A randomized controlled trial of the size-adjustable cryoballoon vs conventional cryoballoon for paroxysmal atrial fibrillation: The CONTRAST-CRYO II trial rationale and design.

Background: Pulmonary vein isolation (PVI) with cryoballoon technology is a well-established therapy for treatment of atrial fibrillation (AF). Recently, a size-adjustable cryoballoon (POLARxTM FIT) that enables delivery in a standard 28-mm or an expanded 31-mm size was introduced. Objective: The purpose of this study was to perform a randomized clinical trial to evaluate the safety and efficacy of this novel cryoballoon compared to the conventional cryoballoon. Methods: The CONTRAST-CRYO II trial is a multicenter, prospective, open-label, randomized controlled trial in which 214 patients with paroxysmal AF will be randomized 1:1 to cryoballoon ablation with either a conventional cryoballoon (Arctic Front AdvanceTM Pro) or a size-adjustable cryoballoon (POLARx FIT). The study was approved by the Institutional Review Boards at all investigational sites and has been registered in the UMIN Clinical Trials Registry (UMIN000052500). Results: The primary endpoint of this study will be the incidence of phrenic nerve injury. Secondary endpoints include procedural success, chronic success through 12 months, procedure-related adverse events, biophysiological parameters during applications for each pulmonary vein (PV), total procedural and fluoroscopy times, level of PVI and isolation area, and probability of non-PV foci initiating AF. Conclusion: The CONTRAST-CRYO II trial is a multicenter, prospective, randomized controlled trial designed to assess the safety and efficacy of the POLARx FIT vs the Arctic Front Advance Pro. The findings from this trial will provide additional utility data on the efficacy of the size-adjustable cryoballoon for isolating PVs in patients with paroxysmal AF.

Incidence of phrenic nerve injury during pulmonary vein isolation using different cryoballoons: data from a large prospective ablation registry.

AIMS: Phrenic nerve injury (PNI) is the most common complication during cryoballoon ablation. Currently, two cryoballoon systems are available, yet the difference is unclear. We sought to compare the acute procedural efficacy and safety of the two cryoballoons. METHODS: This prospective observational study consisted of 2,555 consecutive atrial fibrillation (AF) patients undergoing pulmonary vein isolation (PVI) using either conventional (Arctic Front Advance) (AFA-CB) or novel cryoballoons (POLARx) (POLARx-CB) at 19 centers between January 2022 and October 2023. RESULTS: Among 2,555 patients (68.8 ± 10.9 years, 1,740 men, paroxysmal AF[PAF] 1,670 patients), PVIs were performed by the AFA-CB and POLARx-CB in 1,358 and 1,197 patients, respectively. Touch-up ablation was required in 299(11.7%) patients. The touch-up rate was significantly lower for POLARx-CB than AFA-CB (9.5% vs. 13.6%, p = 0.002), especially for right inferior PVs (RIPVs). The touch-up rate was significantly lower for PAF than non-PAF (8.8% vs. 17.2%, P < 0.001) and was similar between the two cryoballoons in non-PAF patients. Right PNI occurred in 64(2.5%) patients and 22(0.9%) were symptomatic. It occurred during the right superior PV (RSPV) ablation in 39(1.5%) patients. The incidence was significantly higher for POLARx-CB than AFA-CB (3.8% vs. 1.3%, P < 0.001) as was the incidence of symptomatic PNI (1.7% vs. 0.1%, P < 0.001). The difference was significant during RSPV (2.5% vs. 0.7%, P < 0.001) but not RIPV ablation. The PNI recovered more quickly for the AFA-CB than POLARx-CB. CONCLUSIONS: Our study demonstrated a significantly higher incidence of right PNI and lower touch-up rate for the POLARx-CB than AFA-CB in the real-world clinical practice.

A Single Atrial Extrastimulation Resetting His Bundle During Supraventricular Tachycardia to Differentiate Atrial Tachycardia.

