Nadir Balloon Temperature Research Articles

Validation of a prediction model for early reconnection after cryoballoon ablation.

We previously developed an early reconnection/dormant conduction (ERC) prediction model for cryoballoon ablation to avoid a 30-min waiting period with adenosine infusion. We now aimed to validate this model based on time to isolation, number of unsuccessful cryo-applications, and nadir balloon temperature. Consecutive atrial fibrillation patients who underwent their first cryoballoon ablation in 2018-2019 at the Leiden University Medical Center were included. Model performance at the previous and at a new optimal cutoff value was determined. A total of 201 patients were included (85.57% paroxysmal AF, 139 male, median age 61years (IQR 53-69)). ERC was found in 35 of 201 included patients (17.41%) and in 41 of 774 veins (5.30%). In the present study population, the previous cutoff value of - 6.7 provided a sensitivity of 37.84% (previously 70%) and a specificity of 89.07% (previously 86%). Shifting the cutoff value to - 7.2 in both study populations resulted in a sensitivity of 72.50% and 72.97% and a specificity of 78.22% and 78.63% in data from the previous and present study respectively. Negative predictive values were 96.55% and 98.11%. Applying the model on the 101 patients of the present study with all necessary data for all veins resulted in 43 out of 101 patients (43%) not requiring a 30-min waiting period with adenosine testing. Two patients (2%) with ERC would have been missed when applying the model. The previously established ERC prediction model performs well, recommending its use for centers routinely using adenosine testing following PVI.

Variation in the frozen lesion size according to the non-occluded application duration and technique for cryoballoon ablation.

The frozen lesion formation created by cryoballoon ablation, especially with non-occluded applications, has not been fully evaluated. This study aimed to validate the lesion size under different cryoballoon ablation settings: application duration, push-up technique, and laminar flow. The frozen lesion size was evaluated immediately after ending the freezing with three different application durations (120, 150, and 180 seconds) in porcine hearts (N = 24). During the application, the push-up technique was applied at 10, 20, and 30 seconds after starting the freezing with or without laminar flow. The lesion size was significantly correlated with the nadir balloon temperature (P<0.001). The lesion volume became significantly larger after 150 seconds than 120 seconds (1272mm3 versus 1709mm3, P = 0.004), but not after 150 seconds (versus 1876mm3 at 180 seconds, P = 0.29) with a comparable nadir balloon temperature. Furthermore, the lesion volume became significantly larger with the push-up technique with the largest lesion size with a 20-second push-up after the freezing (1193mm3 without the push-up technique versus 1585mm3 with a push-up at 10 seconds versus 1808mm3 with a push-up at 20 seconds versus 1714mm3 with a push-up at 30 seconds, P = 0.04). Further, the absence of laminar flow was not associated with larger lesion size despite a significantly lower nadir balloon temperature. The frozen lesion size created by cryoballoon ablation became larger with longer applications at least 150 seconds and with a push-up technique especially at 20 seconds after the freezing.

Difference in tissue temperature change between two cryoballoons

BackgroundCryoballoon ablation, especially Arctic Front Advance Pro (AFA-Pro) (Medtronic, Minneapolis, Minnesota, USA), has been widely recognised as a standard approach to atrial fibrillation (AF). Recently, Boston Scientific has released a...

Long-term success rates of a stable, low pressure cryo balloon for the treatment of paroxysmal atrial fibrillation - results of the prospective, international, multicenter POLAR-ICE study

