Safety and Performance of the Micra VR Leadless Pacemaker in a Japanese Cohort　- Comparison With Global Studies.

BACKGROUND: The Micra leadless pacemaker has demonstrated favorable outcomes in global trials, but its real-world performance and safety in a Japan-specific population is unknown.Methods and Results: Micra Acute Performance (MAP) Japan enrolled 300 patients undergoing Micra VR leadless pacemaker implantation in 15 centers. The primary endpoint was the acute (30-day) major complication rate. The 30-day and 6-month major complication rates were compared to global Micra studies. All patients underwent successful implantation with an average follow-up of 7.23±2.83 months. Compared with previous Micra studies, Japanese patients were older, smaller, more frequently female, and had a higher pericardial effusion risk score. 11 acute major complications were reported in 10 patients for an acute complication rate of 3.33% (95% confidence interval: 1.61-6.04%), which was in line with global Micra trials. Pericardial effusion occurred in 4 patients (1.33%; 3 major, 1 minor). No procedure or device-related deaths occurred. Frailty significantly improved from baseline to follow-up as assessed by Japan Cardiovascular Health Study criteria. CONCLUSIONS: In a Japanese cohort, implantation of the Micra leadless pacemaker had a high success rate and low major complication rate. Despite the Japan cohort being older, smaller, and at higher risk, the safety and performance was in line with global Micra trials.

Long-term outcomes of percutaneous revascularization for internal mammary artery-left anterior descending artery bypass failure.

Despite the excellent long-term results of internal mammary artery (IMA)-left anterior descending (LAD) bypass, percutaneous revascularization of IMA is sometimes required for IMA-LAD bypass failure. However, its clinical outcomes have not been fully elucidated. The aim of this study was to investigate the long-term clinical outcomes, including target lesion revascularization (TLR) following contemporary percutaneous revascularization of failed IMA bypass graft. We examined data of 59 patients who had undergone percutaneous revascularization of IMA due to IMA-LAD bypass failure at nine hospitals. Patients with IMA graft used for Y-composite graft or sequential bypass graft were excluded. The incidence of TLR was primarily examined, whereas other clinical outcomes including cardiac death, myocardial infarction, and target vessel revascularization were also evaluated. Mean age of the enrolled patients was 67.4 ± 11.3 years, and 74.6% were men. Forty patients (67.8%) had anastomotic lesions, and 17 (28.8%) underwent revascularization within three months after bypass surgery. Procedural success was achieved in 55 (93.2%) patients. Stent implantation was performed in 13 patients (22.0%). During a median follow-up of 1401 days (interquartile range, 282-2521 days), TLR was required in six patients (8.5% at 1, 3, and 5 years). Patients who underwent percutaneous revascularization within 3 months after surgery tended to have a higher incidence of TLR. Clinical outcomes of IMA revascularization for IMA-LAD bypass failure were acceptable.

HotBalloon Pulmonary Vein Isolation Registry Study　- Real-World Efficacy and Safety of HotBalloon Ablation.

BACKGROUND: Radiofrequency hotballoon (RHB) is an ablation device used for atrial fibrillation (AF) treatment. The efficacy and safety of RHB-based pulmonary vein isolation (PVI) in real-world practice are unknown.Methods and Results: A multicenter, prospective registry study (UMIN000029567) enrolled AF patients who underwent RHB-PVI. The primary endpoint was the AF recurrence-free survival rate at 12 months after PVI. Of the 679 patients enrolled, 613 (90.3%; paroxysmal AF, n=370; persistent AF, n=136; long-standing AF, n=107) underwent initial RHB-PVI. Acute isolation using only the RHB was successful for 55.6% of patients and 83.5% of pulmonary veins (PVs). The acute isolation rate was higher for patients with paroxysmal AF and more experienced centers. Antiarrhythmic drugs were prescribed after 3 months for 47.5% of patients. The AF recurrence-free survival rate at 12 months was 83.7%. Procedure-related complications including atrio-esophageal fistula (n=1) and phrenic nerve injury (persistent; n=4, permanent; n=2) were observed in 19 (3.1%) patients. Five (1.7%) of the 302 patients who underwent pre-procedural and post-procedural multidetector computed tomography had severe PV stenosis. CONCLUSIONS: The size-adjustable RHB has been used for the treatment of various AF types. The arrhythmia recurrence-free rate at 12 months, with the use of antiarrhythmic drugs in approximately half of the patients, was acceptable, but the acute isolation rate using the RHB requires further improvement.