BACKGROUND: Catheter ablation is the curative treatment for paroxysmal supraventricular tachycardia (SVT). However, atrial tachycardia (AT) diagnosis is often challenging, especially when SVT is terminated by pacing. OBJECTIVES: This study sought to develop a novel method for AT diagnosis. METHODS: A total of 147 SVTs including 28 ATs, 87 atrioventricular nodal re-entrant tachycardias, and 32 orthodromic reciprocating tachycardias were prospectively studied. Single atrial extrastimulation was performed at the proximal coronary sinus from a coupling interval 20 milliseconds shorter than the tachycardia cycle length and gradually decreased until the His bundle (HB) was first reset and further until the SVT was terminated. The response of the SVT during the first HB resetting and the termination pattern were examined. RESULTS: In 27 of 28 ATs, tachycardia was unaffected when HB resetting whereas, in atrioventricular nodal re-entrant tachycardias or orthodromic reciprocating tachycardias (non-AT), tachycardia was simultaneously reset when HB resetting or was terminated with an atrio-Hisian block. When the coupling interval was further shortened for cases in which tachycardia persisted, all 33 SVTs with tachycardia termination with atrio-Hisian block were non-ATs, whereas 5 ATs and 7 non-ATs were terminated with Hisian-atrial block. The sensitivity, specificity, and positive and negative predictive values of the pattern of tachycardia that was unaffected when HB resetting for AT diagnosis were 96%, 100%, 100%, and 99%, respectively. Those of the pattern of tachycardia termination with atrio-Hisian block for non-AT diagnosis were 92%, 100%, 100%, and 42%, respectively. CONCLUSIONS: Single atrial extrastimulation from the proximal coronary sinus during tachycardia was useful and effective for AT diagnosis.

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.

Acute procedural efficacy and safety of a novel expandable diameter cryoballoon in atrial fibrillation ablation: Early results from a multicenter ablation registry.

INTRODUCTION: The major limitation of the current cryoballoon (CB) system is a fixed 28 mm balloon-size. We sought to analyze real-world early experience with novel-sized adjustable CB. METHODS: This multicenter observational study included 140 consecutive atrial fibrillation patients (71 years, 94 men, 86 paroxysmal) who underwent pulmonary vein (PV) isolation using expandable diameter CB capable of ablation at 28 or 31 mm. RESULTS: Out of 544 targeted PVs, 526 (96.7%) were successfully isolated by a size-adjustable CB with a 770 [690-870] second median application dose, while the remaining 18 required touch-up ablation. Among them, 326 (62.0%) PVs were isolated by a 31 mm balloon, and the rate was significantly higher for upper than lower PVs (73.0% vs. 45.7%, p < .0001) and highest for right superior (78.5%) and lowest for right inferior (39.9%) PVs. The biophysical parameters and time to isolation were comparable between the 28 and 31 mm balloons, however, the real-time PV potential monitoring capability was significantly higher for 31 mm than 28 mm balloons for the left superior PV. The esophageal temperature reached 15°C during left inferior PV ablation significantly more often with 31 mm than 28 mm balloons (43.1% vs. 18.2%, p = .008). Right phrenic nerve injury (PNI) occurred in 9 (6.4%) patients during applications (6 right superior, 2 right inferior PVs), and most occurred with a 31 mm balloon. CONCLUSIONS: Our real-world early data demonstrated high acute efficacy and safety of the novel-sized adjustable CB. The biophysical parameters were similar between the 28 and 31 mm balloons. No marked decrease in the incidence of PNI was observed even with 31 mm balloons.

Adjunctive posterior wall isolation for the treatment of persistent and longstanding persistent atrial fibrillation (CORNERSTONE AF) trial: Design and rationale.

