Publications by authors named "Naoto Otsuka"

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.

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Introduction: Pulsed field ablation (PFA) has emerged as an innovative therapy for cardiac arrhythmias. Drawing parallels with PFA's application in solid tumors, calcium chloride (CaCl) as an adjuvant therapy, known as calcium electroporation, may amplify PFA's apoptotic effects. We propose that PFA in the atrium could enhance calcium uptake through PFA-created pores, thereby increasing ablation efficacy even at reduced power levels by exploiting PFA's permeabilization effects.

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Background: 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.

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Introduction: High-power short-duration (HPSD) ablation at 50 W, guided by ablation index (AI) or lesion size index (LSI), and a 90 W/4 s very HSPD (vHPSD) setting are available for atrial fibrillation (AF) treatment. Yet, tissue temperatures during ablation with different catheters around venoatrial junction and collateral tissues remain unclear.

Methods: In this porcine study, we surgically implanted thermocouples on the epicardium near the superior vena cava (SVC), right pulmonary vein, and esophagus close to the inferior vena cava.

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Background: Ablation strategies and modalities for atrial fibrillation (AF) have transitioned over the past decade, but their impact on post-ablation medication and clinical outcomes remains to be fully investigated.

Methods: We divided 682 patients who had undergone AF ablation in 2014-2019 (420 paroxysmal AFs [PAF], 262 persistent AFs [PerAF]) into three groups according to the period, that is, the 2014-2015 ( = 139), 2016-2017 ( = 244), and 2018-2019 groups ( = 299), respectively.

Results: Persistent AF became more prevalent and the left atrial (LA) diameter larger over the 6 years.

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Article Synopsis
  • - The study investigated how recombinant semaphorin 3A (Sema3A) affects heart function and electrical activity in mice with heart failure induced by isoproterenol (ISP).
  • - ISP treatment led to increased heart tissue fibrosis and reduced left ventricular contractility, but Sema3A administration improved these issues, showing similar contractility to healthy controls and normalized electric signaling.
  • - Molecular analysis revealed that Sema3A upregulates certain proteins (like Kv4.3) associated with heart function, suggesting it helps maintain heart performance by reducing stress on the heart's nervous system and supporting healthy heart tissue.
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Introduction: Neither the actual in vivo tissue temperatures reached with 90 W/4 s-very high-power short-duration (vHPSD) ablation for atrial fibrillation nor the safety and efficacy profile have been fully elucidated.

Methods: We conducted a porcine study (n = 15) in which, after right thoracotomy, we implanted 6-8 thermocouples epicardially in the superior vena cava, right pulmonary vein, and esophagus close to the inferior vena cava. We compared tissue temperatures close to a QDOT MICRO catheter, between during 90 W/4 s-vHPSD ablation during ablation index (AI: target 400)-guided 50 W-HPSD ablation, both targeting a contact force of 8-15 g.

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Background: A subeustachian pouch (SEP) often hinders the completion of a cavotricuspid isthmus (CTI) ablation of typical atrial flutter (AFL) and sometimes causes steam-pops during a power-controlled ablation. We hypothesized that real-time bull's-eye monitoring of the catheter surface temperature might be useful to locate the SEP where the temperature can rise rapidly, and a temperature-controlled ablation might avoid steam pops. This study aimed to demonstrate this hypothesis.

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Background: Neither the actual in vivo tissue temperatures reached with lesion size index (LSI)-guided high-power short-duration (HPSD) ablation for atrial fibrillation nor the safety profile has been elucidated.

Methods: We conducted a porcine study (n = 7) in which, after right thoracotomy, we implanted 6-8 thermocouples epicardially in the superior vena cava, right pulmonary vein, and esophagus close to the inferior vena cava. We compared tissue temperatures reached during 50 W-HPSD ablation with those reached during standard (30 W) ablation, both targeting an LSI of 5.

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Article Synopsis
  • Sleep apnea syndrome (SAS) causes nighttime breathing issues, leading to low oxygen levels and daytime sleepiness, and is linked to serious health problems like hypertension and heart disease.
  • Approximately 50% of those with sleep-disordered breathing experience arrhythmias, particularly in severe cases where the apnea-hypopnea index (AHI) is 30 or more, which can drastically increase the frequency of these heart irregularities during sleep.
  • Treatment with continuous positive airway pressure has been effective in reducing AHI and resolving severe cardiac issues in a case study of a 44-year-old patient experiencing bradyarrhythmias likely related to SAS.
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Article Synopsis
  • * Results showed that RV pacing with an optimal AV delay of 160 ms led to a higher stroke volume compared to intrinsic AV conduction, prompting the use of DDD mode pacing.
  • * However, seven of the patients developed heart failure during the follow-up, particularly when their E/E' ratio was above 15, indicating the need to avoid RV pacing in patients with elevated E/E' ratios.
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Despite emerging recognition of interactions between heart failure (HF) and liver dysfunction, the impact of cardiac hepatopathy on patients with HF undergoing cardiac resynchronization therapy (CRT) has not been fully elucidated. Albumin-bilirubin (ALBI) score is a new assessment of liver function. The relationship between liver dysfunction severity based on ALBI score and clinical outcomes of patients with HF receiving CRT is unclear.

