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.

Acute procedural safety of the latest radiofrequency ablation catheters in atrial fibrillation ablation: Data from a large prospective ablation registry.

BACKGROUND: Safety data of the latest radiofrequency (RF) technologies during atrial fibrillation (AF) ablation in real-world clinical practice are limited. OBJECTIVES: We sought to evaluate the acute procedural safety of the four latest ablation catheters commonly used for AF ablation. METHODS: A total of 3957 AF ablation procedures performed between January 2022 and December 2023 at 20 centers with either the THERMOCOOL SMARTTOUCH SF (STSF), TactiCath (TC), QDOT Micro (QDM), or TactiFlex (TF) were retrospectively analyzed. RESULTS: In total, QDM, STSF, TF, and TC were used in 343 (8.7%), 1793 (45.3%), 1121 (28.4%), and 700(17.7%) procedures. Among 2406 index procedures, electrical pulmonary vein isolations were successfully achieved in 99.5%. Despite similar total procedure times in the four groups, the total fluoroscopic time was significantly shorter for QDM/STSF with CARTO than TF/TC with EnSite (18.7 ± 14 vs. 27.6 ± 20.6 min, p < .001) and longest in the TF group. The incidence of cardiac tamponade was 0.7% (0.5% and 0.9% during index and redo procedures, 0.8% and 0.3% for paroxysmal and non-paroxysmal AF) and was significantly lower for QDM/STSF than TF/TC (0.2% vs. 1.1%, p = .008) and highest in the TF group. The incidence of cardiac tamponade was higher for TF than TC and STSF than QDM. In the multivariate analysis, TF/TC with EnSite was a significant independent predictor of cardiac tamponade during both the index (odds ratio [OR] = 4.8, 95% confidence interval [CI] = 1.3-17.5, p = .02) and all procedures (OR = 3.0, 95% CI = 1.3-7.2, p = .01). CONCLUSIONS: The incidence of cardiac tamponade and the fluoroscopic time during AF ablation significantly differed among the latest RF catheters and mapping systems in real-world clinical practice.

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.

Inappropriate shock incidence in patients with subcutaneous implantable cardioverter-defibrillators with concomitant cardiac implantable electronic devices: A single-center cohort study.

BACKGROUND: Subcutaneous implantable cardioverter defibrillators (S-ICDs) are occasionally used in combination with other cardiac implantable electronic devices (CIEDs). However, whether the incidence of inappropriate shock increases in patients with S-ICDs and concomitant CIEDs remains unclear. This study aimed to investigate the association between the concomitant use of CIEDs and the incidence of inappropriate shock in patients with current-generation S-ICDs. METHODS: A total of 127 consecutive patients received an S-ICD. Patients were assigned to two groups depending on concomitant use of CIEDs at the time of S-ICD implantation: patients without other CIEDs (non-combined group, 106 patients) and patients with other CIEDs (combined group, 21 patients). CIEDs included pacemakers, implantable cardioverter defibrillators, cardiac resynchronization therapy pacemakers, and cardiac resynchronization therapy defibrillators. The primary outcome was inappropriate shock, defined as a shock other than ventricular arrhythmia. Hazard ratios and 95% confidence intervals were calculated using a time-varying Cox proportional hazards model which was adjusted for age because age differed between the groups and could be a confounder. RESULTS: During a median follow-up period of 2.2 years (interquartile range, 1.0-3.4 years), inappropriate shock events occurred in 17 (16%) and five (19%) patients of the non-combined and combined groups, respectively. While the age-adjusted hazard ratio for inappropriate shock was 24% higher in the combined than in the non-combined group (hazard ratio = 1.24, 95% confidence interval, 0.39-3.97), this difference was insignificant (p = .71). CONCLUSION: The incidence of inappropriate shock did not differ between patients with and without concomitant use of CIEDs, suggesting that S-ICDs could potentially be combined with other CIEDs without increasing the number of inappropriate shocks. Further studies are warranted to confirm the safety and feasibility of concomitant use of S-ICDs and CIEDs.

