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.

Electrophysiology lab efficiency comparison between cryoballoon and point-by-point radiofrequency ablation: a German sub-analysis of the FREEZE Cohort study.

BACKGROUND: Pulmonary vein isolation (PVI) is recommended to treat paroxysmal and persistent atrial fibrillation (AF). This analysis aimed to assess the hospital efficiency of single-shot cryoballoon ablation (CBA) and point-by-point radiofrequency ablation (RFA). METHODS: The discrete event simulation used PVI procedure times from the FREEZE Cohort study to establish the electrophysiology (EP) lab occupancy time. 1000 EP lab days were simulated according to an illustrative German hospital, including 3 PVI cases per day using CBA at one site and RFA at the other. RESULTS: The analysis included 1560 CBA patients and 1344 RFA patients from the FREEZE Cohort. Some baseline patients' characteristics were different between groups (age, AF type, and some concomitant diseases), without being statistically associated to ablation procedure time. Mean procedure time was 122.2 ± 39.4 min for CBA and 160.3 ± 53.5 min for RFA (p < 0.0001). RFA was associated with a more than five-fold increase of cumulative overtime compared to CBA over the simulated period (1285 h with RFA and 253 h with CBA). 70.7% of RFA lab days included overtime versus 25.7% for CBA. CBA was associated with more days with an additional hour at the end of the EP lab shift compared to RFA (47.8% vs 11.5% days with one hour left, respectively). CONCLUSION: CBA is faster and more predictable than point-by-point RFA, and enables improvements in EP lab efficiency, including: fewer cumulative overtime hours, more days where overtime is avoided and more days with remaining time for the staff or for any EP lab usage. Clinical trial registration NCT01360008 (first registration 25/05/2011).

Impact of cryoballoon application abortion due to phrenic nerve injury on reconnection rates: a YETI subgroup analysis.

AIMS: Cryoballoon (CB)-based pulmonary vein isolation (PVI) is an effective treatment for atrial fibrillation (AF). The most frequent complication during CB-based PVI is right-sided phrenic nerve injury (PNI) which is leading to premature abortion of the freeze cycle. Here, we analysed reconnection rates after CB-based PVI and PNI in a large-scale population during repeat procedures. METHODS AND RESULTS: In the YETI registry, a total of 17 356 patients underwent CB-based PVI in 33 centres, and 731 (4.2%) patients experienced PNI. A total of 111/731 (15.2%) patients received a repeat procedure for treatment of recurrent AF. In 94/111 (84.7%) patients data on repeat procedures were available. A total of 89/94 (94.7%) index pulmonary veins (PVs) have been isolated during the initial PVI. During repeat procedures, 22 (24.7%) of initially isolated index PVs showed reconnection. The use of a double stop technique did non influence the PV reconnection rate (P = 0.464). The time to PNI was 140.5 ± 45.1 s in patients with persistent PVI and 133.5 ± 53.8 s in patients with reconnection (P = 0.559). No differences were noted between the two populations in terms of CB temperature at the time of PNI (P = 0.362). The only parameter associated with isolation durability was CB temperature after 30 s of freezing. The PV reconnection did not influence the time to AF recurrence. CONCLUSION: In patients with cryoballon application abortion due to PNI, a high rate of persistent PVI rate was found at repeat procedures. Our data may help to identify the optimal dosing protocol in CB-based PVI procedures. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT03645577?term=YETI&cntry=DE&draw=2&rank=1 ClinicalTrials.gov Identifier: NCT03645577.

Phrenic Nerve Injury During Cryoballoon-Based Pulmonary Vein Isolation: Results of the Worldwide YETI Registry.

