Effect of Catheter Ablation for Atrial Fibrillation in Heart Failure With Mid-Range or Preserved Ejection Fraction　- Pooled Analysis of the AF Frontier Ablation Registry and Hokuriku-Plus AF Registry.

BACKGROUND: A recent randomized trial demonstrated that catheter ablation for atrial fibrillation (AF) in patients with heart failure with reduced ejection fraction (EF) is associated with a reduction in death or heart failure. However, the effect of catheter ablation for AF in patients with heart failure with mid-range or preserved EF is unclear.Methods and Results: We screened 899 AF patients (72.4% male, mean age 68.4 years) with heart failure and left ventricular EF ≥40% from 2 Japanese multicenter AF registries: the Atrial Fibrillation registry to Follow the long-teRm Outcomes and use of aNTIcoagulants aftER Ablation (AF Frontier Ablation Registry) as the ablation group (525 patients who underwent ablation) and the Hokuriku-Plus AF Registry as the medical therapy group (374 patients who did not undergo ablation). Propensity score matching was performed in these 2 registries to yield 106 matched patient pairs. The primary endpoint was a composite of cardiovascular death and hospitalization for heart failure. At 24.6 months, the ablation group had a significantly lower incidence of the primary endpoint (hazard ratio 0.32; 95% confidence interval 0.13-0.70; P=0.004) than the medical therapy group. CONCLUSIONS: Compared with medical therapy, catheter ablation for AF in patients with heart failure and mid-range or preserved EF was associated with a significantly lower incidence of cardiovascular death or hospitalization for heart failure.

Use of a QDOT MICRO catheter to identify a premature ventricular contraction origin in the right ventricular anterior papillary muscle in a repaired truncus arteriosus.

The ventricular papillary muscles (VPMs) can be a source of premature ventricular contractions (PVCs). Catheter ablation of VPM PVCs is challenging because of the anatomical complexity, such as the apical structures in proximity to the ventricular walls. The QDOT MICRO catheter (Biosense Webster, Diamond Bar, CA, USA) has microelectrodes embedded along the circumference of its distal tip and can provide information on which side of its tip myocardial activation is earlier. This repaired truncus arteriosus case demonstrates the usefulness of the microelectrode recording in identifying a PVC origin in a right VPM apex close to the right ventricular anterior wall.

Different Determinants of the Recurrence of Atrial Fibrillation and Adverse Clinical Events in the Mid-Term Period After Atrial Fibrillation Ablation.

BACKGROUND: It is unclear whether there are differences in the clinical factors between atrial fibrillation (AF) recurrence and adverse clinical events (AEs), including stroke/transient ischemic attack (TIA), major bleeding, and death, after AF ablation.Methods and Results:We examined the data from a retrospective multicenter Japanese registry conducted at 24 cardiovascular centers between 2011 and 2017. Of the 3,451 patients (74.1% men; 63.3±10.3 years) who underwent AF ablation, 1,046 (30.3%) had AF recurrence and 224 (6.5%) suffered AEs (51 strokes/TIAs, 71 major bleeding events, and 36 deaths) over a median follow-up of 20.7 months. After multivariate adjustment, female sex, persistent and long-lasting persistent AF (vs. paroxysmal AF), and stepwise increased left atrial diameter (LAd) quartiles were significantly associated with post-ablation recurrences. A multivariate analysis revealed that an age ≥75 years (vs. <65 years), body weight <50 kg, diabetes, vascular disease, left ventricular (LV) ejection fraction <40% (vs. ≥50%), Lad ≥44 mm (vs. <36 mm), and creatinine clearance <50 mL/min were independently associated with AE incidences, but not with recurrences. CONCLUSIONS: This study disclosed different determinants of post-ablation recurrence and AEs. Female sex, persistent AF, and enlarged LAd were determinants of post-ablation recurrence, whereas an old age, comorbidities, and LV and renal dysfunction rather than post-ablation recurrence were AEs determinants. These findings will help determine ablation indications and post-ablation management.

Impact of sinus rhythm maintenance on major adverse cardiac and cerebrovascular events after catheter ablation of atrial fibrillation: insights from AF frontier ablation registry.

