Cryoballoon Ablation In Patients Research Articles

Safety and Efficacy of Second-Generation Cryoballoon Ablation in Patients Aged over 75 Years

Objective: The use of second-generation cryoballoon (CB2) for pulmonary vein isolation (PVI) in atrial fibrillation (AF) ablation therapy is common. This study aimed to compare the safety and efficacy of CB2 ablation for PVI in AF patients aged 75 years and older to those under 75 years old. Methods: A retrospective, observational study was conducted, including AF patients who underwent CB2 for PVI between January 2018 and December 2020 at our center. The patients were divided into two groups based on age: those aged 75 years and older (elderly group) and those under 75 years (control group). Procedural characteristics, complications, and one-year follow-up outcomes were compared between the two groups using Student's t-test or the chi-square test for univariate analysis. Results: A total of 156 AF patients treated with CB2 for PVI were included in the study, with 78 patients aged 75 years and older (elderly group, mean age = 78 years) and 78 patients aged under 75 years (control group, mean age = 66 years). The PVI procedure duration was 86.2 ± 25.8 minutes for the elderly group and 83.2 ± 20.8 minutes for the control group (p = 0.413). The elderly group showed a higher trend of complications (8/78, 10.3%) compared to the control group (2/78, 2.6%) (p = 0.049), although no serious complications were observed. One-year follow-up revealed that approximately 80% of patients in both groups did not experience AF recurrence (p = 0.656). Conclusion: CB2 ablation for PVI appears to be safe and effective in AF patients aged 75 years and older, with outcomes comparable to those in younger patients. However, special attention should be given to venous puncture in elderly patients.

Association between baseline glycated hemoglobin level and atrial fibrillation recurrence following cryoballoon ablation among patients with and without diabetes

ObjectivesThe study aims to assess the effect of baseline glycated hemoglobin (HbA1c) levels on atrial fibrillation (AF) recurrence following cryoballoon ablation in patients with and without diabetes.MethodsConsecutive AF patients receiving first cryoballoon ablation between April 2018 and April 2021 were included. AF recurrence and other clinical outcomes were recorded for a minimum of 12 months post-ablation, with regular assessments at 3, 6, and 12 months, followed by annual check-ups. The primary outcome was AF recurrence after ablation at longest follow-up. Multivariate Cox proportional hazards regression models were utilized to calculate the hazard ratio (HR) and 95% CI per standard deviation (SD) increase of baseline HbA1c level.Results335 patients were included in the analysis. The mean age was 61.7 years, 61.8% were male. 12.8% had type 2 diabetes, and 81.7% of patients had paroxysmal AF. The median level of HbA1c was 5.3%, and the mean CHA2DS2-VASc score was 1.8. All cryoballoon ablation procedures, utilizing a 28-mm balloon, achieved successful pulmonary vein isolation. Over a median follow-up of 18 months, 105 patients (31.3%) experienced AF recurrence. In multivariate Cox proportional hazards analysis, a higher HbA1c level, persistent AF (HR 1.91, 95% CI 1.08 to 3.39, P = 0.026), alcohol consumption (HR 2.67, 95% CI 1.33 to 5.37, P = 0.006), and Nadir RSPV (HR 1.04, 95% CI 1.00 to 1.08, P = 0.005) were significant predictors of AF recurrence. Per-SD increase of HbA1c was associated with a 1.75-fold increase risk of AF recurrence (HR 1.75, 95% CI 1.39 to 2.21, P < 0.001). Subgroup analysis revealed that a higher HbA1c level was associated with a higher risk of AF recurrence in patients with and without diabetes, and in patients with paroxysmal and persistent AF.ConclusionBaseline HbA1c level was an independent predictor of AF recurrence following cryoablation, both in patients with and without diabetes.

Pulmonary vein capture is a predictor for long-term success of stand-alone pulmonary vein isolation with cryoballoon ablation in patients with persistent atrial fibrillation.

