Raise-up technique for the creation of left atrial roof lesion: A useful technique with cryoballoon for persistent atrial fibrillation

INTRODUCTION

Recent studies have reported the efficacy of the cryoballoon (CB)-guided left atrial roof block line (LARB) creation in patients with persistent atrial fibrillation (AF). However, it can be technically challenging to attach the balloon to the left atrial (LA) roof due to its anatomical variations. We designed a new procedure called the "Raise-up Technique," which may facilitate the firm adhesion of the CB to the LA roof during freezing. This study aimed to evaluate the efficacy of the Raise-up technique in LARB creation.

METHODS AND RESULTS

In total, 100 consecutive patients with persistent AF who underwent CB-LARB creation were enrolled. Fifty-seven patients underwent LARB creation using the Raise-up technique (Raise-up group), and the remaining 43 did not use it (control group). The Raise-up technique was performed as follows: An Achieve catheter was inserted as deeply as possible into the upper branch of the right superior pulmonary vein to anchor the CB. The balloon was placed below the targeted site on the LA roof and frozen. When the temperature of the CB reached approximately -10°C and the CB was easier to attach to the LA tissue, the CB was raised and pressed against the LA roof immediately by sheath advancement. Then the balloon could be in firm contact with the target site on the roof. If necessary, additional sheath advancement after sufficient freezing (-20°C to -30°C) was allowed the CB to have more firm and broad contact with the target site. LARB creation without touch-up ablation was achieved in 54 of 57 patients (94.7%) in the Raise-up group and 33 of 43 patients (76.7%) in the control group (p < .05). The lesion size of the LARB in the Raise-up group was significantly larger than that in the control group (15.2 cm2 vs. 12.8 cm2, p < .05). Moreover, the width of the LARB lesion in the Raise-up group was wider than that in the control group (32.0 mm vs. 26.6 mm, p < .05).

CONCLUSION

The Raise-up technique enabled the creation of seamless and thick LARB lesions with a single stroke. In addition, the CB-LARB lesions created using the Raise-up technique tended to be large, resulting in extensive debulking of the LA posterior wall arrhythmia substrates. In CB ablation for persistent AF, the Raise-up technique can be considered one of the key strategies for LARB creation.

Characteristics of two different cryoballoon systems for treatment of paroxysmal atrial fibrillation: study protocol for a multicenter randomized controlled trial (CONTRAST-CRYO Trial)

BACKGROUND

Single-shot pulmonary vein isolation (PVI) utilizing cryothermal energy is an effective and safe treatment for atrial fibrillation (AF) patients. A novel cryoballoon system, POLARx™, has been recently introduced. The aim of this study was to compare the efficacy, safety, and biophysical parameters of PVI between the novel cryoballoon system, POLARx™, and the standard cryoballoon system, Arctic Front Advance Pro™ (AFA-Pro), in patients with paroxysmal AF.

METHODS

The CONTRAST-CRYO trial is a prospective, multicenter, open-label, randomized controlled study performed at seven large cardiac centers. This study was approved by the central ethics committee or the local ethics committee of each participating hospital and has been registered at UMIN Clinical Trials Registry (UMIN000049948). The trial will assign 200 patients with paroxysmal AF undergoing PVI to POLARx™ and AFA-Pro in a 1:1 randomization. The primary endpoint is the one-shot acute success rate of the right inferior pulmonary vein. Second endpoints include freedom from documented atrial fibrillation, atrial flutter, or atrial tachycardia without antiarrhythmic drugs at 12 months after the procedure, freedom from re-do procedures, the incidence of procedure-related adverse events, freezing duration, and the biophysical parameters during applications for each PV, total procedure and fluoroscopy time, and PVI durability during re-do procedures.

CONCLUSION

The CONTRAST-CRYO trial is a prospective, multicenter, randomized study designed to elucidate the difference in the efficacy, safety, and biophysical parameters between POLARx™ and AFA-Pro in paroxysmal AF patients undergoing PVI. The findings from this trial may provide a valuable indication for selecting the optimal cryoballoon system.

CLINICAL TRIAL REGISTRATION

 UMIN000049948.