Efficacy and Safety of SATAKE HotBalloon® Catheter for Treatment of Paroxysmal Atrial Fibrillation　- A Post-Marketing Surveillance Study.

BACKGROUND: SATAKE HotBalloon®catheter (HBC) is a radiofrequency balloon catheter for the treatment of atrial fibrillation (AF), and was approved for use in Japan to treat drug-resistant paroxysmal AF in 2015. Post-marketing surveillance study was conducted by Toray Industries, Inc. to evaluate the efficacy and safety of HBC treatment in patients with paroxysmal AF in a real-world setting. This study is the first nation-wide survey of HBC treatment for paroxysmal AF in clinical practice in Japan.Methods and Results:This was a single-arm, multicenter observational study with an observation period of 48 weeks after ablation. Pulmonary vein isolation and AF non-recurrence rates were evaluated and adverse events (AEs) were observed at 46 sites in Japan. An AF event was defined as recurrence of AF or re-ablation from 12 to 48 weeks after ablation. The success rate of pulmonary vein isolation was 99.0% (486/491) for patients with AF. The cumulative AF non-recurrence rate was 94.1% at 24 weeks and 87.8% at 48 weeks. AEs were found to occur 21.5% (114/530), and ablation-related AEs were found to occur 2.6% (14/530) during the study period, with the most common being pericardial effusion (0.8%, 4/530). CONCLUSIONS: This study demonstrates the efficacy and safety of HBC ablation in Japanese patients with recurrent symptomatic paroxysmal AF refractory to antiarrhythmic therapy.

Associations of coronary plaque characteristics by integrated backscatter intravascular ultrasound with detectability of vessel external elastic lamina using optical frequency domain imaging in human coronary arteries: A sub-analysis of the MISTIC-1 trial.

OBJECTIVES: We sought to examine associations between plaque characteristics by intravascular ultrasound (IVUS) and detectability of external elastic lamina (EEL) by optical frequency domain imaging (OFDI) in human coronary arteries. BACKGROUND: It is often challenging to detect EEL which represents vessel size by light-based imaging modalities due to light intensity attenuation through atherosclerotic plaque. METHODS: IVUS and OFDI prior to stent implantation were sequentially investigated per protocol. We identified corresponding cross-sections by minimum lumen area (MLA) or just distally to side branches as anatomical landmarks. Plaque characterization was determined by integrated backscatter IVUS analysis. We categorized detectable EEL arc by OFDI into four groups: 0≤ and <1 quadrant (group 1), 1≤ and <2 quadrants (group 2), 2≤ and <3 quadrants (group 3), or 3≤ and <4 quadrants (group 4). RESULTS: We prospectively studied 103 vessels in 93 patients with stable coronary artery disease. Corresponding 711 cross-sections were analyzed. Cross-sections with detectable EEL arc <2 quadrants (group 1 or 2) were observed in 86.1% of MLA sites but only in 29.3% of non-MLA sites (p < .05). Percentage plaque area (%PA) appeared to be the strongest predictor to detect EEL arc <2 quadrants with the cut-off of 60.3% (AUC 0.90; sensitivity 79.8%, specificity 85.5%). Lipid pool and calcification remained statistically significant in predicting detectable EEL arc <2 quadrants after adjustment with %PA. CONCLUSIONS: Presence of large plaque burden, lipid pool, and calcification significantly predicts the detectability of EEL by OFDI assessment. Locations with detectable EEL arc <2 quadrants should thus be avoided for optimal stent landing zone.

Differences in prothrombotic response between the uninterrupted and interrupted apixaban therapies in patients undergoing cryoballoon ablation for paroxysmal atrial fibrillation: a randomized controlled study.