The mechanisms of AF development and progression are still not completely understood. Despite the relative efficacy of ablation, the risk of AF recurrence is substantial, particularly in patients with persistent AF (perAF). At present we do not have any reliable intra-procedural electrophysiologic predictors of long-term success of AF ablation other than pulmonary vein isolation. We evaluated selected intraprocedural pulmonary vein characteristics that may be helpful in future guidance of persistent AF ablation. 390 consecutive procedures using cryoballoon for initial AF ablation were divided by clinical presentation (paroxysmal or persistent AF), and by pulmonary vein (PV) response to pacing after completion of ablation (discrete electrogram elicited with pacing-"PV capture" or not-"Control"). Patients were followed (median 20 months) for recurrent atrial arrhythmias as the primary end point of the study. PV capture was identified in 20.3% and 17.1% and patients with paroxysmal and persistent AF respectively (ns). In patients with persistent AF presence of PV capture was associated with significantly better outcomes compared to patients without PV capture (p < 0.001). In the group "persistent AF and PV capture", an initial strategy of PV isolation and reisolation of the PVs (without additional lesions) for patients with recurrent atrial arrhythmias resulted in 20/23 (87%) patients in sinus rhythm off antiarrhythmic medications at study completion. In patients with paroxysmal AF, PV capture was not associated with outcome benefits. Specific electrophysiologic characteristics of PV (PV capture cycle length: PVCCL) did not have an impact on AF recurrence, although 25% shortening of PVCCL was observed after 60 s periods of pacing at short cycle lengths. No background demographic patient characteristic differences were identified between patients with vs. without PV capture. The presence of PV capture was associated with better outcomes in patients with persistent AF. PV capture may identify those patients with persistent AF in whom cryoballoon PV isolation alone is sufficient as an initial ablation procedure and as the primary ablation strategy for recurrent AF.

Long-Term Clinical Outcomes Following Cryoballoon Ablation in Patients with Paroxysmal Atrial Fibrillation: Single-Center Experience

Long-Term Clinical Outcomes Following Cryoballoon Ablation in Patients with Paroxysmal Atrial Fibrillation: Single-Center Experience

Occlusion and catheter ablation using a large-size cryoballoon for various pulmonary veins: a case series

Abstract Background It is established that pulmonary vein isolation using the POLARx™ (Boston Scientific, Marlborough, MA, USA) cryoballoon is a rapid, safe, and effective approach. The new POLARx™ FIT (Boston Scientific), which is expandable from 28 to 31 mm in diameter, is currently available. However, there is limited evidence available regarding the treatment of atrial fibrillation in this setting. In this article, we report a case series of cryoballoon ablation in patients with atrial fibrillation using POLARx™ FIT. Case summary This case series describes a comparison of obstruction in three patients with pulmonary veins of different shapes and diameters undergoing cryoballoon ablation and pulmonary vein isolation with a 31 mm diameter balloon. Discussion Cryoballoon ablation using the 31 mm mode of POLARx™ FIT has the potential to provide safe and stable pulmonary vein isolation with good occlusion for a variety of pulmonary vein geometries. In this case series, the 31 mm mode of the POLARx™ FIT resulted in better pulmonary vein occlusion than the 28 mm mode in patients with large left atria and large pulmonary veins, including the left common pulmonary vein. This approach may be considered a first-line therapy option of cryoballoon ablation in patients with atrial fibrillation.

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.

Left atrial functional changes and its predictive value in the early period after cryoballoon ablation for paroxysmal atrial fibrillation