BACKGROUND: Cryoballoon-based pulmonary vein isolation (PVI) has emerged as an effective treatment for atrial fibrillation. The most frequent complication during cryoballoon-based PVI is phrenic nerve injury (PNI). However, data on PNI are scarce. METHODS: The YETI registry is a retrospective, multicenter, and multinational registry evaluating the incidence, characteristics, prognostic factors for PNI recovery and follow-up data of patients with PNI during cryoballoon-based PVI. Experienced electrophysiological centers were invited to participate. All patients with PNI during CB2 or third (CB3) and fourth-generation cryoballoon (CB4)-based PVI were eligible. RESULTS: A total of 17 356 patients underwent cryoballoon-based PVI in 33 centers from 10 countries. A total of 731 (4.2%) patients experienced PNI. The mean time to PNI was 127.7±50.4 seconds, and the mean temperature at the time of PNI was -49±8°C. At the end of the procedure, PNI recovered in 394/731 patients (53.9%). Recovery of PNI at 12 months of follow-up was found in 97.0% of patients (682/703, with 28 patients lost to follow-up). A total of 16/703 (2.3%) reported symptomatic PNI. Only 0.06% of the overall population showed symptomatic and permanent PNI. Prognostic factors improving PNI recovery are immediate stop at PNI by double-stop technique and utilization of a bonus-freeze protocol. Age, cryoballoon temperature at PNI, and compound motor action potential amplitude loss >30% were identified as factors decreasing PNI recovery. Based on these parameters, a score was calculated. The YETI score has a numerical value that will directly represent the probability of a specific patient of recovering from PNI within 12 months. CONCLUSIONS: The incidence of PNI during cryoballoon-based PVI was 4.2%. Overall 97% of PNI recovered within 12 months. Symptomatic and permanent PNI is exceedingly rare in patients after cryoballoon-based PVI. The YETI score estimates the prognosis after iatrogenic cryoballoon-derived PNI. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03645577. Graphic Abstract: A graphic abstract is available for this article.

Cardiac computed tomography angiography-derived analysis of left atrial appendage morphology and left atrial dimensions for the prediction of atrial fibrillation recurrence after pulmonary vein isolation.

BACKGROUND: Left atrial appendage (LAA) is a potential source of atrial fibrillation (AF) triggers. HYPOTHESIS: LAA morphology and dimensions are associated with AF recurrence after pulmonary vein isolation (PVI). METHODS: From cardiac computed tomography angiography (CCTA), left atrial (LA), pulmonary vein (PV), and LAA anatomy were assessed in cryoballoon ablation (CBA) patients. RESULTS: Among 1103 patients undergoing second-generation CBA, 725 (65.7%) received CCTA with 473 (42.9%) qualifying for detailed LAA analysis (66.3 ± 9.5 years). Symptomatic AF reoccurred in 166 (35.1%) patients during a median follow-up of 19 months. Independent predictors of recurrence were LA volume, female sex, and mitral regurgitation ≥°II. LAA volume and AF-type were dependent predictors of recurrence due to their strong correlations with LA volume. LA volumes ≥122.7 ml (sensitivity 0.53, specificity 0.69, area under the curve [AUC] 0.63) and LAA volumes ≥11.25 ml (sensitivity 0.39, specificity 0.79, AUC 0.59) were associated with recurrence. LA volume was significantly smaller in females. LAA volumes showed no sex-specific difference. LAA morphology, classified as windsock (51.4%), chicken-wing (20.7%), cactus (12.5%), and cauliflower-type (15.2%), did not predict successful PVI (log-rank; p = 0.596). CONCLUSIONS: LAA volume was strongly correlated to LA volume and was a dependent predictor of recurrence after CBA. Main independent predictors were LA volume, female sex, and mitral regurgitation ≥°II. Gender differences in LA volumes were observed. Individual LAA morphology was not associated with AF recurrence after cryo-PVI. Our results indicate that preprocedural CCTA might be a useful imaging modality to evaluate ablation strategies for patients with recurrences despite successful PVI.

Impact of age on the outcome of cryoballoon ablation as the primary approach in the interventional treatment of atrial fibrillation: Insights from a large all-comer study.

