A novel double cryoballoon strategy in persistent atrial fibrillation: a pilot study

Impact of intracardiac echocardiography usage on the safety of cryoballoon atrial fibrillation ablation: Subanalysis of the prospective FREEZE cluster cohort study

INTRODUCTION

Cryoballoon ablation (CBA) aiming at pulmonary vein isolation (PVI) became a standardized atrial fibrillation (AF) ablation procedure. Life-threatening complications like cardiac tamponade exist. Intracardiac echocardiography (ICE) usage is associated with superior safety in radiofrequency ablation. It is unclear if ICE has an impact on safety of CBA.

METHODS

The FREEZE Cohort (NCT01360008) subanalysis included patients undergoing "PVI only" CBA. Patients with intraprocedural transesophageal echocardiography were excluded. Group A comprises conventional, group B ICE-guided CBA. Periprocedural results were compared.

RESULTS

From 2011 to 2016, a total of 4189 patients were enrolled, and 1906 (45.5%) were included in this subanalysis, split up in two groups (A: 1066 [55.9%], B: 840 [44.1%]). Group A was younger (60.6 ± 10.8 vs. 62.4 ± 10.5 years, p < .001), with smaller left atria (41 vs. 43 mm, p < .001), and less persistent AF (23.1 vs. 38.1%, p < .001). Procedure, left atrial, and fluoroscopy times were shorter in group A as compared to group B. Dose area product was significantly higher in group A (2911 vs. 2072 cGyxcm2 , p < .001). In-hospital major adverse cerebrovascular and cardiac event rates including two deaths in group A were not different between groups (0.5% vs. 0.1%, p = .18). The rate of total procedural (10.4% vs. 5.1%, p < .001) and major complications (3.2% vs. 1.3%, p < .001) was significantly higher in group A. Cardiac tamponade occurred significantly more frequently in group A (8 [0.8%] vs. 1 [0.1%], p = .046). Independent predictors for major complications were female sex (odds ratio [OR] 2.03, p = .03) and non-ICE usage (OR 2.38, p = .02). No differences were observed for persistent phrenic nerve palsy, nor for groin complications.

CONCLUSION

CBA was significantly safer and required less radiation if ICE was used, although the procedures were more complex. The risk of groin complications was not increased with ICE usage. Non-ICE usage was the only modifiable independent predictor of major complications.

Cryoballoon Ablation Strategy in Persistent Atrial Fibrillation

Background: Cryoballoon ablation is established for pulmonary vein isolation (PVI) in paroxysmal atrial fibrillation (AF). The objective was to evaluate CBA strategy in consecutive patients with persistent AF in the initial AF ablation procedure.

Material and Methods: Prospectively, patients with symptomatic persistent AF scheduled for AF ablation all underwent cryoballoon PVI. Technical enhancements, laboratory management, safety, single-procedure outcome, predictors of recurrence, and durability of PVI were evaluated.

Results: From 2007 to 2020, a total of 1,140 patients with persistent AF, median age 68 years, underwent cryoballoon ablation (CBA). Median left atrial (LA) diameter was 45 mm (interquantile range, IQR, 8), and Congestive heart failure, Hypertension, Age ≥75 years (doubled), Diabetes mellitus, prior Stroke or TIA or thromboembolism (doubled), Vascular disease, Age 65 to 74 years, Sex category (CHA₂DS₂-VASc) score was 3. Acute isolation was achieved in 99.6% of the pulmonary veins by CBA. Median LA time and median dose area product decreased significantly over time (p < 0.001). Major complications occurred in 17 (1.5%) patients including 2 (0.2%) stroke/transitory ischemic attack (TIA), 1 (0.1%) tamponade, relevant groin complications, 1 (0.1%) significant ASD, and 4 (0.4%) persistent phrenic nerve palsy (PNP). Transient PNP occurred in 66 (5.5%) patients. No atrio-esophageal fistula was documented. Five deaths (0.4%), unrelated to the procedure, occurred very late during follow-up. After initial CBA, arrhythmia recurrences occurred in 46.6% of the patients. Freedom from atrial arrhythmias at 1-, and 2-year was 81.8 and 61.7%, respectively. Independent predictors of recurrence were LA diameter, female sex, and use of the first cryoballoon generation. Repeat ablations due to recurrences were performed in 268 (23.5%) of the 1,140 patients. No pulmonary vein (PV) reconduction was found in 49.6% of the patients and 73.5% of PVs. This rate increased to 66.4% of the patients and 88% of PVs if an advanced cryoballoon was used in the first AF ablation procedure.

