fibrillation is the most common supraventricular arrhythmia affecting an increasing proportion of the population in which mainstream therapy, i.e. catheter ablation, provides freedom from arrhythmia in only a limited number of patients. Understanding the mechanism is key in order to find more effective therapies and to improve patient selection. In this review, the structural and electrophysiological changes of the atrial musculature that constitute atrial remodeling in atrial fibrillaton and how risk factors and markers of disease progression can predict catheter ablation outcome will be discussed in detail.

Assessment of Catheter Ablation or Antiarrhythmic Drugs for First-line Therapy of Atrial Fibrillation: A Meta-analysis of Randomized Clinical Trials

Importance

Early rhythm control of atrial fibrillation (AF) with either antiarrhythmic drugs (AADs) or catheter ablation has been reported to improve cardiovascular outcomes compared with usual care; however, the optimal therapeutic modality to achieve early rhythm control is unclear.

Objective

To assess the safety and efficacy of AF ablation as first-line therapy when compared with AADs in patients with paroxysmal AF.

Data Sources

PubMed/MEDLINE, Scopus, Google Scholar, and various major scientific conference sessions from January 1, 2000, through November 23, 2020.

Study Selection

Randomized clinical trials (RCTs) published in English that had at least 12 months of follow-up and compared clinical outcomes of ablation vs AADs as first-line therapy in adults with AF. The quality of individual studies was assessed using the Cochrane risk of bias tool. Six RCTs met inclusion criteria, including 1212 patients.

Data Extraction and Synthesis

Two investigators independently extracted data. Reporting was performed in compliance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analysis) guidelines. Analysis was performed using a random-effects model with the Mantel-Haenszel method, and results are presented as 95% CIs.

Main Outcomes and Measures

Main outcomes were safety and efficacy of AF ablation as first-line therapy when compared with AADs. Trials were evaluated as having low risk of selection and attrition biases, high risk of performance bias, and with unclear risk for detection biases due to unblinding and open-label designs.

Results

A total of 6 RCTs involving 1212 patients with AF were included (609 were randomized to AF ablation and 603 to drug therapy; mean [SD] age, 56 [11] years). Compared with AADs, catheter ablation use was associated with reductions in recurrent atrial arrhythmia (32.3% vs 53%; risk ratio [RR], 0.62; 95% CI, 0.51-0.74; P < .001; I2 = 40%), with a number needed to treat with ablation to prevent 1 arrhythmia of 5. Use of ablation was also associated with reduced symptomatic atrial arrhythmia (11.8% vs 26.4%; RR, 0.44; 95% CI, 0.27-0.72; P = .001; I2 = 54%) and hospitalization (5.6% vs 18.7%; RR, 0.32; 95% CI, 0.19-0.53; P < .001) with no significant difference in serious adverse events between the groups (4.2% vs 2.8%; RR, 1.52; 95% CI, 0.81-2.85; P = .19).

Conclusions and Relevance

In this meta-analysis of randomized clinical trials including first-line therapy of patients with paroxysmal AF, catheter ablation compared with antiarrhythmic drugs was associated with reductions in recurrence of atrial arrhythmias and hospitalizations, with no difference in major adverse events.

Impact of diagnosis-to-ablation time on non-pulmonary vein triggers and ablation outcomes in persistent atrial fibrillation

INTRODUCTION

Non-pulmonary vein (PV) triggers are a major cause of atrial tachyarrhythmia (ATA) recurrence after catheter ablation. However, the effect of the diagnosis-to-ablation time (DAT) on non-PV triggers in persistent atrial fibrillation is unknown.