Abstract Background/Introduction Pulmonary vein isolation (PVI) using a cryo balloon is well-established for the treatment of paroxysmal atrial fibrillation (PAF). Compared to other available technologies, the usage of a stable, low pressure cryo balloon (POLARx, Boston Scientific) has demonstrated lower nadir temperatures and longer thawing times. However, long term efficacy and safety still needs to be proven. Purpose The aim of the POLAR-ICE Study was to evaluate long-term efficacy and safety outcome of cryo balloon ablation in patients with paroxysmal atrial fibrillation. Methods POLAR ICE, a prospective, non-randomized, international, multicenter study, enrolled 399 patients across 19 centers, between Aug 2020 and May 2021. Patients with paroxysmal atrial fibrillation undergoing de novo PVI were included into the study. During the index procedure, procedural characteristics, such as time to isolation (TTI), cryoablations per pulmonary vein, balloon nadir temperature, and occlusion grade were recorded. Procedural success was defined as successful isolation of each vein proven by entrance block. Follow up visits were at 3, 6, and 12 months. Recurrence is defined as any documented (ECG/Holter) episode of atrial fibrillation / atrial tachycardia longer than 30sec. after a blanking period of 3 months. Results 399 patients (mean age 61 years, 36% female) were included into the study. After 12 months, freedom from any arrhythmia was 83.5% and freedom from atrial fibrillation 88.1% (Figure 1). Procedure/ablation related Serious adverse events occurred in 8.7% of patients, and included access complications (2.6%), cardiac tamponade (0.5%), air embolism (0.3%), AV block (0.3%), effusion (0.3%) phrenic nerve palsy (0.3%), stroke (0.3%), transient ischemic attack (0.3%). Redo procedures have been conducted in 19 patients. In 14/19 pts reconnection of at least one PV could be identified (RSPV n=8, RIPV n=12, LSPV n=9, LIPV n=11). Freedom from any arrhythmia was associated with lower nadir temperature (p=0.008) and longer time to thaw (p=0.05) during the index procedure. Conclusions In this prospective, non-randomized, international, multicenter study, isolation of the pulmonary veins using a stable, low pressure cryo balloon was highly effective and safe in patients treated for paroxysmal atrial fibrillation. Lower nadir temperatures and a longer thawing time were predictors of clinical success.

How to perform effective cryoballooon ablation of the left atrial roof: Considerations after experiencing more than 1000 cases.

Cryoballoon ablation (CBA) of the left atrial (LA) roof in addition to a pulmonary vein isolation has been expected to improve the clinical outcomes post-atrial fibrillation (AF) ablation. We demonstrated the characteristics and efficacy of CBA of the LA roof through our experience with a large volume of procedures. Among 1036 AF ablation procedures with CBA of the LA roof, 834 patients who underwent a de novo ablation were analyzed. Complete LA roof line conduction block was obtained in 767 patients (92.0%) solely by CBA (Group A). Compared with the other patients (Group B), the mean nadir balloon temperature during CBA of the LA roof (-44.5 ± 5.6°C for Group A vs. -40.5 ± 7.5°C for Group B, p < .01) and number of cryoballoon applications during the LA roof ablation with a circular mapping catheter located in the left superior pulmonary vein (1.3 ± 0.8 for Group A vs. 1.6 ± 1.0 for Group B, p = .02) were significantly lower in Group A. A multivariate analysis revealed that those were predictors of a complete LA roof conduction block after only CBA. The 1-year Kaplan-Meier atrial arrhythmia free rate estimates were 80.6% for Group A and 59.0% for Group B (p < .01). Complete LA roof line conduction block could be obtained with a cryoballoon without touch-up ablation in most cases. The LA roof CBA with a circular mapping catheter located in the right superior pulmonary vein was preferable to obtaining complete LA roof conduction block, which was important with regard to the clinical outcomes.

When does phrenic nerve injury recover after cryoballoon ablation? Data from Japanese multicenter registry

Abstract Funding Acknowledgements Type of funding sources: None. Background Although phrenic nerve injury (PNI) is most frequently encountered complication in cryoballoon ablation, it recovered in most cases. However, the duration of persisting PNI has not been fully investigated yet. Purpose This study sought to confirm the clinical course of PNI after the procedure in cases in which reduction of diaphragmatic compound motor action potential (CMAP)was confirmed during cryoballoon ablation of right-sided pulmonary veins (PVs). Methods We retrospectively analyzed a total of 237 patients who experienced right PNI confirmed by the CMAP amplitude reduction during cryoballoon ablation in 4 Japanese centers. Cryoballooon ablation of right-sided PVs were performed under CMAP monitoring in all cases, and once CMAP amplitude reduction was observed, freezing was immediately interrupted with a double stop technique. The recovery of PNI was confirmed by chest X-ray, and transient PNI was defined as one recovering before the discharge. Results Among 237 patients, PNI occurred during cryoballoon ablation of right superior PV and right inferior PV in 166 and 71 patients, respectively. The mean freezing time to PNI was 126.9±45.6 seconds and the mean balloon temperature when PNI occurred was -50.2±7.5°C. After PNI was confirmed, additional cryoballoon ablation of the same PV or the other ipsilateral PV was performed under CMAP monitoring in 29 and 97 patients, respectively. Transient PNI accounted for 53.2% of patients with PNI (126 out of 237 patients). Among the remaining 111 patients, the PNI recovery was confirmed within 3 months, 6 months or 12 months after the procedure in 42(37.8%), 55 (49.5%), 74 (66.7%) patients, respectively. When we excluded 32 patients who did not undergo sufficient follow-up of chest X-ray, only 5 patients (2.4%) still suffered from PNI at 12 months after the ablation, and the PNI recovery was confirmed after more than 12 months in 3 out of them. When we compared patients who suffered from PNI at 6 months after the procedure with those who did not, there was no significant difference in nadir balloon temperature (-50.4±6.9°C; for PNI recovery [-] vs -50.0±7.8°C; for PNI recovery [+], p=0.75). When freezing time was less than 60 seconds, PNI recovered within 6 months after ablation in all cases, although 23.2% of the patients in whom freezing time was 60 seconds or more still suffered from PNI at 6 months after the procedure (p=0.045). Conclusion The right-sided PNI confirmed by the CMAP amplitude reduction during cryoballoon ablation recovers within a couple of days in half of cases, and it rarely persists more than 12 months after the procedure. When freezing was interrupted less than 60 seconds, it is highly expected that PNI recovers within 6 months.