INTRODUCTION: The objective was to analyze the impact of patient age on clinical characteristics, procedural results, safety, and outcome of cryoballoon ablation (CBA) as the primary approach in the interventional treatment of symptomatic atrial fibrillation (AF). METHODS AND RESULTS: The single-center prospective observational study investigated consecutive patients who underwent initial left atrial ablation for symptomatic paroxysmal (PAF) or persistent AF (persAF). Age groups (A-F) of less than 40, 40-49, 50-59, 60-69, 70-79 and more than or equal to 80 years were evaluated. Follow-up (FU) included ECG, Holter monitoring and assessment of AF-symptoms. From 2012 to 2016, a total of 786 patients (64 ± 11 years, range 21-85) underwent CBA. With advancing age, more cardiovascular comorbidities and larger LA diameter were observed, more females were included (each p < .001). PAF (57%) and persAF (43%, p = .320) were equally distributed over all age groups. Age was neither related to procedural parameters, nor to the complication rate (3.9%, p = .233). Median FU was 38 months. Two non-procedure related noncardiac deaths occurred late during FU. Freedom from arrhythmia was independent of age at 18 months (p = .210) but decreased for patients more than or equal to 70 years at 24 months (p = .02). At 36 months, freedom from arrhythmia was 66%-74% (groups A-D), 54% (E) and 49% (F), respectively (p = .002). LA diameter and persAF were independent predictors, whereas age was a dependent predictor of recurrence. CONCLUSION: CBA as the primary approach in the initial ablation procedure is safe and highly effective in the young, middle aged, and elderly population. LA diameter and persAF, but not ageing, were independent predictors for arrhythmia recurrence.

Benefit of ultra-high-density mapping-guided radiofrequency reablation in pulmonary vein isolation non-responders after initial cryoballoon procedure.

AIMS: Symptomatic atrial arrhythmias despite complete pulmonary vein isolation (PVI) are common. The purpose was to evaluate ultra-high-density multi-electrode electroanatomical mapping-guided radiofrequency ablation (RFA) in PVI non-responders. METHODS AND RESULTS: Ultra-high-density multi-electrode electroanatomical mapping-guided RFA in consecutive symptomatic atrial fibrillation (AF) patients after initial cryoballoon PVI was performed. Patients were included if all pulmonary veins (PVs) were still isolated. Radiofrequency targets were atrial tachycardia (AT), extra-PV trigger, and/or substrate. Procedural results and outcome were evaluated. Of 95 patients, 67 (70.5%) with complete PVI were included (70 years, CHA2DS2Vasc 2.9, left atrium 45 mm, persistent AF 45%, AT 45%). The median time to reablation was 26 months. One hundred and seven maps (1.6/patient) and 11.890 ± 9.018 electrograms were acquired in 33 ± 12 min. Twenty-eight percent of the left atrial (LA) wall showed pathological voltage signals, predominantly at the anterior (37%) and septal wall (26%). Atrial tachycardia (49 left, 4 right) were ablated in 35 patients (52%), extra-PV trigger in two patients (3%). One atrioventricular nodal re-entry tachycardia and seven right atrial isthmus ablation (10%) were performed. In 32 patients (48%), no AT was present and substrate-based ablation was performed. Mean LA area ablated was 7 ± 6 cm2 (7%). No major complication occurred. The mean follow-up time was 772 ± 317 days. Freedom from atrial arrhythmia recurrence off antiarrhythmic drugs was 49% at 12 months. CONCLUSION: Pulmonary vein isolation non-responders are older, mainly suffering from complex atrial arrhythmias. Left atrial substrate is predominantly located at the anterior and septal wall. Ultra-high-density multi-electrode electroanatomical mapping-guided RFA is safe and effective. At 1 year, 5 out of 10 patients were in stable sinus rhythm off antiarrhythmic drugs.

Outcomes of cryoballoon or radiofrequency ablation in symptomatic paroxysmal or persistent atrial fibrillation.