Abstract Introduction/Purpose In patients with paroxysmal atrial fibrillation (PAF), functional changes are observed in the left atrium (LA) after the pulmonary vein isolation (PVI) procedure. Although previous studies have investigated the altered mechanical functions of the LA with radiofrequency (RF) ablation, changes in the LA functions in the early period after cryoablation (CB-2) and the relationship between early period serial echocardiographic follow-ups after cryoablation and recurrence of atrial fibrillation/atrial tachycardia (AF/AT) have not been clearly demonstrated. This study aims to determine changes in the mechanical functions of LA in patients with PAF during the early period after cryoablation and whether these changes are effective in predicting the risk of recurrence by using echocardiographic parameters including Doppler and strain parameters. Methods Consecutive seventy-seven patients (mean age: 57.5±11.2 years; 57% men) with PAF underwent CB-2 and were prospectively analyzed. All patients were in sinus rhythm before and after the procedure. The LA dimensions, the LA reservoir strain (LASr), the LA atrial contractile strain (LASct), the LA conduit strain (LAScd) and left ventricular diastolic function parameters were evaluated by Doppler echocardiography before and 3 months after the procedure. Patients were monitored with 48-hour Holter at 1-3-6-12th months after the procedure to evaluate for recurrence. Results Acute procedural success was achieved in all cases. No major complications were observed. LASr and LASct showed significant recovery after the procedure (28.3±12.8% vs 34.6±13.8%, p&amp;lt;0.001 and -10.8±7.9% vs -13.9±9.3%, p=0.014 respectively). No significant change was demonstrated in other echocardiographic parameters. During the one-year follow-up after the procedure late recurrence (&amp;gt;3 months) of AF/AT was observed in 9 (11.7%) patients. Although the power of echocardiographic parameters in predicting recurrence was found to be not statistically significant, a downward trend especially in the values of LASr (p=0.068) and LASct (p=0.058) was observed at the 3rd month control echocardiographic results in patients with recurrence. Conclusion Significant improvement in mechanical functions may occur even in the early period after cryoballoon ablation in patients with PAF. In addition, as our study points out strain parameters, indicators of mechanical function tend to decline in patients with late term recurrence.

Left atrial functions in the early period after cryoballoon ablation for paroxysmal atrial fibrillation.

In patients with paroxysmal atrial fibrillation (PAF), functional changes are observed in the left atrium (LA) after pulmonary vein isolation (PVI) procedure. Although previous studies have investigated the altered mechanical functions of the LA with radiofrequency (RF) ablation, changes in the LA functions in the early period after cryoablation (CB-2) have not been clearly demonstrated. This study aims to explore the early periodical changes in mechanical functions of the LA in patients with PAF who underwent CB-2 based ablation through the help of echocardiographic methods which contain Doppler and strain parameters. Consecutive 77 patients (mean age: 57.5 ±11.2; 57% men) with PAF underwent CB-2 were prospectively analyzed. All patients were in sinus rhythm before and after the procedure. The LA dimensions, the LA reservoir strain, the LA atrial contractile strain and the LA conduit strain and left ventricular diastolic function parameters were evaluated by Doppler echocardiography before and 3 months after the procedure. Acute procedural success was achieved in all cases. No major complications were observed. LA reservoir strain and LA contractile strain showed significant recovery after the procedure. (28.3±12.8vs. 34.6±13.8, p<.001 and -10.8±7.9 vs. -13.9±9.3, p=.014 respectively). No significant change was demonstrated in other echocardiographic parameters. Significant improvement in mechanical functions may occur even in the early period after cryoballoon ablation in patients with PAF.

PO-02-038 LESION SIZE PREDICTION MODULE-GUIDED RADIOFREQUENCY ABLATION VERSUS CRYOBALLOON ABLATION FOR PAROXYSMAL ATRIAL FIBRILLATION: A PROPENSITY SCORE MATCHED ANALYSIS