Major in-hospital complications after catheter ablation of cardiac arrhythmias: individual case analysis of 43 031 procedures

AIMS

In-hospital complications of catheter ablation for atrial fibrillation (AF), atrial flutter (AFL), and ventricular tachycardia (VT) may be overestimated by analyses of administrative data.

METHODS AND RESULTS

We determined the incidences of in-hospital mortality, major bleeding, and stroke around AF, AFL, and VT ablations in four German tertiary centres between 2005 and 2020. All cases were coded by the G-DRG- and OPS-systems. Uniform code search terms were applied defining both the types of ablations for AF, AFL, and VT and the occurrence of major adverse events including femoral vascular complications, iatrogenic tamponade, stroke, and in-hospital death. Importantly, all complications were individually reviewed based on patient-level source records. Overall, 43 031 ablations were analysed (30 361 AF; 9364 AFL; 3306 VT). The number of ablations/year more than doubled from 2005 (n = 1569) to 2020 (n = 3317) with 3 times and 2.5 times more AF and VT ablations in 2020 (n = 2404 and n = 301, respectively) as compared to 2005 (n = 817 and n = 120, respectively), but a rather stable number of AFL ablations (n = 554 vs. n = 612). Major peri-procedural complications occurred in 594 (1.4%) patients. Complication rates were 1.1% (n = 325) for AF, 1.0% (n = 95) for AFL, and 5.3% (n = 175) for VT. With an increase in complex AF/VT procedures, the overall complication rate significantly increased (0.76% in 2005 vs. 1.81% in 2020; P = 0.004); but remained low over time. Following patient-adjudication, all in-hospital cardiac tamponades (0.7%) and strokes (0.2%) were related to ablation. Major femoral vascular complications requiring surgical intervention occurred in 0.4% of all patients. The in-hospital mortality rate adjudicated to be ablation-related was lower than the coded mortality rate: AF: 0.03% vs. 0.04%; AFL: 0.04% vs. 0.14%; VT: 0.42% vs. 1.48%.

CONCLUSION

Major adverse events are low and comparable after catheter ablation for AFL and AF (∼1.0%), whereas they are five times higher for VT ablations. In the presence of an increase in complex ablation procedures, a moderate but significant increase in overall complications from 2005-20 was observed. Individual case analysis demonstrated a lower than coded ablation-related in-hospital mortality. This highlights the importance of individual case adjudication when analysing administrative data.

Single-shot technique of cryoablation for atrial fibrillation has comparable effective and safety outcomes compared to standard technique: insights from multiple clinical studies

Background

Although there are many freezing protocols available, the optimal freezing dose is still not determined. We aimed to evaluate the effectiveness and safety of different freeze strategies of CBA in the treatment of AF.

Methods

PubMed, Cochrane Library, Web of Science, and Embase were searched up to 1st December 2022. Studies comparing the outcomes between single-shot technique and standard technique of cryoablation were included. Subgroup analysis identified potential determinants for single-shot technique procedure.

Results

Our search resulted in 3407 records after deduplication. A total of 17 qualified studies met our inclusion criteria. Compared with standard technique, single-shot technique of cryoablation has a comparable rate of freedom from AF/AT(RR 1.00; P = 0.968), a trend for lower rate of procedure complications (RR 0.80; P = 0.069), a lower rate in transient phrenic paralysis (t-PNP) (RR 0.67; P = 0.038), a similar rate in persistent phrenic paralysis (per-PNP) (RR 1.15; P = 0.645), as well as a comparable procedure parameters. Importantly, potentially significant treatment covariable interactions in procedure complications were found in freeze strategy subgroup, male proportion subgroup and age subgroup, including single-shot freeze (RR 1.02; P = 0.915) and TTI-guided (RR 0.63; P = 0.007) with interaction P = 0.051, high male proportion (RR 0.54; P = 0.005) and a low male proportion (RR 0.94; P = 0.759) with interaction P = 0.074, as well as age ≥ 65 (RR0.91; P = 0.642) and age <65 (RR 0.54; P = 0.006),interaction P = 0.090. Meanwhile, only one significant treatment covariable interactions in procedure complications was found in the hypertension subgroup, including HT > 60% (RR 0.89; P = 0.549) and HT ≤ 60% (RR 0. 46; P < 0.01) with interaction P = 0.043.