BACKGROUND: A left atrial posterior wall isolation (LAPWI) is one of the atrial fibrillation (AF) ablation strategies. HYPOTHESIS: We hypothesized that an additional empirical LAPWI would increase the freedom from recurrent atrial arrhythmias as compared to standard AF ablation in persistent AF patients. METHODS: The CORNERSTONE AF study is a prospective, randomized, multicenter study investigating patients with AF persisting for >7 days and <3 years undergoing first-time AF ablation. They will be randomized to pulmonary vein isolation (PVI) or PVI + LAPWI in a 1:1 manner. Although PVI can be performed with either radiofrequency catheters or cryoballoons, only radiofrequency catheters will be permitted to achieve LAPWIs. Additional focal ablation targeting non-pulmonary vein triggers will be allowed. A total of 516 patients will be enrolled in 17 centers between August 2022 and February 2024 based on the calculation with 80% power, considering the assumption that 65% and 75% of the PVI and PVI + LAPWI group patients will be free from atrial arrhythmia recurrence 18-months postprocedure (10% of dropout). The primary endpoint is freedom from documented atrial arrhythmias 18 months postsingle procedures. Clinical follow-up will include 7-day ambulatory electrocardiograms and routine outpatient consultations by electrophysiologists at 1, 3, 6, 9, 12, and 18 months postprocedure. RESULTS: As of August 2023, a total of 331 patients (68 ± 9 years, 270 men, 43 longstanding persistent AF) have been enrolled. CONCLUSIONS: The CORNERSTONE AF study is a prospective, randomized, multicenter trial designed to evaluate the efficacy and safety of an adjunctive empirical LAPWI following standard AF ablation in persistent AF patients.

Effect of isolation feasibility of non-pulmonary vein foci on efficacy of ablation for atrial fibrillation: comparison of the isolation and focal ablation methods.

PURPOSE: Atrial fibrillation (AF) mainly originates from the pulmonary vein (PV). However, some AF triggers originate from other sites, namely non-PV foci, which are related to recurrence after AF ablation. This study aimed to evaluate the effects of isolation feasibility (isolability) of non-PV foci on the efficacy of AF ablation. METHODS: Overall, 1855 patients with AF (age, 64.6 ± 10.9 years; 82% paroxysmal) underwent PV isolation, followed by induction and ablation of non-PV foci. Among them, 545 (29%) patients had non-PV foci; these patients were categorized into those with isolable non-PV foci (n = 196, 36%) and those with non-isolable non-PV foci (n = 349, 64%). RESULTS: During a mean follow-up of 31.2 ± 15.6 months, recurrence was higher in the non-isolable group than in the isolable group (34% vs. 19%, P < 0.01). Kaplan-Meier analyses revealed a significantly better 1-year clinical outcome in the isolable group than in the non-isolable group (88.0% vs. 78.4%, P < 0.001; hazard ratio (HR), 0.56; 95% confidence interval (CI), 0.39-0.81). This outcome was not inferior to that of patients without non-PV foci (88.3% vs. 90.8%, P = 0.81). The non-isolable group showed poorer clinical outcomes than patients without non-PV foci (78.4% vs. 90.8%, P < 0.001; HR, 1.37; 95% CI, 1.22-1.53). Cox regression analysis revealed that isolability (HR, 0.56; 95% CI, 0.36-0.89) and unmappability (HR, 2.89; 95% CI, 1.55-5.37) of non-PV foci were significant predictors of arrhythmia recurrence. CONCLUSION: The isolability of non-PV foci was a significant factor affecting the achievement of better clinical outcomes following AF ablation in patients with non-PV foci.

Primary results from the Japanese Heart Failure and Sudden Cardiac Death Prevention Trial (HINODE).

AIMS: The HINODE study aimed to analyse rates of mortality, appropriately treated ventricular arrhythmias (VA), and heart failure in Japanese patients and compared with those in Western patients. METHODS AND RESULTS: After treatment decisions following contemporary practice in Japan, patients were prospectively enrolled into four cohorts: (i) internal cardioverter-defibrillator (ICD), (ii) cardiac resynchronization therapy (CRT) defibrillator (CRT-D), (iii) standard medical therapy ('non-device': ND), or (iv) pacing (indicated for CRT; received pacemaker or CRT pacing). Cohorts 1-3 required a left ventricular ejection fraction ≤35%, a history of heart failure, and a need for primary prevention of sudden cardiac death based on two to five previously identified risk factors. Endpoint outcomes were adjudicated by the independent committees. ICD and CRT-D cohorts, considered as high-voltage (HV) cohorts, were pooled for Kaplan-Meier analysis and propensity-matched to Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy (MADIT-RIT) arm B and C patients. The study enrolled 354 patients followed for 19.6 ± 6.5 months, with a minimum of 12 months. Propensity-matched HV cohorts showed comparable VA (P = 0.61) and mortality rates (P = 0.29) for HINODE and MADIT-RIT. The ND cohort presented a high crossover rate to ICD therapy (6.1%, n = 7/115), and the CRT-D cohort showed elevated mortality rates. The pacing cohort revealed that patients implanted with pacemakers had higher mortality (26.0%) than those with CRT-Pacing (8.4%, P = 0.05). CONCLUSIONS: The mortality and VA event rates of landmark trials are applicable to patients with primary prevention in Japan. Patients who did not receive guideline-indicated CRT devices had poor outcomes.