Periprocedural bleeding and thromboembolic events are worrisome complications of catheter ablation for atrial fibrillation (AF). Periprocedural anticoagulation management could decrease the risk of these complications. However, evaluation of the complications from pulmonary vein isolation using cryoballoon related to different anticoagulation strategies is limited. Therefore, we aimed to compare prothrombotic responses as assessed on the basis of D-dimer levels between the uninterrupted and interrupted apixaban therapies during cryoballoon ablation. Ninety-seven consecutive patients with paroxysmal AF scheduled to undergo cryoballoon ablation were randomly assigned in a 1:2 ratio to uninterrupted apixaban therapy (Group 1, n = 32) or interrupted apixaban therapy (Group 2, n = 65). D-Dimer levels were measured immediately before the ablation, at the end of the ablation, and 24 and 48 h after the procedure. No statistical difference was observed in the baseline characteristics between the two groups. The rates of hemorrhagic complications were similar in both groups (major bleeding: 3.1 vs. 1.5%; p = 0.61, and minor bleeding: 3.1 vs. 4.6%; p = 0.73, respectively). No thromboembolic events occurred in either group. However, D-dimer levels 48 h after the ablation increased more markedly following the procedure in Group 2 than in Group 1 (from 0.58 ± 0.16 to 1.01 ± 0.42 µg/mL vs. 0.58 ± 0.20 to 0.82 ± 0.25 µg/mL; p = 0.01). In conclusion, uninterrupted apixaban therapy during the periprocedural period of cryoballoon ablation for AF did not increase the risk of bleeding in this study and might reduce the periprocedural risk of subclinical hypercoagulable state.

Correction to: Differences in prothrombotic response between the uninterrupted and interrupted apixaban therapies in patients undergoing cryoballoon ablation for paroxysmal atrial fibrillation: a randomized controlled study.

In the original publication of the article, the table 2 was published incorrectly.

Head-to-head comparison of acute and chronic pulmonary vein stenosis for cryoballoon versus radiofrequency ablation.

BACKGROUND: Cryoballoon (CB) applications to pulmonary veins (PVs) can cause stenosis just as radiofrequency (RF) energy deliveries. The goal of the present study was to clarify whether or not there was any difference in the extent of acute or chronic PV narrowing after PV isolation between the two different energy sources. METHODS: Consecutive patients with paroxysmal atrial fibrillation who were scheduled to undergo a PV isolation were randomized 1:1 to receive CB or RF ablation. The endpoints were any acute PV narrowing assessed with the use of intracardiac ultrasound during the procedure and PV stenosis measured with cardiac computed tomography at the 3-month follow-up. RESULTS: An acute reduction in the luminal area of the left superior PV (mean ± standard deviation, -6.8 ± 8.7 vs -19.9 ± 14.7%; P < 0.001) and left inferior PV (-5.1 ± 20.2 vs -15.3 ± 11.6%; P = 0.03) was significantly smaller in the CB arm (N = 25) than the RF arm (N = 25). There was no difference in the extent of PV stenosis 3 months after the ablation between the arms (0-25% stenosis, 90% vs 88%, 25-50% stenosis, 10% vs 12%, >50% stenosis, both 0%; P = 0.82). A greater acute PV narrowing was likely to lead to chronic stenosis in the RF arm (P = 0.004). CONCLUSIONS: CB ablation may reduce the acute narrowing of the left-sided PVs as compared to RF ablation.

Cardiac resynchronization therapy for patients with cardiac sarcoidosis.

Aims: Sarcoidosis with cardiac involvement is a rare pathological condition, and therefore cardiac resynchronization therapy (CRT) for patients with cardiac sarcoidosis is even further rare. We aimed to clarify the clinical features of patients with cardiac sarcoidosis who received CRT. Methods and results: We retrospectively reviewed the clinical data on CRT at three cardiovascular centres to detect cardiac sarcoidosis patients. We identified 18 (8.9%) patients with cardiac sarcoidosis who met the inclusion criteria out of 202 with systolic heart failure who received CRT based on the guidelines. The majority of the patients were female [15 (83.3%)] and underwent an upgrade from a pacemaker or implantable cardioverter defibrillator [13 (72.2%)]. We found 1 (5.6%) cardiovascular death during the follow-up period (mean ± SD, 4.7 ± 3.0 years). Seven (38.9%) patients had a composite outcome of cardiovascular death or hospitalization from worsening heart failure within 5 years after the CRT. Twelve (66.7%) patients had a history of sustained ventricular arrhythmias or those occurring after the CRT. Among the overall patients, no significant improvement was found in either the end-systolic volume or left ventricular ejection fraction (LVEF) 6 months after the CRT. A worsening LVEF was, however, more likely to be seen in 5 (27.8%) patients with ventricular arrhythmias after the CRT than in those without (P = 0.04). An improved clinical composite score was seen in 10 (55.6%) patients. Conclusions: Cardiac sarcoidosis patients receiving CRT may have poor LV reverse remodelling and a high incidence of ventricular arrhythmias.