AIMS: To evaluate the effectiveness and safety of cryoballoon ablation (CBA) compared with radiofrequency ablation (RFA) for symptomatic paroxysmal or drug-refractory persistent atrial fibrillation (AF). METHODS AND RESULTS: Prospective cluster cohort study in experienced CBA and RFA centres. Primary endpoint was 'atrial arrhythmia recurrence', secondary endpoints were as follows: procedural results, safety, and clinical course. A total of 4189 patients were included: CBA 2329 (55.6%) and RFA 1860 (44.4%). Cryoballoon ablation population was younger, with fewer comorbidities. Procedure time was longer in the RFA group (P = 0.01). Radiation exposure was 2487 (CBA) and 1792 cGycm2 (RFA) (P < 0.001). Follow-up duration was 441 (CBA) and 511 days (RFA) (P < 0.0001). Primary endpoint occurred in 30.7% (CBA) and 39.4% patients (RFA) [adjusted hazard ratio (adjHR) 0.85, 95% confidence interval (CI) 0.70-1.04; P = 0.12). In paroxysmal AF, CBA resulted in a lower risk of recurrence (adjHR 0.80, 95% CI 0.64-0.99; P = 0.047). In persistent AF, the primary outcome was not different between groups. Major adverse cardiovascular and cerebrovascular event rates were 1.0% (CBA) and 2.8% (RFA) (adjHR 0.53, 95% CI 0.26-1.10; P = 0.088). Re-ablations (adjHR 0.46, 95% CI 0.34-0.61; P < 0.0001) and adverse events during follow-up (adjHR 0.64, 95% CI 0.48-0.88; P = 0.005) were less common after CBA. Higher rehospitalization rates with RFA were caused by re-ablations. CONCLUSIONS: The primary endpoint did not differ between CBA and RFA. Cryoballoon ablation was completed rapidly; the radiation exposure was greater. Rehospitalization due to re-ablations and adverse events during follow-up were observed significantly less frequently after CBA than after RFA. Subgroup analysis suggested a lower risk of recurrence after CBA in paroxysmal AF. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01360008), https://clinicaltrials.gov/ct2/show/NCT01360008.

The fourth cryoballoon generation with a shorter tip to facilitate real-time pulmonary vein potential recording: Feasibility and safety results.

INTRODUCTION: Time-to-isolation (TTI) guided ablation protocols have been developed to ensure durable pulmonary vein isolation (PVI) in cryoballoon ablation (CBA). The aim was to determine the feasibility and safety of the fourth generation cryoballoon (CBG4) with a shortened tip. METHODS AND RESULTS: Consecutive patients scheduled for initial atrial fibrillation (AF) ablation were prospectively included. PVI with the 28 mm CBG4 and the latest 20 mm spiral-mapping catheter (SMC) was performed. A total of 302 pulmonary veins (PVs) in 76 patients (64.8 ± 10.4 years, paroxysmal AF 49%) were treated with 617 applications. Left atrium (LA) time, fluoroscopy time, and dose-area product were 65.5 ± 19.2 minutes, 14.6 ± 5.6 minutes, and 1094 (738; 2097) cGy·cm2 , respectively. PVI in cryoballoon technique was achieved in 302 of 302 (100%) PVs. TTI was determined in 256 (84.8%) of PVs. The mean TTI was 45.3 ± 26.4 seconds. Single-shot isolation was achieved in 247 (82%) PVs. In 6 of 302 (2.0%) PV the SMC was changed to a stiff wire to isolate the PV because of instability, and in 17 of 302 (5.6%) of PVs, the 23 mm CB was used to isolate. No radiofrequency touch-up applications were applied. The mean nadir balloon temperature was -44.8°C ± 6.6°C. Balloon dislodgement during positioning occurred in 3 of 617 (0.5%) applications without complications. One PN palsy occurred which resolved until discharge. One patient suffered from the inflammatory syndrome. CONCLUSION: The CBG4 with a shorter distal tip seems to be safe and effective, and allows determining the TTI in 84.8% of PVs. In case of balloon instability, the exchange of the SMC to a stiff wire or, in small PV, the 23 mm cryoballoon facilitate PVI.