METHODS AND RESULTS

This observational study evaluated 502 consecutive persistent AF patients who underwent initial ablation. We compared 408 patients whose DAT was <3 years with 94 patients whose DAT was ≥3 years. Following PV and posterior wall isolation, 193 non-PV triggers, including 50 AFs, 30 atrial tachycardias (ATs), and 113 repetitive atrial premature beats, were elicited and ablated in 137 (27%) patients. Specifically, 80 non-PV AF/AT triggers were provoked in 64 (13%) patients, being identified more frequently in the DAT ≥ 3 years group than in the DAT < 3 years group (20% vs. 11%, p = .025) especially with a higher prevalence of coronary sinus/inferior left atrial triggers. During a median follow-up of 770 days, the ATA recurrence-free rate was higher in the DAT < 3 years group than the DAT ≥ 3 years group (79% vs. 53% at 2 years, p < .001). In a multivariate analysis, female sex (odds ratio: 2.70, p = .002) and a longer DAT (odds ratio: 1.13/year, p = .008) were predictors of non-PV AF/AT triggers, and a longer DAT (hazard ratio: 1.12/year, p < .001) and non-PV AT/AF triggers (hazard ratio: 1.79, p = .009) were associated with ATA recurrence.

CONCLUSION

Early ablation after the first diagnosis of persistent AF may reduce emerging non-PV AF/AT triggers and ATA recurrence.

Machine Learning-Derived Fractal Features of Shape and Texture of the Left Atrium and Pulmonary Veins From Cardiac Computed Tomography Scans Are Associated With Risk of Recurrence of Atrial Fibrillation Postablation

[Figure: see text].

Cryoballoon Ablation as Initial Therapy for Atrial Fibrillation

BACKGROUND

In patients with symptomatic paroxysmal atrial fibrillation that has not responded to medication, catheter ablation is more effective than antiarrhythmic drug therapy for maintaining sinus rhythm. However, the safety and efficacy of cryoballoon ablation as initial first-line therapy have not been established.

METHODS

We performed a multicenter trial in which patients 18 to 80 years of age who had paroxysmal atrial fibrillation for which they had not previously received rhythm-control therapy were randomly assigned (1:1) to receive treatment with antiarrhythmic drugs (class I or III agents) or pulmonary vein isolation with a cryoballoon. Arrhythmia monitoring included 12-lead electrocardiography conducted at baseline and at 1, 3, 6, and 12 months; patient-activated telephone monitoring conducted weekly and when symptoms were present during months 3 through 12; and 24-hour ambulatory monitoring conducted at 6 and 12 months. The primary efficacy end point was treatment success (defined as freedom from initial failure of the procedure or atrial arrhythmia recurrence after a 90-day blanking period to allow recovery from the procedure or drug dose adjustment, evaluated in a Kaplan-Meier analysis). The primary safety end point was assessed in the ablation group only and was a composite of several procedure-related and cryoballoon system-related serious adverse events.

RESULTS

Of the 203 participants who underwent randomization and received treatment, 104 underwent ablation, and 99 initially received drug therapy. In the ablation group, initial success of the procedure was achieved in 97% of patients. The Kaplan-Meier estimate of the percentage of patients with treatment success at 12 months was 74.6% (95% confidence interval [CI], 65.0 to 82.0) in the ablation group and 45.0% (95% CI, 34.6 to 54.7) in the drug-therapy group (P<0.001 by log-rank test). Two primary safety end-point events occurred in the ablation group (Kaplan-Meier estimate of the percentage of patients with an event within 12 months, 1.9%; 95% CI, 0.5 to 7.5).

CONCLUSIONS

Cryoballoon ablation as initial therapy was superior to drug therapy for the prevention of atrial arrhythmia recurrence in patients with paroxysmal atrial fibrillation. Serious procedure-related adverse events were uncommon. (Supported by Medtronic; STOP AF First ClinicalTrials.gov number, NCT03118518.).

Trends and predictors of early ablation for Atrial Fibrillation in a Nationwide population under age 65: a retrospective observational study

BACKGROUND

Catheter ablation (CA) has emerged as an effective treatment for symptomatic atrial fibrillation (AF). However practice patterns and patient factors associated with referral for CA within the first 12 months after diagnosis are poorly characterized. This study examined overall procedural trends and factors predictive of catheter ablation for newly-diagnosed atrial fibrillation in a young, commercially-insured population.

METHODS

A large nationally-representative sample of patients age 20 to 64 from years 2010 to 2016 was studied using the IBM MarketScan® Commercial Database. Patients were included with a new diagnosis of AF in the inpatient or outpatient setting with continuous enrollment for at least 1 year pre and post index visit. Patients were excluded if they had prior history of AF or had filled an anti-arrhythmic drug (AAD) in the pre-index period.

