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.

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.

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.

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.

＜Editors' Choice＞ Prevalence of acute coronary syndrome during the pandemic of COVID-19 in the Tokai Region of Japan.

The outbreak of coronavirus disease 19 (COVID-19) has had a great impact on medical care. During the COVID-19 pandemic, the rate of hospital admissions has been lower and the rate of in-hospital mortality has been higher in patients with acute coronary syndrome (ACS) in Western countries. However, in Japan, it is unknown whether the COVID-19 pandemic has affected the incidence of ACS. In the study, eleven hospitals in the Tokai region participated. Among enrolled hospital, we compared the incidence of ACS during the COVID-19 pandemic (April and May, 2020) with that in equivalent months in the preceding year as the control. During the study period; April and May 2020, 248 patients with ACS were admitted. Compared to April and May 2019, a decline of 8.1% [95% confidence interval (CI) 5.2-12.1; P = 0.33] in admissions for ACS was observed between April and May 2020. There was no significant difference in the strategy for revascularization and in-hospital deaths between 2019 and 2020. In conclusion, the rate of admission for ACS slightly decreased during the COVID-19 pandemic, compared to the same months in the preceding year. Moreover, degeneration of therapeutic procedures for ACS did not occur.

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.

Comparison Between Optical Frequency Domain Imaging and Intravascular Ultrasound for Percutaneous Coronary Intervention Guidance in Biolimus A9-Eluting Stent Implantation: A Randomized MISTIC-1 Non-Inferiority Trial.

BACKGROUND: Given the characteristic differences between intravascular ultrasound (IVUS) and optical frequency domain imaging (OFDI), their approach to therapeutic guidance during percutaneous coronary interventions (PCIs) and arterial healing response after stenting may also vary. METHODS: MISTIC-1 (The Multimodality Imaging Study in Cardiology cohort 1) is a multicenter, randomized-controlled, noninferiority trial that compared imaging end points between OFDI- and IVUS-guided PCI. Patients with stable coronary artery disease were randomly assigned to either OFDI- or IVUS-guided PCI using a Biolimus A9-eluting stent according to a prespecified protocol for imaging guidance. Stent sizing was based on external elastic lamina in IVUS-guided PCI while lumen up-size in OFDI-guided PCI. Postprocedural OFDI was investigated regardless of randomization, while operators in IVUS-guided PCI arm were blinded to the images. The primary end point was in-segment minimum lumen area assessed using OFDI at 8 months, while the secondary end point was a composite of cardiovascular mortality, target-vessel myocardial infarction, or target-lesion revascularization (device-oriented composite end point). Patients were followed up to 3 years after the index procedure. RESULTS: A total of 109 patients (mean age 70 years, male 78%) with 126 lesions were enrolled. Postprocedural minimum stent area was 6.31±1.89 and 6.72±2.08 mm2 in OFDI and IVUS group, respectively (P=0.26). At the 8-month follow-up, in-segment minimum lumen area was 4.56±1.94 and 4.13±1.86 mm2 in OFDI and IVUS group, respectively (Pnon-inferiority <0.001). Both groups had comparable neointimal healing score (median 0.16 [interquartile range, 0.00-3.14] versus 0.90 [0.00-3.30], respectively; P=0.43). The incidence rate of device-oriented composite end point at 3 years was 7.4% and 7.3% in OFDI and IVUS group, respectively (hazard ratio, 1.05 [95% CI, 0.26-4.18]; P=0.95). CONCLUSIONS: OFDI-guided PCI was not inferior to IVUS-guided PCI in terms of in-segment minimum lumen area at 8 months. Although a small sample size was acknowledged, OFDI could be an alternative to IVUS when considering intracoronary imaging-guided PCI in selected populations with coronary artery diseases. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03292081.

Rotational Atherectomy for Severely Calcified Lesions in Patients With Left Ventricular Systolic Dysfunction: One-Year Outcomes From aSingle-Center Registry Analysis.