The impact of catheter ablation for atrial fibrillation (AF) on cardiovascular events and mortality is controversial. We investigated the impact of sinus rhythm maintenance on major adverse cardiac and cerebrovascular events after AF ablation from a Japanese multicenter cohort of AF ablation. We investigated 3326 consecutive patients (25.8% female, mean age 63.3 ± 10.3 years) who underwent catheter ablation for AF from the atrial fibrillation registry to follow the long-term outcomes and use of anti coagulants after ablation (AF frontier ablation registry). The primary endpoint was a composite of stroke, transient ischemic attack, cardiovascular events, and all-cause death. During a mean follow-up of 24.0 months, 2339 (70.3%) patients were free from AF after catheter ablation, and the primary composite endpoint occurred in 144 (4.3%) patients. The AF nonrecurrence group had a significantly lower incidence of the primary endpoint (1.8 per 100 person-years) compared with the AF recurrence group (3.0 per 100 person-years, p = 0.003). The multivariate analysis revealed that freedom from AF (hazard ratio 0.61, 95% confidence interval 0.44-0.86, p = 0.005) was independently associated with the incidence of the composite event. In the multicenter cohort of AF ablation, sinus rhythm maintenance after catheter ablation was independently associated with lower rates of major adverse cardiac and cerebrovascular events.

Clinical outcomes of ablation versus non-ablation therapy for atrial fibrillation in Japan: analysis of pooled data from the AF Frontier Ablation Registry and SAKURA AF Registry.

Whether ablation for atrial fibrillation (AF) is, in terms of clinical outcomes, beneficial for Japanese patients has not been clarified. Drawing data from 2 Japanese AF registries (AF Frontier Ablation Registry and SAKURA AF Registry), we compared the incidence of clinically relevant events (CREs), including stroke/transient ischemic attack (TIA), major bleeding, cardiovascular events, and death, between patients who underwent ablation (n = 3451) and those who did not (n = 2930). We also compared propensity-score matched patients (n = 1414 in each group). In propensity-scored patients who underwent ablation and those who did not, mean follow-up times were 27.2 and 35.8 months, respectively. Annualized rates for stroke/TIA (1.04 vs. 1.06%), major bleeding (1.44 vs. 1.20%), cardiovascular events (2.15 vs. 2.49%) were similar (P = 0.96, 0.39, and 0.35, respectively), but annualized death rates were lower in the ablation group than in the non-ablation group (0.75 vs.1.28%, P = 0.028). After multivariate adjustment, the risk of CREs was statistically equivalent between the ablation and non-ablation groups (hazard ratio [HR] 0.89, 95% confidence interval [CI] 0.71-1.11), but it was significantly low among patients who underwent ablation for paroxysmal AF (HR 0.68 [vs. persistent AF], 95% CI 0.49-0.94) and had a CHA2DS2-VASc score < 3 (HR 0.66 [vs. CHA2DS2-VASc score ≥ 3], 95% CI 0.43-0.98]). The 2-year risk reduction achieved by ablation may be small among Japanese patients, but AF ablation may benefit those with paroxysmal AF and a CHA2DS2-VASc score < 3.

The utility of extracorporeal membrane oxygenation in patients with circulatory collapse by electrical storm.

In patients experiencing electrical storm, intensive care using extracorporeal membrane oxygenation (ECMO) is an efficient treatment to overcome a hemodynamically unstable condition. The aim of this study was to examine the utility of ECMO in patients with circulatory collapse by electrical storm. We retrospectively examined 17 consecutive patients receiving veno-arterial ECMO for electrical storm between January 2016 and December 2018 in our institution. We compared survivors (n = 11) and non-survivors (n = 6). Thirteen were weaned from ECMO, of whom 11 patients (64.7%) survived and were discharged from hospital, while 6 patients died (35.3%). In comparisons between survivors and non-survivors, blood pH before starting ECMO was significantly higher in survivors (pH 7.32) than in non-survivors (pH 6.89, p = 0.027). Blood lactate level was significantly lower in survivors (6.2 mmol/L) than in non-survivors (12.2 mmol/L, p = 0.044). Complications of hypoxic ischemic encephalopathy were found in 4 non-survivors (66.7%), compared to survivors (0%, p = 0.006). Durations of intensive care unit stay and hospital stay were significantly longer in survivors (271 h, 62 days) than in non-survivors (50 h, 3 days, respectively). Outcomes of treatment using ECMO in patients with circulatory collapse due to electrical storm proved satisfactory. Increases in blood lactate level and decreases in blood pH before starting ECMO were thought to be related to mortality due to suspected irreversible organ damage by hypoxia before ECMO.

