Outcomes of left bundle branch area pacing compared to His bundle pacing and right ventricular apical pacing in Japanese patients with bradycardia.

Background: His bundle pacing (HBP) and left bundle branch area pacing (LBBAP) emerge as better alternatives to right ventricular apical pacing (RVAP) in patients with bradycardia requiring permanent cardiac pacing. We aimed to compare the clinical outcomes of LBBAP, HBP, and RVAP in Japanese patients with bradycardia. Methods: A total of 424 patients who underwent successful pacemaker implantation (HBP, n = 53; LBBAP, n = 75; and RVAP, n = 296) were retrospectively enrolled in this study. The primary study endpoint was the cumulative incidence of heart failure hospitalization (HFH) during the follow-up. Results: The success rate for implantation was higher in the LBBAP group than in the HBP group (94.9% and 81.5%, respectively). Capture threshold increase >1V during the follow-up occurred in the HBP and RVAP groups (9.4% and 5.1%, respectively), while it did not in the LBBAP group. The cumulative incidence of HFH was significantly lower in the LBBAP group than the RVAP (adjusted hazard ratio, 0.12 [95% confidence interval: 0.02-0.86]; p = .034); it did not differ between the HBP and RVAP groups (adjusted hazard ratio, 0.48 [95% confidence interval: 0.17-1.34]; p = .16). Advanced age, mean percent right ventricular pacing (per 10% increase), left ventricular ejection fraction <50%, and RVAP were associated with HFH. Conclusions: Compared to RVAP and HBP, LBBAP appeared more feasible and effective in patients with bradycardia requiring permanent cardiac pacing.

Pulmonary Vein Intervention for Severe Pulmonary Vein Stenosis After Atrial Fibrillation Ablation　- A Retrospective Cohort Study.

BACKGROUND: Pulmonary vein (PV) stenosis (PVS) is a serious complication of atrial fibrillation (AF) ablation. The objective of this study was to describe interventional treatments for PVS after AF ablation and long-term outcomes in Japanese patients.Methods and Results: This multicenter retrospective observational study enrolled 30 patients (26 [87%] male; median age 55 years) with 56 severe PVS lesions from 43 PV interventional procedures. Twenty-seven (90%) patients had symptomatic PVS and 19 (63%) had a history of a single AF ablation. Of the 56 lesions, 41 (73%) were de novo lesions and 15 (27%) were retreated. Thirty-three (59%) lesions were treated with bare metal stents, 14 (25%) were treated with plain balloons, and 9 (16%) were treated with drug-coated balloons. All lesions were successfully treated without any systemic embolic event. Over a median follow-up of 584 days (interquartile range 265-1,165 days), restenosis rates at 1 and 2 years were 35% and 47%, respectively. Multivariate Cox regression analysis revealed devices <7 mm in diameter (hazard ratio [HR] 2.52; 95% confidence interval [CI] 1.04-6.0; P=0.040) and totally occluded lesions (HR 3.33; 95% CI 1.21-9.15; P=0.020) were independent risk factors for restenosis. CONCLUSIONS: All PVS lesions were successfully enlarged by the PV intervention; however, restenosis developed in approximately half the lesions within 2 years.

A novel ablation strategy for recurrent atrial fibrillation: Fractionated signal area in the atrial muscle ablation 1-year follow-up.

INTRODUCTION: Treatment of recurrent atrial fibrillation (AF) is sometimes challenging due to non-pulmonary vein (PV) foci. Fractionated signal area in the atrial muscle (FAAM) is a valid predictor of the location of non-PV foci. FAAM ablation has the potential to decrease the recurrence rate of atrial tachyarrhythmia in patients with recurrent AF. We compared the clinical impact of FAAM ablation for recurrent AF, using 1 year follow up date. METHODS: A total of 230 consecutive patients with symptomatic recurrent AF who underwent catheter ablation specifically targeting non-PV foci as FAAM-guided ablation (n = 113) and non-FAAM-guided ablation (n = 117) were retrospectively analyzed. FAAM was assigned a parameter (peaks slider, which indicates the number of components of fractionated signals), ranging from 1 to 15, indicating the location of the FAAM (1: largest, 15: smallest). FAAM-guided ablation was performed by ablating FAAM until none inducibility of non-PV foci. On the other hand, non-FAAM-guided ablation was performed via linear ablation, complex fractionated atrial electrogram ablation, superior vena cava isolation, and focal ablation according to the location of the non-PV foci. The RHYTHMIA system was used to perform all the procedures. The primary endpoints were AF recurrence, atrial flutter, and/or atrial tachycardia. RESULTS: After a 1-year follow up, freedom from atrial tachyarrhythmia was achieved in 90.3% and 75.2% of patients in the FAAM and non-FAAM groups, respectively (hazard ratio = 0.438 [95% confidence interval: 0.243-0.788], p = .005). CONCLUSIONS: FAAM ablation showed a promising decrease in the recurrence rate of atrial tachyarrhythmia in patients with recurrent AF during a 1-year follow-up.