Conclusions

Our study suggested that single-shot technique of cryoablation has comparable effective and safety outcomes for AF ablation compared to standard technique.

Effectiveness and safety of a time to isolation strategy of cryoballoon ablation of atrial fibrillation: A systematic review and meta-analysis

AIM

We conducted a systematic review and meta-analysis of randomized and observational studies with a control group to evaluate the effectiveness and safety of a time to isolation (TTI)-based strategy of cryoballoon ablation (CBA) in the treatment of atrial fibrillation (AF).

METHODS

Three electronic databases (MEDLINE, Cochrane Central Register of Controlled Trials, and Embase) without language restrictions were searched. The intervention assessed was a TTI-based strategy of CBA in the treatment of AF. TTI was defined as the time from the start of freezing to the last recorded pulmonary veins' potential. The comparison of interest was intended conventional protocol of CBA. The primary endpoint was freedom from atrial arrhythmia.

RESULTS

Nine studies were deemed eligible (N = 2289 patients). Eight studies reported freedom from atrial arrhythmia and pooled results showed a marginally similar success rate between the two protocols (odds ratio [OR]: 1.24; 95% confidence interval [CI]: 0.98-1.56). A prespecified subgroup analysis verified that a high dose TTI strategy (with >120 s duration of cryotherapy post-TTI) compared to the conventional protocol could significantly increase the patients without atrial arrhythmia during follow-up (OR: 1.39; 95% CI: 1.05-1.83). TTI strategy could also significantly decrease total procedure time (SMD: -26.24 min; 95% CI: -36.90 to -15.57) and phrenic nerve palsy incidence (OR: 0.49; 95% CI: 0.29-0.84).

CONCLUSION

Moderate confidence evidence suggests that an individualized CBA dosing strategy based on TTI and extended (>2 min post-TTI) duration of CBA is accompanied by fewer recurrences post-AF ablation.

Esophageal temperature management during cryoballoon ablation for atrial fibrillation

INTRODUCTION

Esophageal thermal injury (ETI) is a well-recognized complication of atrial fibrillation (AF) ablation. Previous studies have demonstrated that direct esophageal cooling reduces ETI during radiofrequency AF ablation. The purpose of this study was to evaluate the use of an esophageal warming device to prevent ETI during cryoballoon ablation (CBA) for AF.

METHODS

This prospective, double-blinded study enrolled 42 patients with symptomatic AF undergoing CBA. Patients were randomized to the treatment group with esophageal warming (42°C) using recirculated water through a multilumen, silicone tube inserted into the esophagus (EnsoETM®; Attune Medical) (WRM) or the control group with a luminal single-electrode esophageal temperature monitoring probe (LET). Patients underwent upper endoscopy esophagogastroduodenoscopy (EGD) the following day. ETI was classified into four grades.

RESULTS

Baseline patient characteristics were similar between groups. Procedural characteristics including number of freezes, total freeze time, early freeze terminations, coldest balloon temperature, procedure duration, posterior wall ablation, and proton pump inhibitor and transesophageal echocardiogram use before procedure were not different between groups. The EGD was completed in 40/42 patients. There was significantly more ETI in the WRM group compared to the LET group (n = 8 [38%] vs. n = 1 [5%], p = 0.02). All ETI lesions were grade 1 (erythema) or 2 (superficial ulceration). Total freeze time in the left inferior pulmonary vein was predictive of ETI (360 vs. 300 s, p = 0.03).

CONCLUSION

Use of a luminal heat exchange tube for esophageal warming during CBA for AF was paradoxically associated with a higher risk of ETI.

Incidence and clinical relevance of upper gastrointestinal pathology during preprocedural endoscopy in patients undergoing pulmonary vein isolation

BACKGROUND

Reflux-induced esophagitis might facilitate ablation-induced esophageal lesions (ELs) following pulmonary vein isolation (PVI), and these may progress to atrio-esophageal fistula (AEF). In contrast, preexisting ELs are not prone to progression but may affect procedure planning.

OBJECTIVE

To study the incidence of preexisting esophageal and upper gastrointestinal (UGI) pathology in patients undergoing PVI, and the relation to ablation-induced ELs.