Conclusion: Cryoballoon ablation for symptomatic persistent AF is a reasonable strategy in the initial AF ablation procedure.

Cryoballoon Ablation for the Treatment of Atrial Fibrillation: A Meta-analysis

BACKGROUND

Ablation therapy is the treatment of choice in antiarrhythmic drugrefractory atrial fibrillation (AF). It is performed by either cryoballoon ablation (CBA) or radiofrequency ablation. CBA is gaining popularity due to simplicity with similar efficacy and complication rate compared with RFA. In this meta-analysis, we compare the recurrence rate of AF and the complications from CBA versus RFA for the treatment of AF.

METHODS

We systematically searched PubMed for the articles that compared the outcome of interest. The primary outcome was to compare the recurrence rate of AF between CBA and RFA. We also included subgroup analysis with complications of pericardial effusion, phrenic nerve palsy and cerebral microemboli following ablation therapy.

RESULTS

A total of 24 studies with 3527 patients met our predefined inclusion criteria. Recurrence of AF after CBA or RFA was similar in both groups (RR: 0.84; 95% CI: 0.65, 1.07; I2=48%, Cochrane p=0.16). In subgroup analysis, heterogeneity was less in paroxysmal AF (I2=0%, Cochrane p=0.46) compared to mixed AF (I2=72%, Cochrane p=0.003). Procedure and fluoroscopy time was less by 26.37 and 5.94 minutes respectively in CBA compared to RFA. Complications, pericardial effusion, and silent cerebral microemboli, were not different between the two groups, however, phrenic nerve palsy was exclusively present only in CBA group.

CONCLUSION

This study confirms that the effectiveness of CBA is similar to RFA in the treatment of AF with the added advantages of shorter procedure and fluoroscopy times.

Second-generation cryoballoon ablation for recurrent atrial fibrillation after an index cryoballoon procedure: a staged strategy with variable balloon size

PURPOSE

Currently, information on the optimal approach of redo procedures for paroxysmal atrial fibrillation (PAF) is limited. Radiofrequency ablation is the preferred technique, with reported success rates of 50-70% at 1-2 years, whereas only few reports exist on redo cryoballoon (CB) ablations. We describe outcomes on a systematic approach of repeat procedures with a second-generation cryoballoon (CB-2) after a successful index CB ablation.

METHODS

Cohort study of 40 consecutive patients with recurrent PAF (55% male), median CHA2DS2-VASc score 1 (IQR 0-3). Per protocol, a staged variable balloon size strategy was followed with a different balloon size during the redo as compared to the index procedure. Minimal follow-up was 12 months (median 17 months [IQR 14-39]).

RESULTS

Overall, 120 pulmonary veins (PVs) (75%) showed chronic isolation: 64% (41/64) for first-generation cryoballoon (CB-1) and 82% (79/96) for CB-2 index procedures, respectively (p = 0.01). The overall mean number of reconnected PVs per patient was 1.0 (40/40): 1.4 for CB-1 and 0.7 for CB-2 index procedures (p = 0.008). Phrenic nerve palsies (n = 7) resolved before the end of the procedure. At 1 year, 70% of patients were free of recurrent AF. In multivariate analysis, the only independent predictor of recurrence was the number of prior cardioversions.