Procedural performance between two cryoballoon systems for ablation of atrial fibrillation depends on pulmonary vein anatomy.

Cryoballoon ablation is a first-line therapy for atrial fibrillation. We compared the efficacy and safety of two ablation systems and addressed the influence of pulmonary vein (PV) anatomy on performance and outcome. We consecutively enrolled 122 patients who were planned for first-time cryoballoon ablation. Patients were assigned 1:1 for ablation with the POLARx or the Arctic Front Advance Pro (AFAP) system and followed-up for 12months. Procedural parameters were recorded during the ablation. Before the procedure, a magnetic resonance angiography (MRA) of the PVs was generated and diameter, area, and shape of each PV ostium were assessed. We applied an evaluated PV anatomical scoring system on our MRA measurement data ranging from 0 (best anatomical combination) to 5. Procedures performed with POLARx were associated with shorter time to balloon temperature -30°C (p < .001), lower balloon nadir temperature (p < .001), and longer thawing time till 0°C (p < .001) in all PVs, however, time to isolation was similar. We observed a decreasing performance with each increase in the score for the AFAP, whereas the POLARx performed constant regardless of the score. At 1 year, AF recurred in 14 of 44 patients treated with AFAP (31.8%) and in 10 of 45 patients treated with POLARx (22.2%) (hazard ratio, 0.61; 95% CI 0.28 to 1.37; p=.225). There was no significant correlation between PV anatomy and clinical outcome. We found significant differences in cooling kinetics, especially when anatomical conditions are difficult. However, both systems have a comparable outcome and safety profile.

Clinical utility of the "balloon lever technique" in the right inferior pulmonary vein cryoballoon ablation.

The acute success rate of pulmonary vein isolation (PVI) with cryoballoon (CB) is reported to be lower in the right inferior pulmonary vein (RIPV). This study aimed to investigate the utility of the "balloon lever technique (BLT)" for RIPV CB ablation. We retrospectively studied consecutive patients who underwent CB-PVI for atrial fibrillation between February 21, 2020 and June 3, 2022. RIPV cryoablation was performed according to a specific protocol. The patients underwent RIPV cryoablation using the conventional method. If the method was found ineffective, BLT cryoablation was performed. The acute success rate of RIPV CB ablation was examined. We also investigated the RIPV isolation rate and procedural parameters during conventional and BLT cryoablation. Ninety-three patients were included in the analysis. RIPV isolation was achieved in 89.2% (83/93) of the patients using conventional method and subsequent BLT cryoablation. Meanwhile, 68 patients underwent BLT cryoablation because the conventional method was ineffective. RIPV was isolated with BLT in 85.3% (58/68) of patients. Additionally, BLT was found to be superior to conventional cryoablation in terms of nadir balloon temperature, freezing time, and thawing time to a specific temperature in patients who underwent both conventional and BLT cryoablations. BLT is useful in RIPV cryoablation when the conventional method is ineffective. BLT cryoablation may be helpful, mainly because of the BLT-mediated contact of the balloon with the bottom of the RIPV, which leads to optimal RIPV occlusion.