Spatial relationship of localized sources of persistent atrial fibrillation identified by a unipolar-based automated algorithm to complex fractionated atrial electrocardiograms and atrial low voltage areas.

INTRODUCTION: Spatial characteristics of localized sources of persistent atrial fibrillation (AF) identified by unipolar-based panoramic mapping software (CARTOFINDER) remain unclear. We evaluated spatial characteristics of bi-atrial AF localized sources in relation to complex fractionated atrial electrocardiograms (CFAEs) and atrial low voltage area (LVAs) (≤0.35 mV during AF). METHODS AND RESULTS: Twenty consecutive patients with persistent AF underwent bi-atrial voltage, CFAE, and CARTOFINDER mapping before the beginning of ablation (18 [90%] patients, initial procedure; 2 [10%] patients, repeat procedure). CFAEs were recorded using the interval confidence level (ICL) mode and defined as sites with a confidence level of ≥80% of maximal ICL number. We elucidated the following: (1) differences in the rate of AF localized sources and CFAEs inside or outside the atrial LVAs; (2) distribution of AF localized sources and CFAEs; and (3) distance between the closest points of AF localized sources and CFAEs. A total of 270 AF localized sources and 486 CFAEs were identified in 20 patients. AF localized sources were confirmed more often outside atrial LVAs than CFAEs (71% vs. 46% outside LVA, p < .001). AF localized sources and CFAEs were diffusely distributed without any tendency in bi-atria. Mean distance between closest AF localized sources and CFAEs was 22 ± 8 mm. CONCLUSION: AF localized sources identified by CARTOFINDER are different therapeutic targets as compared to CFAEs and could be confirmed both inside and outside atrial LVAs.

Efficacy of left atrial posterior wall isolation guided by lesion size prediction module for non-paroxysmal atrial fibrillation.

AIMS: The efficacy of left atrial posterior wall isolation (PWI) is controversial. Lesion durability may be a major cause of arrhythmia recurrence. The use of the lesion size prediction module improves lesion durability. This study aimed to compare the clinical outcomes of pulmonary vein isolation (PVI) alone and PWI in addition to PVI (PVI + PWI) in patients with non-paroxysmal atrial fibrillation (AF) using a lesion size prediction module. METHODS AND RESULTS: This study is a sub-analysis of the recently published prospective multicentre observational study called ALCOHOL-AF (association of alcohol consumption with outcome of catheter ablation of AF). In this sub-analysis, patients with non-paroxysmal AF in whom PVI alone or PVI + PWI was performed using the lesion size prediction module were included. Freedom from atrial tachyarrhythmia was compared between PVI alone and PVI + PWI groups using propensity score analyses. Of the 3474 patients registered in the ALCOHOL-AF study, 572 patients (age 65.6 ± 10.1 years, male 77.4%, longstanding persistent AF 25.5%) were included in this sub-analysis. We selected 212 patients treated with PVI alone and 212 treated with PVI + PWI using one-to-one propensity score matching. During the follow-up period, atrial tachyarrhythmia recurrence was documented in 92 (43.4%) and 50 (23.6%) patients in the PVI alone and PVI + PWI groups, respectively. Freedom from atrial tachyarrhythmia recurrence without anti-arrhythmic drugs after a single procedure was significantly higher in PVI + PWI than in PVI alone groups (hazard ratio: 0.452, 95% confidence interval: 0.308-0.664, P < 0.001). CONCLUSION: In this hypothesis-generating study, lesion size prediction module-guided PVI + PWI was associated with better clinical outcomes than PVI alone in patients with persistent or longstanding persistent AF.

Prognostic predictors and echocardiographic time course after device replacement in patients treated chronically with cardiac resynchronization therapy devices.