Lessons from individualized cryoballoon sizing. Is there a role for the small balloon?

BACKGROUND: Cryoablation for paroxysmal atrial fibrillation (PAF) is well established. The single-big-balloon strategy has been preferred for pulmonary vein isolation (PVI) using the second generation cryoballoon (CBG2). Individual PV-morphologies raise the question if an individualized anatomic approach using the 23-mm or 28-mm CB is reasonable. METHODS: Consecutive patients were prospectively enrolled in the non-randomized single-center study. Patients were treated with the 28-mm CB, if any PV was >21mm, the 23-mm CB, if all PV were ≤21mm, or both sizes, if PVI was difficult. The primary endpoint was arrhythmia-free survival. The secondary endpoint considered procedural results and complications. RESULTS: Overall, 197 patients with symptomatic PAF (64±11 years, 36% female) were included. Acute PVI was achieved in 99.9% of PV. Based on preprocedural imaging, the 28-mm CB was applied as the primary catheter in 47% (92/197 patients), the 23-mm CB in 53% (105/197, p=0.23). The 23-mm CB group included more females, patients with short left atrial (LA)-diameters (each p<0.01), and smaller patients (p=0.04). Both CB-sizes were used in 24% (47/197). Additional 23-mm CB usage was necessary in 23% (21/92) of patients, mainly because of insufficient PV-occlusion with the 28-mm CB. Additional 28-mm CB usage was necessary in 25% (26/105, p=0.82), mainly because PV diameters were larger than initially measured. Both CB-sizes were equally safe and effective with a low complication rate and an overall success rate of 86% at 12 and 71% at 18 months (6% on antiarrhythmic drugs). No predictors for AF-recurrence were identified. CONCLUSION: CB ablation can sometimes be challenging. The 28-mm CB is the preferred catheter in all patients. If balloon positioning is difficult, the 23-mm CB is an option to achieve PVI in small veins. Further studies need to investigate if the 23-mm CB could be beneficial as the primary CB in females with small body height and short LA diameter.

Cryoballoon ablation for persistent atrial fibrillation - Large single-center experience.

BACKGROUND: Different catheter ablation (CA) strategies have been established in the treatment of persistent atrial fibrillation (persAF). Pulmonary vein isolation (PVI) only might be an option for the initial ablation procedure. There is a paucity of outcome data on second-generation cryoballoon (CBG2) PVI in persAF. METHODS: Patients with symptomatic drug-refractory persAF who underwent initial CA of AF were prospectively enrolled and PVI was performed with CBG2. The primary composite endpoint was freedom from AF, atrial tachycardia, or related symptoms after a 3-month blanking period. The secondary endpoint referred to periprocedural complications. RESULTS: One hundred seventy-three consecutive patients (64±10 years, 29% female) with symptomatic drug-refractory persAF were identified. Acute PVI was achieved in 100% of pulmonary veins with the CB technique. The left atrial procedure time was 112±30min. Major complications occurred in 1.7% (3 of 173 patients) including two phrenic nerve palsies (1%), which resolved until discharge, and one pericardial effusion (0.6%). Follow-up ≥12 months was completed for 157 of 173 patients (91%). Median follow-up was 14 months. At 12 months, the primary composite endpoint was achieved in 129 of 157 patients (82%). However, 22 of 129 patients at risk (17%) were still on antiarrhythmic drugs. A relapse during the blanking period was identified as the only independent predictor for AF recurrence. CONCLUSION: PVI using the second-generation cryoballoon is a reasonable treatment option for patients with symptomatic drug-refractory persAF with a favorable rate of freedom from AF and a low complication rate.

First-line catheter ablation of paroxysmal atrial fibrillation: outcome of radiofrequency vs. cryoballoon pulmonary vein isolation.