Clinical Outcomes of Off-Label Underdosing of Direct Oral Anticoagulants After Ablation for Atrial Fibrillation.

Direct oral anticoagulants (DOACs) are sometimes prescribed at off-label under-doses for patients who have undergone ablation for atrial fibrillation (AF). This practice may be an attempt to balance the risk of bleeding against that of stroke or AF recurrence.We examined outcomes of 1163 patients who continued use of a DOAC after ablation. The patients were enrolled in a large (3530 patients) multicenter registry in Japan. The study patients were classified as 749 (64.4%) appropriate standard-dose DOAC users, 216 (18.6%) off-label under-dose DOAC users, and 198 (17.0%) appropriate low-dose DOAC users.Age and CHA2DS2-VASc scores differed significantly between DOAC dosing regimens, with patients given an appropriate standard-dose being significantly younger (63.3 ± 9.4 versus 64.8 ± 9.5 versus 73.2 ± 6.8 years, P < 0.0001) and lower (2.1 ± 1.5 versus 2.4 ± 1.6 versus 3.4 ± 1.4, P < 0.0001) than those given an off-label under-dose or an appropriate low-dose. During the median 19.0-month follow-up period, the AF recurrence rate was similar between the appropriate standard-dose and off-label under-dose groups but relatively low in the appropriate low-dose group (42.5% versus 41.2% versus 35.4%, P = 0.08). Annualized rates of thromboembolic events, major bleeding, and death from any cause were 0.47%, 0.70%, and 0.23% in the off-label under-dose group, while those rates were 0.74%, 0.73%, and 0.65% in the appropriate standard-dose, and 1.58%, 2.12%, and 1.57% in the appropriate low-dose groups.In conclusion, the clinical adverse event rates for patients on an off-label under-dose DOAC regimen after ablation, predicated on careful patient evaluations, was not high as seen with that of patients on a standard DOAC dosing regimen.

Current Status and Clinical Outcomes of Oral Anticoagulant Discontinuation After Ablation for Atrial Fibrillation in Japan　- Findings From the AF Frontier Ablation Registry.

BACKGROUND: The safety of discontinuing oral anticoagulant (OAC) after ablation for atrial fibrillation (AF) in Japanese patients has not been clarified.Methods and Results:A study based on the Atrial Fibrillation registry to Follow the long-teRm Outcomes and use of aNTIcoagulants aftER Ablation (AF Frontier Ablation Registry) was conducted. Data were collected from 3,451 consecutive patients (74.1% men; age, 63.3±10.3 years) who had undergone AF ablation at any of 24 cardiovascular centers in Japan between August 2011 and July 2017. During a 20.7-month follow-up period, OAC therapy was discontinued in 1,836 (53.2%) patients; 51 patients (1.5%) suffered a stroke/transient ischemic attack (TIA), 71 (2.1%) suffered major bleeding, and 36 (1.0%) died. Patients in whom OAC therapy was discontinued were significantly younger than those in whom OACs were continued, and their CHA2DS2-VASc scores were significantly lower. The incidences of stroke/TIA, major bleeding, and death were significantly lower among these patients. Upon multivariate adjustment, stroke events were independently associated with relatively high baseline CHA2DS2-VASc scores but not with OAC status. CONCLUSIONS: Although the incidences of stroke/TIA, major bleeding, and death were relatively low among patients for whom OAC therapy was discontinued, stroke/TIA occurrence was strongly associated with a high baseline stroke risk rather than with OAC status. Thus, discontinuation of OAC therapy requires careful consideration, especially in patients with a high baseline stroke risk.

Effects and Risks of Heparin Bridging and Different Modes of Interruption/Resumption of Rivaroxaban on Perioperative Complications of Catheter Ablation for Atrial Fibrillation　- Another Analysis of the JACRE-R Registry.

