Publications by authors named "Nagashima Koichi"
We encountered a single case in which a transition between orthodromic reciprocating tachycardia with a concealed nodoventricular pathway and atrioventricular nodal reentrant tachycardia with a bystander nodoventricular pathway was observed.
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- The study examines surface electrocardiograms (ECGs) during episodes of wide QRS complex tachycardia, a type of irregular heartbeat characterized by a prolonged QRS duration.
- Adenosine triphosphate (ATP) is injected to observe its effects and understand the underlying mechanism of the wide QRS tachycardia.
- The goal is to identify the physiological processes that lead to the conduction abnormalities observed in this type of tachycardia.
Background: Zero-fluoroscopic pulsed field ablation (PFA) is the next step in advancing pulmonary vein isolation (PVI) for atrial fibrillation (AF).
Methods: A workflow incorporating a variable-loop circular PFA catheter, intracardiac echocardiography (ICE), and a visualized sheath was applied to 15 paroxysmal AF patients.
Results: It consisted of three steps: (1) positioning a non-magnetic mapping catheter in the coronary sinus after creating a right atrial matrix, (2) transseptal puncture with the sheath advancement to the left atrium under ICE guidance, and (3) PFA confirming catheter-tissue contact with tissue proximity indication.
Recent advances in three-dimensional (3D) ultra-high-density mapping systems have uncovered previously unknown mechanisms underlying various arrhythmias. This clinical review, titled "3D Mapping Quest," focuses on the recently uncovered mechanisms of four types of arrhythmias. (1) To elucidate the precise mechanisms underlying atrial fibrillation (AF), ultra-high-density mapping with adequate spatial and temporal resolution is essential.
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- The study investigates the effectiveness of catheter ablation in eliminating idiopathic ventricular arrhythmias from different sites in the heart.
- It analyzes data from 58 patients and finds that overall, 72% had successful ablation, with different success rates linked to two specific sites: ECS and endo-EAS.
- Successful ECS ablation is associated with shorter distances to the activation site, while successful endo-EAS ablation is linked to earlier electrical signals and shorter intervals between activation sites.
Impact of Being Underweight on the Safety and Efficacy of Atrial Fibrillation Ablation: An Analysis From the Japanese Catheter Ablation Registry.
Circ Arrhythm Electrophysiol
November 2024
Article Synopsis
- - The study explored how tissue proximity indication (TPI), which assesses catheter contact with tissue, affects the success of lesion formation during pulsed field ablation (PFA) in live porcine models.
- - Researchers compared lesions formed under different contact conditions (no/minimum vs. consistent contact) and found that consistent contact resulted in significantly larger and more effective lesions, with greater transmurality.
- - The results highlight that a reliable TPI signal is crucial for achieving optimal lesion characteristics, suggesting that maintaining good tissue contact can enhance the outcomes of PFA procedures.
Decremental properties of a concealed nodoventricular pathway.
J Cardiovasc Electrophysiol
November 2024
Article Synopsis
- The study investigates the properties of the nodoventricular pathway (NVP) and its role in supraventricular tachycardia events.
- During the research, a specific type of premature ventricular contraction (PVC) was observed to effectively terminate the tachycardia, revealing unique behavior in the NVP.
- The findings suggest that the behavior of the NVP contributes to the mechanism of slow-fast AV nodal reentrant tachycardia (AVNRT), with the timing of the PVC affecting the conduction properties and ultimately the termination of the tachycardia.
Article Synopsis
- In cardiac electrophysiology, researchers are on a quest for a perfect diagnostic method for supraventricular tachycardias (SVTs), aiming to improve both accuracy and specificity in diagnoses.
- Various techniques have been proposed but each has its challenges, leading to a continuous search for better approaches, encapsulated in the review titled "SVT Quest."
- The diagnostic process unfolds in three steps: 1) distinguishing atrial tachycardia from other SVTs, 2) differentiating types of tachycardia based on specific response patterns, and 3) characterizing concealed pathways using various observation metrics, emphasizing the need to apply multiple methods for a comprehensive diagnosis.
Article Synopsis
- Major bleeding events in patients with atrial fibrillation (AF) using oral anticoagulants (OACs) were linked to worse long-term clinical outcomes, particularly major adverse cardiac and cerebrovascular events (MACCE).
- Analysis of two large prospective registries found that 4.5% of AF patients experienced major bleeding, which significantly increased their risk of MACCE compared to those without bleeding.
- Key factors predicting major bleeding included older age and the use of vitamin K antagonists and antiplatelet drugs; thus, minimizing bleeding risk could enhance clinical outcomes for these patients.
Background: Identification of infrequent nonpulmonary vein trigger premature atrial contractions (PACs) is challenging. We hypothesized that pace mapping (PM) assessed by correlation scores calculated by an intracardiac pattern matching (ICPM) module was useful for locating PAC origins, and conducted a validation study to assess the accuracy of ICPM-guided PM.
Methods: Analyzed were 30 patients with atrial fibrillation.