The prognostic predictors of death or heart failure hospitalization and the echocardiographic response after initial cardiac resynchronization therapy (CRT) device replacement (CRT-r) remain unclear. We evaluated the predictors and the echocardiographic time course in patients after CRT-r. Consecutive 60 patients underwent CRT-r because of battery depletion. Patients were divided into two groups depending on the chronic echocardiographic response to CRT (left ventricular end-systolic volume [LVESV] reduction of ≥ 15%) at the time of CRT-r: CRT responders (group A; 35 patients) and CRT nonresponders (group B; 25 patients). The primary endpoint was a composite of death from any cause or heart failure hospitalization. Changes in LVESV and left ventricular ejection fraction (LVEF) after CRT-r were also analyzed. During the mean follow-up of 46 ± 33 months after CRT-r, the primary endpoint occurred more frequently in group B (group A versus group B; 8/35 [23%] patients versus 19/25 [76%] patients, p < 0.001). No significant changes in LVESV and LVEF were observed at the mean of 46 ± 29 months after CRT-r in both groups. A multivariate analysis identified echocardiographic nonresponse to CRT, chronic kidney disease, atrial fibrillation, and New York Heart Association functional class III or IV at the time of CRT-r as independent predictors of the primary endpoint in all patients. Residual echocardiographic nonresponse, comorbidities, and heart failure symptoms at the time of CRT-r predict the subsequent very long-term prognosis after CRT-r. No further echocardiographic response to CRT was found after CRT-r.

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.

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.

Characteristics of the nonpulmonary vein foci induced after second-generation cryoballoon ablation for paroxysmal atrial fibrillation.

INTRODUCTION: Pulmonary vein isolation (PVI) using cryoballoon is effective for patients with paroxysmal atrial fibrillation (PAF); however, few reports have evaluated the non-pulmonary vein (PV) foci after cryoballoon ablation. We aimed to evaluate the characteristics of non-PV foci and predictors of atrial fibrillation (AF) recurrence after cryoballoon ablation. METHODS AND RESULTS: This was a single-center retrospective study of 647 patients with PAF who underwent initial PVI using a second-generation cryoballoon. After PVI, all patients underwent high-dose isoproterenol infusion to assess the existence of non-PV foci. Non-PV foci were observed in 211 patients (32.6%), which were most frequently observed in the superior vena cava. Higher age (odds ratio [OR] = 1.02; 95% confidence interval [CI] = 1.00-1.04; P = .025), female sex (OR = 1.65; 95% CI = 1.13-2.41; P = .009), and lower body mass index (OR = 0.95; 95% CI = 0.89-1.00; P = .049) were significantly associated with non-PV foci. The existence of non-PV foci was an independent predictor of AF recurrence (Hazard's ratio = 1.70; 95% CI = 1.12-2.60; P = .014). When non-PV foci were mappable and successfully ablated, patients with non-PV foci showed similar outcomes with those without non-PV foci (1-year AF-free survival rates of 88.5% vs 91.5%; P = .338). Conversely, when we failed to detect and eliminate non-PV foci because they had multiple origins and were not consistently inducible (multichanging non-PV foci), the 1-year AF-free survival rate was 56.4% even after substrate modification. CONCLUSION: Non-PV foci were observed in one-third of patients with PAF after cryoballoon ablation and were associated with AF recurrence. Catheter ablation for non-PV foci was effective when they were mappable; however, multichanging non-PV foci were associated with worse prognosis.

Comparison of dragging ablation and point-by-point ablation with a laser balloon on linear lesion formation.