METHODS

From 08/2018 to 09/2021, consecutive patients undergoing (radiofrequency [RF] or cryoballoon [CB]) PVI were examined by esophagogastroscopy (EGD) before and following ablation. Postprocedural endoscopic ultrasound (EUS) was added in 2021.

RESULTS

412 patients (median age 67.5 [IQR 61.3-75.0] years, 56.1% male) were studied. Preprocedural EGD showed abnormalities in 226/399 patients, 15% in the lower third of the esophagus. Half (99/226) were relevant for PVI, 13 procedures were postponed, 6 due to pathological EGD results. A third of the patients with new esophageal injury following ablation had preexisting esophagitis which was associated with a trend for a higher incidence of ELs after RF ablation (12.5 vs. 6.9%, p = 0.232), and a six- and two-fold higher rate of food retention after CB-PVI (28.6 vs. 4.5%, p = 0.008) and RF ablation (8.3 vs. 4.4%, p = 0.279), respectively.

CONCLUSION

(1) EGD before PVI showed UGI abnormalities in > 50% of patients, one-fourth of these relevant for PVI. (2) Esophageal inflammation was associated with a higher incidence of post-ablation (peri)-esophageal injury. Whether having this information before ablation is able to reduce ELs or AEF remains to be shown.

Calculated parameters of luminal esophageal temperatures predict esophageal injury following conventional and high-power short-duration radiofrequency pulmonary vein isolation

BACKGROUND

Luminal esophageal temperature (LET) monitoring is not associated with reduced esophageal injury following pulmonary vein isolation (PVI).

OBJECTIVE

Detailed analysis of (the temporal and spatial gradients of) LET measurements may better predict the risk for esophageal injury.

METHODS

Between January 2020 and December 2021, LET maxima, duration of LET rise above baseline, and area under the LET curve (AUC) were calculated offline and correlated with (endoscopy and endoscopic ultrasound detected) esophageal injury (i.e., mucosal esophageal lesions [ELs], periesophageal edema, and gastric motility disorders) following PVI using moderate-power moderate-duration (MPMD [25-30 W/25-30s]) and high-power short-duration (HPSD [50 W/13s]) radiofrequency (RF) settings.

RESULTS

63 patients (69 ± 9 years old, 32 male, 51 MPMD and 12 HPSD) were studied. The esophageal injury was frequent (40% in both groups), mucosal ELs were more common with MPMD, and edema was frequently observed following HPSD. RF-duration, total RF-energy at the left atrial (LA) posterior wall, and distance between LA and esophagus were not different between patients with/without esophageal injury. In contrast, to LET and LET duration above baseline, AUC was the best predictor and significantly increased in patients with esophageal injury (3422 vs. 2444 K^. s).

CONCLUSION

For both ablation strategies, AUC of the LET curves best predicted esophageal injury. HPSD is associated with similar rates of esophageal injury when (mostly subclinical) periesophageal alterations (that are of unclear clinical relevance) are included. Whether integration of these calculated LET parameters is useful to prevent esophageal injury remains to be seen.

Improvement of Retinal Microcirculation after Pulmonary Vein Isolation in Patients with Atrial Fibrillation—An Optical Coherence Tomography Angiography Study

Purpose: To evaluate retinal and optic nerve head (ONH) perfusion in patients with atrial fibrillation (AF) before and after catheter ablation of AF with pulmonary vein isolation (PVI). Methods: 34 eyes of 34 patients with AF and 35 eyes of 35 healthy subjects were included in this study. Flow density data were obtained using spectral-domain OCT-A (RTVue XR Avanti with AngioVue, Optovue, Inc, Fremont, California, USA). The data of the superficial and deep vascular layers of the macula and the ONH (radial peripapillary capillary network, RPC) before and after PVI were extracted and analysed. Results: The flow density in the superficial OCT-angiogram (whole en face) and the ONH (RPC) in patients with AF was significantly lower compared to healthy controls (OCT-A superficial: study group: 48.77 (45.19; 52.12)%; control group: 53.01 (50.00; 54.25)%; p < 0.001; ONH: study group: 51.82 (48.41; 54.03)%; control group: 56.00 (54.35; 57.70)%; p < 0.001;). The flow density in the ONH (RPC) improved significantly in the study group following PVI (before: 51.82 (48.41; 54.03)%; after: 52.49 (50.34; 55.62)%; p = 0.007). Conclusions: Patients with AF showed altered ocular perfusion as measured using OCTA when compared with healthy controls. Rhythm control using PVI significantly improved ocular perfusion as measured using OCT-A. Non-contact imaging using OCTA provides novel information about the central global microperfusion of patients with AF.