AIMS: First-line ablation prior to antiarrhythmic drug (AAD) therapy is an option for symptomatic paroxysmal atrial fibrillation (PAF); however, the optimal ablation technique, radiofrequency (RF), or cryoballoon (CB) has to be determined. METHODS AND RESULTS: The FREEZE Cohort Study compares RF and CB ablation. Treatment-naïve patients were documented in the FREEZEplus Registry. Periprocedural data and outcome were analysed. From 2011 to 2014, a total of 373/4184 (8.9%) patients with PAF naïve to AAD were identified. Pulmonary vein isolation (PVI) was performed with RF (n = 180) or CB (n = 193). In the RF group, patients were older (65 vs. 61 years, P < 0.01) compared with the CB group. The procedure time was significantly shorter and radiation exposure higher in the CB group. Major adverse events occurred in 1.6% (CB) and 3.7% (RF) of patients (P = 0.22). AF/atrial tachycardia (AT) recurrence until discharge was 4.5% (RF) and 8.5% (CB, P = 0.2). Follow-up (FU) ≥12 months was available in 99 (RF) and 107 (CB) patients. After 1.4 years of FU, freedom from AF/atrial tachycardia (AT) was 61% (RF) and 71% (CB, P = 0.11). In the RF group, more patients underwent cardioversion, and a trend for more repeat ablations was observed. Persistent phrenic nerve palsy was observed in one patient treated by CB. CONCLUSION: First-line ablation for PAF is safe and effective with either RF or CB. The procedure was faster with the CB, but the radiation exposure was higher. Although there was a trend for more recurrences and complications in the RF group, a more favourable risk profile in patients undergoing CB ablation might have biased the results. CLINICALTRIALSGOV IDENTIFIER: NCT01360008.

Outcome of paroxysmal atrial fibrillation ablation with the cryoballoon using two different application times: the 4- versus 3-min protocol.

PURPOSE: The second-generation cryoballoon (CBG2) is highly effective for pulmonary vein isolation (PVI) in paroxysmal atrial fibrillation (PAF). One-year outcome data are consistent among different research groups. First results suggest that a shortened application time might be equally effective. The objective of the study was to compare procedural and outcome data for a 240 and 180-s protocol. METHODS: Prospectively, consecutive patients with symptomatic PAF underwent initial PVI with CBG2. In succession, two groups were created: the application time was 240 s in group 1 and 180 s in group 2. In both groups, a bonus application was applied. Periprocedural data, complications, and freedom from atrial fibrillation (AF)/AT/symptoms were compared between the groups. RESULTS: From May 2012 to June 2013, 114 patients (57 per group, 38% female) were included. The mean left atrial dwelling time decreased by 19 min (-16%) in group 2 compared to group 1 (p = 0.005). Intraprocedural pulmonary vein (PV) reconduction occurred infrequently (0.4% in both groups, p = 1.0). One persistent PNP occurred and resolved during the follow-up. Complications were without significant differences. One patient was lost to follow-up. The cumulative rates of freedom from recurrence at 12 months are 76.8% in group 1 and 83.6% in group 2. After a mean follow-up of 491 ± 208 days, the rates of freedom from AF/AT/symptoms at last visit were 38/57 (67%) and 44/56 (78.6%) in groups 1 and 2 (p = 0.14), respectively. Female sex was identified as a predictor for recurrence. CONCLUSIONS: Compared to a protocol with cryoballoon applications of 240 s, a shortened application time to 180 s results in a faster procedure with comparable high rates of freedom from AF at 16 months. Female sex seems to be predictive for recurrences; this finding has to be reconfirmed in a larger population.

[Advances in cryoballoon technology: benefits and risks in daily practice]. / Fortschritte der Kryoballon-Technik : Nutzen und Risiken in der täglichen Anwendung.