Cryoballoon ablation of left atrial roof with a novel cryoballoon system

Abstract Introduction A novel cryoballoon system (POLARx) has emerged and its efficacy regarding pulmonary vein isolation (PVI) has been already investigated. On the other hand, cryoballoon ablation of left atrial (LA) roof has been performed using a conventional cryoballoon system (Arctic Front Advance Pro [AFA-Pro]) in addition to PVI. However, cryoballoon ablation of LA roof with POLARx has not been investigated yet. Methods We performed cryoballoon ablation of LA roof with POLARx in 22 patients after we achieved PVI. After the cryoballoon ablation, complete conduction block at LA roof and isolation of all PVs were confirmed by creating an activation map during high right atrium pacing. If they could not be obtained with solely a cryoballoon, touch up ablation with radiofrequency ablation was permitted. The procedural data during ablation with POLARx was compared with those during ablation with AFA-Pro we had performed in a historical cohort of patients (n=46). Results Complete conduction block at LA roof without touch up ablation could be obtained in all the patients in POLARx group and 44 (95.7%) patients in AFA-Pro group. Total procedure time was almost similar in both groups (164.2±35.4 min for POLARx vs 180.3±35.4 min for AFA-Pro, p=0.10). During LA roof line ablation, nadir balloon temperature was significantly lower in POLARx group (right side: −53.6±4.4°C for POLARx vs −45.6±4.6°C for AFA-Pro, p&amp;lt;0.01, central part: −56.4±4.3°C for POLARx vs −46.0±3.7°C for AFA-Pro, p&amp;lt;0.01, left side: −55.1±3.5°C for POLARx vs −45.7±5.3°C for AFA-Pro, p&amp;lt;0.01), and balloon temperature reached −40°C earlier in POLARx (right side: 30.7±8.9 sec for POLARx vs 78.0±39.8 sec for AFA-Pro, p&amp;lt;0.01, central part: 30.6±9.3 sec for POLARx vs 65.9±33.3 sec for AFA-Pro, p&amp;lt;0.01, left side: 30.4±4.2 sec for POLARx vs 78.8±49.6 sec for AFA-Pro, p&amp;lt;0.01). Total freezing time required for LA roof line ablation was significantly shorter in POLARx group (589.3±163.6 sec for POLARx vs 877.5±191.7 sec for AFA-Pro, p&amp;lt;0.01).The scar area created after LA roof line ablation was similar in both groups (9.3±4.1 cm2 for POLARx vs 11.0±4.8 cm2 for AFA-Pro, p=0.23). Conclusion Complete conduction block at LA roof could be obtained after cryoballoon ablation with POLARx, in the same way as AFA-Pro. Lower nadir balloon temperature could be expected in shorter freezing time during LA roof line ablation in using POLARx compared with AFA-Pro. Funding Acknowledgement Type of funding sources: None.

Durability of pulmonary vein isolation following cryoballoon ablation: lessons from a large series of repeat ablation procedures

Abstract Funding Acknowledgements Type of funding sources: None. Background The cryoballoon technology has been widely proven to be effective in achieving acute pulmonary vein (PV) isolation and favorable clinical outcome. To date, little information is still available about occurrence of late PV reconnection after cryoballoon ablation. Purpose To assess the rate of durable PV isolation following cryoballoon ablation of atrial fibrillation in the setting of repeat procedures. Methods and Results A total of 154 consecutive patients (90 male, 58.4%; mean age 60.6±12.6 years) underwent a repeat procedure, after a mean 21.5±12.4 months (median 14 months), after index ablation using the 28-mm second-generation cryoballoon. All repeat ablations were performed using a 3-dimensional electro-anatomical mapping system. Among all 590 PVs, including 26 left common ostiums (LCOs), 99 (16.8%) showed a PV reconnection in 86 patients (1.15 per patient). Persistent PV isolation could be documented in 491 of 590 PVs (83.2%). In 68 of 154 patients (44%), all PVs were electrically isolated. In the multivariable analysis, balloon nadir temperature (p&amp;lt;0.01) and time to PV isolation (P=0.02) independently predicted late PV reconnection. Conclusions The rate of late PV reconnection after second-generation cryoballoon ablation was low (1.15 PVs/patient). Globally, the rate of durable PV isolation assessed during repeat procedures was 83.2%. The balloon nadir temperature and faster time to isolation were independently associated with durable PV isolation.

Acute procedural characteristics, efficacy, and safety of a novel cryoballoon for the treatment of paroxysmal atrial fibrillation: Results from the POLAR-ICE study