BACKGROUND: High-risk percutaneous coronary intervention (PCI) in patients with left ventricular (LV) systolic dysfunction has been proven to induce reverse LV remodeling. However, the impact of high-risk PCI focusing on rotational atherectomy (RA) in patients with severe LV systolic dysfunction has not been completely addressed. METHODS: Among 4339 consecutive patients who underwent PCI, 178 patients with 192 lesions were treated with RA. The reduced ejection fraction (EF) group (LVEF ≤35%) included 25 patients, the mid-range EF group (LVEF 36-50%) included 44 patients, and the preserved EF group (LVEF >50%) included 109 patients. The primary outcome was a composite of cardiac death, non-fatal myocardial infarction, target-vessel revascularization, and ischemic stroke. RESULTS: The cumulative 1-year incidence of the primary outcome was similar among the three groups (reduced EF, 29%; mid-range EF, 25%; preserved EF, 26%; p = 0.95). After adjusting for confounding factors, the incidence of the primary outcome in the reduced EF group (hazard ratio [HR], 1.07; 95% confidence interval [CI], 0.43-2.37; p = 0.87) and the mid-range EF group (HR, 0.99; 95% CI, 0.47-1.94; p = 0.97) was similar to that in the preserved EF group. LVEF was significantly improved in the reduced EF and mid-range EF groups compared with the preserved EF group (absolute change in LVEF: 13.6 ± 11.3%, 9.0 ± 10.1%, and -0.7 ± 7.8%, respectively; p < 0.0001). CONCLUSIONS: Reduced EF was not associated with increase in the primary outcome in patients undergoing RA. This seemed to result from the improved LV function after PCI. SUMMARY FOR ANNOTATED TABLE OF CONTENTS: This single center analysis study investigated 1-year composite outcome of cardiac death, non-fatal myocardial infarction, target-vessel revascularization, and ischemic stroke in patients with severe LV systolic dysfunction undergoing RA compared with that in patients with preserved LV function. The cumulative 1-year incidence of the composite outcome was similar among the three groups (reduced EF, 29%; mid-range EF, 25%; preserved EF, 26%; p = 0.95). LVEF was significantly improved in the reduced EF and mid-range EF groups compared with the preserved EF group (absolute change in LVEF: 13.6 ± 11.3%, 9.0 ± 10.1%, and -0.7 ± 7.8%, respectively; p < 0.0001).

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.

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.

Safety and Efficacy of Minimally Interrupted Dabigatran vs Uninterrupted Warfarin Therapy in Adults Undergoing Atrial Fibrillation Catheter Ablation: A Randomized Clinical Trial.

Importance: Uninterrupted dabigatran therapy reduces stroke risk in patients with nonvalvular atrial fibrillation (NVAF) undergoing ablation and is associated with a lower bleeding risk than uninterrupted warfarin therapy. Minimally interrupted direct oral anticoagulant therapy is widely used, but data from controlled studies are insufficient. Objective: To compare the safety and efficacy of minimally interrupted dabigatran vs uninterrupted warfarin therapy in patients undergoing catheter ablation for NVAF. Design, Setting, and Participants: The ABRIDGE-J (ABlation peRIoperative DabiGatran in use Envisioning in Japan) trial is a open-label, randomized clinical trial performed in 28 Japanese treatment centers. A total of 504 patients scheduled for NVAF ablation were enrolled; 500 were randomized to the study treatments; 499 received at least 1 dose of dabigatran etexilate (n = 248) or warfarin potassium (n = 251); and 442 underwent ablation (220 in the dabigatran group and 222 in the warfarin group). Data were collected from May 1, 2014, through September 14, 2015, and analyzed from March 7, 2017, through January 28, 2019. Interventions: Appropriate dose anticoagulation was administered 4 weeks before and at least 3 months after ablation in all patients. Dabigatran therapy was interrupted before catheter ablation (holding of 1-2 doses) and resumed after ablation. Main Outcomes and Measures: Primary end points were the incidence of embolism during the perioperative period and atrial thrombus just before the ablation. The main secondary end point was the incidence of major bleeding events until 3 months after ablation. Results: Of the 442 patients who underwent ablation, 74.9% were men and the median age was 66 years (interquartile range, 59-71 years). Before ablation, 1 cerebral infarction and 1 thrombus in the left atrium occurred in the warfarin group, but no events occurred in the interrupted dabigatran group. After ablation, the mean (SD) incidence of major bleeding events was significantly lower with dabigatran (3 patients [1.4% {0.8%}; 95% CI, 0.4%-4.2%]) vs warfarin (11 patients [5.0% {1.5%}; 95% CI, 2.8%-8.8%]; P = .03). No thromboembolic events occurred after ablation in the dabigatran group; 1 (0.5%) occurred in the warfarin group. Conclusions and Relevance: In patients undergoing ablation for NVAF, anticoagulation with minimally interrupted dabigatran therapy did not increase thromboembolic events and was associated with fewer bleeding complications than uninterrupted warfarin therapy. Trial Registration: umin.ac.jp Identifier: UMIN000013129.

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.

HCN4 Gene Polymorphisms Are Associated With Occurrence of Tachycardia-Induced Cardiomyopathy in Patients With Atrial Fibrillation.