Optimal single procedure strategy of pulmonary vein isolation with cryoballoon or radiofrequency and non-pulmonary vein triggers ablation for non-paroxysmal atrial fibrillation.

Background: Limited data exist on pulmonary vein isolation (PVI) using cryoballoon (CB) or radiofrequency (RF) ablation and additional non-pulmonary vein trigger ablation for non-paroxysmal atrial fibrillation (non-PAF). We aimed to assess the outcomes of first-stage catheter ablation for non-PAF patients. Methods: Initial PVI was performed on 734 non-PAF patients (age: 64 ± 10 years; male: 584 (80%)) between September 2014 and June 2018 [315 (43%), CB ablation; 419 (57%), RF catheter]. A logistic regression model was used to match 257 pairs (514 patients) according to the propensity scores (CB or RF group). After PVI, additional non-PV trigger ablation was performed if induced by isoproterenol. We analysed the clinical outcomes of both groups. Results: The mean procedural time was significantly shorter in the CB group (125 [range, 89-165] min) than in the RF group (190 [160-224] min; P < 0.001). The 1-year Kaplan-Meier event rate revealed similar atrial fibrillation-free survival rates between the two groups (CB: 77.9%, RF: 82.3%; log-rank P = 0.111). The additional ablation percentage for non-PV foci (CB: 39%, RF: 41%; P = 0.653) and complication incidence (CB: 5%, RF: 4%; P = 0.670) were also similar. Conclusions: In non-PAF patients, the combination strategy of PVI using CB or RF ablation and non-PV trigger ablation achieved comparable outcomes.

Novel lead anchor technique using an active fixation quadripolar left ventricular lead in cardiac resynchronization therapy.

In this report, we present a case of successful advancement of a LV lead into tortuous vessels. This was achieved by deep engagement of the coronary sinus with a cannulation catheter by applying the anchor technique using the Medtronic Attain Stability Quad lead.

Impact of diagnosis-to-ablation time on non-pulmonary vein triggers and ablation outcomes in persistent atrial fibrillation.

INTRODUCTION: Non-pulmonary vein (PV) triggers are a major cause of atrial tachyarrhythmia (ATA) recurrence after catheter ablation. However, the effect of the diagnosis-to-ablation time (DAT) on non-PV triggers in persistent atrial fibrillation is unknown. METHODS AND RESULTS: This observational study evaluated 502 consecutive persistent AF patients who underwent initial ablation. We compared 408 patients whose DAT was <3 years with 94 patients whose DAT was ≥3 years. Following PV and posterior wall isolation, 193 non-PV triggers, including 50 AFs, 30 atrial tachycardias (ATs), and 113 repetitive atrial premature beats, were elicited and ablated in 137 (27%) patients. Specifically, 80 non-PV AF/AT triggers were provoked in 64 (13%) patients, being identified more frequently in the DAT ≥ 3 years group than in the DAT < 3 years group (20% vs. 11%, p = .025) especially with a higher prevalence of coronary sinus/inferior left atrial triggers. During a median follow-up of 770 days, the ATA recurrence-free rate was higher in the DAT < 3 years group than the DAT ≥ 3 years group (79% vs. 53% at 2 years, p < .001). In a multivariate analysis, female sex (odds ratio: 2.70, p = .002) and a longer DAT (odds ratio: 1.13/year, p = .008) were predictors of non-PV AF/AT triggers, and a longer DAT (hazard ratio: 1.12/year, p < .001) and non-PV AT/AF triggers (hazard ratio: 1.79, p = .009) were associated with ATA recurrence. CONCLUSION: Early ablation after the first diagnosis of persistent AF may reduce emerging non-PV AF/AT triggers and ATA recurrence.

