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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.

Background: Demand is growing for remote electrocardiogram (ECG) monitoring systems in the COVID-19 era in Japan. This study describes initial experiences with a small wireless ECG monitoring device and the utility of delivery via the postal service for outpatient care in Japan. Methods and Results: Long-term ECG monitoring following postal delivery of the small ECG device was evaluated in 25 patients. The patients had no difficulties with either the postal delivery or self-fitting and wearing the devices. A median of 57 h monitoring per patient was performed. Arrhythmic events were detected in 8 patients. Most patients were satisfied with both the ECG devices and postal delivery. Conclusions: Postal delivery of ECG devices could be used in clinical practice to achieve less or no in-person contact during the COVID-19 era.

Background A computational model demonstrated that atrial fibrillation (AF) rotors could be distributed in patchy late-gadolinium enhancement (LGE) areas and play an important role in AF drivers. However, this was not validated in humans. Objective The purpose of this study was to evaluate the LGE area properties of AF rotors in patients with persistent AF. Methods A total of 287 segments in 15 patients with persistent AF (longstanding persistent AF in 9 patients) that underwent AF ablation were assessed. Non-passively activated areas (NPAs), where rotational activation (AF rotor) was frequently observed, were detected by the novel real-time phase mapping (ExTRa Mapping). The properties of the LGE areas were assessed using the LGE heterogeneity, and the density was assessed by the entropy (LGE-entropy) and volume ratio of the enhancement voxel (LGE-volume ratio), respectively. Results NPAs were found in 61 (21%) of 287 segments and were mostly found around the pulmonary vein antrum. A receiver operating characteristic curve analysis yielded an optimal cutoff value of 5.7 and 10% for the LGE-entropy and LGE-volume ratio, respectively. The incidence of NPAs was significantly higher at segments with an LGE-entropy of >5.7 and LGE-volume ratio of >10% than at the other segments (38 [30%] of 126 vs. 23 [14%] of 161 segments, p = 0.001). No NPAs were found at segments with an LGE-volume ratio of >50% regardless of the LGE-entropy. Of 5 patients with AF recurrence, NPAs outside the PV antrum were not ablated in 3 patients and the remaining NPAs were ablated, but their LGE-entropy and LGE-volume ratio were low. Conclusion AF rotors are mostly distributed in relatively weak and much more heterogenous LGE areas. This article is protected by copyright. All rights reserved.

Background Inflammation, such as that associated with intermediate CD14++ CD16+ monocytes and atrial structural remodeling (SRM), may be important in the recurrence of atrial fibrillation (AF) after catheter ablation. However, the relationship between the intermediate CD14++ CD16+ monocytes, SRM, and AF recurrence is unclear. Methods Twenty-four patients with AF were enrolled. The proportion of intermediate monocytes (PIM) was assessed before ablation by flow cytometry. As a surrogate marker of SRM, the volume ratio (VR) of signal intensity greater than 1 standard deviation on late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) was calculated. We investigated whether PIM correlated with SRM on LGE-MRI and determined the optimal cutoff value for predicting AF recurrence. Results Univariate analysis revealed positive correlations between PIM and BNP with SRM (PIM: r = .593, p = .002; BNP: r = .567, p = .004). Multivariable analysis revealed that PIM was independently associated with VR on LGE-MRI (β = .522; p = .033). The finding of an area under the receiver operating characteristic curve of 0.750 revealed that a VR ≥ 13.3% on LGE-MRI as the optimal cutoff value to predict AF recurrence with 80% sensitivity and 71% specificity, which was associated with PIM ≥ 10.0%. Conclusion Intermediate monocytes were significantly positively correlated with SRM. PIM ≥ 10% was associated with a VR ≥ 13.3% on LGE-MRI, which predicted AF recurrence after catheter ablation.

BACKGROUND: A computer simulation model has demonstrated that an atrial fibrillation (AF) driver can be attached to heterogeneous fibrosis assessed by late gadolinium enhancement magnetic resonance imaging (LGE-MRI). However, it has not been well elucidated in patients with persistent AF. The aim of this study was to investigate whether radiofrequency (RF) applications in the fragmented LGE area (FLA) could terminate AF or convert it to atrial tachycardia (AT) and improve the rhythm outcome. METHODS: A total of 31 consecutive persistent AF patients with FLAs were enrolled (FLA ablation group, mean age: 69 ± 8 years, mean left atrial diameter: 42 ± 6 mm). A favorable response was defined as direct AF termination or AT conversion during RF applications at the FLA. The rhythm outcome was compared between the FLA ablation group and FLA burden-matched pulmonary vein isolation (PVI) group. RESULTS: Favorable responses were found in 15 (48%) of 31 patients in the FLA group (AF termination in 7, AT conversion in 8 patients), but not in the PVI group. AF recurrence at 12 months follow-up was significantly less in the FLA ablation group than in the PVI group (4 [13%] vs. 12 [39%] of 31 patients, log-rank p=0.023). In patients with a favorable response, AT recurred in 1 (7%) of 15 patients but AF did not. CONCLUSIONS: FLA ablation could terminate AF or convert it to AT in half of the patients. No AF recurrence was documented in patients with a favorable response. This article is protected by copyright. All rights reserved.

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.