Who is the operator, that is the question: a multicentre study of catheter ablation of atrial fibrillation.

AIMS: A worldwide survey reported that the success rate of atrial fibrillation (AF) ablation was higher in high-volume centers compared with low-volume centers. We tested whether the procedure volume of each operator was associated with the outcome of AF ablation in high-volume centres. METHODS AND RESULTS: We studied 471 patients with paroxysmal AF who underwent pulmonary vein (PV) isolation for the first time in three cardiovascular centers where the annual AF ablation volume was >100 procedures. We classified a total of 10 primary operators according to their operation volume on the basis of ACC/AHA/ACP CLINICAL COMPETENCE STATEMENT; high-volume operator (≥50 cases/year, N = 3) or low-volume operator (<50 cases/year, N = 7). The patients included were dichotomized according to the annual operation volume of their attending physician. The endpoints were the freedom from AF recurrence 1 year after the ablation, major complications including thromboembolisms, massive bleeding or death, and the procedural duration. RESULTS: A complete isolation of the four PVs was achieved in 99.1%. The freedom from AF recurrence was more common in patients treated by high-volume operators than those treated by low-volume operators (165/216 [76.4%] vs. 160/255 [62.8%]; P = 0.001). A high-volume operator was the only independent predictor of the freedom from AF recurrence (hazard ratio 1.73, 95% confidence interval 1.23-2.48; P = 0.002). The patients treated by high-volume operators were less likely to have major complications (1.4% vs. 7.8%; P = 0.001), and had a shorter procedural duration (139.9 ± 25.3 vs. 149.3 ± 27.1 min; P = 0.03). CONCLUSIONS: Operator proficiency may predict the outcome after AF ablation even in high-volume centres.

A nonsynonymous polymorphism in semaphorin 3A as a risk factor for human unexplained cardiac arrest with documented ventricular fibrillation.

Unexplained cardiac arrest (UCA) with documented ventricular fibrillation (VF) is a major cause of sudden cardiac death. Abnormal sympathetic innervations have been shown to be a trigger of ventricular fibrillation. Further, adequate expression of SEMA3A was reported to be critical for normal patterning of cardiac sympathetic innervation. We investigated the relevance of the semaphorin 3A (SEMA3A) gene located at chromosome 5 in the etiology of UCA. Eighty-three Japanese patients diagnosed with UCA and 2,958 healthy controls from two different geographic regions in Japan were enrolled. A nonsynonymous polymorphism (I334V, rs138694505A>G) in exon 10 of the SEMA3A gene identified through resequencing was significantly associated with UCA (combined P = 0.0004, OR 3.08, 95%CI 1.67-5.7). Overall, 15.7% of UCA patients carried the risk genotype G, whereas only 5.6% did in controls. In patients with SEMA3A(I334V), VF predominantly occurred at rest during the night. They showed sinus bradycardia, and their RR intervals on the 12-lead electrocardiography tended to be longer than those in patients without SEMA3A(I334V) (1031±111 ms versus 932±182 ms, P = 0.039). Immunofluorescence staining of cardiac biopsy specimens revealed that sympathetic nerves, which are absent in the subendocardial layer in normal hearts, extended to the subendocardial layer only in patients with SEMA3A(I334V). Functional analyses revealed that the axon-repelling and axon-collapsing activities of mutant SEMA3A(I334V) genes were significantly weaker than those of wild-type SEMA3A genes. A high incidence of SEMA3A(I334V) in UCA patients and inappropriate innervation patterning in their hearts implicate involvement of the SEMA3A gene in the pathogenesis of UCA.