In previous studies show cryoballoon ablation (CBA) and radiofrequency ablation (RFA) are similar results. However, RFA technology has progressed in few years, lesion size assessment module developed to improve lesion durability. The aim of this study was to compare clinical outcome of RFA guided by lesion size prediction module and second or fourth-generation CBA in patients with paroxysmal atrial fibrillation (PAF). We enrolled 1905 patients with PAF (65.2 ± 11.3years, male 68.0%). 205 patients after RFA who underwent ablation guided by lesion size prediction module, Ablation Index or Lesion Size Index, and 1700 patients after second or fourth-generation CBA in September 2014 to August 2020, and evaluated retrospectively. We performed pulmonary vein isolation with CBA or RFA followed by additional non-pulmonary vein foci ablation. We selected 194 patients treated with RFA (follow-up period 14.1 ± 7.9months) and 194 patients treated with CBA (follow-up period 23.9 ± 12.9months) using propensity score matching. During a follow-up period, atrial tachyarrhythmia recurrence was documented in 34 patients (17.5%) in RFA and 38 patients (19.6%) in CBA. Freedom from atrial tachyarrhythmia recurrence without anti-arrhythmic-drugs after single procedure was a similar in 2 groups (1-year Kaplan–Meier survival rate estimates, RFA:84.9% and CBA:88.9%, p=0.358). The mean total procedure time was shorter in CBA than in RFA (109 ± 45 vs 148 ± 54 minutes, P<0.001), and the mean total fluoroscopy time was shorter in RFA than in CBA (20 ± 18 vs 33 ± 21 minutes, P<0.001). The proportion of non-pulmonary vein foci was slightly higher for CBA (42patients, 21.7%) than for RFA (36patients, 18.6%), but this difference was not significant (P=0.447). Similarly, there was no significant difference in ablation of non-pulmonary vein foci in the left atrium, although CBA was slightly more common (CBA: 16 patients, 8.3% and RFA: 10 patients 5.2%, p=0.223). [image] And, A second procedure was treated to 20 patients in the RFA and 32 in the CBA. The number of people with pulmonary vein reconnection in each was 10 patients (50.0%) in RFA and 15 patients (46.9%) in CBA, respectively, with no difference as a percentage(P=0.83). We found that in the treatment of patients with PAF, lesion size prediction module-guided procedure was not statistically significant efficacy to CBA. CBA and RFA are still similar results even today.

Prognostic implication of early recurrence after cryoballoon ablation in patients with atrial fibrillation.

It remains uncertain whether the implication of early recurrence and blanking period can be applied to patients with atrial fibrillation (AF) treated with cryoballoon ablation (CBA). We aimed to explore the prognostic value of early recurrence in patients with AF treated with CBA. We studied consecutive AF patients who were treated with CBA between April 2019 and September 2020 in two tertiary medical institutes and followed for up to 12months. The endpoint was the late recurrence of atrial arrhythmia, including AF, atrial flutter, and atrial tachycardia, following a 90-day blanking period. Atrial arrhythmia during the blanking period was defined as early recurrence and was not considered as an endpoint. This study included 406 patients with AF who underwent CBA. During the follow-up, 147 (36.2%) cases of late recurrence were observed. Of the 104 patients with early recurrence, 85 experienced late recurrence during follow-up. Early recurrence was associated with an increased risk of late recurrence in the univariate and multivariate analyses (P < 0.001). When we classified the patients into paroxysmal AF and persistent AF groups, early recurrence was still significantly associated with a higher risk of late recurrence (P = 0.005 and P < 0.001, respectively). Early recurrence after CBA was an independent risk factor for late recurrence in all patients as well as in those with paroxysmal AF and persistent AF. Therefore, further prospective studies could be considered to verify the risks and benefits of early rhythm control in patients with early recurrence.

Amplified sinus-P-wave analysis predicts outcomes of cryoballoon ablation in patients with persistent and long-standing persistent atrial fibrillation: A multicentre study.

