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Introduction: Typical atrial flutter (AFL) is a macroreentrant tachycardia in which intracardiac conduction rotates counterclockwise around the tricuspid annulus. Typical AFL has specific electrocardiographic characteristics, including a negative sawtooth‐like wave in the inferior lead and a positive F wave in lead V1. This study aimed to analyze the origin of the positive F wave in lead V1, which has not been completely understood. Methods: This study enrolled 10 patients who underwent radiofrequency catheter ablation for a typical AFL. Electroanatomical mapping was performed both during typical AFL and entrainment from the right atrial appendage (RAA). The 12‐lead electrocardiogram (ECG) and three‐dimensional (3D) electroanatomical maps were analyzed. Results: The positive F wave in lead V1 changed during entrainment from the RAA in all the cases. The 3D map during entrainment from the RAA revealed an area of antidromic capture around the RAA, which collided with the orthodromic wave in the anterior right atrium. This area of antidromic capture around the RAA was the only difference from the 3D electroanatomical map of AFL and is considered the cause of the change in the F wave in lead V1 during entrainment. Conclusion: The analysis of the differences in the 12‐lead ECG and 3D maps between tachycardia and entrainment from the RAA clearly demonstrated that activation around the RAA is responsible for the generation of the positive F wave in lead V1 of typical AFL. [ABSTRACT FROM AUTHOR]

Background: Since the local impedance (LI) of the ablation catheter reflects tissue characteristics, the efficacy of higher power (HP) compared to lower power (LP) in LI‐guided ablation may differ from other index‐guided ablations. Objective: This study aimed to assess the efficacy of HP ablation in LI‐guided ablation of atrial fibrillation (AF). Methods: A prospective observational study was conducted, enrolling patients undergoing de novo ablation for AF. Pulmonary vein isolation was performed using point‐by‐point ablation with a RHYTHMIA HDxTM Mapping System and an open‐irrigated ablation catheter with mini‐electrodes (IntellaNav MIFI OI). Ablation was stopped when the LI drop reached 30 ohms, three seconds after the LI plateaued, or when ablation time reached 30 s. To balance the baseline differences, a unique method was used in which the power was changed between HP (45 W to anterior wall/40 W to posterior wall) and LP (35 W/30 W) alternately for each adjacent point. Results: A total of 551 ablations in 10 patients were analyzed (HP, n = 276; LP, n = 275). The maximum LI drop was significantly larger (HP: 28.3 ± 5.4 vs. LP: 24.8 ± 6.3 ohm), and the time to minimum LI was significantly shorter (HP: 15.0 ± 6.3 vs. LP: 19.3 ± 6.6 s) in the HP setting. The unipolar electrogram analysis of three patients revealed that the electrogram indicating transmural lesion formation was observed more frequently in the HP setting. Conclusion: In LI‐guided ablation, the HP could achieve a larger LI drop and shorter time to minimum LI, which may result in more transmural lesion formation compared to a LP setting. [ABSTRACT FROM AUTHOR]

Background: Micra leadless pacemaker is secured to the myocardium by engagement of at least 2/4 tines confirmed with pull and hold test. However, the pull and hold test is sometimes difficult to assess. This study was performed to evaluate whether the angle of the tines before the pull and hold test predicts engagement of the tines in Micra leadless pacemaker implantation. Methods: We retrospectively enrolled 93 consecutive patients (52.7% male, age 82.4 ± 9.4 years), who received Micra implantation from September 2017 to June 2020 at our institution. After deployment and before the pull and hold test, the angle of the visible tines to the body of the pacemaker was measured using the RAO view of the fluoroscopy image. The engagement of the tines was then confirmed with the pull and hold test. Results: A total of 326 tines were analyzed. The angle of the engaged tines was significantly lower than the non‐engaged tines (9.2 degrees [4.0–14.0] vs. 16.6 degrees [14.2–18.8], p <.0001). All tines with angles <10 degrees were engaged. In higher angles, engagement could not be predicted. Conclusion: A low angle of the tines before the pull and hold test can predict engagement of the tines in Micra leadless pacemaker implantation. The tines which are already open after deployment may be presumed that they are engaged. [ABSTRACT FROM AUTHOR]