INTRODUCTION: Lesion size and continuity in dragging laser balloon (LB) ablation, which may enable fast and durable pulmonary vein isolation for atrial fibrillation, are unknown. We evaluated the differences in size and continuity of linear lesions formed by dragging ablation and conventional point-by-point ablation using an LB in vitro model. METHODS AND RESULTS: Chicken muscles were cauterized using the first-generation LB in dragging and point-by-point fashion. Dragging ablation was manually performed with different dragging speeds (0.5-2°/s) using an overlap ratio of the beginning and last site during one application at 12 W/20 s and 8.5 W/30 s. Point-by-point ablation was performed with 25% and 50% overlap ratios at six energy settings (5.5 W/30 s to 12 W/20 s). Lesion depth, width, and continuity were compared. Lesion continuity was assessed by the surface and deep visible gap degree categorized from 1 (perfect) to 3 (poor). Twenty lesions were evaluated for each ablation protocol. Lesion depth and width in dragging ablation at high power (12 W) were comparable with most measurements in point-by-point ablation. Lesion depth and width were smaller at faster-dragging speed and lower power (8.5 W) in dragging ablation. The surface visible gap degree was better in dragging ablation at all dragging speeds than a 25% overlapped point-by-point ablation (p < .001). CONCLUSION: Dragging LB ablation at high power provides deep and continuous linear lesion formation comparable with that of point-by-point LB ablation. However, lesion depth and width depending on the dragging speed and power.

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.

Identification of an epicardial slow conduction channel using ripple mapping in ablation of postinfarct ventricular tachycardia.

An 82-year-old man underwent redo catheter ablation of ventricular tachycardia (VT) after anterior infarction. A ripple mapping conducting channel (RMCC) was identified within the anterior scar in the left ventricular epicardium during sinus rhythm. Along the RMCC, delayed potentials during sinus rhythm, a good pace map with a long stimulus to the QRS interval, and mid-diastolic potentials during VT were recorded, and epicardial ablation at this site eliminated the VT. These findings suggested that the RMCC in the epicardial scar served as a critical isthmus of the postinfarct VT, and ablation targeting the RMCC was effective.

Differences in the electrophysiological findings of repeat ablation between patients who first underwent cryoballoon ablation and radiofrequency catheter ablation for paroxysmal atrial fibrillation.

INTRODUCTION: Several studies have revealed that second-generation cryoballoon (CB)-based pulmonary vein (PV) isolation is noninferior to radiofrequency (RF)-based PV isolation for patients with drug-refractory paroxysmal atrial fibrillation (AF). However, electrophysiological differences in repeat ablation remain unclear. METHODS AND RESULTS: This study examined electrophysiological differences during the repeat ablation between patients who first underwent RF catheter ablation and CB ablation; PV durability and non-PV AF foci were assessed for these patients. We enrolled 919 and 491 patients who underwent CB ablation (CB group) and RF catheter ablation (RF group), respectively, for paroxysmal AF between January 2013 and June 2017 at our institution. PV isolation using RF ablation involved the left atrium (LA) antrum and part of the LA posterior wall. After 2 years of follow-up, 62 and 80 patients in the CB and RF groups, respectively, underwent repeat ablation. PV reconnections were more frequent in the RF group than in the CB group (left superior PV: 46.2% and 14.5%, P < .001; left inferior PV: 35.0% and 11.2%, P = .001; right superior PV: 40.0% and 22.6%, P = .031; right inferior PV: 36.2% and 19.4%, P = .039; PVs: 39.8% and 16.9%, P < .001). LA AF foci were more frequent in the CB group than in the RF group (27.4% and 7.5%; P = .002). Other non-PV foci were prevalent in both groups. CONCLUSION: Fewer LA-PV reconnections occurred with CB ablation. However, extensive PV isolation may eliminate many LA AF foci.