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

Background Atrial inflammation plays an important role in initiating atrial fibrosis, which could perpetuate atrial fibrillation (AF). However, the method of visualization of atrial inflammation has not been established. We sought to investigate whether the intensive atrial inflammation caused by cryoballoon ablation (CBA) could be detected by positron emission tomography/ magnetic resonance imaging (PET/MRI) and whether the atrial inflammation could be associated with consequent fibrosis. Methods A total of 10 paroxysmal atrial fibrillation patients after CBA were enrolled. To detect and quantify intensive atrial inflammation, PET/MRI was performed to assess regional 18F‐fluorodeoxyglucose (18F‐FDG) uptake one day after the CBA, and the standardized uptake values (SUV) max were compared between the pulmonary vein (PV) antrum where CBA could be applied and the healthy left atrial (LA) wall where CBA could not be applied. Furthermore, the atrial inflammation one day after the procedure and atrial fibrosis areas one month after the procedure were three‐dimensionally quantified by PET/MRI and late‐gadolinium enhancement magnetic resonance imaging (LGE‐MRI), respectively. Results The mean SUV max at the PV antrum was significantly higher than that on the healthy LA wall (2.12 ± 0.35 vs 1.73 ± 0.30, P = .00021). The volume of the atrial inflammation strongly correlated with that of the atrial fibrosis (r = .94 [.76‐.99], P = .00006). Conclusions The atrial inflammation after CBA could be detected by PET/MRI. CBA‐induced atrial inflammation was strongly associated with consequent lesion maturation., Atrial inflammation plays an important role in initiating atrial fibrosis, which could perpetuate atrial fibrillation (AF).This study demonstrated the feasibility of the PET/MRI visualizing inflammation in the left atrium.

Inflammation has been suggested to play a key role in the pathogenesis of atrial fibrillation (AF). Our hypothesis was that this inflammation, mediated by intermediate monocytes and toll-like receptor 4 (TLR4), causes the formation and expansion of low-voltage zones (LVZs). Prior to ablation, the monocyte subsets of 78 AF patients and TLR4 expression of 66 AF patients were analyzed via a flow cytometric analysis. Based on the CD14/CD16 expression, the monocytes were divided into three subsets: classical, intermediate, and non-classical. At the beginning of the ablation session, voltage mapping was performed. LVZs were defined as all bipolar electrogram amplitudes of

Background Although anticoagulation therapy could reduce the risk of strokes in patients with atrial fibrillation (AF), large‐scale investigations in the direct oral anticoagulant (DOAC) and AF catheter ablation (CA) era are lacking. Methods This study was designed as a prospective, multicenter, observational study and a total of 2113 patients from 22 institutions were enrolled in the Hyogo area. Results The mean age and CHADS2 score were 70.1 ± 10.8 years old and 1.5 ± 1.1, respectively. The follow‐up period was 355 ± 43 days. CA was performed in 614 (29%) and DOACs were prescribed in 1118 (53%) patients. Ischemic strokes/systemic embolisms (SEs) and major bleeding occurred in 13 (0.6%) and 17 (0.8%) patients, respectively. New onset dementia, hospitalizations for cardiac events, and all‐cause death occurred in eight (0.4%), 60 (2.8%), and 29 (1.4%) patients, respectively. A multivariate analysis demonstrated that persistent AF and the body weight (BW) were associated with ischemic strokes/SEs and major bleeding, respectively (persistent AF: hazard ratio, 9.57; 95%CI, 1.2‐74.0; P = .03; BW: hazard ratio, 0.94; 95%CI, 0.90‐0.99; P = .02). AFCA history was associated with the cardiac events (hazard ratio, 0.44; 95%CI, 0.20‐0.99; P = .04). Age was associated with new onset dementia (hazard ratio, 1.1; 95%CI, 1.0‐1.2; P = .03). Conclusions In the DOAC and CA era, the incidence of ischemic strokes/SEs, major bleeding and cardiac events could be dramatically reduced in patients with AF. However, some unsolved issues of AF management still remain especially in elderly patients with persistent AF and a low BW.

A 41‐year‐old man with persistent atrial fibrillation (AF) underwent radiofrequency (RF) catheter ablation using an online real‐time phase mapping system: ExTRa Mapping. Box isolation could not terminate AF. Subsequently, RF applications on nonpassively activated areas (NPAs), where rotational activations were frequently observed, at the posterior bottom of left atrium outside of box lesion could convert AF to common atrial flutter. Of interest, the NPA near the posterior bottom were located on the patchy fibrotic tissue area assessed by the late‐gadolinium enhancement magnetic resonance imaging. This indicated the possibility of the critical AF rotor meandering through the fibrotic tissue area.

Objectives This study aimed to confirm the precise course of a pericardiocentesis with the anterior approach using post-procedural computed tomography (CT). Background Percutaneous epicardial ventricular tachycardia (VT) ablation has been increasingly performed. Although the inferior approach has been the common method, the feasibility of the anterior approach has subsequently been reported. However, the precise course of the anterior approach has not been presented. Methods An epicardial ablation with the anterior approach was performed in 15 patients. At the end of the procedure, the epicardial sheath was exchanged for a drainage tube to monitor bleeding. Of those patients, in 9 procedures in 8 patients a CT scan was performed just after the procedure to confirm the course of the drainage tube and to rule out any complications. Epicardial ablation was indicated for a failed endocardial VT ablation in 7 patients and epicardial substrate modification in 1 patient with Brugada syndrome. Results Volume-rendered images reconstructed from CT demonstrated each course of the drainage tubes and their relation to the surrounding organs. These images revealed that the tube had a curved trace, and did not penetrate the diaphragm or pass through the abdominal cavity. No injury to the surrounding organs was detected in any of the cases. Conclusions The precise course of the drainage tube placed along the trajectory of the anterior approach was able to be confirmed using post-procedural CT images. These images support the safety and feasibility of the anterior approach from the anatomic standpoint with a low incidence of abdominal viscera injury.