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Boston Scientific Background/Introduction Pulmonary vein isolation (PVI) using a cryoballoon is well-established for the treatment of paroxysmal atrial fibrillation (PAF). Initial experience with a novel cryoballoon (CB) with a stable low balloon pressure (POLARx, Boston Scientific) has demonstrated acute procedural safety and efficacy in de novo PVI procedures in patients with paroxysmal AF. However, to date, there is limited multicenter data on real world acute outcomes and procedural characteristics with this novel cryoballoon. Purpose The purpose of POLAR ICE was to provide real-world data on the acute and chronic outcomes of cryoballoon ablation with POLARx for the treatment of PAF. Here we report on the initial acute outcomes up to 3 months including procedural efficacy, safety, and biophysical parameters. Methods POLAR ICE, a prospective, non-randomized, multicenter (international) registry (NCT04250714), enrolled 400 patients across 19 centers, between Aug 2020 and May 2021. This study included any patients indicated for treatment of PAF with the POLARx cryoablation system. The study protocol did not mandate any specific cryodosing regimen, this was left to the operator. Procedural characteristics, such as time to isolation (TTI), cryoablations per pulmonary vein, balloon nadir temperature, and occlusion grade were recorded. PVI was confirmed with entrance block testing. Results Complete PVI was achieved in 96.1% of PVs (1437/1496). Procedure and fluoroscopy times were 69.0±25.2 min and 15.8±10.0 min, respectively. Left atrial dwell time was 47.3±18.8 min. The cryoablation characteristics by vein are shown in the Table 1. An average of 4.9±1.8 ablations were performed per patient (1.3±0.7 per vein). Grade 3 or 4 occlusion was achieved in 98.1% of PVs reported. Electrical isolation was achieved with an average TTI of 50±33.8s and in 81.4% of PVs isolation required only a single cryoablation. Nadir temperatures across all pulmonary veins averaged -56.3± 6.5C. Time to -40C was 32.9±11s and Time to Thaw (0C) was 19.5±6.7s across all veins. PVI was performed on atypical anatomies (12 LCPV, 7 RMPV, &amp; 3 RCPV) in 19 pts. Serious adverse events included phrenic nerve palsy (0.5%), tamponade (0.5%), AV block (0.3%), stroke (0.3%), and transient ischemic attack (0.3%). Conclusions Real world usage data on the novel CB suggests that this device is safe and effective, with a PV isolation success rate of 96.2% and 81.4% of PVs isolated with a single cryoablation. These data are in keeping with reports on other cryoballon systems and have markedly shorter procedure times than have been previously reported on this cryoballon.

Cryoballoon Ablation for Persistent and Paroxysmal Atrial Fibrillation: Procedural Differences and Results from the Spanish Registry (RECABA).

Introduction: Cryoballoon ablation (CBA) has become a standard treatment for paroxysmal atrial fibrillation (PaAF) but limited data is available for outcomes in patients with persistent atrial fibrillation (PeAF). Methods: We analyzed the first 944 patients included in the Spanish Prospective Multi-center Observation Post-market Registry to compare characteristics and outcomes of patients undergoing CBA for PeAF versus PaAF. Results: A total of 944 patients (57.8 ± 10.4 years; 70.1% male) with AF (27.9% persistent) were prospectively included from 25 centers. PeAF patients were more likely to have structural heart disease (67.7 vs. 11.4%; p < 0.001) and left atrium dilation (72.6 vs. 43.3%; p < 0.001). CBA of PeAF was less likely to be performed under general anesthesia (10.7 vs. 22.2%; p < 0.001), with an arterial line (32.2 vs. 44.6%; p < 0.001) and assisted transeptal puncture (11.9 vs. 17.9%; p = 0.025). During an application, PeAF patients had a longer time to −30 °C (35.91 ± 14.20 vs. 34.93 ± 12.87 s; p = 0.021) and a colder balloon nadir temperature during vein isolation (−35.04 ± 9.58 vs. −33.61 ± 10.32 °C; p = 0.004), but received fewer bonus freeze applications (30.7 vs. 41.1%; p < 0.001). There were no differences in acute pulmonary vein isolation and procedure-related complications. Overall, 76.7% of patients were free from AF recurrences at 15-month follow-up (78.9% in PaAF vs. 70.9% in PeAF; p = 0.09). Conclusions: Patients with PeAF have a more diseased substrate, and CBA procedures performed in such patients were more simplified, although longer/colder freeze applications were often applied. The acute efficacy/safety profile of CBA was similar between PaAF and PeAF patients, but long-term results were better in PaAF patients.