Background: Implantations of leadless pacemakers in the septum lower the risk of cardiac perforation. However, the relationship between the implantation site and the success rate, complication rate, and pacemaker parameters are not well‐investigated. Methods: Patients who underwent leadless pacemaker implantation with postprocedural computed tomography (CT) between September 2017 and November 2020 were analyzed. Septum was targeted with fluoroscopic guidance with contrast injection. We divided patients into two groups based on the implantation site confirmed by CT: septal and non‐septal, which included the anterior/posterior edge of the septum and free wall. We compared the complication rates and pacemaker parameters between the two groups. Results: A total of 67 patients underwent CT after the procedure; among them, 28 were included in the septal group and 39 were included in the non‐septal group. The non‐septal group had significantly higher R wave amplitudes (6.5 ± 3.3 vs. 9.7 ± 3.9 mV, p =.001), lower pacing threshold (1.0 ± 0.94 vs. 0.63 ± 0.45 V/0.24 ms, p =.02), and higher pacing impedance (615 ± 114.1 vs. 712.8 ± 181.3 ohms, p =.014) after the procedure compared to the septal group. Cardiac injuries were observed in four patients (one cardiac tamponade, one possible apical hematoma, two asymptomatic pericardial effusion), which were only observed in the non‐septal group. Conclusions: Leadless pacemaker implantation may be technically challenging with substantial number of patients with non‐septal implantation when assessed by CT. Septal implantation may have a lower risk of cardiac injury but may lead to inferior pacemaker parameters than non‐septal implantation. [ABSTRACT FROM AUTHOR]

Introduction: Atrioventricular nodal re‐entry tachycardia (AVNRT) is the most common, regular narrow‐complex tachycardia. The established treatment is catheter ablation of the AV nodal slow pathway (SP). However, in a select group of patients with long PR intervals in sinus rhythm, SP ablation can lead to AV block due to the absence of robust anterograde conduction through the fast pathway (FP). This report aims to demonstrate that AV nodal FP ablation is a reasonable approach in patients with AVNRT and poor or absent anterograde FP conduction. Methods and Results: Standard electrophysiology study techniques were used in the electrophysiology laboratory. Catheter ablations were performed using radiofrequency energy. Mapping of intracardiac activation was performed with electroanatomical mapping systems. Outcomes were assessed acutely during the procedure and during routine clinical follow‐up. Six patients with first‐degree AV block and recurrent AVNRT who underwent ablation of their tachycardia at our institution are presented. One patient underwent ablation of AV nodal SP resulting in high‐degree AV block necessitating pacemaker implantation. The remaining five patients underwent ablation of the AV nodal FP guided by electroanatomical mapping of the earliest atrial activation in tachycardia. These five had successful treatment of the tachycardia with preservation of anterograde AV nodal conduction. Mapping and ablation approach to eliminate retrograde FP conduction are described. Conclusion: In select patients with AVNRT and poor anterograde FP conduction, retrograde FP ablation is reasonable and is less likely to result in AV block and pacemaker dependency. [ABSTRACT FROM AUTHOR]

Introduction: Strong evidence exists for the utility of remote monitoring in cardiac implantable electronic devices for early detection of arrhythmias and evaluation of system performance. The application of remote monitoring for the management of chronic disease such as heart failure has been an active area of research. Areas covered: This review aims to cover the latest evidence of remote monitoring of implantable cardiac defibrillators in terms of heart failure prognosis. This article also updates the current technology relating to the method and discusses key factors to be addressed in order to better use the approach. PubMed and internet searches were conducted to acquire most recent data and technology information. Expert commentary: Multiparameter monitoring with automatic transmission is useful for heart failure management. Improved adherence to remote monitoring and an optimal algorithm for transmitted alerts and their management are warranted in the management of heart failure. [ABSTRACT FROM AUTHOR]

Background: Catheter ablation (CA) for premature ventricular contractions (PVCs) restores cardiac and renal functions in patients with reduced left ventricular ejection fraction (LVEF); however, its effects on preserved EF remain unelucidated., Methods: The study cohort comprised 246 patients with a PVC burden of >10% on Holter electrocardiography. Using propensity matching, we compared the changes in B-type natriuretic peptide (BNP) levels and estimated glomerular filtration rate (eGFR) in patients who underwent CA or did not., Results: Postoperative BNP levels were decreased significantly in the CA group, regardless of the degree of LVEF, whereas there was no change in those of the non-CA group. Among patients who underwent CA, BNP levels decreased from 44.1 to 33.0 pg/mL in those with LVEF ≥50% ( p  = .002) and from 141.0 to 87.9 pg/mL in those with LVEF <50% ( p  < .001). Regarding eGFR, postoperative eGFR was significantly improved in the CA group of patients with LVEF ≥50% (from 71.4 to 74.7 mL/min/1.73 m 2 , p  = .006), whereas it decreased in the non-CA group. A similar trend was observed in the group with a reduced LVEF. Adjusted for propensity score matching, there was a significant decrease in the BNP level and recovery of eGFR after CA in patients with LVEF >50%., Conclusions: This study showed that CA for frequent PVCs decreases BNP levels and increases eGFR even in patients with preserved LVEF., Competing Interests: Authors declare that there no conflicts of interest for this article., (© 2024 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of Japanese Heart Rhythm Society.)