BACKGROUND: The JACRE-R Registry, in which 42 Japanese institutions participated, monitored the efficacy and safety of rivaroxaban in catheter ablation (CA) of atrial fibrillation (AF). In the present analysis, we sought to elucidate the effects and risks of heparin bridging and different patterns of interruption/resumption of rivaroxaban on complications of CA.Methods and Results:We administered rivaroxaban during the perioperative period and recorded the incidence of complications up to 30 days after CA. A total of 1,118 patients were registered; 546 received heparin bridging and 572 did not. The bridging group showed a significantly higher incidence of non-major bleeding than the no-bridging group (4.03% vs. 0.87%; P=0.001). In the group receiving their last dose of rivaroxaban at 8-28 h before CA, neither thromboembolism nor major bleeding was observed during or after CA and the incidence of non-major bleeding was low (4/435, 0.92%). The incidence of non-major bleeding was significantly higher in the group resuming rivaroxaban ≥12 h after CA than in the group resuming <12 h (1.79% vs. 0.27%, P=0.045). CONCLUSIONS: Heparin bridging increased the risk of non-major bleeding perioperatively. It was safe to stop rivaroxaban 8-28 h before the CA procedure, whereas resumption of the drug within 12 h of CA was associated with a lower incidence of non-major bleeding.

Safety and Efficacy of Subcutaneous Cardioverter Defibrillator in Patients at High Risk of Sudden Cardiac Death　- Primary Japanese Experience.

BACKGROUND: The entirely subcutaneous implantable cardioverter defibrillator (S-ICD) was introduced as a new alternative to conventional transvenous ICD (TV-ICD) in Japan in February 2016, but its safety and efficacy are unclear.Methods and Results:A total of 60 patients (48 men, median age, 60 years; IQR, 44-67 years; primary prevention, n=24) underwent S-ICD implantation between February 2016 and August 2017. The device pocket was formed in the intermuscular space between the serratus anterior muscle and the latissimus dorsi muscle, and the parasternal S-ICD lead was placed according to pre-implant screening. Defibrillation test was performed in 56 patients (93%). Ventricular fibrillation (VF) was induced in 55 patients and terminated by a single 65-J shock in all patients. The median time to shock therapy was 13.4 s (IQR, 12.1-14.9 s) and the median post-shock impedance of the S-ICD lead was 64 Ω (IQR, 58-77 Ω). There were no operation-related complications or subsequent infectious complications. During follow-up (median, 275 days; IQR, 107-421 days), 1 patient (1.7%) had appropriate shock for VF with successful termination, whereas 5 patients (8.3%) had inappropriate shock due to oversensing of myopotential (n=3) or T-wave (n=1), and detection of supraventricular tachycardia (n=1). CONCLUSIONS: S-ICD is a safe and effective alternative to conventional TV-ICD. The long-term safety and efficacy of the S-ICD need further investigation.

Long Postpacing Interval After Entrainment of Tachycardia Including a Slow Conduction Zone Within the Circuit.

BACKGROUNDS: Postpacing interval (PPI) measured after entrainment pacing describes the distance between pacing site and reentrant circuit. However, the influential features to PPI remain to be elucidated. METHODS AND RESULTS: This study included 22 cases with slow/fast atrioventricular (AV) nodal reentrant tachycardia (AVNRT), 14 orthodromic AV reciprocating tachycardia (AVRT) using an accessary pathway, 22 typical atrial flutter (AFL), and 18 other macroreentrant atrial tachycardia (atypical AFL). Rapid pacing at a pacing cycle length (PCL) 5% shorter than tachycardia cycle length (TCL) was done from a site on or close to the reentry circuit. Pacing sites included the coronary sinus ostium in AVNRT, earliest atrial activation site in AVRT, and cavotricuspid isthmus in typical AFL. In atypical AFL, tachycardia circuit was determined on the basis of CARTO mapping, and then the pacing site was. TCL was significantly longer in AVNRT and AVRT than in typical AFL and atypical AFL (both P < 0.05). PCL minus TCL value was similar among the 4 groups. PPI minus TCL value (milliseconds) was significantly longer in AVNRT (median, 40 [IQR, 29-60.8]) and AVRT (34 [20-47]) than in typical AFL (0 [0-4]) and atypical AFL (3.5 [0-8]) (both P < 0.05). Furthermore, PPI minus TCL was prolonged with shortening of PCL in AVNRT and AVRT (both P < 0.05), whereas it was unchanged in typical AFL (P = 0.50). CONCLUSION: PPI after concealed entrainment is prolonged compared with TCL when the reentry circuit involves a slow conduction zone with a decremental conduction property such as the AV node.