RESULTS

Early CA increased from 5.0% in 2010 to 10.5% in 2016. Patients were less likely to undergo CA if they were located in the Northeast (OR: 0.80, CI: 0.73-0.88) or North Central (OR: 0.91, CI: 0.83-0.99) regions (compared with the West), had higher CHA2DS2-VASc scores, or had Charlson Comorbidity Index (CCI) score of 3 or greater (OR: 0.61; CI: 0.51-0.72).

CONCLUSIONS

CA within 12 months for new-diagnosed AF increased significantly from 2010 to 2016, with most patients still trialed on an AAD prior to CA. Patients are less likely to be referred for early CA if they are located in the Northeast and North Central regions, have more comorbidities, or higher CHA2DS2-VASc scores.

Longer diagnosis-to-ablation time is associated with recurrence of atrial fibrillation after catheter ablation-Systematic review and meta-analysis

BACKGROUND

Diagnosis-to-ablation time (DTAT) has been postulated to be one of the predictors of atrial fibrillation (AF) recurrence, and it is a "modifiable" risk factor unlike that of many electrocardiographic or echocardiographic parameters. This development may change our consideration for ablation. In this systematic review and meta-analysis, we aim to analyze the latest evidence on the importance of DTAT and whether they predict the AF recurrence after catheter ablation.

METHODS

We performed a comprehensive search on topics that assess diagnosis-to-ablation time (DTAT) and AF recurrence from inception up until August 2019 through PubMed, EuropePMC, Cochrane Central Database, and http://ClinicalTrials.gov.

RESULTS

There was a total of 3548 patients from six studies. Longer DTAT was associated with increased risk for AF recurrence in all studies included. Meta-analysis of these studies showed that DTAT had a hazard ratio (HR) of 1.19 [1.02, 1.39], P = .03; I 2: 92% for AF recurrence. Upon sensitivity analysis by removing a study, HR became 1.24 [1.16, 1.32], P < .001; I 2: 29%. Meta-analysis on DTAT time >3 years had HR 1.73 [1.54, 1.93], P < .001; I 2: 45% for the recurrence of AF. Upon subgroup analysis of data that compared >6 years to <1 year, the HR was 1.93 [1.62, 2.29], P < .001; I 2: 0%.

CONCLUSION

Longer DTAT time is associated with an increased risk of AF recurrence. Hence, determining management at the earliest possible moment to avoid delay is of utmost importance.

Diagnosis-to-Ablation Time and Recurrence of Atrial Fibrillation Following Catheter Ablation: A Systematic Review and Meta-Analysis of Observational Studies

BACKGROUND

The optimal timing of catheter ablation for atrial fibrillation (AF) in reference to the time of diagnosis is unknown. We sought to assess the impact of the duration between first diagnosis of AF and ablation, or diagnosis-to-ablation time (DAT), on AF recurrence following catheter ablation.

METHODS

We conducted a systematic electronic search for observational studies reporting the outcomes associated with catheter ablation for atrial fibrillation stratified by diagnosis-to-ablation time. The primary meta-analysis using a random effects model assessed AF recurrence stratified by DAT ≤1 year versus >1 year. A secondary analysis assessed outcomes stratified by DAT ≤3 years versus >3 years.

RESULTS

Of the 632 screened studies, 6 studies met inclusion criteria for a total of 4950 participants undergoing AF ablation for symptomatic AF. A shorter DAT ≤1 year was associated with a lower relative risk of AF recurrence compared with DAT >1 year (relative risk, 0.73 [95% CI, 0.65-0.82]; P<0.001). Heterogeneity was moderate (I²=51%). When excluding the one study consisting of only patients with persistent AF, the heterogeneity improved substantially (I²=0%, Cochran's Q P=0.55) with a similar estimate of effect (relative risk, 0.78 [95% CI, 0.71-0.85]; P<0.001).

