Sex-specific efficacy and safety of cryoballoon versus radiofrequency ablation for atrial fibrillation: An individual patient data meta-analysis

Development and validation of a predictive model for atrial fibrillation recurrence post-catheter ablation in patients with nonvalvular atrial fibrillation on the basis of hemodynamic parameters

BACKGROUND

The influence of hemodynamic parameters on the recurrence of atrial fibrillation (AF) after catheter ablation is not well known, and it remains unclear whether a nomogram combining risk factors and hemodynamic parameters improves prediction accuracy.

OBJECTIVE

This study aimed to develop a nomogram on the basis of echocardiographic hemodynamic parameters for predicting AF recurrence after catheter ablation in nonvalvular atrial fibrillation (NVAF).

METHODS

A total of 380 consecutive patients with NVAF undergoing AF catheter ablation treatment were prospectively included. Patients were divided into training and validation cohorts in a 7:3 ratio. The follow-up time averaged 9 months with a median of 12 months, during which 132 patients (34.7%) experienced AF recurrence.

RESULTS

Least absolute shrinkage and selection operator regression and Cox regression analyses identified 4 significant predictors of AF recurrence: persistent AF (hazard ratio [HR] 1.63; 95% confidence interval [CI] 1.02-2.61; P = .041), S/D ratio of pulmonary vein (HR 0.50; 95% CI 0.30-0.84; P = .009), left atrial acceleration factor α (HR 1.31; 95% CI 1.02-1.68; P = .032), and left atrial appendage peak emptying flow velocity (HR 0.98; 95% CI 0.97-0.99; P = .004). On the basis of these 4 variables, a predictive nomogram was constructed. The nomogram demonstrated C indices of 0.664 and 0.728 for predicting 1- and 2-year AF recurrence, respectively, in the validation cohort. The Kaplan-Meier survival analysis indicated that a Nomo score of >128 was associated with a higher risk of AF recurrence.

CONCLUSION

Hemodynamic parameters may offer valuable insight into predicting AF recurrence after catheter ablation. Our study successfully developed a reliable nomogram on the basis of echocardiographic hemodynamic parameters to estimate the risk of AF recurrence after catheter ablation in patients with NVAF.

Severe Periprocedural Complications After Ablation for Atrial Fibrillation: An International Collaborative Individual Patient Data Registry

BACKGROUND

Catheter ablation for atrial fibrillation (AF) including pulmonary vein isolation and possibly further substrate ablation is the most common electrophysiological procedure. Severe complications are uncommon, but their detailed assessment in a large worldwide cohort is lacking.

OBJECTIVES

The aim of this study was to determine the incidence of periprocedural severe complications and to provide a detailed characterization of the diagnostic evaluation and management of these complications in patients undergoing AF ablation.

METHODS

Individual patient data were collected from 23 centers worldwide. Limited data were collected for all patients who underwent catheter ablation, and an expanded series of data points were collected for patients who experienced severe complications during periprocedural follow-up. Incidence, predictors, patient characteristics, management details, and overall outcomes of patients who experienced ablation-related complications were investigated.

RESULTS

Data were collected from 23 participating centers at which 33,879 procedures were performed (median age 63 years, 30% women, 71% radiofrequency ablations). The incidence of severe complications (n = 271) was low (tamponade 6.8‰, stroke 0.97‰, cardiac arrest 0.41‰, esophageal fistula 0.21‰, and death 0.21‰). Age, female sex, a dilated left atrium, procedure duration, and the use of radiofrequency energy were independently associated with the composite endpoint of all severe complications. Among patients experiencing tamponade, 13% required cardiac surgery. Ninety-three percent of patients with complications were discharged directly home after a median length of stay of 5 days (Q1-Q3: 3-7 days).

CONCLUSIONS

This large worldwide collaborative study highlighted that tamponade, stroke, cardiac arrest, esophageal fistula, and death are rare after AF ablation. Older age, female sex, procedure duration, a dilated left atrium, and the use of radiofrequency energy were associated with severe complications in this multinational cohort. One in 8 patients with tamponade required cardiac surgery.

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.

Efficacy and safety of pulmonary vein isolation with pulsed field ablation vs. novel cryoballoon ablation system for atrial fibrillation

AIMS

Pulsed-field ablation (PFA) has emerged as a novel treatment technology for patients with atrial fibrillation (AF). Cryoballoon (CB) is the most frequently used single shot technology. A direct comparison to a novel CB system is lacking. We aimed to compare pulmonary vein isolation (PVI) using PFA vs. a novel CB system regarding efficiency, safety, myocardial injury, and outcomes.