Influence of the irrigation flow pattern and catheter tip design on the lesion formation: an ex vivo experimental model.

BACKGROUND: Lesion formation during catheter ablation is influenced by the power, contact force (CF), time, and catheter stability. However, the influence of the irrigation effects on lesion formation remains unknown. METHODS: An ex vivo experiment using conductive gel was performed. Using three different catheter designs (TactiFlex ™ SE [TF], IntellaNav MiFi ™ OI [MiFi], QDOT MICRO™ [QDOT]), a cross-sectional analysis of the lesion size and surface lesion type of 10g/40W lesions with a combination of various ablation times was performed in protocol 1. A longitudinal analysis (combination of various powers [30, 40, and 50W] and various ablation times with a 10g setting) was performed to investigate the influence of the auto-regulated irrigation system (QDOT) on lesion formation in protocol 2. RESULTS: The lesion formation with the QDOT catheter tended to create larger ablation lesions, while that with the TF catheter created smaller lesions than the other catheters. The lesion surface characteristics were divided into two patterns: ring (MiFi catheter and QDOT) and crescent (TF) patterns. The auto-regulated irrigation system did not influence the lesion formation, and the relationship between the lesion formation and RF energy exhibited similar changes regardless of the ablation power setting. CONCLUSION: The lesion formation and lesion surface characteristics differed among the different irrigation tip designs. An auto-regulated irrigation system did not affect the lesion creation or surface lesion characteristics. Care should be given to the inter-product differences in the lesion characteristics during RF catheter ablation, partly due to the irrigation flow control and tip design.

Subcutaneous ICDs implantation following removal of normally functioning non-infected transvenous ICDs in two young patients.

In young patients with transvenous implantable cardioverter defibrillations (TV-ICDs), the possibility of device infection or lead fracture would be high in their long lifetimes. Furthermore, the risk of lead removal will gradually increase over the years. We reported two cases of subcutaneous ICDs implantation following removal of TV-ICDs. Patient 1, 35-year-old man, underwent TV-ICD implantation 9 years ago for idiopathic ventricular fibrillation, and Patient 2, 46-year-old man, underwent TV-ICD implantation 8 years ago for asymptomatic Brugada syndrome. In both cases, the electrical performance was stable, and there was no incidence of arrythmia or no pacing demand during the follow-up duration. Considering future risk of device infection or lead fracture, and difficulty in future lead removal, TV-ICDs were removed with sufficient informed consent, and then, subcutaneous ICDs (S-ICDs) implantation were performed as an alternative to them. Although indication of the TV-ICD removal should be carefully considered in individual cases, long-term risks leaving it in place should be also considered in the management of young patient. Learning objective: In young patient with TV-ICD, even for a normally functioning non-infected lead, S-ICD implantation following removal of the TV-ICD would represent a strategy associated with less long-term risks than leaving it in place.

Registry for Evaluating Healthy Life Expectancy and Long-Term Outcomes after Catheter Ablation of Atrial Fibrillation in the Very Elderly (REHEALTH AF) study: rationale and design of a prospective, multicentre, observational, comparative study.