CONCLUSIONS

A systematic approach of repeat procedures with a CB-2 using a different balloon size than during the index CB ablation is safe, with acceptable 1-year outcomes. Future comparative studies on the optimal redo technique and approach are warranted to further improve rhythm control in AF.

Radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique : Long-term outcome

BACKGROUND

Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory atrial fibrillation (AF). Cryoablation has been shown to be a safe and effective technique for pulmonary vein (PV) isolation. However, the arrhythmia recurrence rate is high after cryoablation procedures. Radiofrequency catheter ablation has been shown to be an effective strategy for redo procedures in these patients and to provide a favourable outcome during midterm follow-up. The aim of this study was to analyse whether the strategy also provides favourable results during long-term follow-up (5 years).

METHODS

In this study 30 patients (paroxysmal AF: 22 patients, persistent AF: 8 patients) underwent a redo procedure after initially successful circumferential PV isolation with the cryoballoon technique (Arctic Front Balloon, Medtronic). The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy (CARTO; Biosense Webster, Diamond Bar, CA, USA) depending on the intraprocedural findings.

RESULTS

During the repeat procedure, a mean number of 2.9 reconnected PV (SD ± 1.0) were detected. In 20 patients, a segmental approach was sufficient to eliminate the residual PV conduction because only a few PV fibres were recovered (1-3 reconnected PV; group A). In the remaining 10 patients, a circumferential ablation strategy was used because of a complete recovery of the pulmonary vein - left atrial (PV-LA) conduction (group B). All reconnected PV were isolated successfully again. A third or fourth ablation procedure had to be performed in 4 (3 and 1, respectively) patients (13.3%). At 5‑year follow-up, 66.7% of all patients were free from an arrhythmia recurrence (20 out of 30). There were no major complications during long-term follow-up.

CONCLUSION

In patients with an initial circumferential PV isolation using the cryoballoon technique, a repeat ablation procedure can be safely and effectively performed using radiofrequency catheter ablation providing good long-term follow-up results.

Experience matters: long-term results of pulmonary vein isolation using a robotic navigation system for the treatment of paroxysmal atrial fibrillation

BACKGROUND

Long-term results after circumferential pulmonary vein isolation (CPVI) for the treatment of paroxysmal atrial fibrillation (PAF) using a robotic navigation system (RNS) have not yet been reported.

OBJECTIVE

To evaluate long-term results of patients with PAF after CPVI using RNS.

METHODS

In this study, 200 patients (n = 151 (75.5%) male; median age 62.2 (54.7-67.7) years) with PAF were evaluated. In 100 patients, RNS (RN-group) was used for CPVI and compared to 100 manually ablated control patients (MN-group). Radiofrequency was used in conjunction with 3D electroanatomic mapping. Power was limited to 30 watts (W) at the posterior left atrial (LA) wall in the first 49 RNS patients (RN-group-a). After esophageal perforation occurred in one RN-group-a patient, maximum power was reduced to 20 W for the subsequent 51 patients (RN-group-b).

RESULTS

After a median follow-up of 2 years, single (77/100 vs 77/100, p = 0.89) and multiple (90/100 vs 93/100, p = 0.29) procedure success rates were comparable between RN-group and MN-group. Single procedure success rate was significantly lower in RN-group-a as compared to RN-group-b (65.3 vs 88.2%, p = 0.047). In RN-group-a patients, procedural times [200 (170-230) vs 152 (132-200) minutes, p < 0.01] and fluoroscopy times [16.6 (12.9-21.6) minutes vs 13.7 (9.5-19) minutes, p = 0.043] were significantly longer compared to RN-group-b patients.

CONCLUSION

Long-term success rate after CPVI using RNS was comparable to manual ablation. Despite a lower power limit of 20 W at the posterior LA wall, single procedure success rate was higher in RN-group-b as compared to RN-group-a. Procedure time and fluoroscopy time decreased, whilst success rate increased with increasing experience in the RN-group.