BACKGROUND A substantial number of patients with shock devices (implantable cardioverter defibrillators [ICDs] or ICDs with resynchronization [CRTDs]) experience psychological distress. OBJECTIVE We investigated the device nurse telephone intervention's effect on improving the patient's adaptation to shock devices, quality of life (QOL), and anxiety in the remote monitoring era. METHODS The patient's adaptation to the device, health-related QOL, and anxiety were investigated by the modified Implanted Devices Adjustment-Japan score (IDAS), Short Form-36, and State-Trait Anxiety Inventory (STAI) before and 1-year after the device nurse telephone intervention, performed every 3 months. A total of 95 patients (median age 69 years and 25 females) participated. Sixty patients had ICDs and 35 CRTDs. Structural heart disease was observed in 72 patients, and idiopathic ventricular arrhythmias in the others. The mean left ventricular ejection fraction was 46% ± 15%. The median duration since the device implantation was 5.2 years. RESULTS The total IDAS score significantly improved from 28.42 ± 7.11 at baseline to 26.77 ± 7.68 (p = 0.0076) at 1 year. Both the state and trait anxiety significantly improved (from 38.9 ± 9.6 to 35.3 ± 9.0 [

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.

Background: Some of atrial fibrillation (AF) drivers are found in lesser late-gadolinium enhancement (LGE) areas, as well as heterogenous ones. The atrial wall thickness (AWT) has been reported to be important as a possible AF substrate. However, the AWT and degree of LGEs as an AF substrate has not been fully validated in humans. Objective: The purpose of this study was to evaluate the impact of the AWT in lesser LGE areas on AF drivers. Methods: A total of 287 segments in 15 persistent AF patients were assessed. AF drivers were defined as non-passively activated areas (NPAs), where rotational activation was frequently observed, and were detected by the novel real-time phase mapping (ExTRa Mapping). Lesser LGE areas were defined as areas with a volume ratio of the enhancement voxel of

Background: Coronary artery spasms (CASs), which can cause angina attacks and sudden death, have been recently reported during catheter ablation. The aim of the present study was to report the incidence, characteristics, and prognosis of CASs related to atrial fibrillation (AF) ablation procedures. Methods and Results: The AF ablation records of 22,232 patients treated in 15 Japanese hospitals were reviewed. CASs associated with AF ablation occurred in 42 of 22,232 patients (0.19%). CASs occurred during ablation energy applications in 21 patients (50%). CASs also occurred before ablation in 9 patients (21%) and after ablation in 12 patients (29%). The initial change in the electrocardiogram was ST-segment elevation in the inferior leads in 33 patients (79%). Emergency coronary angiography revealed coronary artery stenosis and occlusions, which were relieved by nitrate administration. No air bubbles were observed. A comparison of the incidence of CASs during pulmonary vein isolation between the different ablation energy sources revealed a significantly higher incidence with cryoballoon ablation (11/3,288; 0.34%) than with radiofrequency catheter, hot balloon, or laser balloon ablation (8/18,596 [0.04%], 0/237 [0%], and 0/111 [0%], respectively; P

Introduction: 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. Methods and Results: We investigated 2737 consecutive patients (25.6% female, mean age 63.4 ± 10.3 years) who underwent a first catheter ablation for AF from the Atrial Fibrillation registry to Follow the long-teRm Outcomes and use of aNTIcoagulants 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 25.2 months, 2070 (75.6%) patients were free from AF after catheter ablation, and the primary composite endpoint occurred in 122 (4.5%) patients. The AF nonrecurrence group had a significantly lower incidence of the primary endpoint (1.7 per 100 person-years) compared with the AF recurrence group (3.2 per 100 person-years; P = 0.001). The multivariate analysis revealed that freedom from AF (hazard ratio 0.57; 95% confidence interval 0.39–0.83; P = 0.003) was independently associated with the incidence of the composite event.¬¬ Conclusion: 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.

Background: A computational model demonstrated that atrial fibrillation (AF) rotors could be distributed in patchy fibrotic tissue and play an important role in AF drivers. However, this was not validated in humans. Objective: The purpose of this study was to evaluate the fibrotic tissue properties of AF rotors in patients with persistent AF. Methods: A total of 287 segments in 15 patients with persistent AF (longstanding persistent AF in 9 patients) that underwent AF ablation were assessed. Non-passively activated areas (NPAs), where rotational activation (AF rotor) was frequently observed, were detected by the novel real-time phase mapping (ExTRa Mapping). Atrial fibrosis was detected by late-gadolinium enhancement magnetic resonance imaging (LGE-MRI), and the fibrotic heterogeneity and density were assessed by the entropy (LGE-entropy) and volume ratio of the enhancement voxel (LGE-volume ratio), respectively. Results: NPAs were found in 61 (21%) of 287 segments and were mostly found around the pulmonary vein antrum. A receiver operating characteristic curve analysis yielded an optimal cutoff value of 5.7 and 10% for the LGE-entropy and LGE-volume ratio, respectively. The incidence of NPAs was significantly higher at segments with an LGE-entropy of >5.7 and LGE-volume ratio of >10% than at the other segments (38 [30%] of 126 vs. 23 [14%] of 161 segments, p = 0.001). No NPAs were found at segments with an LGE-volume ratio of >50% regardless of the LGE-entropy. Conclusion: AF rotors are mostly distributed in relatively weak and much more heterogenous fibrotic tissue.