Background: Micra leadless pacemaker is secured to the myocardium by engagement of at least 2/4 tines confirmed with pull and hold test. However, the pull and hold test is sometimes difficult to assess. This study was performed to evaluate whether the angle of the tines before the pull and hold test predicts engagement of the tines in Micra leadless pacemaker implantation., Methods: We retrospectively enrolled 93 consecutive patients (52.7% male, age 82.4 ± 9.4 years), who received Micra implantation from September 2017 to June 2020 at our institution. After deployment and before the pull and hold test, the angle of the visible tines to the body of the pacemaker was measured using the RAO view of the fluoroscopy image. The engagement of the tines was then confirmed with the pull and hold test., Results: A total of 326 tines were analyzed. The angle of the engaged tines was significantly lower than the non-engaged tines (9.2 degrees [4.0-14.0] vs. 16.6 degrees [14.2-18.8], p  < .0001). All tines with angles <10 degrees were engaged. In higher angles, engagement could not be predicted., Conclusion: A low angle of the tines before the pull and hold test can predict engagement of the tines in Micra leadless pacemaker implantation. The tines which are already open after deployment may be presumed that they are engaged., Competing Interests: Masahiko Goya received a lecture fee from Johnson and Johnson, Daiichi‐Sankyo, Bayer, and Japan Lifeline and a research grant from Japan Lifeline. The other authors have no conflict of interest to disclose. This research did not receive any specific grant from funding agencies in the public, commercial, or not‐for‐profit sectors., (© 2022 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of Japanese Heart Rhythm Society.)

Aim: Atrial fibrillation (AF), regardless of subtype, is associated with a prothrombotic state, which is related to endothelial dysfunction (ED).We hypothesized that paroxysmal atrial fibrillation (PAF) patients have endothelial dysfunction, and this may partially explain the high thromboembolic risk and poorer outcome in this category of patients., Methods: The study population consisted of 100 consecutive outpatients with AF (mean age 65.9±7.9 years; 68 (68%) male) and 21 characteristics and comorbidity matched control subjects (mean age 64.8±7.0 years; 13 (61.9%) male). AF patients were divided into the PAF group (n=50) and permanent/persistent AF (PeAF) group (n=50).Reactive hyperemia pulse amplitude tonometry index (RHI) was measured to evaluate endothelial function., Results: RHI was significantly lower in the PAF (1.67±0.30) and PeAF (1.63±0.28) groups in comparison with control subjects (2.12±0.40, both p< 0.001). There was no significant difference in RHI between the PAF and PeAF groups (p= 0.88). On linear regression analysis, both PeAF and PAF are significant independent predictors of RHI., Conclusions: In conclusion, ED in PAF patients was comparable to PeAF patients, and the presence of PAF itself is a contributing factor for ED independent of other coexisting comorbidities. This may provide a mechanism explaining why the risk of thromboembolism in PAF is comparable with PeAF patients.

Background: Diabetes mellitus (DM) is a risk factor of poor prognosis in patients with heart failure (HF). The prevalence and prognostic impact of the pre-diabetic state, however, are not well understood., Methods and Results: One hundred and thirty-six consecutive patients admitted due to HF were included in this prospective study. The 75-g oral glucose tolerance test (OGTT) was performed in all patients without known DM, and patients were classified into normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and DM groups. Forty-two of the 136 patients had previously been diagnosed with diabetes. Of the remaining 94 patients without known diabetes, 35 (37.2%) patients were classified as NGT, 9 (9.6%) as having IFG, 37 (39.4%) were classified as having IGT, and 13 (13.8%) were newly diagnosed with DM. During follow-up, patients with DM or IGT had significantly lower major adverse cardiac and cerebrovascular event (MACCE)-free rates than NGT patients (P=0.006, P=0.036, respectively). IFG, however, was not significantly related to increased MACCE risk. The presence of IGT (hazard ratio [HR], 4.51; P=0.011) and DM (HR, 4.74; P=0.005) were independent predictors of MACCE even after multivariate analysis., Conclusions: IGT and DM contribute to adverse prognosis in patients with HF. It is feasible to perform diabetes screening using OGTT in patients with HF for risk stratification.