Clinical Characteristics and Long-Term Outcomes of Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) has various morphological and clinical features. A decade has passed since the previous survey of the epidemiological and clinical characteristics of Japanese HCM patients. The Aichi Hypertrophic Cardiomyopathy (AHC) Registry is based on a prospective multicenter observational study of HCM patients. The clinical characteristics of 42 ambulant HCM patients followed up for up to 5 years were investigated. The primary endpoint was major adverse cardiac events (MACE), defined as death, non-fatal stroke, admission due to congestive heart failure (CHF), or episodes of sustained ventricular tachycardia/fibrillation. The MACE-free survival during the 5-year follow-up period was 76% according to Kaplan-Meier analysis. HCM-related death occurred in 3 (7%) patients and SCD occurred in 2 (5%) patients. Additionally, 3 (7%) patients were admitted to the hospital due to CHF. Meanwhile, sustained VT was detected in one (2%) of the patients who received ICD implantation and subsequently terminated with antitachycardia pacing using an ICD. The patients with HCM exhibiting left ventricular outflow obstruction (HOCM) had a slightly lower MACE-free survival rate than those with neither HOCM nor dilated-HCM (dHCM) (71% versus 81%, log-rank P = 0.581). Furthermore, the patients with dHCM demonstrated a significantly lower MACE-free survival rate than those with neither HOCM nor dHCM (33% versus 81%, log-rank P = 0.029). In the AHC Registry targeting current Japanese HCM patients, we demonstrated that many HCM patients continue to suffer from MACE despite the development of various treatments for HCM.

Procedural sedation with dexmedetomidine during ablation of atrial fibrillation: a randomized controlled trial.

AIMS: Procedural sedation by non-anaesthesiologists with GABAergic anaesthetics has the potential risk of fatal respiratory depression. Dexmedetomidine works its sedative action via α2-adrenergic receptors, and is less associated with respiratory depression. We tested the usability of dexmedetomidine as a procedural sedative during ablation of atrial fibrillation (AF). METHODS AND RESULTS: Consecutive patients were randomized to be treated with dexmedetomidine (n = 43) or thiamylal (n = 44) as sedatives during AF ablation. Apnoeic and body movement events were monitored using a novel portable respiratory monitor, the SD-101, during the procedure. Although the majority of the patients receiving dexmedetomidine required rescue sedations with thiamylal, the respiratory disturbance index (RDI) defined as the total number of sleep-disordered breathing events divided by the recording time (10.4 ± 5.1 vs. 18.2 ± 8.1 events/h; P < 0.0001) and movement index defined as the number of body movement events per hour (7.6 ± 6.1 vs. 11.0 ± 5.5 events/h; P = 0.0098) were both significantly lower in the dexmedetomidine arm than in the thiamylal arm. A multivariate linear regression analysis including potential factors revealed that dexmedetomidine vs. thiamylal was solely and independently associated with the RDI (ß = -0.62; P = 0.0031). The occurrence of hypotension [9 (21%) vs. 4 (9%); P = 0.14] and bradycardia [4 (9%) vs. 4 (9%); P = 1.0] were similar in the patients with dexmedetomidine and thiamylal. CONCLUSION: Procedural sedation with dexmedetomidine may assure safety and patient immobility during AF ablation, and therefore may be a potential alternative for that with GABAergic anaesthetics.

Patterns of pulmonary vein potential disappearance during encircling ipsilateral pulmonary vein isolation can predict recurrence of atrial fibrillation.

BACKGROUND: The relationship between pulmonary vein (PV) potential (PVP) disappearance patterns during encircling ipsilateral pulmonary vein isolation (EIPVI) of atrial fibrillation (AF), and outcome was examined. METHODS AND RESULTS: A total of 352 consecutive AF patients (age, 61±12 years; 269 men, 76.4%; paroxysmal AF, n=239; persistent AF, n=73; and long-standing persistent AF, n=40) who underwent initial AF ablation were studied. After EIPVI with a double Lasso technique, pacing was performed from the PV carina to confirm isolation of the carina. PVP disappearance patterns were classified into 3 types: A, both superior and inferior PVP disappeared simultaneously; B, superior and inferior PVP disappeared separately; and C, additional RF applications were required inside the encircling lesions to eliminate the PVP after creating anatomical encircling lesions. The relationship between these patterns and outcome was examined. Six groups were defined according to the combination of right and left ipsilateral PVP disappearance patterns. The incidence of A-A, A-B, B-B, A-C, B-C, and C-C was 7.1%, 14.2%, 16.2%, 15.3%, 27.3%, and 19.9%, respectively. AF recurrence-free rate at 2 years for these 6 groups was 96%, 81%, 78%, 64%, 64%, and 59%, respectively (P<0.02). The incidence of a carina isolation was 153/154 (99.4%) for type A, 221/259 (85.3%) for type B, and 145/290 (50.0%) for type C. CONCLUSIONS: PVP disappearance pattern during EIPVI was significantly associated with the incidence of residual PV carina conduction and AF recurrence.