CONCLUSIONS

Shorter duration between time of first AF diagnosis and AF ablation is associated with an increased likelihood of ablation procedural success. Additional study is required to confirm these results and to explore implementation of earlier catheter AF ablation and patient outcomes within the current AF care pathway. Visual Overview A visual overview is available for this article.

Association of Obesity Measures with Atrial Fibrillation Recurrence After Cryoablation in Patients with Paroxysmal Atrial Fibrillation

BACKGROUND Obesity increases the risk of atrial fibrillation (AF) recurrence after ablation. This study explored the relationship between various obesity indexes and risk of recurrence after cryoablation of paroxysmal AF (PAF). MATERIAL AND METHODS Our prospective study included 100 patients with PAF who underwent first cryoablation. Physical examination and fasting blood lipids levels were measured at baseline. Seven obesity indexes were determined: body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), waist-hip ratio (WHR), cardiometabolic index (CMI), lipid accumulation product (LAP), and body adiposity index (BAI). AF recurrence was confirmed by electrocardiograms and Holter monitor at follow-up visits after the initial 3-month blanking period. Receiver operating characteristic (ROC) curves were drawn to assess the abilities of obesity indicators in predicting AF recurrence. Multivariable Cox regression analysis was used to examine independent predictors of AF recurrence. RESULTS During a mean follow-up of 13.4 months, 31 patients (31.0%) had recurrent AF. Patients with recurrence had higher BMI, WC, WHtR, LAP, and BAI compared with those without recurrence. ROC analysis indicated the potential predictive value of BAI with an AUC of 0.657 (95% confidence interval [CI]: 0.534-0.779), followed by WC, WHtR, LAP, and BMI (all P<0.05). Diagnosis-to-ablation time (HR 1.034, 95% CI: 1.002-1.068), left atrial diameter (HR 1.147, 95% CI: 1.026-1.281), and WC (HR 1.026, 95% CI: 1.000-1.053) were independent predictive factors for AF recurrence after multivariable adjustment. CONCLUSIONS In this study population, WC appears to be a potential indicator for the prediction of recurrence in patients with PAF after cryoablation.

Efficacy and safety of cryoballoon ablation for Chinese patients over 75 years old: A comparison with a younger cohort

INTRODUCTION

Cryoballoon ablation (CBA) results in satisfactory outcomes for drug-resistant atrial fibrillation (AF) patients. However, the efficacy and safety of CBA have not yet been tested in the Chinese elderly population. Therefore, this study compared the recurrence of AF and complications of CBA in patients ≥75 years and <75 years.

METHODS

A total of 677 patients (<75 years, n = 550; ≥ 75 years, n = 127) with paroxysmal (n = 603) or persistent (n = 74) non-valvular drug-resistant AF were included. The efficacy was assessed by the recurrence of AF, and the safety was evaluated by peri- and post-procedural complications.

RESULTS

The CHA2DS2-VASc (2.6 ± 1.7 vs 4.8 ± 1.6, P < .01) and HAS-BLED (1.8 ± 0.8 vs 2.0 ± 0.8, P = .01) scores were significantly higher in the elderly group. The instant pulmonary vein isolation success rate was comparable (99.11% younger vs 98.98% older, P = .99). After a mean follow-up time of 12.8 ± 9.6 months, the 1-year freedom from AF rate was 80.6% vs 85.8% in the older and younger groups, respectively, while the survival analysis showed a nonsignificant difference in the rate of freedom from AF (log-rank P = .46). Cox regression showed that age was not a predictive factor for AF recurrence and was not dichotomized (hazard ratio [HR] = 0.868, 95% confidence interval [CI] 0.509-1.481; P = .6046) or continuous (HR = 0.990, 95% CI, 0.968-1.012, P = .3642). Similar complications rates were observed, including stroke (1.0% younger vs 0.93% older, P = .95) and major hemorrhagic events (1.2% younger vs 0% elder, P = .25).

CONCLUSIONS

The efficacy and safety profiles of CBA in patients older than 75 years are comparable with those in younger patients.