BACKGROUND: Cryoballoon ablation is nowadays a standard approach for pulmonary vein isolation in symptomatic atrial fibrillation. The second generation cryoballoon was introduced in 2012 and modifications and enhancement to the system promised a higher efficiency. OBJECTIVES, MATERIALS AND METHODS: A comprehensive overview of advances in cryoballoon ablation is provided and the consequences for daily practice are described based on a PubMed literature search, taking into account own experiences. RESULTS AND CONCLUSION: Advances in cryoballoon ablation result in a significantly higher efficiency. To maintain the overall safety of the procedure and to avoid phrenic nerve palsy and esophageal lesions, special care needs to be taken by following some safety aspects and cut-off criteria. More data are necessary to clarify if recommendations for cryoenergy titration with the new balloon are reasonable. Ongoing prospective studies comparing cryoballoon and radiofrequency (RF) ablation will give answers to the question which energy source is more favorable, and upcoming studies will evaluate the impact of cryoballoon ablation as a first line treatment option.

Differences of two cryoballoon generations: insights from the prospective multicentre, multinational FREEZE Cohort Substudy.

AIMS: Cryoballoon (CB) ablation with the second-generation cryoballoon (CBG2) seems to be more effective than its predecessor [first-generation cryoballoon (CBG1)], but phrenic nerve palsies were observed more frequently. The aim of this study was to compare the safety and efficacy of CBG1 and CBG2 in a substudy of the prospective multicentre, multinational FREEZE Cohort Study. METHODS AND RESULTS: Periprocedural data were analysed, and a total of 532 patients with paroxysmal atrial fibrillation (AF) were examined (n = 224 for CBG1 and n = 308 for CBG2). Procedure time decreased significantly from 149 to 130 min when comparing CBG1 with CBG2 (P < 0.0001), and pulmonary vein isolation (PVI) was achieved in 97.8 and 97.6% of PVs with CBG1 and CBG2 (P = 0.77), respectively. The need for dual-balloon usage within a procedure dropped (20.1 vs. 9.0%, P < 0.001), and the fluoroscopy time was reduced when operating the CBG2. Atrial fibrillation recurrence rates until discharge were similar (5.0 vs. 5.8%, P = 0.69). Comparable low rates of major complications were observed with both CBs, and there was a non-significant trend for more phrenic nerve palsies. CONCLUSION: Second-generation cryoballoon demonstrated a high rate of acute PVI in a significant faster procedure, which also utilized less radiation exposure and less dual-balloon usage during an average procedure. The safety profile remains favourable with a non-significant trend for more phrenic nerve palsies. If the enhancements lead to a higher clinical benefit has to be determined. The 1-year outcome data from the ongoing FREEZE Cohort Study comparing radiofrequency and CB ablation will shed some light on that issue. CLINICAL TRIALS GOV IDENTIFIER: NCT01360008.

Comparison of the first and second cryoballoon: high-volume single-center safety and efficacy analysis.

BACKGROUND: Cryoballoon (CB) ablation results in >70% freedom from atrial fibrillation at 1 year. Single-center data of the first (CBG1) and second (CBG2) cryoballoon, recently introduced, were analyzed to compare safety and efficacy. METHODS AND RESULTS: From March 2011 to December 2012, CB ablation with spiral mapping was performed consecutively in 484 patients with symptomatic atrial fibrillation. CBG1 was used in 364 of 484 (75%) and CBG2 in 120 of 484 (25%) patients. Periprocedural data were analyzed. Acute pulmonary vein (PV) isolation with CB only was achieved in 99.86% and 100% of veins with CBG1 and CBG2, respectively (P=0.43). Number of applications until PV isolation decreased significantly with CBG2 (1.45±0.81 versus 1.28±0.64; P=0.001). Procedural, left atrial, and fluoroscopy time were reduced by -5%, -11%, and -15% (P<0.05), respectively. Two balloons were used less frequently. Time to isolation decreased significantly with 23-mm (48 versus 33 seconds; P<0.0001) and 28-mm CBG2 (76 versus 52 seconds; P<0.0001). Early PV reconduction rarely occurred with CBG2 (2.6% versus 0.42%; P=0.0023). In-hospital atrial fibrillation recurrence rates were similar. Balloon temperatures were significantly warmer with 23-mm CBG2 and a trend for colder balloon temperature with 28-mm CBG2 were observed compared with their predecessors. Comparable low rates of phrenic nerve palsy were recorded (1.1% versus 1.7%; P=0.64). Esophageal temperatures were similar. Major complication rates were low (3.3% versus 3.33%; P=1.0). CONCLUSIONS: CBG2 attains high rates of acute PV isolation within a significant faster and less complex procedure. Time to isolation is shorter, and PV isolation is achieved with fewer applications using CBG2. These enhancements were not at the cost of complications. Long-term success rates remain to be demonstrated.

