Publications by authors named "Hiroaki Ohya"

Background: Left atrial epicardial adipose tissue (LA-EAT) is associated with the recurrence of atrial tachyarrhythmias (AF/AT) after catheter ablation for atrial fibrillation (AF). However, no previous studies have assessed the predictive value of segment-specific LA-EAT volumes for AF/AT recurrence. This study aimed to assess the relationship between segmental LA-EAT volume and AF/AT recurrence.

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Background: The concept of ablation index (AI) was introduced to evaluate radiofrequency (RF) ablation lesions. It is calculated from power, contact force (CF), and RF duration. However, other factors may also affect the quality of ablation lesions.

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Background: Catheter ablation is the curative treatment for paroxysmal supraventricular tachycardia (SVT). However, atrial tachycardia (AT) diagnosis is often challenging, especially when SVT is terminated by pacing.

Objectives: This study sought to develop a novel method for AT diagnosis.

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Radiofrequency catheter ablation (RFCA) for pulmonary artery ventricular arrhythmia (PAVA) can be difficult because of the occasional existence of PAVA with preferential conduction.This study described the characteristics of PAVA that demonstrate preferential conduction.We analyzed electrocardiographic and electrophysiological data from 8 patients found to have PAVAs with preferential conduction out of 183 patients (4.

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Background: Pacemaker positioning on the right ventricular (RV) septum during implantation is conventionally conducted utilizing two fixed fluoroscopy angles, a 45° left anterior oblique (LAO) and 35° right anterior oblique projection. However, placement location can be suboptimal, especially for leadless pacemakers (LPMs).

Objective: To evaluate the safety and ease of LPM implantation using individualized LAO projection.

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Introduction: The optimal ablation strategy is unknown regarding a superior vena cava isolation (SVCI). This study aimed to examine the feasibility and safety and to analyze the lesion characteristics of the SVCI using high-power, short-duration (HPSD) ablation.

Methods And Results: A total of 100 patients underwent an index SVCI using HPSD (n = 50, HPSD group) or conventional lower-power and longer-duration (n = 50, LPLD group) ablation, using the Thermocool Smarttouch SF.

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Background Recent studies have reported the association between pericoronary inflammation assessed by pericoronary adipose tissue attenuation (PCATA) on computed tomography angiography and worse outcomes in patients with coronary artery disease. We investigated the determinants predicting increased PCATA in patients with known or suspected coronary artery disease. Methods and Results A total of 540 patients who underwent computed tomography angiography and invasive coronary angiography were studied.

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Article Synopsis
  • The authors acknowledge that the published article has mistakes.
  • They have formally requested that these errors be recognized.
  • The statement serves as a correction to inform readers about the inaccuracies in the original text.
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Central nervous system (CNS) involvement, including encephalopathy, encephalitis, leptomeningitis, and pachymeningitis, in rheumatoid arthritis (RA) is rather rare. We report the case of a 61-year-old female with a history of RA in remission for 7 years, who presented with numbness, weakness of the left upper limb, dysarthria, and headache. Magnetic resonance imaging (MRI) of the brain showed meningeal enhancement in the frontal, parietal, and temporal lobes.

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Background: There remains a residual risk for acute myocardial infarction (AMI) even with low low-density lipoprotein cholesterol (LDL-C) levels. This study aimed to characterize the culprit lesion morphology of AMI by optical coherence tomography (OCT) in patients with low LDL-C.

Methods: Four-hundred and nine culprit lesions of 409 patients with their first presentation of AMI imaged by OCT were investigated.

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Background: Measurement of the contrast-flow quantitative flow ratio (cQFR) is a novel method for rapid computational estimation of fractional flow reserve (FFR). Discordance between FFR and cQFR has not been completely characterised.

Methods: We performed a post-hoc analysis of 504 vessels with angiographically intermediate stenosis in 504 patients who underwent measurement of FFR, coronary flow reserve (CFR), the index of microcirculatory resistance (IMR) and Duke jeopardy score.

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Objective: This study aimed to investigate the prevalence and prognostic significance of atherosclerotic aortic plaques (AAPs) or specific AAP types detected by nonobstructive angioscopy (NOA) in patients who underwent percutaneous coronary intervention (PCI).

Background: Although recent studies have reported the presence of various patterns of AAPs, identified by NOA, the clinical significance of the presence of AAPs remains elusive.

Methods: In this retrospective, multicenter cohort study, a total of 167 patients who underwent PCI and intra-aortic scans with NOA were studied.

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Background Although most coronary thromboses occur on the surface of lipid-rich plaque ( LRP ) with plaque rupture ( PR ), previous pathological and optical coherence tomography studies demonstrated diversity in the morphological characteristics of culprit plaque underlying the thrombus, including lesions with intact fibrous cap ( IFC ). We investigated the clinical significance of IFC in relation to the presence or absence of LRP observed via optical coherence tomography in culprit lesions of acute coronary syndrome. Methods and Results We investigated 510 patients with acute coronary syndrome who underwent optical coherence tomography for the culprit lesion.