Study of the Impact of the Patient Rhythm during Cryoballoon Ablation on the Acute Biophysical Parameters

Background: Pulmonary vein isolation by means of cryoballoon is a well-established way of treatment of atrial fibrillation. The aim of the study was to compare the acute cryoballoon biophysical parameters attained during energy applications to the individual pulmonary vein during sinus rhythm versus atrial fibrillation. Methods: 100 Patients who underwent their first-time PVI using second-generation cryoballoon for symptomatic and drug-refractory AF, between the beginning of March to end of August 2016, were initially screened. 61 patients with paroxysmal AF were included in the present study. 39 patients with persistent AF were excluded. No pre-procedural anatomical imaging was reported. Results: A total of 61 patients (male 80%, age 59.3 ± 13.4 years) were included in the present analysis. A total of 243 pulmonary veins were isolated with an average of 1.87 ± 1.14 cryo energy applications per individual vein. During cryo application, there were no significant differences between applications delivered during sinus rhythm or ongoing AF in the rate of temperature drop at 5 and 30 s, rate of warming at 5 s after freezing stop or achieved balloon nadir temperature. The same also was observed for both the balloon cooling rate and warming times. Conclusions: The present analysis shows no impact of the patient baseline rhythm at the time of energy application upon the acute balloon biophysical parameters in patients with normal sinus rhythm and those with ongoing atrial fibrillation using the second-generation cryoballoon.

Comparison of procedural efficacy, balloon nadir temperature, and incidence of phrenic nerve palsy between two cryoballoon technologies for pulmonary vein isolation: A systematic review and meta-analysis.

IntroductionIn May 2020, a novel cryoballoon system (POLARx; Boston Scientific) became available for catheter ablation of atrial fibrillation (AF). The design of the cryoballoon is comparable to the Arctic Front Advance Pro (AFA‐Pro; Medtronic), but it is more compliant during freezing. We compared the procedural efficacy, biophysical parameters, and risk of phrenic nerve palsy (PNP) between the two cryoballoons.MethodsEmbase, MEDLINE, Web of Science, Cochrane, and Google Scholar databases were searched until June 1, 2021 for relevant studies comparing POLARx versus AFA‐Pro in patients undergoing pulmonary vein isolation (PVI) for AF.ResultsA total of four studies, involving 310 patients were included. There was no difference between the two groups for outcomes regarding procedural efficacy: acute PVI (odds ratio [OR]: 0.43; 95% confidence interval [CI]: 0.06 to 3.03; p = .40), procedure time (mean difference [MD]: 8.15 min; 95% CI: −8.09 to 24.39; p = .33), fluoroscopy time (MD: 1.32 min; 95% CI: −1.61 to 4.25; p = .38) and ablation time (MD: 1.00 min; 95% CI: −0.20 to 2.20; p = .10). The balloon nadir temperature was lower for all individual pulmonary veins (PV) in POLARx compared with AFA‐Pro (MD: −9.74°C, −9.98°C, −6.72°C, −7.76°C, for left superior PV, left inferior PV, right superior PV, and right inferior PV, respectively; all p < .001). The incidence of PNP was similar between groups (OR: 0.79; 95% CI: 0.22 to 2.85; p = .72).ConclusionIn AF patients undergoing PVI, POLARx and AFA‐Pro had a similar procedural efficacy. Balloon nadir temperatures were lower with POLARx, however, the incidence of PNP was similar.

Durability of a right superior pulmonary vein isolation after an inevitably interrupted single short freeze during cryoballoon ablation

In cryoballoon ablation, applications for right superior pulmonary veins (RSPVs) inevitably need to be interrupted for some safety reasons. We retrospectively investigated the RSPV isolation durability after single interrupted short freezes. Data from 30 patients who underwent repeat procedures 8.2 (4.1-13.8) months after an inevitably interrupted single short freeze (<180 s) for RSPVs during the index cryoballoon procedures were analyzed. It was interrupted by active deflation due to phrenic nerve injury (PNI) (Group 1: n = 14) or passive deflation due to a balloon temperature of -60°C (Group 2: n = 16). The freezing time was 145 (107-166) and 142 (127-160) s and nadir balloon temperature -50.7 ± 3.6 and -60°C in Groups 1 and 2, respectively. Pulmonary vein isolation was achieved after interrupted freezing in all except in one patient requiring touch-up ablation in Group 1. All PNI was asymptomatic and recovered during the follow-up. Eight/13 (61.5%) and 16/16 (100%) RSPVs were durable during the second procedure in Groups 1 and 2. In Group 1, the freezing time was significantly longer in durable than reconnected RSPVs (p = .032), and the optimal cutoff point for the freezing duration to predict the durability was 94.0 s (sensitivity 100%, specificity 60.0%). When the freezing time was ≥120 s, 80% of the RSPVs were durable. However, when the freezing time was ≤68 s, all RSPVs were reconnected. The feasibility of second cryoapplications for RSPVs should be discussed considering the freezing time of the interrupted initial applications in Group 1, however, it was not necessary in Group 2.