Impact of Female Sex on Clinical Outcomes in the FIRE AND ICE Trial of Catheter Ablation for Atrial Fibrillation

BACKGROUND

Data on predictors of long-term clinical outcomes after catheter ablation of atrial fibrillation (AF) are limited. We sought to assess the association of baseline covariates with clinical outcomes in the 750 patients with drug-refractory paroxysmal AF enrolled in FIRE AND ICE.

METHODS

In a 2-part analysis, univariate and multivariable Cox regression models were first used to identify baseline patient characteristics predictive of catheter ablation efficacy determined by the clinical end points of (1) atrial arrhythmia recurrence (primary efficacy failure), (2) cardiovascular rehospitalization, and (3) repeat ablation. Propensity score stratification methods were then used to account for differences in baseline characteristics between sexes.

RESULTS

Female sex (hazard ratio [HR], 1.37; 95% confidence interval [CI], 1.08-1.73; P=0.010) and prior direct current cardioversion (HR, 1.40; 95% CI, 1.07-1.82; P=0.013) were independently associated with atrial arrhythmia recurrence. Female sex (HR, 1.36; 95% CI, 1.02-1.80; P=0.035) and hypertension (HR, 1.48; 95% CI, 1.09-2.00; P=0.013) independently predicted cardiovascular rehospitalization. A longer history of AF (HR, 1.03; 95% CI, 1.00-1.06; P=0.039) increased the rate of repeat ablation. Women continued to have higher rates of primary efficacy failure and cardiovascular rehospitalization after propensity score adjustment, with adjusted HRs of 1.51 (95% CI, 1.16-2.18; P<0.05) and 1.40 (95% CI, 1.15-2.17; P<0.05), respectively.

CONCLUSIONS

After catheter ablation of paroxysmal AF, female sex was associated with an almost 40% increase in the risks of primary efficacy failure and cardiovascular rehospitalization. Primary efficacy failure was also adversely impacted by a history of direct current cardioversion, whereas hypertension had a negative impact on cardiovascular rehospitalization. History of AF was the only predictor of repeat ablation.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01490814.

Study on the relationship between telomere length changes and recurrence of atrial fibrillation after radiofrequency catheter ablation

INTRODUCTION

Advanced age is the foremost risk factor for atrial fibrillation (AF). Telomere length is a surrogate for biological aging, but the association between shortened leukocyte telomere length (LTL) and recurrence of AF (RAF) after ablation remains inconclusive.

METHODS

In this prospective analysis, 282 patients underwent an initial catheter ablation for paroxysmal or persistent AF. The association between RAF and LTL was analyzed by univariate and multivariate Cox regression, as well as time-dependent receiver operating characteristic (ROC) analysis and Kaplan-Meier analysis.

RESULTS

After a mean follow-up of 14.20 ± 5.04 months, RAF was documented in 78 of the 277 patients who completed the study (28.16%). In Cox proportional hazards models, LTL, age, diagnosis to ablation time (DTAT), N-terminal pronatriuretic peptide, and CHA2DS2-VASc score were significantly associated with RAF. After multivariable adjustment, LTL and DTAT were predicted as independent risk factors for RAF with hazard ratio (HR) of 3.17 (95% confidence interval [CI]: 1.23-8.15, P = 0.017) and 1.43 (95% CI: 1.10-1.86, P = 0.007), respectively. In addition, ROC analysis indicated the potential diagnostic value of LTL with an area under the curve of 0.64 (P < 0.001; sensitivity = 60.3%, specificity = 57.8%), and an optimum cut-off value of 1.040. LTL less than or equal to 1.040 was defined as shortened LTL, while LTL greater than 1.040 nonshortened LTL. Kaplan-Meier analysis showed RAF rate curve was separated significantly between two groups (21.2% vs 35.9%, log-rank test result P = 0.007). Patients with shortened LTL might have a higher risk for RAF with HR = 1.84 (P = 0.008).

CONCLUSIONS

Shortened LTL is an independent risk factor for AF recurrence. Shortened LTL could be a potential biomarker in predicting RAF after ablation.

Early choice for catheter ablation reduced readmission in management of atrial fibrillation: Impact of diagnosis-to-ablation time

BACKGROUND

The impact of delays in the treatment with radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) has not been well evaluated. The aim of this study was to investigate the impact of diagnosis-to-ablation time (DAT) on the long-term clinical outcomes after AF-RFCA.