Background: Despite the positive impact of implantable cardioverter defibrillators (ICDs) and wearable cardioverter defibrillators (WCDs) on prognosis, their implantation is often withheld especially in Japanese heart failure patients with reduced left ventricular ejection fraction (HFrEF) who have not experienced ventricular tachycardia (VT) or ventricular fibrillation (VF) for uncertain reasons. Recent advancements in heart failure (HF) medications have significantly improved the prognosis for HFrEF. Given this context, a critical reassessment of the treatment and prognosis of ICDs and WCDs is essential, as it has the potential to reshape awareness and treatment strategies for these patients.
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- Atrioventricular nodal reentrant tachycardia (AVNRT) can return even after successful ablation of the slow pathway, prompting a study on recurrence reasons in 46 patients.
- The study found that while many patients initially had successful RF ablation targeting the rightward inferior extension (RIE), some still experienced recurrent AVNRT, with various types showing up in follow-up cases.
- Most recurrences were treated successfully again within the RIE area, and notably, the new successful ablation sites were often higher than where the initial procedure targeted.
Article Synopsis
- Studies have identified the histological features of the triangle of Koch (ToK) surrounding the atrioventricular (AV) node and suggested that unique myocytes facilitate conduction between atria and ventricles, but a complete understanding of this process remains elusive.
- There are various proposed pathways for electrical conduction in atrioventricular nodal reentrant tachycardia (AVNRT), but the details of these reentrant circuits are not thoroughly understood, leading to traditional approaches targeting slow pathways based on anatomical markers.
- Recent advancements in high-density 3D mapping have improved the ability to analyze electrophysiological patterns in the ToK, helping identify key targets for effective slow pathway ablation during AVNRT, which
One-Shot Diagnosis for Atrial Tachycardia: The Utility of a Single Atrial Extrastimulus.
JACC Clin Electrophysiol
June 2024
Article Synopsis
- The study examined the timing of electrical cardioversion (ECV) in patients with acute decompensated heart failure (ADHF) and atrial arrhythmias, comparing early ECV (within 8 days) to delayed ECV (9 days or more).
- Out of 73 patients, ECV successfully restored sinus rhythm in 85%, but there was no significant difference in short-term failure rates between early and delayed ECV groups.
- Early ECV was linked to a shorter hospital stay (14 vs. 17 days) and a notable increase in left ventricular ejection fraction (from 38% to 51%), suggesting better outcomes with earlier intervention.
Background: Although pulmonary vein isolation (PVI) for atrial fibrillation (AF) utilizing radiofrequency (RF) applications with a very high-power and short-duration (vHPSD) has shortened the procedure time, the determinants of pulmonary vein (PV) gaps in the first-pass PVI and acute PV reconnections are unclear.
Methods: An extensive encircling PVI was performed with the QDOT MICRO catheter with a vHPSD (90 W-4 s) in 30 patients with AF (19 men, 64 ± 10 years). The association of the PV gap sites (first-pass PVI failure, acute PV reconnections [spontaneous reconnections or dormant conduction provoked by adenosine triphosphate] or both) with the left atrial (LA) wall thickness and LA bipolar voltage on the PVI line and ablation-related parameters were assessed.
The coexistence of 2 Mahaim pathways represents a diagnostic challenge. We present a case in which the SH/HA intervals were useful for identifying concealed nodoventricular or His-ventricular pathways.
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- - The study aimed to develop a systematic method for diagnosing atrioventricular nodal reentrant tachycardia (AVNRT) that has a concealed nodoventricular pathway (cNVP).
- - Researchers analyzed 13 cases of AVNRT involving cNVP, focusing on how the pathway connected to either the slow or fast pathways, and also looked at cases of orthodromic reciprocating tachycardia related to cNVP.
- - The diagnostic process involves three key steps: identifying accessory pathways via His-refractory PVCs, excluding orthodromic reciprocating tachycardia, and confirming the AVN as the cNVP insertion site, with specific criteria for tachy
The intracardiac electrograms are shown during scanned single premature ventricular extrastimuli with a decreasing coupling interval in a very short RP tachycardia. What is the diagnosis and is the fast pathway essential for sustaining the tachycardia?
View Article and Find Full Text PDFBackground: The effects of the patient's disease awareness on the management of postablation of atrial fibrillation (AF) are unknown.
Methods: One hundred thirty-three AF patients undergoing an initial ablation were given a disease awareness questionnaire with a score of 16 points (8 points about AF in general and 8 points about oral anticoagulants) for the Jessa Atrial Fibrillation Knowledge Questionnaire (JAKQ) before and 1-year-after ablation. We divided them into the poor disease awareness group and good disease awareness group according to the median value (75%) of the total JAKQ score about AF in general, and compared the baseline patient characteristics and the 1-year changes in the JAKQ score, medication adherence, blood pressure, laboratory data, echocardiographic parameters, and AF/atrial tachycardia (AT) recurrence rate between the two groups.
Article Synopsis
- * The procedure involved using the Advisor™ HD Grid catheter and EnSite™ X EP system to identify the slow pathway (SP) area through a fractionation map.
- * The authors suggest that using cryomapping to directly target fractionated potential areas could offer a quick and safe method for ablation, presenting a potentially new workflow for similar cases.