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Aims: Multi-organ dysfunction was recently reported to be a common condition in patients with heart failure (HF). The Model for End-stage Liver Disease eXcluding International normalized ratio (MELD-XI) score reflects liver and kidney function. The prognostic relevance of this score has been reported in patients with a variety of cardiovascular diseases who are undergoing interventional therapies.

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Background: Actual in vivo tissue temperatures and the safety profile during high-power short-duration (HPSD) ablation of atrial fibrillation have not been clarified.

Methods: We conducted an animal study in which, after a right thoracotomy, we implanted 6-8 thermocouples epicardially in the superior vena cava, right pulmonary vein, and esophagus close to the inferior vena cava. We recorded tissue temperatures during a 50 W-HPSD ablation and 30 W-standard ablation targeting an ablation index (AI) of 400 (5-15 g contact force).

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Article Synopsis
  • Malnutrition is prevalent in heart failure patients and worsens their clinical outcomes; the CONUT score serves as a tool for assessing this malnutrition.
  • A study of 263 patients undergoing cardiac resynchronization therapy revealed that those with moderate to severe malnutrition had worse health indicators and significantly lower response rates to the treatment.
  • The findings showed a clear link between higher CONUT scores and increased mortality rates, indicating that malnutrition severity is crucial for predicting survival in heart failure patients post-CRT.
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  • This study investigates the effectiveness of a modified ablation index for predicting successful isolation of the left atrial posterior wall in patients with persistent atrial fibrillation.
  • The analysis involved 55 patients, focusing on factors like bipolar voltage, wall thickness, and the length of the ablation line, to identify potential gaps in the isolation process.
  • Results showed that certain thresholds for modified AI, voltage, and wall thickness significantly correlated with the likelihood of incomplete isolation, suggesting these metrics could help optimize ablation techniques.
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  • The study examines the relationship between the shape of the white line of a horse's hoof and the notch on the distal phalanx (P3) in 163 Thoroughbred yearlings.
  • It found that as the toe white line separation grade increased (rated from 0 to 3), both the depth and width of the notch on the P3 also significantly increased.
  • This suggests that radiographic examinations of the P3 could help determine necessary hoof care to prevent toe white line separation issues.
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  • The study investigated clinical factors associated with atrial fibrillation (AF) recurrence and adverse clinical events (AEs) after AF ablation in a large Japanese population over a median follow-up of 20.7 months.
  • A total of 3,451 patients were analyzed, with 30.3% experiencing AF recurrence and 6.5% facing AEs, including strokes, major bleeding, and deaths.
  • Key findings indicated that different risk factors are linked to each outcome, as female sex and persistent AF were associated with recurrence, while age, comorbidities, and cardiac/renal conditions were linked to AEs.
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Objective Following the introduction of magnetic resonance (MR)-conditional cardiac implantable electrical devices (CIEDs), patients with CIEDs have undergone MRI scanning more frequently. As the required settings of MRI equipment for scanning patients with a CIED vary by device, a number of precautions should be taken to allow safe examinations, including the confirmation of conditions and selection of MRI modes appropriate for pacing status in individual patients. In this study, we examined the current status and issues concerning the performance of MRI examinations in patients with an MRI-conditional CIED.

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Atrial fibrillation (AF) is a progressive disease that starts with structural or functional changes in the left atrium and left ventricle, and evolves from paroxysmal toward sustained forms. Early detection of structural or functional changes in the left atrium and left ventricle in the paroxysmal stage could be useful for identifying a higher risk of progression to persistent AF and future cardio-cerebrovascular events. The aim of this study was to test the hypothesis that the feature tracking (FT) left atrial (LA) strain and left ventricular (LV) extracellular volume fraction (ECV) derived from cardiovascular magnetic resonance (CMR) could detect early changes in remodeling of the left atrium and ventricle in the paroxysmal AF (PAF) stage.

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Article Synopsis
  • - The study investigates the link between low-voltage zones (LVZs) in the left atrium (LA) and the anatomical position of the ascending aorta in patients with atrial fibrillation (AF), revealing that specific geometric relationships are tied to LVZ formation.
  • - Out of 102 patients analyzed, 29 (28%) had LVZs on the LA wall, with findings showing significant differences in aorta-LA angles and other anatomical measures between those with and without LVZs.
  • - The researchers conclude that the shape and pressure from the ascending aorta might play a key role in developing LVZs, suggesting that external pressures and limited space in the chest could contribute to this condition in AF patients.
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