METHODS

We enrolled 1206 consecutive patients undergoing first-time RFCA for AF. The study population was divided into 2 groups based on DAT: short (<3 years) (N = 675) and long (>3 years) (N = 531) DAT groups.

RESULTS

Mean follow-up duration was 5.0 ± 2.5 years. The 5-year event-free rates from recurrent atrial tachyarrhythmias after the first and second RFCAs were significantly higher in short DAT group than in long DAT group (60.2% versus 48.3%, log-rank P < 0.001; 83.2% versus 75.2%, log-rank P = 0.02, respectively), leading to reduced cardiovascular hospitalization in short DAT group. After adjusting baseline differences, short DAT was independently associated with lower arrhythmia recurrence rates after the first and second RFCAs (hazard ratio [HR] 0.72, 95% confidence interval [CI] 0.60-0.86 and HR 0.72, 95%CI 0.55-0.95, respectively). There were no significant differences between the 2 groups in the event-free rates from all-cause and cardiovascular deaths, heart failure hospitalization, and ischemic stroke. However, among patients with a history of heart failure or reduced left ventricular function, the event-free rate from heart failure readmission was significantly higher in short DAT group (85.0% versus 61.0%, P = 0.004).

CONCLUSIONS

In the management of AF, early RFCA was associated with significantly lower arrhythmia recurrence compared with delayed RFCA, leading to reduced cardiovascular hospitalization, especially in heart failure patients.

Immunopathogenesis and biomarkers of recurrent atrial fibrillation following ablation therapy in patients with preexisting atrial fibrillation

INTRODUCTION

Recurrent atrial fibrillation (RAF) following ablation therapy occurs in about 50% of patients. The pathogenesis of RAF is unknown, but is believed to be driven by atrial remodeling in the setting of background inflammation. Structural, electrophysiological and mechanical remodeling has been associated with atrial fibrillation (AF). Inflammation and fibrotic remodeling are the major factors perpetuating AF, as mediators released from the atrial tissues and cardiomyocytes due to mechanical and surgical injury could initiate the inflammatory process. In this article, we have critically reviewed the key mediators that may serve as potential biomarkers to predict RAF. Areas covered: Damage associated molecular patterns, heat shock proteins, inflammatory cytokines, non-inflammatory markers, markers of inflammatory cell activity, and markers of collagen deposition and metabolism are evaluated as potential biomarkers with molecular treatment options in RAF. Expert commentary: Establishing biomarkers to predict RAF could be useful in reducing morbidity and mortality. Investigations into the role of DAMPs participating in a sterile immune response may provide greater insight into the pathogenesis of RAF. Markers evaluating immune cell activity, collagen deposition, and levels of heat shock proteins show the greatest promise as potential biomarkers to predict RAF and develop novel therapies.

Catheter Ablation of Atrial Fibrillation in Patients With Heart Failure

Atrial fibrillation (AF) and heart failure (HF) both have become major cardiovascular epidemics, adversely affecting quality of life, decreasing longevity, and imparting a large economic burden on the healthcare system. Both share similar risk factors and frequently coexist, leading to increased morbidity and mortality relative to patients with either condition alone. Although evidence-based treatment guidelines for both diseases exist, consensus treatment strategies are less clear when AF and HF co-occur. Given the risks of antiarrhythmic drugs and their incomplete success in maintaining sinus rhythm, catheter ablation has become an increasingly popular alternative to pharmacologic rhythm control in symptomatic patients with AF with normal cardiac function. Although multiple studies have demonstrated the efficacy of catheter ablation in AF, studies examining the use of catheter ablation specifically in patients with HF have recently begun to emerge and provide some guidance in this group of patients. In this review, we examine the effects of catheter ablation of AF in patients with HF on maintenance of sinus rhythm, left ventricular ejection fraction, exercise capacity, quality of life, hospitalization, and mortality rates. Data regarding both HF with reduced ejection fraction and preserved ejection fraction are discussed.