INTRODUCTION: Data are lacking on the extent to which patients with non-valvular atrial fibrillation (AF) who are aged ≥80 years benefit from ablation treatment. The question pertains especially to patients' postablation quality of life (QoL) and long-term clinical outcomes. METHODS AND ANALYSIS: We are initiating a prospective, registry-based, multicentre observational study that will include patients aged ≥80 years with non-valvular AF who choose to undergo treatment by catheter ablation and, for comparison, such patients who do not choose to undergo ablation (either according to their physician's advice or their own preference). Study subjects are to be enrolled from 52 participant hospitals and three clinics located throughout Japan from 1 June 2022 to 31 December 2023, and each will be followed up for 1 year. The planned sample size is 660, comprising 220 ablation group patients and 440 non-ablation group patients. The primary endpoint will be the composite incidence of stroke/transient ischaemic attack (TIA) or systemic embolism (SE), another cardiovascular event, major bleeding and/or death from any cause. Other clinical events such as postablation AF recurrence, a fall or bone fracture will be recorded. We will collect standard clinical background information plus each patient's Clinical Frailty Scale score, AF-related symptoms, QoL (Five-Level Version of EQ-5D) scores, Mini-Mental State Examination (optional) score and laboratory test results, including measures of nutritional status, on entry into the study and 1 year later, and serial changes in symptoms and QoL will also be secondary endpoints. Propensity score matching will be performed to account for covariates that could affect study results. ETHICS AND DISSEMINATION: The study conforms to the Declaration of Helsinki and the Ethical Guidelines for Clinical Studies issued by the Ministry of Health, Labour and Welfare, Japan. Results of the study will be published in one or more peer-reviewed journals. TRIAL REGISTRATION NUMBER: UMIN000047023.

Initial multicenter clinical experience with the first-generation endoscopic guided laser balloon in Japan.

BACKGROUND: Isolation of the pulmonary veins (PVs) is the golden standard for atrial fibrillation (AF) ablation. To achieve a permanent PV isolation, the endoscopic guided HeartLight laser balloon system was invented. We analyzed the safety and efficacy of this laser balloon system. METHODS AND RESULTS: Three hundred four patients from 21 investigational sites inside Japan were enrolled in this study. One thousand sixty-two out of 1175 PVs (90.4%) were isolated using the HeartLight laser balloon. The isolation rate of the left superior, left inferior, right superior, and right inferior PVs was 87.8%, 91.3%, 91.6%, and 92.1%, respectively. The procedure time, defined as the time from the venous access to taking out the balloon, was 155 ± 39 min. The fluoroscopic time was 44 ± 25 min. The mean follow-up period was 309 ± 125 days. The freedom from AF recurrence at 3 months was 89.0% and at 12 months 82.1%. Adverse events occurred in 22 patients (7.2%) including phrenic nerve injury lasting more than 3 months in 1.6% and strokes in 1.0% of the patients. CONCLUSIONS: This initial experience demonstrated that the laser balloon ablation was feasible for PV isolation in Japanese AF patients.

Clinical outcome for heart failure hospitalizations in patients with leadless pacemaker.

Introduction: The long-term performance of leadless pacemaker (LPM) has not been well evaluated. Methods: Between September 2017 and January 2021, 929 consecutive patients who underwent pacemaker implantation were grouped according to the types of pacemakers: LPM (LPM group, n = 368) and conventional pacemaker (PM group, n = 561). Results: The median follow-up duration was 1.7 years (interquartile range 0.8-2.6 years). Hospitalization rate for heart failure in the LPM group was 9.3%, 15.6%, and 21.6% at 1, 2, 3 years, respectively. The LPM group had a significantly higher adjusted heart failure hospitalization risk than the PM group [hazard ratio (HR) 1.70, 95% confidence interval (CI) 1.09-2.64, p = .01]. More patients with symptomatic bradycardia caused by sinus node dysfunction (SND) in the LPM group (n = 150) were admitted to the hospital for heart failure compared to those in the PM group (n = 219) (HR 2.02, 95%CI 1.04-3.90, p = .03), whereas no significant difference was observed between the two groups in the patients with bradycardia caused by atrial fibrillation (LPM group, n = 71; PM group, n = 18) or atrioventricular block (LPM group, n = 147; PM group, n = 324). Conclusions: Patients who received LPM implantation had greater hospitalization risk for heart failure, compared to those who received conventional pacemaker implantation. The increased risk was mainly attributed to patients with SND.

Real-World Investigation on Anticoagulation Management Before and After Catheter Ablation for Atrial Fibrillation in Japan　- Periprocedural and Long-Term Outcomes.