Association of the Clinical and Genetic Factors With Superior Vena Cava Arrhythmogenicity in Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) can be initiated from arrhythmogenic foci within the muscular sleeves that extend not only into the pulmonary veins but also into both vena cavae. The superior vena cava (SVC) is a key target site for catheter ablation. Patients with SVC-derived AF often lack the clinical risk factors of AF.Methods and Results:We conducted a meta-analysis of the clinical and genetic factors of 2,170 AF patients with and without SVC arrhythmogenicity. In agreement with previous reports, the left atrial diameter was smaller in AF patients with SVC arrhythmogenicity. Among 6 variants identified in a previous genome-wide association study in Japanese patients, rs2634073 and rs6584555 were associated with SVC arrhythmogenicity. This finding was confirmed in our meta-analysis using independent cohorts. We also found that SVC arrhythmogenicity was conditionally dependent on age, body mass index, and left ventricular ejection fraction. CONCLUSIONS: Both clinical and genetic factors are associated with SVC arrhythmogenicity.

The Efficacy of Isochronal 3D Mapping-Based Ablation of Ventricular Arrhythmia.

Treatment of ventricular arrhythmias (VAs) commonly involves ablating sites showing electrograms with the earliest activity relative to the VA, but there is no threshold value for prematurity guaranteeing success. Ablation of sites with great prematurity can still result in failure.We hypothesized that isochronal map area (ISCA), derived from isochrones indicating electrogram prematurity, could help identify ablation targets in VA patients, as well as predict outcome. Specifically, we hypothesized that smaller ICSA for a given prematurity value would indicate a shallower arrhythmogenic focus leading to a higher likelihood of successful ablation.We studied ICSA in 29 patients (12 males, 57 [17-65] years old) undergoing VA ablation. The VAs originated from the right and left ventricles in 11 and 18 patients, respectively. The earliest activation site of the VAs, ECG morphology of sinus beats and premature ventricular complexes (PVCs), and ISCA of activation preceding PVCs were evaluated.RF ablation at the site showing earliest prematurity resulted in VA elimination in 21 patients (success group). The 5-ms ISCA was smaller in the success group than in the failure group (0.2 [0.1-0.6] versus 1.0 [0.8-1.5] cm2, respectively; P < 0.01). No significant difference was noted in prematurity itself (36 [30-45] versus 30 [29-33] ms, respectively; P = 0.07). The cut-off value of the 5 ms ISCA for successful RF ablation was 0.7 cm2 with 87.5% sensitivity and 85.6% specificity.Isochrones of activity preceding PVCs appear to contain information beyond prematurity values and may help dictate suitable areas for successful ablation of VAs.

Rivaroxaban for Periprocedural Anticoagulation Therapy in Japanese Patients Undergoing Catheter Ablation of Paroxysmal Non-Valvular Atrial Fibrillation.

Direct oral anticoagulants (DOACs) have been shown to be safe and effective for the prevention of stroke in nonvalvular atrial fibrillation (NVAF) patients, however, experience with peri-AF ablation management of DOACs is scarce. This study aimed to investigate the safety and feasibility of periprocedural anticoagulation therapy with rivaroxaban in Japanese patients undergoing paroxysmal non-valvular AF (NVAF) ablation using radiofrequency energy.This study was a multicenter, prospective pilot study. In paroxysmal NVAF patients, rivaroxaban (15 mg or 10 mg once-daily) was started at least 4 weeks prior to AF ablation, discontinued on the day of the procedure, resumed within 24 hours after ablation, and continued at least 3 months afterwards. During the interruption of rivaroxaban, bridging anticoagulation therapy with unfractionated heparin was given. Follow-up of the patients continued for 3 months.A total of consecutive 74 patients (mean age, 62 ± 9 years, 58 [78.4%] male) were enrolled. The mean follow-up period was 108 ± 79 days. Their mean CHADS2 score and CHA2DS2-VASc score were 1.2 ± 1.0 and 0.6 ± 0.7, respectively. Their mean HAS-BLED score was 1.0 ± 0.8. Neither major bleeding nor thromboembolic events, except in a case with bleeding from gastric cancer (1.4%), were observed in the periprocedural period of the AF ablation.The present multicenter study demonstrated the safety and feasibility of periprocedural anticoagulation therapy with rivaroxaban in Japanese patients undergoing catheter ablation of paroxysmal NVAF.