METHODS AND RESULTS

One hundred and eighty-one consecutive patients underwent PVI and were included (age 64 ± 9.7 years, ejection fraction 0.58 ± 0.09, left atrial size 40 ± 6.4 mm, paroxysmal AF 64%). 106 patients (59%) underwent PFA (FARAPULSE, Boston Scientific) and 75 patients (41%) underwent CB ablation (PolarX, Boston Scientific). The median procedure time, left atrial dwell time and fluoroscopic time were similar between the PFA and the CB group with 55 [interquartile range (IQR) 43-64] min vs. 58 (IQR 48-69) min (P < 0.087), 38 (30-49) min vs. 37 (31-48) min, (P = 0.871), and 11 (IQR 9.3-14) min vs. 11 (IQR 8.7-16) min, (P < 0.81), respectively. Three procedural complications were observed in the PFA group (two tamponades, one temporary ST elevation) and three complications in the CB group (3× reversible phrenic nerve palsies). During the median follow-up of 404 days (IQR 208-560), AF recurrence was similar in the PFA group and the CB group with 24 vs. 30%, P = 0.406.

CONCLUSION

Procedural characteristics were very similar between PFA and CB in regard to procedure duration fluoroscopy time and complications. Atrial fibrillation free survival did not differ between the PFA and CB groups.

Driver characteristics associated with structurally and electrically remodeled atria in persistent atrial fibrillation

Background

Recent studies suggest persistent atrial fibrillation (AF) is maintained by localized focal or rotational electrical activations termed drivers.

Objective

The purpose of this study was to evaluate how left atrial (LA) dilation and time in AF impact persistent AF mechanisms.

Methods

Patients with persistent AF <2 years underwent electrocardiographic image mapping. Potential drivers (PDs) were defined as rotational wavefront activity ≥1.5 revolutions or focal activations. Distribution of PDs was recorded using an 18-segment model.

Results

One hundred patients were enrolled (age 61.3 ± 12.1 years). Of these patients, 47 were hypertensive, 14 had diabetes mellitus, and 10 had ischemic heart disease. AF duration was 8 [5-15] months. Median LA diameter was 39 [33-43] mm. Although LA dimensions did not correlate with overall PD burden or distribution, there was a modest correlation between increasing LA area (r = 0.235; P = .024) and LA volume (r = 0.216; P = .039) with proportion of PDs that were rotational. Although time in AF did not correlate with overall PD burden or distribution, there was a correlation between time in AF and the number of focal PDs (r = 0.203; P = .044). Female gender, increasing age, and hypertension also were associated with an increase in focal PDs.

Conclusion

This is the first study to demonstrate different AF mechanisms in patient subgroups. Greater understanding of patient-specific AF mechanisms may facilitate a tailored approach to AF mapping and ablation.

Percutaneous Treatment Approaches in Atrial Fibrillation: Current Landscape and Future Perspectives

Atrial fibrillation (AF), the most common sustained arrhythmia in clinical practice, represents a major cause of morbidity and mortality, with an increasing prevalence. Pharmacologic treatment remains the cornerstone of its management through rhythm and rate control, as well as the prevention of thromboembolism with the use of oral anticoagulants. Recent progress in percutaneous interventional approaches have provided additional options in the therapeutic arsenal, however. The use of the different catheter ablation techniques can now lead to long arrhythmia-free intervals and significantly lower AF burden, thus reducing the rate of its complications. Particularly encouraging evidence is now available for patients with persistent AF or concomitant heart failure, situations in which catheter ablation could even be a first-line option. In the field of stroke prevention, targeting the left atrial appendage with percutaneous device implantation may reduce the risk of thromboembolism to lower rates than that predicted with conventional ischemic risk scores. Left atrial appendage occlusion through the approved Watchman or Amplatzer devices is a well-established, efficacious, and safe method, especially in high-ischemic and bleeding risk patients with contraindications for oral anticoagulation.

ECG-I Phenotyping of Persistent AF Based on Driver Burden and Distribution to Predict Response to Pulmonary Vein Isolation (PHENOTYPE-AF)

BACKGROUND

This prospective trial sought to phenotype persistent AF based on AF mechanisms using ECGI mapping to determine whether this would predict long term freedom from arrhythmia after pulmonary vein isolation (PVI).