Background: Computer simulation model demonstrated that atrial fibrillation (AF) driver attached to the patchy fibrosis assessed by late gadolinium enhancement magnetic resonance imaging (LGE-MRI). However, it has not been well elucidated in patients with persistent AF. The aim of this study is to investigate whether radiofrequency (RF) application on the patchy LGE site (PLS) could terminate AF or convert to atrial tachycardia (AT) and improve the rhythm outcome. Methods: A total of 31consecutive persistent AF patients with PLS were enrolled (PLS ablation group, mean age: 69 ± 8 years, mean left atrial diameter: 42 ± 6 mm). AF direct termination or AT conversion during RF application on the PLS were defined as favorable response. The rhythm outcome was compared between the PLS ablation group and the propensity matched conventional ablation group. Results: Favorable response was found in 15 (48%) of 31 patients (AF termination in 7, AT conversion in 8 patients). AF recurrence at 12 months follow-up was significantly less in the PLS group as compared to the control group (4 (13%) of 31 patients vs. 11 (35%) of 31 patients, log-rank p = 0.019). In patients with favorable response, AT recurred in 1 (7%) of 15 patients but AF. Conclusions: The PLS ablation could terminate AF or convert to AT in half of the patients and improve the rhythm outcome as compared to the conventional ablation. No AF recurrence was documented in patients with a favorable response.

Background: Atrial fibrosis and inflammation play important roles in perpetuating and initiating atrial fibrillation (AF). Although the fibrotic area can be visualized as a delayed enhancement area on late gadolinium enhancement magnetic resonance imaging (LGE-MRI), atrial inflammation has not yet been visualized on any imaging modality. We describe the protocol for a feasibility study to visualize atrial inflammation on positron emission tomography/MRI (PET/MRI). Methods and Results: This is a single-arm, prospective, open-label proof-of concept trial, involving AF patients after cryoballoon ablation (CBA). A total of 30 paroxysmal AF patients will be enrolled and undergo simultaneous PET/MRI for the assessment of regional 18F-fluorodeoxyglucose (18F-FDG) uptake 1 day after the CBA. Furthermore, LGE-MRI will be performed before CBA, and at 1 and 4 weeks after assessing the regional LGE area. The main outcome measures will be (1) the feasibility of imaging inflammation in the left atrium on PET/MRI; and (2) the safety of the intervention. Conclusions: There are few data on the visualization of atrial inflammation using PET/MRI. Establishing the visualization methodology will contribute to elucidating the fundamental histopathologic findings of the progress to fibrosis, and to the planning and execution of a larger definitive trial to test the usefulness of PET/MRI.

Background Pulmonary vein isolation (PVI) lesions after cryoballoon ablation (CBA) are characterized as a wider and more continuous than that after conventional radiofrequency catheter ablation (RFCA) without the contact force (CF)-sensing technology. However, the impact on the lesion characteristics of ablation with a CF-sensing catheter has not been well discussed. We sought to assess the lesions using late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) and to compare the differences between the two groups (CB group vs. RF group). Methods A total of 30 consecutive patients who underwent PVI were enrolled (CB group, 18; RF group, 12). The RF applications were delivered with a target lesion size index (LSI) of 5. The PVI lesions were assessed by LGE-MRI 3 months after the PVI. The region around the PV was divided into eight segments: roof, anterior-superior, anterior carina, anterior inferior, bottom, posterior inferior, posterior carina, and posterior superior segment. The lesion width and visual gap of each segment were compared between the two groups. The visual gaps were defined as no-enhancement site of >4 mm. Results The mean LSI was 4.7 ± 0.7. The lesion width was significantly wider but the visual gaps were more frequently documented at the bottom segment of right PV in the CBA group (lesion width: 8.1 ± 2.2 vs. 6.3 ± 2.2 mm; p = .032; visual gap at the bottom segment or right PV: 39% vs. 0%; p = .016). Conclusions The PVI lesion was wider after CBA, while the visual gaps were fewer after RFCA with a CF-sensing catheter.

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.

Background Spontaneous coronary artery rupture (SCAR) is an extremely rare but life-threatening state. The aetiology and the pathologic findings remain to be fully elucidated. Case summary A 62-year-old woman, who had been on haemodialysis for 27 years, presented with chest discomfort worsening on deep inspiration that had been ongoing for the past 2 weeks. An echocardiogram and computed tomography showed diffuse pericardial fluid. ST elevation in the broad leads, especially in leads I, II, and aVF, and increased C-reactive peptide and Troponin I levels suggested pericarditis. The patient initially had a stable course with no medications. The chest symptoms disappeared and her vital signs were stable. On Day 13 after admission, however, she had a sudden cardiopulmonary arrest due to a cardiac tamponade. An emergency coronary angiography showed extravasation of the contrast into the epicardium from the branch of the circumflex artery. She was diagnosed with SCAR and underwent a successful coil embolization. However, she went into an irreversible coma due to the cerebral hypoxia. On Day 33, she died of pneumonia. An autopsy showed a rupture of the internal elastic layer of the coronary artery. However, no specific findings, such as aneurysm and dissection, were evident. The common atherosclerotic changes were observed. Discussion The stable condition lasting for over 2 weeks was a rare clinical course for SCAR. Long-term hypertension and dialysis would have caused the rupture of the coronary artery with common atherosclerotic changes. We should consider SCAR as one of the differential diagnoses when we observe pericardial fluid.