Outcomes of catheter ablation for non-paroxysmal atrial fibrillation (AF) remain suboptimal. Non-invasive stratification of patients based on the presence of atrial cardiomyopathy (ACM) could allow to identify the best responders to pulmonary vein isolation (PVI). Observational multicentre retrospective study in patients undergoing cryoballoon-PVI for non-paroxysmal AF. The duration of amplified P-wave (APW) was measured from a digitally recorded 12-lead electrocardiogram during the procedure. If patients were in AF, direct-current cardioversion was performed to allow APW measurement in sinus rhythm. An APW cut-off of 150 ms was used to identify patients with significant ACM. We assessed freedom from arrhythmia recurrence at long-term follow-up in patients with APW ≥ 150 ms vs. APW < 150 ms. We included 295 patients (mean age 62.3 ± 10.6), of whom 193 (65.4%) suffered from persistent AF and the remaining 102 (34.6%) from long-standing persistent AF. One-hundred-forty-two patients (50.2%) experienced arrhythmia recurrence during a mean follow-up of 793 ± 604 days. Patients with APW ≥ 150 ms had a significantly higher recurrence rate post ablation compared to those with APW < 150 ms (57.0% vs. 41.6%; log-rank p < 0.001). On a multivariable Cox-regression analysis, APW≥150 ms was the only independent predictor of arrhythmia recurrence post ablation (HR 2.03 CI95% 1.28-3.21; p = 0.002). APW duration predicts arrhythmia recurrence post cryoballoon-PVI in persistent and long-standing persistent AF. An APW cut-off of 150 ms allows to identify patients with significant ACM who have worse outcomes post PVI. Analysis of APW represents an easy, non-invasive and highly reproducible diagnostic tool which allows to identify patients who are the most likely to benefit from PVI-only approach.

Coupled thermal-hemodynamics computational modeling of cryoballoon ablation for pulmonary vein isolation

Cryoballoon ablation (CBA) is a cryo-energy based minimally invasive treatment procedure for patients suffering from left atrial (LA) fibrillation. Although this technique has proved to be effective, it is prone to reoccurrences and some serious thermal complications. Also, the factors affecting thermal distribution at the pulmonary vein-antrum junction that are critical to the treatment success is poorly understood. Computer modeling of CBA can resolve this issue and help understand the factors affecting this treatment. To do so, however, numerical challenges associated with the simulation of advection-dominant transport process must be resolved. Here, we describe the development of a thermal-hemodynamics computational framework to simulate incomplete occlusion in a patient-specific LA geometry during CBA. The modeling framework uses the finite element method to predict hemodynamics, thermal distribution, and lesion formation during CBA. An incremental pressure correction scheme is used to decouple velocity and pressure in the Navier-Stokes equation, whereas several stabilization techniques are also applied to overcome numerical instabilities. The framework was implemented using an open-source FE library (FEniCS). We show that model predictions of the hemodynamics in a realistic human LA geometry match well with measurements. The effects of cryoballoon position, pulmonary vein blood velocity and mitral regurgitation on lesion formation during CBA was investigated. For a −700C cryoballoon temperature, the model predicts lesion formation for gaps less than 2.5 mm and increasing efficiency of CBA for higher balloon tissue contact areas. The simulations also predict that lesion formation is not sensitive to variation in pulmonary vein blood velocity and mitral regurgitation. The framework can be applied to optimize CBA in patients for future clinical studies.

Сhanges in the deformation of the pulmonary vein ostia after radiofrequency and cryoballoon ablation in patients with paroxysmal atrial fibrillation

Aim. To study changes in pulmonary vein ostia strain after radiofrequency (RFA) and cryoballoon ablation (CBA) in patients with paroxysmal atrial fibrillation (AF) by intracardiac echocardiography.Methods. Patients with paroxysmal AF (n=41) aged 60.1±7.1 years and duration of the disease 7.7±4.8 years were included in the study. Pulmonary vein (PV) isolation was performed with RFA (n=23) and CBA (n=18). All patients underwent transthoracic and intraoperative intracardiac echocardiography. Longitudinal strain of PV ostia was assessed before and after isolation.Results. Groups were comparable in main clinical parameters. Regress of PV ostia strain after RFA and CBA was achieved in all of PV, which corresponded to complete PV isolation. Remarked trend toward a more pronounced regression of PV ostia longitudinal strain after CBA compared with RFA for left superior (10±0.7% and 6.1±0.8% respectively, p&lt;0.001) and right inferior PV (9.3±0.7% vs 7.3±0.6%, p&lt;0.001) requires continued observation and analysis of data in a larger group. There were no complications.Conclusion. PV isolation is accompanied by a significant change in their longitudinal strain using intracardiac echocardiography both after CBA and after RFA.

Impact of first-line cryoablation for atrial fibrillation on healthcare utilization, arrhythmia disease burden and efficacy outcomes: real-world evidence from the Cryo Global Registry.