Periprocedural coagulability in patients undergoing ablation of atrial fibrillation: lessons from a periablation anticoagulation strategy of a brief withdrawal of warfarin without heparin bridging.

We aimed to examine what becomes of the coagulable state when warfarin is interrupted in patients undergoing ablation of atrial fibrillation (AF). We studied 62 patients with a CHADS2 score of 0 or 1 who underwent ablation for paroxysmal AF. Warfarin was discontinued the day before the ablation without heparin-bridging, and intravenous heparin was administered during the procedure in a conventional manner, and warfarin was then resumed after achieving hemostasis of the access site. The international normalized ratio (INR) values or D-dimer levels were measured at five different time points during the periprocedural period, and the periprocedural hemorrhagic and thromboembolic complications were assessed. The INR value constantly decreased after withdrawal of warfarin, and did not recover to the level before its discontinuation at the time of hospital discharge despite a short interruption of warfarin (mean ± SD, 1.75 ± 0.52 to 1.41 ± 0.27, p < 0.0001). However, the D-dimer level continued to increase over a period of 48 h after the ablation in spite of the administration of a sufficient amount of heparin during the procedure and a quick resumption of warfarin (mean ± SD, 0.57 ± 0.19 to 0.85 ± 0.36 µg/mL, p < 0.0001). The INR value measured just before the ablation had a significant inverse correlation to the D-dimer levels assessed just before (r = -0.304), immediately after (r = -0.440), 24 h after (r = -0.442) and 48 h after the ablation (r = -0.463). In conclusion, the risk of hyper-coagulability may increase during the early postprocedural period of AF ablation in patients who were inappropriately anticoagulated with warfarin.

Impact of pulmonary vein isolation on fractionated atrial potentials and ganglionated plexi in patients with persistent atrial fibrillation.

Some patients with persistent atrial fibrillation (AF) acquire long-term freedom from AF by pulmonary vein (PV) isolation alone. The aim of the present study was to evaluate the characteristics of their atrial substrate.We studied 20 patients with persistent AF to examine the distribution of fractionated atrial potentials (FAP) and that of the anatomic sites of ganglionated plexi (GPs) with vagal reflexes elicited by high frequency stimulation (HFS) with the use of the CARTO system before and after the PV isolation.Both the %FAP area defined as a proportion of the FAP area to the total left atrial area (34.3 ± 10.3 to 21.5 ± 10.2%; P < 0.0001) and number of GP sites with vagal reflexes (4.0 [3.0, 5.0] to 2.0 [1.0, 2.8]; P < 0.0001) were markedly decreased after the PV isolation. Seven (35%) patients had AF recurrences, and they had a greater %FAP area after the PV isolation than those without (32.8 [22.1, 37.3] versus 13.8 [10.9, 19.9]%; P = 0.0049). A %FAP area after the PV isolation of > 20% was significantly associated with an AF recurrence (odds ratio 20.0, 95% confidence interval 2.26470.34; P = 0.018). No significant difference was found between the patients with and without AF recurrence in the reduction rate of anatomic sites of GPs with a vagal reflex induced by the HFS.A more marked reduction in the FAP area by the PV isolation was significantly associated with a better outcome in patients with persistent AF.

The incidence and clinical significance of non-isolation of the pulmonary vein carina after encircling ipsilateral pulmonary veins isolation for paroxysmal atrial fibrillation: a pitfall of the double-Lasso technique.