INTRODUCTION Pulmonary vein isolation (PVI) lesions after cryoballoon ablation (CBA) are wide and continuous, however, the distribution can depend on the pulmonary vein (PV) size. We sought to assess the relationship between the lesion distribution and PV size after CBA and hotballoon ablation (HBA). METHODS AND RESULTS A total of 80 consecutive patients who underwent PVI were enrolled (40 with CBA). The lesions were visualized by late-gadolinium enhancement magnetic resonance imaging. The lesion width, lesion gaps, and distance from the PV ostium (PVos) to distal lesion edge (DLE) were assessed. If the DLE extended inside the PV, the value was expressed as a negative value. Although the lesion width was significantly wider in the CB group (7.8 ± 2.0 vs 4.9 ± 1.0 mm, P

Background— This study sought to investigate external photon beam radiation for catheter-free ablation of the atrioventricular junction in intact pigs. Methods and Results— Ten pigs were randomized to either sham irradiation or irradiation of the atrioventricular junction (55, 50, 40, and 25 Gy). Animals underwent baseline electrophysiological evaluation, cardiac gated multi-row computed tomographic imaging for beam delivery planning, and intensity-modulated radiation therapy. Doses to the coronary arteries were optimized. Invasive follow-up was conducted ≤4 months after the irradiation. A mean volume of 2.5±0.5 mL was irradiated with target dose. The mean follow-up length after irradiation was 124.8±30.8 days. Out of 7 irradiated animals, complete atrioventricular block was achieved in 6 animals of all 4 dose groups (86%). Using the same targeting margins, ablation lesion size notably increased with the delivered dose because of volumetric effects of isodose lines around the target volume. The mean macroscopically calculated atrial lesion volume for all 4 dose groups was 3.8±1.1 mL, lesions extended anteriorly into the interventricular septum. No short-term side effects were observed. No damage was observed in the tissues of the esophagus, phrenic nerves, or trachea. However, histology revealed in-field beam effects outside of the target volume. Conclusions— Single-fraction doses as low as 25 Gy caused a lesion with interruption of cardiac impulse propagation using this respective target volume. With doses of ≤55 Gy, maximal point-doses to coronary arteries could be kept

Background: We assessed high-frequency stimulation (HFS)-induced changes in the atrial fibrillation (AF) cycle length (AFCL) in the pulmonary vein (PV) after ganglionated plexi (GP) ablation. Methods: Twenty-two patients undergoing catheter ablation for AF were retrospectively enrolled. Sites showing a vagal response (VR) to HFS were defined as GP-positive sites. AFCL was determined in the adjacent PV, distant PV, coronary sinus, and right atrium. Twenty cycles were counted before and after each HFS. After radiofrequency application to the GP site, HFS was repeated. Results: At GP-positive sites (n=57), significant shortening of the AFCL was detected in the adjacent PV (17% shortening, 165±38 to 137±27 ms, p

Background The purpose of this study is to evaluate the rate of perioperative bleeding complications following anticoagulation therapy in patients undergoing implantable electronic device implantation. Methods and results We retrospectively analyzed the data from 161 consecutive patients with new device implants or generator replacement performed between February 2008 and June 2009 in our hospital. Sixty-five (40.3%) patients took warfarin, 55 (34.2%) took antiplatelet therapy, and 16 (9.9%) took dual antiplatelet therapy prior to implantation. Heparin bridging was performed in 7 of 65 patients taking warfarin. Pocket hematoma was observed in 10 (6.2%) patients and device infection was observed in 1 (0.6%) patient. No cases of thromboembolism were observed. There were no complications associated with warfarin ( P =0.19) or antiplatelet therapy ( P =0.69). However, the patients that had undergone heparin bridging were significantly more likely to have complications (3 of 10) ( P =0.005). In multivariate analysis, heparin bridging was the only independent predictor of complications. Conclusion Our study suggests that heparin bridging increases the risk of perioperative bleeding complications in cardiac device implantation.

Functional Block in the Posterior Right Atrium. Introduction: Conduction block in the posterior right atrium (RA) plays an important role in perpetuating atrial flutter (AFL). Although conduction blocks have functional properties, it is not clear how the block line changes with the pacing rate, pacing site, and administration of antiarrhythmic drugs. Methods and Results: Forty patients with typical AFL were enrolled. Pacing (110, 170, 230 ppm) from the coronary sinus ostium (CSo) and low lateral RA was performed. After 1 mg/kg pilsicainide (pure sodium channel blockade) administration, the pacing protocol was repeated. Conduction block was assessed based on a color-coded isopotential map and 20 points of virtual unipolar electrograms in the posterior RA using noncontact mapping. Block line proportion was defined as the percentage of length of the block line between the superior and inferior vena cava. The pacing rate-dependent extension of the block proportion was significant during pacing from both sides (pacing from the CSo: 59 ± 17% at 110 ppm, 69 ± 16% at 230 ppm, P < 0.05; pacing from the low lateral RA: 43 ± 19% at 110 ppm, 55 ± 22% at 230 ppm, P < 0.05). The block line was significantly longer during CSo pacing than during low lateral RA pacing at each rate (all P < 0.05). After pilsicainide administration, the block line extended further. Conclusion: In addition to pacing rate-dependent and site-dependent changes in the block line, pilsicainide further extended the block line length. This phenomenon explains the clinical observation that counterclockwise AFL occurs more frequently than clockwise AFL, and the mechanism of class IC AFL. (J Cardiovasc Electrophysiol, Vol. 23, pp. 827-834, August 2012)