Clinical Experience With a Novel Electromyographic Approach to Preventing Phrenic Nerve Injury During Cryoballoon Ablation in Atrial Fibrillation

Background—

Phrenic nerve palsy remains the most frequent complication associated with cryoballoon-based pulmonary vein (PV) isolation. We sought to characterize our experience using a novel monitoring technique for the prevention of phrenic nerve palsy.

Methods and Results—

Two hundred consecutive cryoballoon-based PV isolation procedures between October 2010 and October 2013 were studied. In addition to standard abdominal palpation during right phrenic nerve pacing from the superior vena cava, all patients underwent diaphragmatic electromyographic monitoring using surface electrodes. Cryoablation was terminated on any perceived reduction in diaphragmatic motion or a 30% decrease in the compound motor action potential (CMAP). During right-sided ablation, a ≥30% reduction in CMAP amplitude occurred in 49 patients (24.5%). Diaphragmatic motion decreased in 30 of 49 patients and was preceded by a 30% reduction in CMAP amplitude in all. In 82% of cases, this reduction in CMAP amplitude occurred during right superior PV isolation. The baseline CMAP amplitude was 946.5±609.2 mV and decreased by 13.8±13.8% at the end of application. This decrease was more marked in the 33 PVs with a reduction in diaphragmatic motion than in those without (40.9±15.3% versus 11.3±10.5%; P <0.001). In 3 cases, phrenic nerve palsy persisted beyond the end of the procedure, with all cases recovering within 6 months. Despite the shortened application all veins were isolated. At repeat procedure the right-sided PVs reconnected less frequently than the left-sided PVs in those with phrenic nerve palsy.

Conclusions—

Electromyographic phrenic nerve monitoring using the surface CMAP is reliable, easy to perform, and offers an early warning to impending phrenic nerve injury.

Left atrial isthmus line ablation using a remote robotic navigation system: feasibility, efficacy and long-term outcome

BACKGROUND

Left atrial isthmus (LAI)-ablation in addition to circumferential pulmonary vein isolation (CPVI) may improve outcomes in select patients with atrial fibrillation (AF). However, bidirectional LAI-block is difficult to obtain. No systematic evaluation reporting on the feasibility and efficacy of LAI-ablation using a robotic navigation system (RNS) exists.

METHODS AND RESULTS

In this pilot study, CPVI combined with LAI-ablation were performed using a RNS and 3D-mapping system in 42 patients with persistent (n = 24, 57.1 %) or longstanding persistent AF. Ablation was performed using either a 3.5 mm irrigated tip catheter (ITC) with 6 (group-A, n = 16; max. 40 W, contact force 10-40 g) or (after a steam pop occurred in one patient) with a 4 mm ITC with 12 irrigation holes (group-B, n = 26; max. 30 W, contact force 10-30 g). Epicardial ablation was performed manually whenever bidirectional LAI-block could not be obtained with a maximum of 20 endocardial RF-applications. LAI-conduction block was achieved in all patients using RNS; in six patients (14.3 %), additional epicardial ablation was required to achieve LAI-block. A steam pop occurred during LAI-ablation resulting in cardiac tamponade in one patient in group-A. After a median follow-up period of 21 months, arrhythmia recurrence was seen in in 23/42 patients (18 patients with AF and 5 patients with atrial tachycardia) and repeat procedure was performed in 12 (28.6 %) patients; recovered LAI-conduction was found in 5/12 (41.7 %) patients. The RNS-group was compared to a historical group of 20 patients with manual LAI-ablation. Using RNS, LAI-block was more often achieved (42 (100 %) vs 16 (80 %), p < 0.01) and epicardial ablation was required in a significantly smaller number of patients (6 (14.3) vs 10 (50 %), p < 0.01).

CONCLUSIONS

LAI-ablation using RNS appears to be feasible in all patients. At repeat procedure, LAI-conduction can frequently occur; power and contact-force adaption appears to be mandatory to reduce the risk of complications. Using RNS, instead of a manual approach for LAI-line ablation may facilitate creation of a bidirectional LAI-block.