[Practical guide for safe and efficient cryoballoon ablation for atrial fibrillation : Practical procedure, tips and tricks]

In the current guidelines on treatment of atrial fibrillation, cryoballoon-based catheter ablation of atrial fibrillation is recommended in addition to radiofrequency ablation and has become established as a standard procedure in the clinical routine of many centers for index pulmonary vein isolation. A safe, simplified and often durable pulmonary vein isolation can be achieved by a systematic approach. This review article provides a practical guide for all steps of cryoballoon-based pulmonary vein isolation, including preprocedural preparation and postinterventional follow-up. Both cryoballoon systems currently available on the market are considered.

Comparison for the efficacy and safety of time-to-isolation protocol and conventional protocol of cryoballoon in the treatment of atrial fibrillation: a meta-analysis and systematic review

BACKGROUND

Cryoballoon (CB) has been widely utilized in the treatment of drug-refractory atrial fibrillation (AF), but the balance point between efficacy and safety has been unclear. The protocol based on the time-to-isolation (TTI) was expected to provide patients with individualized ablation strategies.

METHODS

All studies up to June 2020 comparing the CB of TTI-based protocol (TTIP) and conventional protocol (ConP) in PubMed, Embase, and Cochrane Library databases were searched. The pooled OR or SMD with 95% CIs for each outcome were calculated with inverse-variance random effect model. The Egger method was used to evaluate the publication bias and the subgroup analysis was conducted according to the type of atrial fibrillation.

RESULTS

Six studies enrolling a total of 1770 patients with drug-refractory AF were included. The pool real-time recording of pulmonary veins potential was 71% (95% CI: 61 ~ 81%, I2 = 97.9%) and a similar incidence of freedom from ATs after 1 year (OR: 1.12; 95% CI: 0.86 ~ 1.46, I2 = 0.0%, P = 0.481) was observed between two protocols. No difference was observed in complications (OR: 0.67; 95% CI: 0.43 ~ 1.04, I2 = 0.0%, P = 0.717) and phrenic nerve palsy (OR: 0.70; 95% CI: 0.37 ~ 1.35, I2 = 0.0%, P = 0.807). TTIP could significantly decrease the CB freezes per patient (SMD: - 2.44; 95% CI: - 4.46 to approximately - 0.41; I2 = 99.5%, P = 0.00) and shorten the cryotherapy application time (SMD: - 3.04; 95% CI: - 4.18 to approximately - 1.89; I2 = 97.4%, P = 0.00), procedure time (SMD: - 1.51; 95% CI: - 2.08 to approximately - 0.94; I2 = 95.4%, P = 0.00), and fluorescence time (SMD: - 0.70; 95% CI: - 1.25 to approximately - 0.15; I2 = 95.7%, P = 0.00).

CONCLUSION

TTIP is safe and effective and it opens a new chapter in the field of individualized protocol of CB for patients with AF.

Effectiveness and safety of a single freeze strategy of cryoballoon ablation of atrial fibrillation: an EHRA systematic review and meta-analysis