AIMS: Encircling ipsilateral pulmonary veins (PVs) isolation (EIPVsI) with the double-Lasso technique has proven to be effective to cure atrial fibrillation (AF). However, in this technique, PV mapping with circular catheters may miss a non-isolation of the PV carina. The purpose of this study was to reveal the incidence and clinical significance of a non-isolation of the PV carina after EIPVsI. METHODS AND RESULTS: We studied 81 consecutive paroxysmal AF patients (age 61 ± 12 years, 56 men), in whom EIPVsI was successfully performed in one encircling line with the endpoint of the demonstration of bidirectional conduction block between the PVs and left atrium (LA) with the double-Lasso technique. After a successful EIPVsI, pacing from the PV carina was performed and it captured the LA in 17 (21.0%) patients. During a mean follow-up period of 19 ± 13 months, AF recurred in 13 (16.0%) patients. A multivariate Cox proportional analysis revealed that a non-isolation of the PV carina after the EIPVsI was a significant predictor (hazard ratio = 3.91, 95% confidence interval = 1.13-14.16, P = 0.03) of AF recurrence. CONCLUSIONS: Pulmonary vein mapping with the double-Lasso technique did miss the non-isolation of the PV carina after a successful EIPVsI, which was an independent predictor of AF recurrence after the EIPVsI. Pacing from the PV carina may be required to confirm the electrical isolation of the PV carina after EIPVsI with the double-Lasso technique.

A randomized controlled trial of dabigatran versus warfarin for periablation anticoagulation in patients undergoing ablation of atrial fibrillation.

BACKGROUND: We aimed to evaluate the feasibility of an oral direct thrombin inhibitor, dabigatran, as a periprocedural anticoagulant for use with ablation of atrial fibrillation (AF). METHODS: Consecutive patients scheduled to undergo an AF ablation were randomly assigned to receive dabigatran (n = 45) or warfarin (n = 45) to compare their clinical feasibility. Both of those oral anticoagulants were discontinued the day before the ablation and were resumed after confirming hemostasis of the venipuncture site. A bridging therapy with heparin was not used in either of the patient groups. RESULTS: Dabigatran was switched to warfarin before the ablation because of dyspepsia in three patients. An occurrence of rebleeding from the venipuncture site was less common in dabigatran-allocated patients than in warfarin-allocated patients (20% vs 44%; P = 0.013). The reduction in the D-dimer level after the initiation of oral anticoagulants was greater in the dabigatran-allocated patients than in the warfarin-allocated patients. The time from the initiation of the anticoagulants to the ablation was significantly shorter in the dabigatran-allocated patients than in the warfarin-allocated patients (43 ± 7 vs 63 ± 13 days; P < 0.0001). There was only one fatal periprocedural complication in a patient receiving warfarin, who had a mesenteric arterial thrombosis after the ablation. CONCLUSIONS: An anticoagulation strategy with dabigatran may surpass that with warfarin in reducing both the periprocedural risk of minor bleeding and a hypercoagulable state, and the time to ablation in patients undergoing ablation of AF.

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.

The potential of dynamic 99mTc-sestamibi cadmium zinc telluride-single-photon emission computed tomography camera assessing myocardial flow reserve in patients with heart failure with preserved ejection fraction.

Aims: Coronary microvascular dysfunction (CMD) is related to the pathophysiology, mortality, and morbidity of heart failure with preserved ejection fraction (HFpEF). A novel single-photon emission computed tomography (SPECT) camera with cadmium zinc telluride (CZT) detectors allows for the quantification of absolute myocardial blood flow and myocardial flow reserve (MFR) in patients with coronary artery disease. However, the potential of CZT-SPECT assessing for CMD has never been evaluated in patients with HFpEF. Methods and results: The clinical records of 127 consecutive patients who underwent dynamic CZT-SPECT were retrospectively reviewed. Rest and stress scanning were started simultaneously with 3 and 9 MBq/kg of 99mTc-sestamibi administration, respectively. Dynamic CZT-SPECT imaging data were analysed using a net-retention model with commercially available software. Transthoracic echocardiography was performed in all patients. The MFR value was significantly lower in the HFpEF group (mean ± SEM = 2.00 ± 0.097) than that in the non-HFpEF group (mean ± SEM = 2.74 ± 0.14, P = 0.0004). A receiver operating characteristic analysis indicated that if a cut-off value of 2.525 was applied, MFR could efficiently distinguish HFpEF from non-HFpEF. Heart failure with preserved ejection fraction had a consistently low MFR, regardless of the diastolic dysfunction score. Heart failure with preserved ejection fraction patients with MFR values lower than 2.075 had a significantly higher incidence of heart failure exacerbation. Conclusion: Myocardial flow reserve assessed by CZT-SPECT was significantly reduced in patients with HFpEF. A lower MFR was associated with a higher hospitalization rate in these patients. Myocardial flow reserve assessed by CZT-SPECT has the potential to predict future adverse events and stratify the severity of disease in patients with HFpEF.