METHODS

Patients with persistent AF of < 2 years duration underwent cryoballoon PVI. ECGI mapping was performed prior to PVI to determine potential drivers (PDs) defined as rotational activations completing ≥ 1.5 revolutions or focal activations. The co-primary end point was the association between (1) PD burden (defined as the number of PD occurrences) and (2) PD distribution (defined as the number of segments on an 18 segment model of the atria harbouring PDs) with freedom from arrhythmia at 1 year follow up.

RESULTS

Of 100 patients, 97 completed follow up and 52 (53.6%) remained in sinus rhythm off antiarrhythmic drugs. Neither PD burden nor PD distribution predicted freedom from arrhythmia (HR 1.01, 95% CI 0.99 - 1.03, p = 0.164; and HR 1.04, 95% CI 0.91 - 1.17, p = 0.591 respectively). Otherwise, the burden of rotational PDs, rotational stability, and the burden of PDs occurring at the pulmonary veins and posterior wall all failed to predict arrhythmia recurrence (all p > 0.10).

CONCLUSIONS

AF mechanisms as determined using ECGI mapping do not predict outcome after PVI for persistent AF. Further studies using different methodologies to characterise AF mechanisms are warranted. (NCT03394404) This article is protected by copyright. All rights reserved.

How effective is cryoablation in the treatment of atrial fibrillation?

Pulmonary vein isolation is the standard for atrial fibrillation ablation. Although the most commonly applied energy source is radiofrequency (RF), cryoablation has rapidly evolved as a powerful one-shot tool, particularly after the introduction of the second-generation catheter, gaining widespread use in recent years. The efficacy in maintaining sinus rhythm after a first ablative procedure is ∼70–80%, and the randomization studies comparing cryoablation to RF have not been able to reveal significant differences up to now. Although different baseline characteristics may influence the efficacy of cryoablation, we are not yet able to distinguish which patients may benefit from a personalized choice of ablative source. Regarding safety, cryoballoon ablation appears to be associated with a lower rate of pericardial effusion and cardiac tamponade, mainly due to the lack of risk of overheating. The other side of the coin is a higher incidence of phrenic nerve damage, which occurs in 1–2% of procedures. In conclusion, we do not yet have definitive data to affirm the superiority of the RF technique over that of cryoablation. The choice of energy source currently depends on the availability of the centre and on the experience of the operator.

Technical and procedural comparison of two different cryoballoon ablation systems in patients with atrial fibrillation

PURPOSE

The aim was to report procedural and technical differences of a novel cryoballoon (NCB) ablation catheter for pulmonary vein isolation (PVI) compared to the standard cryoballoon (SCB) catheter.

METHODS

Consecutive patients with atrial fibrillation (AF) undergoing PVI using the NCB and the SCB were included. Procedural parameters, technical differences, acute efficacy, and safety are reported.

RESULTS

Eighty patients (age 66 ± 10 years, ejection fraction 57 ± 10%, left atrial volume index 40 ± 6 ml/m²) were studied. With the NCB, 156 of 158 PVs (99%) were isolated compared to isolation of 159 of 159 PVs (100%) with the SCB. The median number of freezes in the NCB and the SCB group was 6 (IQR 5-8) and 5 (IQR 4-7), respectively (p = 0.051), with 73% and 71% of the PVs isolated with a single freeze, respectively. Nadir temperature and temperature at isolation were - 59 ± 6 °C and - 45 ± 17 °C in the NCB group and - 46 ± 7 °C and - 32 ± 23 °C in the SCB group, respectively (both p < 0.001) with no difference in time to isolation (TTI). Procedural differences were observed for the total procedure time (84 ± 29 min in the NCB group and 65 ± 17 min in the SCB group, p = 0.003). There was a peri-procedural stroke in one patient in the NCB group. Differences in catheter design were observed that may account for the differences in temperature recordings and ice cap formation.

CONCLUSIONS

Acute efficacy and TTI were similar with the NCB compared to the SCB. Measured temperatures were lower with the NCB, most likely due to differences in catheter design.

Safety of cryoballoon ablation for the treatment of atrial fibrillation: First European results from the cryo AF Global Registry

BACKGROUND

Cryoballoon ablation for the treatment of patients with atrial fibrillation (AF) has been utilized in Europe for >15 years.

OBJECTIVES

Report patient and procedural characteristics that influence the safety of cryoablation for the treatment of AF.

METHODS

Patients enrolled in the prospective, multicenter Cryo AF Global Registry were treated at 38 European centers. Freedom from a ≥30s episode of AF/atrial flutter (AFL)/atrial tachycardia (AT) at 12-months and serious complications were analyzed. Univariate and multivariable models identified baseline patient and procedural characteristics that predicted a procedure-related complication.