Efficacy of anti-tachycardia pacing for terminating fast ventricular tachycardia in Japanese implantable cardioverter defibrillator patients. Primary results of the SATISFACTION study.

BACKGROUND: Anti-tachycardia pacing (ATP) delivered by implantable cardioverter defibrillators (ICD) safely avoids painful shocks with minimum risk of tachycardia acceleration. The etiology of ventricular tachycardia (VT) in those studies, however, was predominantly coronary artery disease (CAD). Patient etiology differs by geography and could affect ATP efficacy rate. The primary objective of this study was to examine how often the first ATP therapy terminates fast VT (FVT) in Japanese ICD patients with regional etiologies. METHODS AND RESULTS: Seven hundred and fifteen patients received ICD or cardiac resynchronization therapy defibrillator with the function of ATP during capacitor charging. The primary endpoint was the first ATP success rate for terminating FVT with cycle length 240-320 ms. During a mean follow-up of 11.3 months, 888 spontaneous VT episodes were detected, including 276 FVT (31.1%) in 42 patients. The first-ATP success rate for FVT in the overall group (41% CAD, 59% non-CAD including 23% idiopathic VT) was 62.1% (61.7% adjusted). Success rate was not different between non-CAD and CAD patients (61.4% adjusted and 57.5% adjusted, respectively, P=0.75). Eight FVT episodes (2.9%) accelerated after the first ATP attempt, all of which were terminated by subsequent device therapy (additional ATP or shock). CONCLUSIONS: ATP efficacy for FVT was similar between ICD patients with and without CAD etiology.

Successful non-operative management of left atrioesophageal fistula following catheter ablation.

Atrioesophageal fistula (AEF) is a potentially lethal complication of catheter radiofrequency ablation for atrial fibrillation. A 49-year-old man with paroxysmal atrial fibrillation who underwent catheter ablation around the pulmonary vein was admitted 31 days after the procedure, suffering seizures and fever. Magnetic resonance imaging of the brain showed ischemia and multiple lesions of acute infarction in the right occipital lobe of the cerebrum. Computed tomography (CT) of the chest showed a small accumulation of air between the posterior left atrium and the esophagus, suggesting an AEF. Endoscopic snaring of the esophageal mucosa, repeated a few times, supported by nil by mouth and antibiotic therapy, resulted in improvement of his condition with no recurrence of symptoms. Subsequent chest CT scans confirmed disappearance of the leaked air and the patient was discharged home 45 days after admission with no neurological compromise.

Initial clinical experience with the novel POLARx FIT cryoballoon system for pulmonary vein isolation in patients with atrial fibrillation.

Background: The POLARx FIT system (Boston Scientific, MA, USA) is a novel cryoballoon (CB) ablation technology in which the balloon diameter can be expanded from 28 to 31 mm. The aim of this study was to compare the benefits and safety of the new POLARx FIT system to those of the existing POLARx system currently in use for pulmonary vein (PV) isolation (PVI) in patients with atrial fibrillation. Methods: The first 70 consecutive patients who underwent CB-based PVI with the POLARx FIT system were retrospectively compared with 200 consecutive patients treated with the POLARx system at Sakakibara Heart Institute from October 2021 to May 2023. Results: The POLARx FIT system yielded a higher mean ± standard deviation nadir temperature in the right inferior PV (-59.2 ± 5.29 °C vs. - 62.0 ± 5.08 °C, p = 0.006), but this required a balloon size reduction to 28 mm in 30 % of cases. No significant differences were detected in the time to isolation and thaw time of any PV between the two groups. After the CB-based PVI procedure, no residual PV carina potentials were observed with the POLARx FIT system, whereas 4/20 were with the POLARx system (p = 0.04). Conclusions: The POLARx FIT system had comparable effectiveness and safety to the basic POLARx system. This technology may improve the ablation area, including the PV carina. However, the 31-mm balloon alone was not sufficient to isolate certain PVs.