Catheter ablation for atrial fibrillation in patients with congestive heart failure.

BACKGROUND: We evaluated the 1-year success rate of maintaining sinus rhythm after catheter ablation (CA) for atrial fibrillation (AF) in patients with or without congestive heart failure (CHF). METHODS: In this single-centre retrospective matched-pair cohort study of 3,018 AF patients who underwent initial CA between January 2012 and June 2018, 227 pairs with (CHF group) or without CHF (control group) were matched using propensity scores. In the CHF group, 108 patients were assigned to the arrhythmia-induced cardiomyopathy (AIC) group whose left ventricular systolic dysfunction was explained only by lasting AF or atrial tachycardia; the remaining 119 had organic heart diseases (non-AIC group). We evaluated the 1-year AF-free survival and changes in clinical findings before and after CA. RESULTS: The CHF and control groups showed similar AF-free survival; however, AIC patients had significantly better survival than non-AIC patients. AF recurrence was significantly related to CHF re-hospitalisation, which was significantly more frequent in the non-AIC group than in the AIC group. The clinical outcomes of left atrial dilation, brain natriuretic peptide level, and left ventricular ejection function improved significantly before and after CA in both groups. The degree of improvement was significantly better in the AIC group than in the non-AIC group. CONCLUSIONS: The 1-year success rate was not significantly different between the CHF and control groups. The 1-year success rate in the AIC group was similar to that in the AIC-control group and was better than that in the non-AIC group. CHF clinical outcomes were improved significantly.

Presence of non-pulmonary vein foci in patients with atrial fibrillation undergoing standard ablation of pulmonary vein isolation: Clinical characteristics and long-term ablation outcome.

BACKGROUND: The clinical characteristics of atrial fibrillation (AF) resulting from non-pulmonary vein (PV) triggers remain unknown. This study aimed to evaluate the clinical characteristics of patients with AF caused by non-PV triggers, localization of non-PV foci, clinical differences, and clinical outcomes after catheter ablation in each AF focus. METHODS: A total of 2967 patients who underwent initial catheter ablation for paroxysmal or persistent AF were examined. After PV isolation, all patients underwent high-dose isoproterenol infusion to assess the existence of non-PV foci. RESULTS: Non-PV foci were identified in 564 patients (19.2%). The localization of successfully ablated non-PV foci in 514 patients were the superior vena cava (SVC: 213 cases), interatrial septum (IAS: 125 cases), coronary sinus (CS: 98 cases), right atrium (RA: 125 cases), left atrium (LA: 114 cases), and unmappable (50 cases). Multivariate analysis revealed that female gender, low body mass index (BMI), non-paroxysmal AF (PAF), and sick sinus syndrome were independent and significant indicators of non-PV foci. In the multivariate analysis of each AF focus, female gender, low BMI, and non-PAF were significant predictors of IAS and CS foci, RA and IAS foci, and CS foci, respectively. In addition, dilatation of the LA was significantly associated with LA foci, whereas RA, LA, IAS, and CS foci were associated with AF recurrence. CONCLUSION: These findings could help to identify patients at a higher risk of AF caused by non-PV triggers and clarify the clinical difference according to the localization of non-PV foci.

Predictors of non-pulmonary vein foci in paroxysmal atrial fibrillation.