Cryoballoon ablation (CBA) is an effective first-line treatment for symptomatic atrial fibrillation (AF), as recently demonstrated by three randomized trials. This sub-analysis of the Cryo Global Registry aims to examine current clinical practices of first-line CBA. AF patients treated with first-line CBA were compared to CBA in antiarrhythmic drug (AAD)-refractory patients at 12months. Efficacy was examined using time-to-first atrial arrhythmia recurrence following a 90-day blanking period. Healthcare utilization was evaluated by repeat ablations and hospitalizations. Disease burden was examined by assessing quality of life (QOL) and patients' reporting of symptoms. Of 1394 patients, 433 (31.1%) were treated with first-line CBA, which was more frequent in high-volume centers. Serious procedure-related adverse event rates were similar. Efficacy at 12months was higher in the first-line group (87.8 vs. 81.6%, HRunadj 0.64 (95% CI 0.47-0.88); p < 0.01) regardless of the centers' CBA experience; when controlling for baseline characteristics, the difference was not significant (HRadj 0.87 (95% CI 0.56-1.37); p = 0.55). No difference was observed in repeat ablations and hospitalizations between cohorts. First-line patients experienced a larger mean reduction in symptoms and were prescribed AADs at a lower rate at 12-month follow-up (9.7 vs. 29.9%). QOL improved in both cohorts from baseline to 12months with no significant difference between groups (p = 0.29). In this global real-world experience, first-line CBA in patients with symptomatic AF is effective, with a larger symptom reduction compared with CBA after AAD failure and without a difference in healthcare utilization at mid-term follow-up. https://clinicaltrials.gov/ct2/show/NCT02752737.

Left atrial functions in the early period after cryoballoon ablation for paroxysmal atrial fibrillation

Abstract Introduction In patients with paroxysmal atrial fibrillation (PAF), functional changes are observed in the left atrium (LA) after pulmonary vein isolation (PVI) with catheter ablation. Although previous studies have investigated the altered mechanical functions of LA with radiofrequency (RF) ablation, changes in LA functions in the early period after cryoablation have not been clearly demonstrated. Methods Thirty three patients (mean age: 57±11; 54.5% men) with PAF underwent cryoablation procedure with second generation cryoballoon (CB-2). All patients were in sinus rhythm before and after the procedure. LA dimensions, LA strain parameters (LAsr-LAscd-LAsct) and left ventricular diastolic function parameters were evaluated by Doppler echocardiography before and 3 months after the procedure. Results Acute procedural success was achieved in all cases. No major complications were occurred. A significant recovery in LA reservoir strain (p=0.009) was observed. No significant change was demonstrated in remaining echocardiographic parameters. Conclusion LA reservoir strain is an indicator of left atrial compliance and significant improvement in mechanical functions may occur even in the early period after cryoballoon ablation in patients with PAF in contrast to LA function deterioration observed in RF ablation. Funding Acknowledgement Type of funding sources: None.