Reduced residual conduction gaps and favourable outcome in contact force-guided circumferential pulmonary vein isolation.

AIMS: Although contact force (CF)-guided circumferential pulmonary vein isolation (CPVI) for paroxysmal atrial fibrillation (PAF) is useful, AF recurrence at long-term follow-up still remains to be resolved. The purpose of this study was to assess safety and efficacy of CF-guided CPVI and to compare residual conduction gaps during CPVI and long-term outcome between the conventional (non-CF-guided) and the CF-guided CPVI. METHODS AND RESULTS: We studied the 50 consecutive PAF patients undergoing CPVI by a ThermoCool EZ Steer catheter (conventional group, mean age 61 ± 10 years) and the other 50 consecutive PAF patients by a ThermoCool SmartTouch catheter (CF group, 65 ± 11 years). The procedure parameters and residual conduction gaps during CPVI, and long-term outcome for 12 months were compared between the two groups. Circumferential pulmonary vein isolation was successfully accomplished without any major complications in both groups. Total procedure and total fluoroscopy times were both significantly shorter in the CF group than in the conventional group (160 ± 30 vs. 245 ± 61 min, P < 0.001, and 17 ± 8 vs. 54 ± 27 min, P < 0.001, respectively). Total number of residual conduction gaps was significantly less in the CF group than in the conventional group (2.7 ± 1.7 vs. 6.3 ± 2.7, P < 0.05). The AF recurrence-free rates after CPVI during 12-month follow-up were 96% (48/50) in the CF group and 82% (41/50) in the conventional group (P = 0.02 by log rank test). Multivariate Cox regression analysis further supported this finding. CONCLUSION: Contact force-guided CPVI is safe and more effective in reducing not only the procedure time but also the AF recurrence than the conventional CPVI, possibly due to reduced residual conduction gaps during CPVI procedure.

Efficacy and Safety of Rivaroxaban and Warfarin in the Perioperative Period of Catheter Ablation for Atrial Fibrillation　- Outcome Analysis From a Prospective Multicenter Registry Study in Japan.

BACKGROUND: Catheter ablation (CA) is a common treatment for atrial fibrillation (AF). Although rivaroxaban is increasingly used as a substitute for warfarin, its safety and efficacy during CA have not been established in Japanese patients. In the present study we explored the efficacy/safety of rivaroxaban during the CA perioperative period.Methods and Results:We prospectively enrolled Japanese AF patients scheduled for CA who had received either rivaroxaban (rivaroxaban cohort, JACRE-R) or warfarin (warfarin cohort, JACRE-W) during the perioperative period. Primary outcome was a composite of thromboembolism and major bleeding within 30 days after CA. In JACRE-R and JACRE-W, 1,118 (median age, 65 years) and 204 patients (median, 69 years) were enrolled from 42 and 22 institutions, respectively. In JACRE-R, the primary outcome occurred in 7 patients (0.6%), comprising thromboembolism in 2 and major bleeding in 5. Non-major bleeding occurred in 27 patients (2.4%), and the incidence was significantly lower in patients without heparin bridging (n=572) than in those with heparin bridging (n=546). In JACRE-W, the primary outcome occurred in 3 patients (1.5%), all of which were major bleeding. After adjustment for patients' characteristics, no significant difference was observed between the JACRE-R and JACRE-W cohorts for the primary outcome. CONCLUSIONS: The rates of thromboembolism and major bleeding events during the AF ablation perioperative period in Japanese patients treated with rivaroxaban was as low as in those treated with warfarin. (Circ J 2016; 80: 2295-2301).