PURPOSE: Progress of balloon devices for pulmonary vein (PV) isolation in atrial fibrillation (AF) has been remarkable. However, these techniques were specialized in pulmonary vein treatment; predicting non-PV foci in advance is important to decide the treatment strategy. In this study, we investigate the predictors for paroxysmal AF. METHODS: Subjects were consecutive paroxysmal AF patients who underwent high-dose isoproterenol provocation after PV isolation in the first session. The PV group (n = 102) and non-PV group (n = 222) were defined as the patients with and without non-PV ablation, respectively. Non-PV ablation was performed when frequent repetitive premature atrial contractions or triggered AF occurred spontaneously or by isoproterenol provocation. Predictors of non-PV origin in paroxysmal AF patients were examined using clinical characteristics and preoperative echocardiography. RESULTS: In the multivariate logistic regression analysis, female sex, body mass index (BMI < 23.8), absence of hypertension, and higher ratio of mitral early diastolic peak (E-wave) to early diastolic mitral annulus peak (e') velocity (E/e' > 8.44) were significant independent predictors of non-PV foci (hazard ratio 2.04, 1.88, 3.63, and 2.33; 95% confidence interval 1.17-3.55, 1.05-3.39, 1.72-7.67, and 1.34-4.05; p = 0.011, 0.035, < 0.001, and 0.003, respectively). If a patient had these four factors, non-PV was detected with 96.8% specificity. CONCLUSION: Female sex, lower BMI, absence of hypertension, and higher E/e' were significant indicators of non-PV foci in patients with paroxysmal AF. Reviewing these factors in advance may be useful for selecting a device to perform pulmonary vein isolation.

Association between the locations of non-pulmonary vein triggers and ablation outcomes in repeat procedures after cryoballoon ablation of paroxysmal atrial fibrillation.

PURPOSE: We examined the characteristics of non-pulmonary vein (PV) triggers in repeat ablation after cryoballoon ablation for paroxysmal atrial fibrillation (PAF). METHODS: This study evaluated 119 patients undergoing a second ablation procedure for recurrent atrial tachyarrhythmia (ATA) after cryoballoon PV isolation (CB-PVI) for PAF. RESULTS: Fifty-three of 119 (45%) patients had PV reconnection. All reconnected PVs were isolated. No non-PV triggers were elicited in 42/119 (35%) patients (NNPV group). In 77/119 (65%) patients, 139 isoproterenol-induced non-PV triggers, including 45 triggers that initiated AF, were identified. Non-PV triggers initiating AF were observed at the superior vena cava (SVC), left atrial posterior wall (LAPW) including the PV antra, interatrial septum, right atrium, left atrial appendage/mitral anulus, and coronary sinus in 14 (12%), 10 (8%), 8 (7%), 7 (6%), 4 (3%), and 2 (2%) patients, respectively. Non-PV triggers originated from only the SVC and/or LAPW including the PV antra, and the SVC and/or LAPW was isolated in 18/119 (15%) patients (SVC/LAPW group). Non-PV triggers originating from other sites were focally ablated in 59/119 (50%) patients (OS group). During a median 461 days of follow-up, 39/42 (93%), 17/18 (94%), and 38/59 (64%) patients in the NNPV, SVC/LAPW, and OS groups, respectively, remained ATA recurrence-free. The recurrence rate was higher in the OS group than in the NNPV (P = 0.005) or SVC/LAPW groups (P = 0.042). CONCLUSIONS: Over half of patients had non-PV triggers at subsequent ablation after CB-PVI. Non-PV triggers from the SVC/LAPW can be eliminated more successfully than triggers from other sites.

The impact of left atrium size on selection of the pulmonary vein isolation method for atrial fibrillation: Cryoballoon or radiofrequency catheter ablation.

BACKGROUND: Pulmonary vein isolation (PVI) is the cornerstone of ablation strategies for atrial fibrillation (AF), and noninferiority of cryoballoon (CB) over radiofrequency (RF) ablation has been previously reported. One of the risk factors of recurrence is left atrium (LA) enlargement. This study aimed to analyze the impact of LA enlargement on the selection of CB or RF ablation for AF patients. METHODS: A total of 2,224 AF patients (64.4 ±â€¯10.7 years, 65.5% male) who underwent PVI were analyzed retrospectively. Left atrial diameter (LAD) and volume (LAV) were measured using echocardiography before the procedures. LA enlargement was defined as LAD ≥40 mm and LAV index (LAVI) ≥35 mL/m2. Patients undergoing CB and RF ablation were propensity score matched, and 376 matched pairs were evaluated. RESULTS: Cox proportional hazard analysis revealed that LAD (95% CI, 1.01-1.05), LAV (95% CI, 1.01-1.02), and LAVI (95% CI, 1.01-1.03) were independent predictors of recurrence. CB showed equivalent clinical outcomes to those of RF with shorter procedure time required for patients without LA enlargement. CB was inferior to RF in patients with LA enlargement (LAD, 74.5% vs 84.6%, P = .028; LAVI, 74.7% vs 83.4%, P = .015), and large LAVI was associated with a higher prevalence of non-PV foci (35% vs 29%, P = .008). CONCLUSIONS: CB ablation may be recommended for patients without enlarged LA based on the short procedure time and efficacy, whereas RF would be more appropriate in large LAs. LAVI may be a valuable reference to predict PVI outcomes and in selecting the ablation method.