SummaryWe describe a case of a 60-year-old male with dilated phase of hypertrophic cardiomyopathy caused by Fabry disease. He was diagnosed to have a cardiac variant of Fabry disease by an enzyme assay and a right ventricular endomyocardial biopsy which revealed specific features of this disease and cardiac involvement was the sole manifestation. He has developed dilated cardiomyopathy with sustained atrial flutter and frequent non-sustained ventricular tachycardia requiring isthmus ablation and cardiac resynchronization therapy with defibrillator.

Background— Formation of microemboli during catheter ablation has been suggested as a cause for asymptomatic cerebral emboli. However, it is unknown which part of the process and ablation setting/strategy is most strongly related to this occurrence. Methods and Results— A total of 27 pigs were used. Catheter/sheath manipulations in left atrium were performed in 25 of 27 pigs outfitted with microemboli monitoring systems. Ablations using open-irrigated radiofrequency catheters were performed in 18 of 25 pigs. Two of 27 pigs did not undergo left atrial procedures and were injected with microembolic materials in the carotid artery to serve as positive controls. In total, 334 sheath/catheter manipulations (transseptal puncture, sheath flushing, catheter insertion, pulmonary vein venography, and sheath exchange) and 333 radiofrequency applications (power setting, 30/50 W; point-by-point/drag ablations) were analyzed. High microbubble volume in the extracorporeal circulation loop and a high number of microembolic signals in carotid artery were observed during sheath/catheter manipulations especially in saline/contrast injections at fast speed and ablations with steam pop. Fast sheath flushing produced significantly higher microbubble volume than slow sheath flushing (median, 12 200 versus 121 nL; P Conclusions— Formation of microbubbles was the greatest during fast saline/contrast injections and steam pops, whereas high-power radiofrequency applications, drag ablations, and steam pops produced most of the microparticles.

Background— The differences in ablation characteristics of freezing time and balloon size using second generation cryoballoon are still unknown. Methods and Results— Twenty-six dogs underwent pulmonary vein (PV) isolation. Balloon and tissue temperatures (left atrial–PV junction, phrenic nerve, and internal esophagus) were monitored. The ablation duration was randomized to either 3 or 4 minutes, which did not show significant differences in temperature profiles, PV isolation success rate, complications, or histological changes. Twenty dogs underwent cryoablation using 28-mm cryoballoon, 6 dogs were done using the 23-mm cryoballoon. Positioning of the 23-mm cryoballoon was more distal in the PV, which resulted in better PV occlusion. Temperature profiles showed lower temperatures in the 23-mm cryoballoon than in the 28-mm cryoballoon (inner balloon, median [range]: −51.5 [−66.0 to −31.0] versus −43.0 [−64.0 to −26.0]°C, P P P Conclusions— The efficacy of 3-minute ablation was not significantly different from 4-minute ablation in dogs. The 23-mm cryoballoon had a greater cooling effect than the 28-mm cryoballoon for small PVs, but showed narrower ablative lesions in the left atrial antrum.

Background— Particle therapy, with heavy ions such as carbon-12 ( 12 C), delivered to arrhythmogenic locations of the heart could be a promising new means for catheter-free ablation. As a first investigation, we tested the feasibility of in vivo atrioventricular node ablation, in Langendorff-perfused porcine hearts, using a scanned 12C beam. Methods and Results— Intact hearts were explanted from 4 (30–40 kg) pigs and were perfused in a Langendorff organ bath. Computed tomgraphic scans (1 mm voxel and slice spacing) were acquired and 12 C ion beam treatment planning (optimal accelerator energies, beam positions, and particle numbers) for atrioventricular node ablation was conducted. Orthogonal x-rays with matching of 4 implanted clips were used for positioning. Ten Gray treatment plans were repeatedly administered, using pencil beam scanning. After delivery, positron emission tomography-computed tomgraphic scans for detection of β + ( 11 C) activity were obtained. A 12 C beam with a full width at half maximum of 10 mm was delivered to the atrioventricular node. Delivery of 130 Gy caused disturbance of atrioventricular conduction with transition into complete heart block after 160 Gy. Positron emission computed tomgraphy demonstrated dose delivery into the intended area. Application did not induce arrhythmias. Macroscopic inspection did not reveal damage to myocardium. Immunostaining revealed strong γH2AX signals in the target region, whereas no γH2AX signals were detected in the unirradiated control heart. Conclusions— This is the first report of the application of a 12 C beam for ablation of cardiac tissue to treat arrhythmias. Catheter-free ablation using 12C beams is feasible and merits exploration in intact animal studies as an energy source for arrhythmia elimination.