To conduct a systematic review and meta-analysis to compare the effectiveness and safety of cryoballoon ablation of atrial fibrillation (AF) performed using a single freeze strategy in comparison to an empiric double ('bonus') freeze strategy. We systematically searched MEDLINE, EMBASE, and CENTRAL databases from inception to 12 July 2020, for prospective and retrospective studies of patients undergoing cryoballoon for paroxysmal or persistent AF comparing a single vs. bonus freeze strategy. The main outcome was atrial arrhythmia-free survival and eligible studies required at least 12 months of follow-up; the primary safety outcome was a composite of all complications. Study quality was assessed using the Cochrane risk of bias tool and the Newcastle-Ottawa Scale. Thirteen studies (3 randomized controlled trials and 10 observational studies) comprising 3163 patients were eligible for inclusion (64% males, 71.5% paroxysmal AF, mean CHA2DS2-VASc score 1.3 ± 0.9). There was no significant difference in pooled effectiveness between single freeze strategy compared to double freeze strategy [relative risk (RR) 1.03; 95% confidence interval (CI): 0.98-1.07; I2 = 0%]. Single freeze procedures were associated with a significantly lower adverse event rate (RR 0.72; 95% CI: 0.53-0.98; I2 = 0%) and shorter average procedure time (90 ± 27 min vs. 121 ± 36 min, P < 0.001). A trend for lower risk of persistent phrenic nerve palsy was observed (RR 0.61; 95% CI: 0.37-1.01; I2 = 0%). The quality of included studies was moderate/good, with no evidence of significant publication bias. Single freeze strategy for cryoballoon of AF is as effective as an empiric double ('bonus') freeze strategy while appearing safer and probably quicker (PROSPERO registration number CRD42020158696).

Pre-procedural proton pump inhibition is associated with fewer peri-oesophageal lesions after cryoballoon pulmonary vein isolation

Pulmonary vein isolation (PVI) using cryoenergy is safe and efficient for treatment of atrial fibrillation (AF). Pre-existing upper gastrointestinal (GI) pathologies have been shown to increase the risk for AF. Therefore, this study aimed at assessing incidental pathologies of the upper GI tract in patients scheduled for PVI and to analyse the impact of patients’ characteristics on PVI safety outcome. In 71 AF patients, who participated in the MADE-PVI trial, oesophagogastroduodenoscopy and endosonography were prospectively performed directly before and the day after PVI to assess pre-existing upper GI pathologies and post-interventional occurrence of PVI-associated lesions. Subgroup analysis of the MADE-PVI trial identified clinically relevant incidental findings in 53 patients (74.6%) with age > 50 years being a significant risk factor. Pre-existing reflux oesophagitis increased risk for PVI-associated mediastinal oedema, while patients already treated with proton pump inhibitors (PPI) had significantly fewer mediastinal oedema. Our results suggest that AF patients with pre-existing reflux oesophagitis are at higher risk for PVI-associated mediastinal lesions, which is decreased in patients with constant PPI-treatment prior to PVI. Since PVI-associated mediastinal lesions are regarded as surrogate parameter for an increased risk of the fatal complication of an oesophago-atrial fistula, our findings hint at a beneficial effect of pre-interventional prophylactic PPI-treatment to reduce risk for PVI-associated complications.

German Clinical Trials Register (DRKS00016006; date of registration: 17/12/2018).

Ablation of paroxysmal and persistent atrial fibrillation in the very elderly real-world data on safety and efficacy

Background

The role and technique of catheter ablation of atrial fibrillation (AF) in the elderly is unclear. While in young patients pulmonary vein isolation (PVI) has evolved as first option, in older patients decision is often made in favor of drugs as higher complication rates and less benefit are suspected. Therefore, data on PVI of paroxysmal and persistent AF in these patients is still sparse but of eminent importance.

Hypothesis

PVI is comparably safe in the very elderly with similar recurrence and complication rates.

Methods

We enrolled all patients (n = 146) aged >75 years who underwent a first PVI over a period of 10 years (2009‐2019) from our prospective single‐center ablation registry. Mean follow‐up time was 231 ± 399 days.

Results

Acute ablation success defined as complete PVI and sinus rhythm at the end of the ablation procedure was high (99%). Severe periprocedural complications occurred in 3.3% (stroke/TIA n = 2; 1.3%; pericardial effusion n = 3; 2%). In 4.6% of patients symptomatic sick‐sinus‐syndrome was unmasked after PVI resulting in pacemaker implantation. There were no deaths related to PVI. Recurrence rate of symptomatic AF was 37.3% resulting in a Re‐PVI and/or substrate ablation in 32 pts (20.9%). During follow‐up pacemaker implantation plus atrioventricular node ablation was performed in 10 pts (6.8%). There was a trend toward lower recurrence rates with single‐shot devices (cryoballoon, multielectrode phased‐radiofrequency ablation catheter) than with point‐by‐point radiofrequency while complication rates did not differ.