Hot balloon versus cryoballoon ablation in patients with atrial fibrillation: a systematic review and meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial fibrillation (AF) incidence is expected to increase more than 60% in the following 30 years. Catheter ablation is the treatment of choice for medically intractable AF with arrhythmia recurrence remaining an unsolved issue. Purpose We systematically reviewed existing literature to compare the efficacy of hot balloon (HBA) versus cryoballoon ablation (CBA). Methods PubMed, Scopus, ClinicalTrials.gov, medRxiv and Cochrane Library (according to PRISMA guidelines) were scrutinized for relevant articles up to 2 December 2021. Eligible studies had to compare clinical outcomes (arrhythmia recurrence rates or/and procedural data or/and safety outcomes) between patients undergoing HBA and CBA for AF. Quality assessment of studies was conducted via the Newcastle-Ottawa Scale (high quality≥ 7, moderate 4-6, poor &amp;lt;4). Statistical pooling was performed according to a random-effect model with generic inverse-variance weighting of odds ratios and mean differences computing risk estimates with 95% confidence intervals. The presence of heterogeneity among studies was evaluated under the Cochran Q chi-square test. I² values of 25%, 50% and 75% have been assigned adjectives of low, moderate, and high heterogeneity. Publication biases were assessed by visual inspection of funnel plots. Results PRISMA study search and individual study characteristics are presented in Figure 1. Literature search identified 131 studies, 5 of which (evaluating 513 patients) met inclusion criteria. Patients undergoing HBA demonstrated similar long term recurrence rate as compared to CBA treated controls (OR: 0.68; 95% CI: 0.38-1.22; p-value: 0.19; I2: 0%). Procedural aspects, such as touch-up radiofrequency ablation (per pulmonary vein), procedure time (min) and fluoroscopic time (min) did not differ among treatment arms (OR: 1.79; 95% CI: 0.84-3.83; p-value: 0.13, I2: 80%, MD: 9.69; 95% CI: -2.78-22.16; p-value: 0.13, I2: 63%, and OR: 1.03; 95% CI: -9.50-7.44; p-value: 0.81, I2: 87%, respectively). Regarding safety outcomes (Figure 1), the small number of the reported events precluded us from analyzing these data. Yet, tamponade and phrenic nerve injury were infrequent in both modalities; pulmonary vein stenosis of at least moderate severity (&amp;gt;50% luminal narrowing) was reported in 18 instances in the HBA arm as compared to zero events in the CBA arm. Of note, all events were asymptomatic. Quality assessment scores are shown in Figure 1. Four studies were of high quality and one study was of moderate quality. Funnel-plot distributions of the pre-specified outcomes indicated absence of publication bias for all outcomes. High statistical heterogeneity and the small number of patients included are the main limitations of this study. Conclusion Hotballoon ablation is a promising therapeutic option for patients suffering from AF, featuring comparable efficacy and procedural outcomes with cryoablation. Safety outcomes, especially PV stenosis, mandate further evaluation.

Impact of cryoballoon contact angle and acute myocardial injury on pulmonary vein reconnection.

At present, it remains unclear whether the effect on cryoinjury can be strongly exerted by contact of the balloon with the pulmonary vein (PV) ostium. The present study included 204 paroxysmal atrial fibrillation (PAF) patients who underwent an initial pulmonary vein isolation (PVI) using a cryoballoon from the Osaka Rosai Atrial Fibrillation ablation (ORAF) registry. The total balloon contact angle was measured from the equator line (sum of the angles of the upper side and bottom side in all PVs) under fluoroscopic imaging. The patients were stratified into three tertile groups according to the total balloon contact angle. We evaluated the relationship between the total balloon contact angle and clinical outcomes, including the value of acute myocardial injury marker (high-sensitive cardiac troponin I [hs-TnI]), arrhythmia recurrence, and PV reconnections in the repeated ablation. The total balloon contact angle was significantly associated with the hs-TnI value among the tertile groups (p < 0.001) and a multiple regression analysis showed that the total balloon contact angle significantly correlated with the hs-TnI value (standardized beta-coefficient = 0.572, p < 0.001). The balloon contact angle in PVs with PV reconnections was significantly lower than in those without (p = 0.044), while no significant differences in the recurrence of atrial fibrillation among the tertile groups were observed in the enrolled patients. The total balloon contact angle was significantly associated with the acute myocardial injury marker, hs-TnI. The total balloon contact angle was significantly associated with PV reconnections after cryoballoon ablation in patients who underwent a repeat ablation.