RESULTS

Of the 1418 subjects who completed an index procedure, the cohort was 62 ± 11 years of age, 37.7% female, and 72.2% paroxysmal AF (PAF). The mean procedure, left atrial dwell, and fluoroscopy times were 81 ± 34, 54 ± 25, and 14 ± 13 min, respectively. Among the 766 patients with 12-month follow-up, freedom from a ≥30 s AF/AFL/AT recurrence was 83.3% (95% CI: 79.8%-86.3%) and 71.6% (95% CI: 64.6%-77.4%) in patients with PAF and persistent AF. The serious procedure- and device-related adverse event rates were 4.7% and 2.0%. No baseline patient characteristic independently predicted a procedure-related adverse event; however, prolonged procedure duration (OR = 1.01 [95% CI: 1.00-1.01]), use of general anesthesia (OR = 1.71 [95% CI: 1.01-2.92]), and delivery of a cavotricuspid isthmus line (OR = 3.04 [95% CI: 1.01-9.20]) were each independently associated with the occurrence of a serious procedural safety event (all p < .05).

CONCLUSIONS

Cryoballoon ablation is safe and effective in real-world use across a broad cohort of patients with AF.

Cryoballoon vs radiofrequency ablation of atrial fibrillation: insights from the Veterans Healthcare System

PURPOSE

Catheter ablation is considered the mainstay treatment for drug-refractory atrial fibrillation (AF). The aims of our study were to compare the efficacy and safety of the most two currently approved approaches (point-by-point radiofrequency ablation (RFA), either with contact force (CF) or without contact force (nCF) catheters, and cryoballoon ablation (CBA)) in the Veterans Healthcare System.

METHODS

We performed a retrospective study of patients who underwent ablation for treatment of AF at the veterans affairs healthcare system between 2013 and 2018. Only the first reported ablation procedure was included.

RESULTS

We included 956 patients in the study (97.4% males, 91.5% Caucasians, 67% paroxysmal AF), with 682 patients in RFA-nCF, 139 in RFA-CF, and 135 in CBA. Thirty-day complication rates were comparable between the three groups with the exception of higher incidence of phrenic nerve injury in CBA group when compared to RFA-nCF (2.2% vs 0.0%, p < 0.01). Long-term recurrence rate of AF was significantly lower in the CBA group when compared to RFA-nCF (33.3% vs 47.7%, adjusted HR 0.60, 95% CI 0.44-0.83, p < 0.01). On the other hand, it was similar between RFA-CF and RFA-nCF groups (43.9% vs 47.7%, adjusted HR 1.01, 95% CI 0.76-1.33, p 0.97). After stratifying patients based on AF type, these findings were only present in patients with paroxysmal AF.

CONCLUSION

CBA for paroxysmal AF, in male dominant patients' population, was associated with lower incidence of AF recurrence rate while having a comparable safety profile to RFA independent of the use of CF catheters.

Sex-Related Differences in Catheter Ablation for Patients With Atrial Fibrillation and Heart Failure

The coexistence of atrial fibrillation and heart failure significantly increases the risk of all-cause mortality and heart failure hospitalizations. Sex-related differences in all patients undergoing atrial fibrillation catheter ablation include the referral of fewer women for catheter ablation (15–25%), older age of women at ablation, and higher risk of post-ablation recurrence of atrial fibrillation. We searched the existing literature for sex-related differences in patients undergoing atrial fibrillation catheter ablation with a focus on heart failure. Randomized controlled trials assessing atrial fibrillation catheter ablation in patients with heart failure have demonstrated a significant reduction in all-cause mortality and heart failure hospitalizations. Within the eight existing randomized controlled trials on heart failure with reduced ejection fraction, women composed a small proportion of the study population. Only two studies (CASTLE-AF and AATAC-HF) specifically assessed the effect of gender on outcome and showed no difference in post-ablation outcomes. Registry data-based studies assessing sex-related differences in atrial fibrillation catheter ablation in heart failure reveal that women are half as likely as men to undergo ablation. Conflicting data exist on the interaction of gender and heart failure as they may affect peri-ablation and post-ablation long-term outcomes such as atrial fibrillation recurrence or heart failure hospitalizations. In conclusion, existing studies provide insight into the gender-based differences in patients undergoing catheter ablation for atrial fibrillation as it pertains to heart failure. Further prospective studies with higher proportions of female participants are required to accurately determine gender-based differences in this population.