BACKGROUND: Optimal periprocedural oral anticoagulant (OAC) therapy before catheter ablation (CA) for atrial fibrillation (AF) and the safety profile of OAC discontinuation during the remote period (from 31 days and up to 1 year after CA) have not been well defined.Methods and Results: The RYOUMA registry is a prospective multicenter observational study of Japanese patients who underwent CA for AF in 2017-2018. Of the 3,072 patients, 82.3% received minimally interrupted direct-acting OACs (DOACs) and 10.2% received uninterrupted DOACs. Both uninterrupted and minimally interrupted DOACs were associated with an extremely low thromboembolic event rate. Female, long-standing persistent AF, low creatinine clearance, hepatic disorder, and high intraprocedural heparin dose were independent factors associated with periprocedural major bleeding. At 1 year after CA, DOAC was continued in 55.9% of patients and warfarin in 56.4%. The incidence of thromboembolic and major bleeding events for 1 year was 0.3% and 1.2%, respectively. Age ≥73 years, dementia, and AF recurrence were independently associated with major bleeding events. Univariate analyses revealed that warfarin continuation and off-label overdose of DOACs were risk factors for major bleeding after CA. CONCLUSIONS: High intraprocedural dose of heparin was associated with periprocedural major bleeding events. At 1 year after CA, over half of the patients had continued OAC therapy. Thromboembolic events were extremely low; however, major bleeding occurred in 1.2%. Age ≥73 years, dementia, and AF recurrence were independently associated with major bleeding after CA.

Cryoballoon ablation for paroxysmal atrial fibrillation in Japan: 2-year safety and efficacy results from the Cryo AF Global Registry.

PURPOSE: Catheter ablation is a recommended rhythm control therapy after failed or intolerant antiarrhythmic drug (AAD) treatment for patients with atrial fibrillation (AF). This study evaluates clinical performance and safety of pulmonary vein isolation (PVI) using the cryoballoon (Arctic Front Advance) in Japan. METHODS: Cryo AF Global Registry is a prospective, multi-center registry. Patients with paroxysmal AF (PAF) were treated at 10 Japanese hospitals. Efficacy was evaluated by freedom from a ≥ 30-s recurrence of AF/atrial flutter (AFL)/atrial tachycardia (AT), AF-related symptoms, and quality of life using the EQ-5D-3L questionnaire. The safety endpoint was serious device- and procedure-related adverse events. RESULTS: The study included 352 patients with PAF (65 ± 10 years of age, 36% female, 36% without prior failure of AAD). Mean duration since first diagnosis of AF was 3.0 ± 5.5 years. Serious device- and procedure-related adverse event rate was 2.6% (95% CI: 1.2-4.8%). Freedom from AF/AFL/AT was 88.5% (95% CI: 84.7-91.4%) at 12 months and 86.7% (95% CI: 81.1-90.8%) at 24 months. The number of patients with ≥ 1 AF symptom was significantly decreased from 88% at enrollment to 22% (p < 0.01) at 12-month follow-up. General quality of life using EQ-5D did not improve significantly after 12 months in the summary score. However, in the visual analog scale score, there was improvement (5.8 ± 18.4; p < 0.01). CONCLUSIONS: This study demonstrates that cryoablation used for PVI is a safe and effective treatment in real-world use for patients with PAF in Japan.

Initial practice of left atrial appendage closure device in Japan; single-center experience.

BACKGROUND: The left atrial appendage closure (LAAC) device for patients with nonvalvular atrial fibrillation (NVAF) has recently been introduced in Japan. However, clinical data of Japanese patients are insufficient. METHODS: In this single-center study, 55 consecutive patients (mean age, 74 years) who received LAAC therapy from September 2019 to December 2020 were analyzed. The WATCHMAN implant procedure (Boston Scientific, St. Paul, MN, USA) was performed under transesophageal echocardiography and general anesthesia for all cases. RESULTS: The baseline CHA2DS2-VASc score was 4.6 ± 1.4, and the baseline HAS-BLED score was 3.8 ± 0.9. All procedures (98.2%) were successful, except for one, and no procedure-related complications were observed. After the procedures, various antithrombotic regimens were employed according to the bleeding risk of each patient; warfarin was used in 27 patients (49%), direct oral anticoagulants (DOACs) were used in 22 patients (40%), and dual antiplatelet therapy (DAPT) was employed in 6 patients. During a mean follow-up of 360 days, three cases of device-related thrombus (DRT) were detected. One DRT case was related to ischemic stroke. Nine patients had major bleeding during follow-up: two patients received DOACs, six patients received DAPT, and one patient received aspirin. CONCLUSIONS: In this initial Japanese experience, LAAC therapy for high bleeding risk patients with NVAF seems feasible. Optimal antithrombotic regimens are warranted for better clinical outcomes.