Conclusion

PVI for AF is a feasible treatment option also in patients >75 years with a reasonable success and safety profile. Higher success rates occurred in patients treated with a single‐shot device as compared to point‐by‐point ablation.

Severe hypoperistalsis caused by a 3-min single shot cryoballoon ablation for paroxysmal atrial fibrillation: A case report

A 61-year-old male was referred to our hospital to receive catheter ablation of paroxysmal atrial fibrillation. Since no anatomical abnormalities were detected by preoperative computed tomography of left atrium and pulmonary veins (PVs), he underwent a cryoballoon ablation for a PV isolation. We performed single, 3-min freeze applications to all four PVs while monitoring the esophageal temperature. Immediately after the procedure, he complained of nausea, followed by a body weight loss of 9 kg over 2 months. Since no structural abnormalities were detected even through careful evaluation, he was diagnosed with hypoperistalsis caused by the cryoballoon ablation. Although his symptoms partially improved, they persisted over a year. The cryoballoon procedure is believed to be relatively safe, but even just a simple 3-min freeze application caused severe hypoperistalsis in the present case. Operators should recognize the risk of such complications. <Learning objective: Cryoballoon ablation is thought to be a safe procedure, however, there are important complications. Asymptomatic or mild-symptomatic hypoperistalsis after cryoballoon ablation is not uncommon. In this case, even just a single 3-min freeze for each pulmonary vein caused severe hypoperistalsis. Repetitive or longer freezes are reported as a risk for this complication, therefore, the operator should recognize the risk of this complication, and a shorter freeze time may be considered instead of a fixed 3-min freeze.>.

Balloon-Based Ablation Technologies

Pulmonary vein isolation (PVI) is widely accepted as the mainstay of interventional treatment of atrial fibrillation. Ablation with radiofrequency (RF) point-by-point catheters is highly operator dependent and may fail because of ineffective lesions or gaps. Several balloon-based catheter ablation technologies have emerged as an alternative to effect PVI. Cryoballoon ablation is widely used, and current iterations of the technology show comparable acute and long-term efficacy to RF ablation. Techniques such as time to isolation have emerged to improve efficacy and safety. Laser balloon is a highly compliant variably sized balloon that has been validated as an effective strategy for PVI.

Risk of atrioesophageal fistula with cryoballoon ablation of atrial fibrillation

Background

Although there are considerable data on the safety of cryoablation, data on the rare but severe complication of atrioesophageal fistula (AEF) following cryoballoon ablation are limited.

Objective

To report the global, user-reported incidence of AEF associated with cryoballoon ablation for the treatment of atrial fibrillation using Medtronic's complaint database.

Methods

User-reported cryoballoon ablation complications occurring between July 1, 2009, and March 31, 2019, were reviewed to identify cases of AEF. A global event rate of AEF was calculated by dividing the event count by total catheter utilization over the same period. Data on symptoms and patient sequalae were reported as available.

Results

More than 500,000 Arctic Front cryoballoon catheters (Arctic Front, Arctic Front Advance, Arctic Front Advance ST, and Arctic Front Advance Pro; Medtronic, Inc) were distributed globally during the 9.75-year study period. During this time, 18 confirmed AEF, 1 suspected AEF, and 1 pericardial esophageal fistula were identified; therefore, global incidence of AEF associated with the Arctic Front family of ablation catheters was 0.00396%. Patients most commonly presented with fever (88.2%), and initial symptoms were reported a median of 21 (interquartile range: 4-30) days after the ablation. Although rare, the development of an AEF resulted in death in 68.8% (11/16) of patients with known outcomes.

Conclusions

AEF is a possible but rare complication of cryoballoon ablation with a reported frequency of 1 in every 25,000 patients treated. Awareness of the prevalence and manifestation of AEF associated with cryoballoon ablation is critical for early identification and treatment of this complication.