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Article Synopsis
  • - The study investigated the use of phase-contrast cine-magnetic resonance imaging (PC-CMR) to assess coronary sinus flow (CSF) and global coronary flow reserve (G-CFR) in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) who underwent urgent PCI.
  • - Out of 116 enrolled patients, results showed that a corrected G-CFR of less than 2.33 was associated with a significantly worse prognosis for major adverse cardiac events over a median follow-up period of 17 months.
  • - The findings suggest that post-PCI G-CFR measurements from PC-CMR can be valuable for predicting adverse cardiac events, independent of traditional risk factors and infarct size.
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Aims: Contrast-flow quantitative flow ratio (cQFR) is a novel index of the functional severity of coronary stenosis, which can be calculated from three-dimensional quantitative coronary angiography. Previous studies have shown a high correlation between cQFR and fractional flow reserve. This study sought to investigate the prognostic value of the sum of cQFR in three vessels (3V-cQFR) in patients with stable coronary artery disease (CAD).

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Baseline cardiac troponin is a strong predictor of major adverse cardiac events (MACE), and the high sensitive assay can provide risk stratification under the 99th percentile values. Currently, prognostic benefit of PCI has not been established in patients with stable coronary artery disease (CAD), and the influence on baseline troponin levels is unknown. This study aimed to investigate the impact of PCI on baseline high-sensitivity cardiac troponin-I (hs-cTnI) levels and the association with MACE incidence.

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Objectives: This study sought to investigate the relationship of unstable plaque features with physiological lesion severity and microvascular dysfunction.

Background: The functional severity of epicardial lesions and microvascular dysfunction are both related to adverse clinical outcomes.

Methods: We investigated 382 de novo intermediate and severe coronary lesions in 340 patients who underwent optical coherence tomography, fractional flow reserve (FFR), and index of microcirculatory resistance (IMR) examinations.

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Background: Few studies have documented changes in global absolute coronary blood flow and global coronary flow reserve after percutaneous coronary intervention (PCI) in relation to regional physiological measures. Phase-contrast cine-magnetic resonance of the coronary sinus is a promising approach to quantify global absolute coronary blood flow. We aimed to assess the impact of elective PCI on global absolute coronary blood flow and global coronary flow reserve by quantifying coronary sinus flow (CSF) using phase-contrast cine-magnetic resonance in relation to regional physiological indices.

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Background: Few studies have documented changes in myocardial blood flow (MBF) after percutaneous coronary intervention (PCI). Phase-contrast cine cardiovascular MRI (PC-CCMR) of the coronary sinus (CS) is a promising approach to quantify MBF. The aim of this study was to quantify CS flow (CSF) on PC-CCMR as a measure of volumetric MBF before and after elective PCI.

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Background: Although several previous studies have indicated that optical coherence tomography (OCT)-derived minimal lumen area (MLA) correlates with fractional flow reserve (FFR) severity, other morphologic criteria for functionally significant coronary stenosis assessed by FFR have not been fully elucidated. This study aimed to identify OCT-based morphological predictors of physiologically significant ischemia assessed by FFR in angiographically intermediate coronary lesions.

Methods: We investigated 194 de novo intermediate coronary lesions in 178 patients with stable angina pectoris who underwent OCT imaging and FFR measurement.

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Descending mediastinitis caused by Streptococcus pyogenes (group A streptococcus, GAS) is rare among cases of invasive GAS infection. In this report, we describe a case of a cervical abscess and secondary descending mediastinitis in a previously healthy 39-year-old Japanese man. The patient presented with a 2-week history of a sore throat, and subsequently developed an abscess and descending mediastinitis.

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The aims of this study were to develop and improve the sensitivity of an electron spin resonance (ESR) spectrometer and to demonstrate its functionality for dosimetry in measuring ESR signals from radiation-exposed fingernails. The newly-developed spectrometer was a lightweight (22 kg) one-box ESR device with a resonator showing a Q-factor higher than that of a previous Keycom model, which is quieter, without influence from magnetic modulation, and contains a fingernail positioner. The authors obtained the best measurement result after the cavity Q-factor was increased to more than 7,200 by continuous polishing of the inner surface of the cavity using deerskin.

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Various hybrid compounds comprised of two types of nitroxide radicals and either a pentamethine (Cy5) or trimethine cyanine (Cy3) were synthesized. The nitroxide radicals were linked either via an ester-bond to one or two N-alkyl carboxyl-terminated groups of Cy5, or via two amido-bonds (aminocarbonyl or carbonylamino group) to the 5-position of the indolenine moieties of Cy5 and Cy3. Changes in fluorescence and ESR intensities of the hybrid compounds were measured before and after addition of Na ascorbate in PBS (pH 7.

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