Predictors of the "Crosstalk" Phenomenon During Cryoballoon Ablation in Patients with Atrial Fibrillation.

Second-generation cryoballoon (CB) ablation is effective in achieving pulmonary vein (PV) isolation (PVI) in atrial fibrillation (AF) patients. The "crosstalk" (CST) phenomenon has been reported to reduce unnecessary applications during CB ablation. Nevertheless, it is unclear under what conditions the CST phenomenon occurs.To seek the predictors of the CST phenomenon during CB-guided PVI, CST phenomenon in achieving ipsilateral superior PVI during inferior PV ablation was analyzed in AF patients who underwent de novo ablation using CB. CB occlusion status and nadir balloon temperature (NT) were compared in these patients, and all ablated superior PVs were categorized into three groups according to the necessity of the touch up ablation and effectiveness of the phenomenon.Of 1082 superior PVs, 16, 40, and 1026 were classified into the CST success, CST failure, and control groups (unnecessary CST), respectively. The proportion of superior PVs ablated with complete occlusion using the CB was significantly higher in the CST success group than in the other two groups. The proportion of superior PVs ablated with NT ≤ -46°C was higher in the CST success group than in the CST failure group. The CST phenomenon was always observed if CB ablation of the superior PVs was performed with both complete occlusion and NT ≤ -46°C and was almost always ineffective if it did not meet these two criteria (sensitivity, 100%; specificity, 93%).Successful CST ablation was highly predicted if complete PV occlusion and NT ≤ -46°C during CB ablation of the superior PVs were achieved.

Predicting early reconnection after cryoballoon ablation with procedural and biophysical parameters.

BackgroundPredicting early reconnection/dormant conduction (ERC) immediately after pulmonary vein isolation (PVI) can avoid a waiting period with adenosine testing.ObjectiveTo identify procedural and biophysical parameters predicting ERC.MethodsConsecutive atrial fibrillation (AF) patients undergoing a first cryoballoon ablation (Arctic Front Advance) between 2014 and 2017 were included. ERC was defined as manifest or dormant pulmonary vein (PV) reconnection with adenosine 30 minutes after PVI. Time to isolation (TTI), balloon temperatures (BT), and thawing times were evaluated as potential predictors for ERC. Based on a multivariable model, cut-off-values were defined and a formula was constructed to be used in clinical practice.ResultsA total of 136 patients (60 ± 10 years, 96 male, 95% paroxysmal AF) were included. ERC was found in 40 (29%) patients (ERC group) and in 53 of 575 (9%) veins. Procedural and total ablation time and the number of unsuccessful freezes were significantly longer/higher in the ERC group compared to the non-ERC group (150 ± 40 vs 125 ± 34 minutes; 24 ± 5 vs 17 ± 4 minutes, and 38% vs 24%, respectively (P = .028). Multivariable analysis showed that a higher nadir balloon temperature (hazard ratio [HR] 1.17 [1.09–1.23, P < .001), a higher number of unsuccessful freezes (HR 1.69 [1.15–2.49], P = .008) and a longer TTI (HR 1.02 [1.01–1.03], P < .001) were independently associated with ERC, leading to the following formula: 0.02 × TTI + 0.5 × number of unsuccessful freezes + 0.2 × nadir BT with a cut-off value of ≤-6.7 to refrain from a waiting period with adenosine testing.ConclusionThree easily available parameters were associated with ERC. Using these parameters during ablation can help to avoid a 30-minute waiting period and adenosine testing.

Comparison of procedural efficacy and biophysical parameters between two competing cryoballoon technologies for pulmonary vein isolation: Insights from an initial multicenter experience.

IntroductionRecently a novel cryoballoon system (POLARx, Boston Scientific) became available for the treatment of atrial fibrillation. This cryoballoon is comparable with Arctic Front Advance Pro (AFA‐Pro, Medtronic), however, it maintains a constant balloon pressure. We compared the procedural efficacy and biophysical characteristics of both systems.MethodsOne hundred and ten consecutive patients who underwent first‐time cryoballoon ablation (POLARx: n = 57; AFA‐Pro: n = 53) were included in this prospective cohort study.ResultsAcute isolation was achieved in 99.8% of all pulmonary veins (POLARx: 99.5% vs. AFA‐Pro: 100%, p = 1.00). Total procedure time (81 vs. 67 min, p < .001) and balloon in body time (51 vs. 35 min, p < .001) were longer with POLARx. After a learning curve, these times were similar. Cryoablation with POLARx was associated with shorter time to balloon temperature −30°C (27 vs. 31 s, p < .001) and −40°C (32 vs. 54 s, p < .001), lower balloon nadir temperature (−55°C vs. −47°C, p < .001), and longer thawing time till 0°C (16 vs. 9 s, p < .001). There were no differences in time‐to‐isolation (TTI; POLARx: 45 s vs. AFA‐Pro 43 s, p = .441), however, POLARx was associated with a lower balloon temperature at TTI (−46°C vs. −37°C, p < .001). Factors associated with acute isolation differed between groups. The incidence of phrenic nerve palsy was comparable (POLARx: 3.5% vs. AFA‐Pro: 3.7%).ConclusionThe novel cryoballoon is comparable to AFA‐Pro and requires only a short learning curve to get used to the slightly different handling. It was associated with faster cooling rates and lower balloon temperatures but TTI was similar to AFA‐Pro.