BACKGROUND: Tachycardia-induced cardiomyopathy (TIC) is a reversible cardiomyopathy induced by tachyarrhythmia, and the genetic background of the TIC is not well understood. The hyperpolarization-activated cyclic nucleotide-gated channel gene HCN4 is highly expressed in the conduction system where it is involved in heart rate control. We speculated that the HCN4 gene is associated with TIC. METHODS: We enrolled 930 Japanese patients with atrial fibrillation (AF) for screening, 350 Japanese patients with AF for replication, and 1635 non-AF controls. In the screening AF set, we compared HCN4 single-nucleotide polymorphism genotypes between AF subjects with TIC (TIC, n=73) and without TIC (non-TIC, n=857). Of 17 HCN4 gene-tag single-nucleotide polymorphisms, rs7172796, rs2680344, rs7164883, rs11631816, and rs12905211 were significantly associated with TIC. Among them, only rs7164883 was independently associated with TIC after conditional analysis (TIC versus non-TIC: minor allele frequency, 26.0% versus 9.7%; P=1.62×10-9; odds ratio=3.2). RESULTS: We confirmed this association of HCN4 single-nucleotide polymorphism rs7164883 with TIC in the replication set (TIC=41 and non-TIC=309; minor allele frequency, 28% versus 9.9%; P=1.94×10-6; odds ratio=3.6). The minor allele frequency of rs7164883 was similar in patients with AF and non-AF controls (11% versus 10.9%; P=0.908). CONCLUSIONS: The HCN4 gene single-nucleotide polymorphism rs7164883 may be a new genetic marker for TIC in patients with AF.

Comparison of uninterrupted anticoagulation with dabigatran etexilate or warfarin in the periprocedural period for atrial fibrillation catheter ablation: Results of the Japanese subgroup of the RE-CIRCUIT trial.

Background: There are limited data on uninterrupted anticoagulation with direct oral anticoagulants during catheter ablation for atrial fibrillation (AF), particularly in Japan. We planned a subgroup analysis of the RE-CIRCUIT study, comparing the use of uninterrupted dabigatran therapy with warfarin therapy during catheter ablation among the Japanese subgroup and with that in the total population. Methods: The RE-CIRCUIT study utilized a prospective, randomized, open-label, blinded endpoint design, and the primary endpoint was the incidence of major bleeding events (MBEs). Patients were randomized to uninterrupted dabigatran 150 mg twice daily or warfarin. In this study, we analyzed the results in Japanese patients. Results: Of 704 enrolled patients in the study, 112 Japanese patients were randomized to dabigatran (n = 65) or warfarin (n = 47). MBEs were experienced by two patients: one in the dabigatran group (1.6%, cardiac tamponade) and one in the warfarin group (2.2%, groin hematoma) (risk difference vs warfarin -0.6%; 95% CI -5.8, 4.7). Within the Japanese subgroup, there were no thromboembolic events in both groups. Conclusion: While not designed to show statistical difference between two treatment groups, our results from the Japanese subgroup supported those from the overall population. Furthermore, this study provided clinical information regarding MBE, especially cardiac tamponade, in Japanese patients.

Focal intra-cavotricuspid isthmus atrial tachycardias occurring after typical atrial flutter ablation: incidence and electrocardiographic and electrophysiological characteristics.

PURPOSE: Focal atrial tachycardias (ATs) from the septal cavotricuspid isthmus (CTI) occurring after successful CTI ablation can mimic typical atrial flutter (tAFL). This study investigated the incidence, and electrocardiographic and electrophysiological characteristics of these ATs. METHODS: Among 1082 consecutive patients undergoing successful CTI ablation without any congenital heart diseases, 7 were diagnosed with focal ATs originating from the septal CTI that occurred a median of 74 days after the CTI ablation. RESULTS: The electrocardiographic characteristics of the ATs were similar to those of the tAFLs. The AT's cycle length was never shorter than and often similar to that of tAFLs. The activation patterns along the tricuspid annulus during the ATs were the same as those of tAFLs in 4 patients with foci adjacent to the CTI line, and centrifugal from foci around the coronary sinus (CS) ostium in 3. Entrainment pacing from the lateral CTI during the ATs revealed a manifest fusion and long post-pacing interval. Entrainment pacing from the lateral CTI during the ATs revealed that the atrial electrograms recorded from the CS and high-lateral right atrium were orthodromically captured, while that from the proximal CS revealed that the atrial electrograms recorded from the CS and lateral right atrium were antidromically captured without manifest fusion. CONCLUSIONS: Focal intra-CTI ATs with a microreentrant mechanism very rarely occurred after successful CTI ablation. The electrocardiographic and electrophysiological characteristics of these ATs were similar to those of tAFLs. Overdrive pacing from the lateral CTI and proximal CS was helpful for distinguishing these ATs from recurrent tAFLs.

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.