Predictors of lead break during transvenous lead extraction.

BACKGROUND: The incidence, predictors, and clinical impact of lead break during transvenous lead extraction (TLE) were previously unknown. METHODS: We included consecutive patients who underwent TLE between September 2013 and July 2019 at our institute. Lead break during removal was defined as lead stretching and becoming misshapen, as assessed by fluoroscopy. RESULTS: A total of 246 patients underwent TLE for 501 leads. At a patient level, complete success was achieved in 226 patients (91.9%). At a lead level, 481 leads (96.0%) were completely removed and 101 leads (20.1%) were broken during the procedure. Of 392 identified pacemaker leads, 71 (18.3%) were broken during the TLE procedure. A multivariable analysis confirmed high lead age (odds ratio [OR] 1.12, 95% confidence interval (CI) 1.07-1.17; P < .001), passive leads (OR 2.29 95% CI 1.09-4.80; P = .028), coradial leads (OR 3.45 95% CI 1.72-6.92; P < .001), and insulators made of nonpolyurethane (OR 2.38 95% CI 1.03-5.26; P = .04) as predictors of lead break. Broken leads needed longer procedure times and were associated with a higher rate of cardiac tamponade. CONCLUSIONS: Lead age, coradial bipolar leads, passive leads, and leads without polyurethane insulation were predictors of lead break and could increase the difficulty of lead extraction.

Clinical impact of eliminating nonpulmonary vein triggers of atrial fibrillation and nonpulmonary vein premature atrial contractions at initial ablation for persistent atrial fibrillation.

BACKGROUND: The role of nonpulmonary vein (PV) triggers ablation in persistent atrial fibrillation (PEAF) was suggested but it is still under debate. OBJECTIVES: We aimed to assess the effectiveness of non-PV trigger-targeted ablation for patients with PEAF. METHODS: Consecutive patients with PEAF undergoing catheter ablation (CA) between January 2015 and April 2017 were enrolled. Isoproterenol plus adenosine challenge was performed to provoke non-PV triggers. Non-PV triggers were defined as the trigger beats inducing AF (non-PV AF triggers) and/or frequent premature contractions (non-PV PACs) from other than PVs. Three groups were defined: Group 1 (n = 186) without non-PV triggers; Group 2 (n = 65) with non-PV triggers that could be completely eliminated with CA; Group 3 (n = 49) with non-PV triggers still inducible after CA. The primary endpoint was freedom from any atrial tachyarrhythmia (ATa) recurrence. RESULTS: A total of 300 patients (230 males, age 64 ± 10) were enrolled. The mean follow-up period was 27 ± 10 months. Freedom from ATa recurrence at 1 and 2 years were significantly lower in Group 3 compared to the other two groups (Group 1; 74.7%, 67.2% vs. Group 2; 75.8%, 68.3% vs. Group 3: 52.1%, 38.6%, p = .0005), irrespective of the type of non-PV triggers (non-PV AF triggers vs. non-PV PACs). On multivariate analysis, unsuccessful elimination of non-PV triggers was an independent predictor for ATa recurrence (hazard ratio = 1.80, 95% confidence interval = 1.07-2.95, p = .026). CONCLUSION: Successful non-PV triggers elimination can improve the ATa recurrence rate in PEAF ablation. ATa recurrence rate is higher, if non-PV AF triggers or even non-PV PACs remain in patients with PEAF.

Japan ablation registry: cryoablation in atrioventricular nodal reentrant tachycardia ("JARCANRET study"): results from large multicenter retrospective investigation.