Background: The upper lim it of vulnerability (UL V) closely correlates with the defibrillation threshold (OFT) . The aim of th is study was to establish the optimal protocol for using the UL V test to predict high OFT (>20 J) without inducing ventricular fibrillation (VF) . Methods and Results: The 10-J and 15-J ULV test with 3 coupling intervals (-20, 0, and +20ms to the peak of T-wave) and the OFT test were performed in 96 patients receiving implantable cardioverter defibrillator. ULV ::; 10J was confirmed in 47 (49%). ULV ::; 15J was confirmed in 70 (77%) of 91 patients (15-J ULV test could not be done in 5). The sensitivity and negative predictive value of both ULV > 1 OJ and> 15J for predicting high OFT were 100%. The specificity and positive predictive value of ULV > 15 J were higher than those for ULV > 1 OJ (85% vs. 55%, 43% vs. 22%, respectively). The rate of VF inducibility for confirming ULV ::; 15J was lower than that for ULV ::; 10J (23% vs. 51 %, P

Slow pathway (SP) ablation of atrioventricular (AV) nodal reentrant tachycardia (AVNRT) can be complicated by unexpected AV block even at sites10 mm inferior to the bundle of His (HB), and one cause is thought to be the inferior dislocation of an antegrade fast pathway (A-FP). We assessed locations of FPs guided by CARTO.Sites of FPs were mapped guided by CARTO before SP ablation in 18 patients with slow-fast AVNRT. The A-FP was defined as the site with the minimum interval between the stimulus and HB potential when pace mapping in the right atrial septum.The A-FP was 7.9 ± 7.5 mm inferior and 2.9 ± 5.0 mm posterior to the HB. In 6 of 18 patients (33%), the A-FP was inferiorly dislocated10 mm to the HB. SP ablation was successfully performed in all patients at sites10 mm from both the HB and the A-FP without AV block. In the inferiorly dislocated A-FP group, A-FPs seemed to be positioned much more on atrial sites and sufficiently posterior to SP ablation sites.The A-FP inferiorly dislocated10 mm to the HB in one third of patients with AVNRT and seemed to be positioned deep on atrial sites. It is again emphasized that SP ablation within the triangle of Koch should be performed at a very ventricular annulus site, particularly in the inferiorly dislocated A-FP group.

Background: The posteromedial right atrium (PMRA) forms a block line during typical atrial flutter (AFL). However, whether upper turnover portion exists at the anterior or posterior superior vena cava (SVC) has not been determined. Methods: We performed right atrial mapping during AFL in 20 patients (typical AFL, n = 17; reverse typical AFL, n = 3) using an electroanatomical mapping system. Results: Mean AFL cycle length was 224 ± 20 ms and mean number of mapping points was 140 ± 27. PMRA formed a block line during both typical and reverse AFL in all patients. However, in 16 of 17 patients mapped with typical AFL, PMRA did not extend superiorly to the orifice of the SVC and AFL wave propagated between the upper limit of the PMRA and the posterior SVC. In the remaining patient mapped with typical AFL, a double potential was recorded along the PMRA continuously between the orifices of the inferior vena cava (IVC) and SVC. In the three patients mapped with reverse typical AFL, a posterior barrier was detected from IVC to the upper limit of the PMRA and AFL wave propagated between the upper limit of the PMRA and the posterior SVC. Mean length from IVC to upper limit of the PMRA was 81 ± 8% of the length from IVC to SVC. Conclusions: PMRA forms a functional block line during both typical and reverse typical AFL. The upper turnover portion of reentry circuit for AFL was observed between the upper limit of the PMRA and the posterior SVC in the majority of isthmus-dependent AFL patients.

Mitral isthmus (MI) ablation is challenging. Blood flow in the CS and circumflex artery (LCx) may act as a heat sink and reduce the efficacy of radiofrequency ablation. Ablation in the CS also has the risk of injury to the LCx. We have reported to be able to visualize the precise anatomical characteristics between CS and LCx on MI obtained by MDCT. The aim of this study was to evaluate usefulness of MDCT guided MI ablation. Methods: Twenty patients (14 males, 61±11 y) whose CS and LCx images could be obtained simultaneously by MDCT were included in this study. We performed MI ablation between LIPV and the mitral annulus. The strategy for MDCT guided MI ablation were 1. MI line was designed just below LAA, 2. In case of LCx below CS, MI line was designed proximal the crossing point of LCX and CS, and 3. If LCX is presence on MI, MI line designed more laterally on comparatively peripheral LCX. Irrigated-tip catheters were used during MI ablation with the following settings: endocardial surface (maximum power: 40 W); CS (maximum power: 20 W). Results: The MI was blocked in 94.5% (19/20) of patients with 594±293 seconds of radiofrequency application. The epicardial ablation inside the CS was required in 45% (9/20) patients. No complications occurred. Conclusion: The MDCT guided MI ablation resulted in a high success rate of MI block without complications.

Purpose: Non-pulmonary vein (PV) foci are sometimes difficult to identify and eliminate. This study aimed to characterize non-PV foci using the EnSite array or NavX system. Methods and Results: 138 patients with atrial fibrillation (AF) were included. All patients underwent PV isolation and additional ablation of non-PV foci if present. We revealed 17 non-PV foci in 15 patients. Nine foci induced AF and 8 foci showed more than 3 beats firing. Eight foci occurred spontaneously and the others were induced by low dose of isoproterenol (0.5γ, n=1) or high dose (≥10γ, n=8). The non-PV foci were distributed in the SVC (n=9, 50%), left atrium (LA) (n=5, 29%; 2 anterior wall, interatrial septum, appendage and mitral annulus), right atrium (RA) (n=3, 18%; lateral, posterolateral, anterolateral). 2nd session ablation was required in 36 patients (26%) and 31 patients had LA-PV reconnection. We revealed 16 non-PV foci in 14 patients in the 2nd session. Only one patient had non-PV foci recurrence from SVC. The others were firing at the different site from 1st session. Conclusion: The site of Non-PV foci was half in the SVC and each quarter in the LA and RA. The distribution of LA foci was various while RA foci existed near lateral side. If non-PV foci were successfully terminated, other foci may cause the recurrence of atrial fibrillation.