Cryoballoon in AF ablation: impact of PV ovality on AF recurrence.

INTRODUCTION: Complete occlusion of the pulmonary veins (PV) is crucial for successful PV isolation. While two different sizes of cryoballoons (23 and 28 mm) are available, complete occlusion is not always achieved in any given PV. We investigated the role of PV ostial anatomy during cryoballoon PV occlusion grading and atrial fibrillation (AF) recurrence rate. METHODS: PV ostial diameter was analyzed in 168 consecutive patients (111 men, 61 ± 10 years, 124 paroxysmal (px) and 44 persistent AF) using cardiac computed tomography (CT) prior to procedure. The ovality index at the PV ostial level was calculated in any given PV. During follow-up, 7-day holter monitors were performed at 1, 3, 6, 9, 12, 18 and 24 months post-ablation. RESULTS: The success rate at 12 ± 6 months follow-up was 69% including a 3-month blanking period (px AF: 66%; persistent AF 77%). The ovality index of the left-sided PVs was significantly larger ("more oval") than that of the right-sided PVs (p<0.001). An optimized PV occlusion in all individual PVs (complete occlusion, grading 4/4) was achieved during ablation in 49% of patients with AF recurrence and in 73% of patients without AF recurrence (p=0.004). Patients with AF recurrence had "more oval" left-sided PVs compared to patients free from AF recurrence (LSPV 0.40 ± 0.2 vs. 0.33 ± 0.2; p=0.04 and LIPV 0.41 ± 0.3 vs. 0.32 ± 0.2; p=0.03), whereas no significant association was found for right sided PVs. CONCLUSION: The ostial PV anatomy seems to have an important impact on clinical outcome and should be considered when planning and performing cryoballoon AF ablation procedures.

Pulmonary vein electrophysiology during cryoballoon ablation as a predictor for procedural success.

BACKGROUND: Cryoballoon technique is an innovative alternative to radiofrequency ablation for atrial fibrillation (AF). However, with current cryoballoon application techniques, the operator has no access to electrical information for 300 s during the freezing cycle. OBJECTIVE: The objective of this study is to investigate the novel approach of real-time monitoring of pulmonary vein (PV) potentials throughout freezing using a circular mapping catheter introduced into the central lumen of the cryoballoon catheter. METHODS: Patients had paroxysmal or persistent AF. Standard balloon catheters (23 or 28 mm diameter, 10.5 F shaft) were used. A coaxial mapping catheter (shaft diameter 0.9 mm; 15 mm loop with six electrodes) was advanced through the lumen of the cryoballoon catheter, replacing the guide wire. The primary procedural end point was successful PV isolation and real-time PV potential recording. Secondary end points were procedural data, complications, and the time to successful PV isolation. RESULTS: In 141 consecutively enrolled patients, balloon positioning and ablation were successful in 439/568 veins (77%). Real-time recording of PV conduction during the freeze cycle was possible in 235/568 PVs (41%). Main reasons for failure to obtain real-time PV recordings were a distal position of the circular mapping catheter or insufficient catheter-vessel wall contact during ablation. A cutoff value of 83 s to PV isolation was predictive of stable procedural PV isolation without reconduction. One minor hemoptysis was observed possibly related to the mapping catheter. CONCLUSIONS: This study, the largest to date, showed that real-time monitoring of PV conduction during cryoballoon freezing can be safely performed with a circular mapping catheter. A cutoff time of 83 s to PV isolation was predictive of sustained procedural PV isolation success without reconduction.