Optimal diameter of the pulmonary vein ostium for second-generation 28-mm cryoballoon ablation of atrial fibrillation.

Large pulmonary veins (PVs) have the risk of excessive cooling when the cryoballoon is moved into them, whereas smaller PVs may not be isolated because of insufficient balloon-tissue contact. We previously reported that the effective nadir balloon temperature (NBT) was <- 44°C for predicting early PV reconnections. However, the ideal PV and left atrial (LA) diameters for cooling temperatures during cryoballoon ablation (CBA) are unknown. We measured the PV ostium (PVos) and LA diameters on computed tomography images in 71 atrial fibrillation patients who underwent a 28-mm CBA. We defined -60°C ≤ NBT <- 44°C as the optimal NBT. The optimal PVos diameters and elliptical area were determined using the receiver operating characteristic curve cutoff values for the optimal NBT. The maximum PVos diameter (PVmax), minimum PVos diameter (PVmin), and PV elliptical area correlated negatively with the NBT (PVmax: r = -.34, P < .0001; PVmin: r = -.41, P < .0001; PV elliptical area: r = -.41, P < .0001). Based on the NBT-derived definition, the optimal PVmax, PVmin, and PV elliptical area were 19 < PVmax ≤ 21 mm, 14 < PVmin ≤ 16 mm, and 186.83 < PV elliptical area ≤ 254.34 mm2 , respectively. In addition, a positive correlation between the LA longitudinal diameter and NBT was observed in the right superior PV (r = .34, P = .004), and the LA transverse diameter correlated inversely with the NBT in the left inferior PV (r = -.34, P = .004). We identified the optimal PV diameters and elliptical area to establish the optimal NBT during the second-generation 28-mm CBA. These data will help for the preclinical judgment for a successful CBA.

Predictors of durable pulmonary vein isolation after second-generation cryoballoon ablation with a single short freeze strategy — Different criteria for the best freeze of the 4 individual PVs

BackgroundParameters predicting the second-generation cryoballoon pulmonary vein isolation (CB-PVI) durability of each individual PV have not been investigated. ObjectiveWe explored the PVI durability predictors after left superior (LS), left inferior (LI), right superior (RS), and right inferior (RI) PV CB-PVI. MethodsData from 101 consecutive patients who underwent repeat procedures 7.0 [4.5–10.0] months after index cryoballoon procedures with single short freeze strategies were analyzed. ResultsAmong 369 PVs successfully isolated by cryoballoons with mean freezing times of 207 s, 82/94 (87.2%) LSPVs, 78/93 (83.9%) LIPVs, 80/98 (81.6%) RSPVs, and 63/84 (75.0%) RIPVs were durable. In the remaining 25 PVs requiring touch-up ablation, 20 (83.3%) PVs had reconnections. In analyzing all PVs together, lower nadir balloon temperature, faster freezing speed (FS), slower thawing speed (TS), and shorter time-to-isolation were significantly associated with higher PVI durability, however, all parameters significantly differed among the 4 individual PVs (p < 0.0001). In individual analyses, for the LSPV, faster FS to −40 °C predicted higher PVI durability, but younger patients more likely had reconnections. For the LIPV, faster FS to −30 °C predicted higher PVI durability. For the RSPV, a lower nadir temperature, faster FS (to −30 and −40 °C), slower TS (to 0 and 15 °C), shorter time-to-isolation, and smaller PV diameter predicted higher PVI durability. For the RIPV, a slower TS (to 0 and 15 °C) predicted higher PVI durability. ConclusionsThe durability of the CB-PVI was high even with a single short freeze strategy. The parameters predicting the PVI durability differed among the 4 PVs, suggesting that best freeze criterion should be considered separately for each of the 4 PVs.