Relationship Between Autonomic Nervous System Activity and Recurrence After Cryoballoon Ablation in Patients with Paroxysmal Atrial Fibrillation

Introduction: In this study, we aimed to investigate the relationship between autonomic dysfunction (AD) determined according to the blood pressure (BP) and heart rate (HR) response in exercise treadmill test (ETT) prior to cryoballoon ablation (CBA), and the recurrence of atrial fibrillation (AF) after CBA in patients with paroxysmal AF. Patients and Methods: Seventy-six patients (mean age 53 ± 11 years, 61.8% male) with paroxysmal AF who underwent CBA were enrolled. Before CBA the ETT was performed by all patients. BP and HR responses in ETT were compared between patients with and without AF recurrence. Results: AD rate was significantly higher in the group with recurrence compared to the non-recurrent group (p&lt; 0.001). In addition to AD, age, female gender, and lower exercise capacity were also associated with post-CBA AF recurrence (p&gt; 0.05 for all). Examining AD parameters, systolic blood pressure at peak exercise (SBPpeak) (p&lt; 0.001) and diastolic blood pressure at peak exercise (DBPpeak) (p&lt; 0.001), slow heart rate recovery (HRR) (p&lt; 0.001) were significantly higher in the recurrent group. Conclusion: AD may be associated with AF recurrence after CBA in patients with paroxysmal AF. SBPpeak, DBPpeak, and slow HRR appear to be predictors of AF recurrence after ablation.

New Minimally Invasive and Tailor-Made Strategy for Cryoballoon Ablation in Patients With Paroxysmal Atrial Fibrillation

The optimal dosage for cryoballoon ablation (CBA) of atrial fibrillation (AF) is still unknown. This study aimed to evaluate the clinical implications of a reduction in the freezing duration to <180 seconds during CBA guided by the time to the target temperature. This study enrolled 325 consecutive paroxysmal AF patients who underwent CBA. It was a retrospective observational study in a single centre. It compared 164 patients who underwent a tailor-made CBA procedure (group T) with 161 who had a standard CBA procedure (group S). In group T, the freezing duration was reduced to 150 seconds when the temperature reached ≤ -40 °C within 40 seconds. Furthermore, it was reduced to 120 seconds when it reached ≤ -50 °C within 60 seconds. In the other patients, the freezing duration was 180 seconds, except for excessive freezing of ≤ -60 °C and/or emergent situations while monitoring the oesophageal temperature, and for phrenic nerve injury, as in group S. In group T, 89 patients (83%) underwent CBA with a reduction in the freezing duration. The total freezing time for each pulmonary vein was significantly shorter in group T than group S, and the total procedure time in group T decreased by an average of 4 minutes compared with group S. The rate of requiring additional radio frequency ablation following the CBA was significantly lower in group T than group S. The AF-free survival rate during the follow-up period (median, 366 days) was similar between the two groups. The safety and efficacy of the new CBA strategy were non-inferior to the standard procedure.

Fluoroscopy and contrast media use in cryoballoon ablation of atrial fibrillation using a novel imaging system.

Pulmonary vein (PV) isolation using cryoballoon (CB) catheter is generally characterized by a high radiation and contrast media exposure. A new dielectric imaging system (KODEX-EPD imaging system) allows pulmonary vein (PV) occlusion assessment without dye use. The purpose of this study was to verify the feasibility of reducing the radiation and dye use during CB ablation in patients with atrial fibrillation (AF) using the new dielectric imaging system. In a retrospective, single center study, we enrolled 34 consecutive patients with paroxysmal AF divided in two groups: 17 patients in Conventional Group underwent the procedure under fluoroscopy guidance before the new system introduction, while 17 patient in KODEX-EPD Group underwent the procedure under fluoroscopy and KODEX-EPD imaging system guidance. There were no differences in any clinical and anatomical characteristics between the two study groups. Overall procedure time was comparable between the two groups (69 [IQR 63-98] min in Conventional Group vs. 65 [IQR 58-74] min in KODEX-EPD Group, p = 0.16), while fluoroscopy time (8 [IQR 5-9] min vs. 11 [IQR 9-12] min, p = 0.014) and dye use (35 [IQR 28-45] ml vs. 70 [IQR 57-83] ml, p < 0.001) were significantly lower in the KODEX-EPD Group. No 30-day complications were observed. At 12-month follow-up 7/37 (19%) patients had an atrial arrhythmias recurrence, without any difference between the two study groups (17.6% vs. 23.5%, p = 0.68). The use of a new dielectric imaging system allowed a significantly reduction in radiation exposure and dye use during CB ablation in patients with AF.