PURPOSE: Cryoenergy has been demonstrated to be a safe alternative to radiofrequency ablation for catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT). This study aimed to evaluate the safety and efficacy of cryoablation in patients with AVNRT. METHODS: A multicenter retrospective study was performed. Two hundred eighty-three consecutive patients with AVNRT underwent cryoablation. Cryomapping at - 30 °C and - 80 °C was performed to predict cryoablation outcome and ascertain antegrade conduction. Cryoenergy was delivered subsequently at the same spot (cryoablation at - 80 °C) for 240 s. RESULTS: Ablation procedure was acutely successful in 281 out of 283 patients (99.3%). Of note, 22 patients (10.1%) had transient AV block during the cryoablation, but no injurious effects on AV conduction were provoked during cryomapping. During a follow-up period of 367 ± 35 days, the recurrence rate was 3.9% (11 out of 281). There were no significant differences among the patients with a complete elimination of slow pathway conduction, AH jump without an echo beat, and AH jump with a single echo beat, in terms of the long-term recurrence of AVNRT. CONCLUSIONS: Cryoablation of AVNRT appears to be effective both acutely and during the long-term with a minimal risk of unwanted injuries to the conduction system. It seems to be important to monitor the antegrade conduction during cryoenergy applications, even when cryomapping demonstrates a safe location for cryoablation. The recurrence rate of AVNRT did not differ according to the properties of the residual slow pathway conduction.

Ostial atresia of the coronary sinus in patients with supraventricular arrhythmias.

Of 3577 patients with supraventricular arrhythmias, 3 demonstrated an atresia of the coronary sinus (CS) ostium. Two patients had the accessory pathways. One had atrial fibrillation. No unroofed CS or apparent persistent left superior vena cava was observed. Venous drainage through a small cardiac vein located on the lateral portion of the tricuspid annulus was observed in all patients. Those cases demonstrated that the incidence of ostial atresia of the CS was 0.084%. Accessory pathways were often accompanied by this anomaly. An abnormal venous orifice located on the lateral tricuspid annulus often functioned as the drainage of the CS flow.

Retrieval of a Micra transcatheter pacing system in a heart with a preexisting lead.

We report the case of a 74-year-old man with a previously implanted pacemaker lead. He had undergone Medtronic™ Micra Transcatheter Pacing System (TPS, Medtronic plc, MN, USA) implantation because of lead fracture. We implanted a new TPS and retrieved the dislodged one. We used a multiple-loop snare (EN snare®) and an 8.5F steerable sheath (Agilis NXT; St. Jude Medical, St Paul, MN, USA). The TPS was obstructed by the chordae tendineae of the tricuspid valve and the pacemaker lead. We pushed the TPS to the apex site; this enabled us to move the TPS away from the chordae tendineae and pacemaker lead. The TPS body was caught in the inferior vena cava and was successfully retrieved. To our knowledge, this is the first case reporting TPS retrieval in a heart with preexisting lead.

Transvenous extraction of advisory implantable cardioverter defibrillator leads with a relatively long implant duration.

BACKGROUND: Optimal management of advisory implantable cardioverter defibrillator (ICD) leads has not been established. Several studies were reported concerning the lead extraction of advisory ICD leads, but the implant duration of those studies was short. We estimated the efficacy of lead extractions of advisory ICD leads with a relatively longer duration in Japanese patients. METHODS: We retrospectively analyzed 28 patients who underwent a lead extraction at Kokura Memorial Hospital and Tokyo Medical and Dental University Hospital [Fidelis (Medtronic, Minneapolis, MN, USA): n=19, Riata (St. Jude Medical, Sylmar, CA, USA): n=8, Isoline (SORIN CRM SAS, Clamart, France): n=1]. The mean implant duration was 63.3±19.3 months. The indications were device related infections in 3, electrical lead failures in 18, electrical lead failures and venous obstructions in 3, and prophylactic reasons in 4 patients. Inappropriate shocks because of electrical lead failures were observed in 9 patients. RESULTS: Complete removals were achieved of all 28 advisory leads. In 23 out of 28 patients, new ICD leads were implanted during the same procedure. In one patient, open chest surgery was performed for a hemothorax that occurred during a new ICD lead implantation just after successfully removing the advisory ICD lead. There were no other major or minor complications. CONCLUSION: Transvenous extractions of advisory ICD leads with relatively long implant duration were performed with a high success rate and low complication and mortality rate in Japanese patients.