A prospective multicenter study of direct comparison of feasibility and safety of pulmonary vein isolation using the minimally interrupted apixaban between second-generation cryoballoon and radiofrequency ablation of paroxysmal atrial fibrillation: J-HIT apixaban.

BACKGROUND: The feasibility and safety of pulmonary vein isolation (PVI) using cryoballoon (CB) for paroxysmal atrial fibrillation (PAF) with minimally interrupted apixaban has not fully explored. METHODS: In this multicenter, randomized prospective study, we enrolled patients with PAF undergoing CB or radiofrequency (RF) ablation with interrupted (holding 1 dose) apixaban. The primary composite end point consisted of bleeding events, including pericardial effusion and major bleeding requiring blood transfusion, or thromboembolic events at 4 weeks after ablation; secondary end points included early recurrence of AF and procedural duration. RESULTS: A total of 250 patients underwent PVI (125 assigned to the RF ablation and 125 assigned to the CB ablation). The primary end point occurred in 1 patient in the CB ablation group (0.8%; 90% confidence interval [CI], 0.04 to 3.70) and 3 patients in the RF group (2.4%, P = .622; risk ratio, 0333; 90% CI, 0.05 to 2.20). All events were pericardial effusion, all of whom recovered after pericardiocentesis. Early recurrence of AF occurred in 4 patients (3.2%) in the RF group and in 6 patients (4.8%) in the CB group (P = .749). The procedural duration was shorter in the CB group than that in the RF group (136.5 ± 39.9 vs 179.5 ± 44.8 min, P < .001). CONCLUSION: CB ablation with minimally interrupted apixaban was feasible and safe in patients with PAF undergoing PVI, which was equivalent to RF ablation.

Cryoballoon versus radiofrequency ablation for paroxysmal atrial fibrillation in hemodialysis patients.

INTRODUCTION: Little evidence exists regarding cryoballoon ablation (CBA) of paroxysmal atrial fibrillation (PAF) in hemodialysis (HD) patients. We compared CBA and radiofrequency ablation (RFA) of PAF in HD patients, referring to CBA of PAF in non-HD patients. METHODS AND RESULTS: This historical cohort study examined 88 patients who underwent catheter ablation of PAF, including 21 HD patients with a second-generation 28-mm cryoballoon (CB-HD group), 17 HD patients with a non-force-sensing radiofrequency catheter (RF-HD group), and 50 non-HD patients with a cryoballoon (CB-non-HD group). Pulmonary vein (PV) isolation alone aside from cavotricuspid isthmus ablation was performed in 14 (67%) in the CB-HD group, 12 (71%) in the RF-HD group, and 36 (72%) in the CB-non-HD group (P = 0.95), without isoproterenol-induced non-PV triggers. Non-PV trigger ablation was added to the other patients. The Kaplan-Meier estimated 1-year freedom from atrial tachyarrhythmia recurrence without antiarrhythmic drugs after a single procedure was 76%, 59%, and, 92% in the CB-HD, RF-HD, and CB-non-HD groups, respectively (P = 0.002). The mean procedure time was shorter in the CB-HD group than in the RF-HD group (127 vs. 199 min; P < 0.001). In the second procedure, the median number of reconnected pulmonary veins was 0.5 in the CB-HD group versus 2.0 in the RF-HD group (P = 0.17). CONCLUSION: For PAF in HD patients, CBA showed a comparable single-procedure efficacy to that of RFA with a short procedure time. CBA may be a reasonable initial procedure for HD patients suffering from symptomatic PAF.