Current Status of Esophageal Protection

Catheter ablation of atrial fibrillation necessitates ablation on the posterior left atrium. The anterior esophagus touches the posterior left atrium, although its course is highly variable. The proximity of the left atrium to the esophagus confers risk of injury with radiofrequency and cryoablation owing to the heat transfer that occurs with thermal ablation. Early detection of esophageal temperature changes with probes may decrease the extent of damage to the esophagus, but evidence is mixed. Avoiding ablation on the esophagus with esophageal deviation and modifying ablation approaches may decrease the risk of injury.

Cryoballoon ablation dosing: From the bench to the bedside and back

To date, multiple modes of research have been leveraged to study the optimal cryoballoon ablation parameters to safely, effectively, and efficiently isolate the pulmonary veins for the treatment of atrial fibrillation. Basic scientific investigation, preclinical studies, clinical observations, trials, and, more recently, computational modeling have helped to generate and test new hypotheses for the advancement of cryoballoon treatment in patients with atrial fibrillation. In this review, we examine the data and evidence that have contributed to the development of patient-tailored dosing strategies that are currently used for pulmonary vein isolation by using the Arctic Front series of cryoballoon ablation catheters.

Characteristics of Atrial Fibrillation Patients Suffering Esophageal Injury Caused by Ablation for Atrial Fibrillation

The close proximity of esophagus to the left atrial posterior wall predisposes esophagus to thermal injury during catheter ablation for atrial fibrillation (AF). In this retrospective study, we aimed to investigate risk factors of esophageal injury (EI) caused by catheter ablation for AF. Patients who underwent first-time AF ablation from July 2013 to June 2018 were included. The esophagus was visualized by oral soluble contrast during ablation for all patients and a subset of patients were selected to undergo endoscopic ultrasonography (EUS) to estimate EI post ablation. Degree of EI was categorized as Kansas City classification: type 1: erythema; type 2: ulcers (2a: superficial ulcers; 2b: deep ulcers); type 3: perforation (3a: perforation without communication with the atria; 3b: atrioesophageal fistula [AEF]). Of 3,852 patients, 236 patients (61.5 ± 9.7 years; male, 69%) received EUS (EUS group) and 3616 (63.2 ± 10.9 years; male, 61.1%) without EUS (No-EUS group). In EUS group, EI occurred in 63 patients (type 1 EI in 35 and type 2 EI in 28), and no type 3 EI was observed during follow up. In a multivariable logistic regression analysis, an overlap between the ablation lesion and esophagus was an independent predictor of EI (odds ratio, 21.2; 95% CI: 6.23–72.0; P < 0.001). In No-EUS group, esophagopericardial fistula (EPF; n = 3,0.08%) or AEF (n = 2,0.06%) was diagnosed 4–37 days after ablation. In 3 EPF patients, 2 completely recovered with conservative management and 1 died. Two AEF patients died. Ablation at the vicinity of the esophagus predicts risk of EI. EUS post ablation may prevent the progression of EI and should be considered in management of EI. It remains challenging to identify patients with high risk of EI.

Diagnosis and management of cold urticaria in cryoablation of atrial fibrillation: a case report

Background

Cold-induced urticaria is triggered by exposure to local or environmental cold and manifests as localized or systemic pruritic papules, sometimes accompanied by angio-oedema and anaphylaxis representing a life-threatening condition. Therapy options of atrial fibrillation (AF) include catheter ablation with different energy sources, of which cryoenergy may be superior to other energy sources regarding safety and efficacy.

Case summary

We report the case of a 60-year-old man suffering from symptomatic paroxysmal AF. The patient had a history of cold-induced urticaria without occurrence of systemic reactions to date. After successful pulmonary vein isolation (PVI) using cryoenergy, post-interventional oesophagogastroduodenoscopy and endosonography revealed newly occurred oedema in the middle oesophagus with inclusion of all oesophageal wall layers. Due to missing peri-atrial lesions, activation of cold urticaria during cryoablation rather than procedure-associated alterations was diagnosed. The patient reported no systemic or gastrointestinal symptoms after PVI.

Discussion

We could demonstrate that cold urticaria can manifest as oesophageal angio-oedema in AF patients undergoing cryoablation. Therefore, these patients should be carefully considered for an alternative energy source for PVI or premedication with antihistamines when using cryoenergy.