The Ganglionated Plexi (GP) and complex fractionated atrial electrograms (CFAE) play the important role as the perpetuator of atrial fibrillation (AF). GP ablation is known as alternative procedure for AF. The aim of this study was to evaluate the contrast between the area of the GP and CFAE. Method: Ten consecutive patients with AF were studied. For patients with sinus rhythm, AF was induced by rapid atrial pacing. The geometry of Left atrium (LA) was reconstructed with electroanatomical mapping system (CARTO XP). Bipolar electrograms recorded during 2.5 second were analyzed using CFAE software module. The algorism was customized to demonstrate the classification as follows in Interval confidence level (ICL) map. Sites with continuous or transient fractionated atrial potentials were colored red. Sites with irregular amplitude, polarity, cycle length but not rapid were colored green. Sites with slow organized atrial potential were purple. The sites where vagal response was evoked by high-frequency stimulation were identified as GP sites and marked on the geometry. Result: A total of 1,107 points were taken in LA. Among a total of 197 GP points, 139 (77.2%) points were in colored red and categorized as in CFAE area. GP points in colored purple categorized as in slow organized area were only 4 points (2.3%). Conclusion: The Ganglionated Plexi is strongly related to CFAE.

The antifibrillatory effect of ganglionated plexi (GP) ablation is not well established. The aim of this study was to evaluate the factors associated with termination during GP ablation in patient with paroxysmal AF. Methods: Thirty-two consecutive paroxysmal AF patients (age 61±10 years, 25 male) who underwent the selective GP ablation guided by high frequency stimulation (HFS) were enrolled in this study. The five major left atrial GP were localized by delivering HFS (20 Hz, 20 V, 10 ms pulse width). Radiofrequency current is then applied to that site to eliminate the parasympathetic response. We ablated GP first, and antrum PV electrical isolation (APVI) adjunctively. We measured cycle length (CL) in each PV, left atrial appendage (LAA), coronary sinus (CS), RA, during AF before any ablation. We investigated the termination of AF in relation with GP ablation. Results: AF was induced and sustained in 29 patients. AF terminated during GP ablation in 14 patients (48%), during APVI in 6 patients (21%). Two of 3 patients without sustained AF had SVC foci. The LAA and CS AFCL (142±22 ms, 138±19 ms) in 9 patients without termination were shorter than that in 20 patients with termination (170±33 ms, 171±27 ms, p

Background Noncontact mapping is useful for the diagnosis of various arrhythmias. Virtual unipolar electrogram morphologies (VUEM) of the conduction block and the turnaround points, however, are not well defined. We compared the VUEM characteristics of a transverse conduction block in the posterior right atrium (RA) with those of contact bipolar electrograms obtained during typical atrial flutter (AFL). Methods Contact bipolar electrograms were used to map the posterior RA during typical AFL in 16 patients. Twenty points of the VUEM recorded along the block line were analyzed and compared with contact bipolar electrograms. Results Seventeen AFLs were analyzed. Fifteen AFLs showed an incomplete transverse conduction block in the posterior RA by contact bipolar mapping. A double potential on the block line corresponded to the two components of the VUEM, in which the second component showed an Rs, RS, or rS pattern. At the turnaround point, a fused double potential of the contact bipolar electrograms corresponded to a change of the second component of the VUEM from an rS to a QS morphology. Two AFLs showed a complete block line in the posterior RA. The contact bipolar electrogram showed double potentials from the inferior vena cava to the superior vena cava, whereas the second component of the VUEM remained in an unchanged Rs, RS, or rS pattern. Conclusion VUEM analysis was a reliable method for identifying the posterior block line during AFL. This method may also be applicable for detecting block lines and turnaround points of circuits in other unmappable arrhythmias.

Purpose Dabigatran is effective for both the prevention of stroke and bleeding in patients with atrial fibrillation (AF). However, the safety and efficacy of the use of dabigatran in the peri-procedural period for radiofrequency catheter ablation (RFCA) of AF is unknown. Therefore, the purpose of this study was to evaluate the safety and efficacy of dabigatran in the peri-procedural period for RFCA of AF and the duration of hospital stay. Methods Consecutive patients (n = 227) who underwent RFCA for AF were prospectively analyzed. Peri-procedural anticoagulant therapy with dabigatran (n = 101, D group) was compared with warfarin and heparin bridging (n = 126, W group). Dabigatran was discontinued 12–24 h before and restarted 3 h after the procedure. Warfarin was stopped 3 days before the procedure and unfractionated heparin was administered. Results Ischemic stroke occurred in one patient of the D group (0.8 %). There was no significant difference between the two groups in the incidence of major bleeding (three cases of cardiac tamponade in each group and one case of intracranial bleeding in the W group, p = 0.93) or minor bleeding (five cases in the D group vs. five in the W group, p = 0.54). The duration of hospital stay was significantly shorter in the D group than in the W group (7.2 vs. 10.3 days, p = 0.0001). Conclusions Peri-procedural anticoagulation therapy with dabigatran for RFCA of AF was equally safe and effective compared with warfarin and heparin bridging. The use of dabigatran for RFCA of AF shortened the duration of hospital stay.