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Dive into the research topics where Ryudo Fujiwara is active.

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Featured researches published by Ryudo Fujiwara.


Europace | 2016

Circulating intermediate CD14++CD16+monocytes are increased in patients with atrial fibrillation and reflect the functional remodelling of the left atrium

Atsushi Suzuki; Koji Fukuzawa; Tomoya Yamashita; Akihiro Yoshida; Naoto Sasaki; Takuo Emoto; Asumi Takei; Ryudo Fujiwara; Tomoyuki Nakanishi; Soichiro Yamashita; Akinori Matsumoto; Hiroki Konishi; Hirotoshi Ichibori; Ken-ichi Hirata

Aims A recent large clinical study demonstrated the association between intermediate CD14++CD16+monocytes and cardiovascular events. However, whether that monocyte subset contributes to the pathogenesis of atrial fibrillation (AF) has not been clarified. We compared the circulating monocyte subsets in AF patients and healthy people, and investigated the possible role of intermediate CD14++CD16+monocytes in the pathophysiology of AF. Methods and results This case–control study included 44 consecutive AF patients without systemic diseases referred for catheter ablation at our hospital, and 40 healthy controls. Patients with systemic diseases, including structural heart disease, hepatic or renal dysfunction, collagen disease, malignancy, and inflammation were excluded. Monocyte subset analyses were performed (three distinct human monocyte subsets: classical CD14++CD16−, intermediate CD14++CD16+, and non-classical CD14+CD16++monocytes). We compared the monocyte subsets and evaluated the correlation with other clinical findings. A total of 60 participants (30 AF patients and 30 controls as an age-matched group) were included after excluding 14 AF patients due to inflammation. Atrial fibrillation patients had a higher proportion of circulating intermediate CD14++CD16+monocytes than the controls (17.0 ± 9.6 vs. 7.5 ± 4.1%, P < 0.001). A multivariable logistic regression analysis demonstrated that only the proportion of intermediate CD14++CD16+monocytes (odds ratio: 1.316; 95% confidence interval: 1.095–1.582, P = 0.003) was independently associated with the presence of AF. Intermediate CD14++CD16+monocytes were negatively correlated with the left atrial appendage flow during sinus rhythm (r= −0.679, P = 0.003) and positively with the brain natriuretic peptide (r = 0.439, P = 0.015). Conclusion Intermediate CD14++CD16+monocytes might be closely related to the pathogenesis of AF and reflect functional remodelling of the left atrium.


Europace | 2013

Time-dependent effect of cardiac resynchronization therapy on ventricular repolarization and ventricular arrhythmias.

Mitsuaki Itoh; Akihiro Yoshida; Koji Fukuzawa; Kunihiko Kiuchi; Kimitake Imamura; Ryudo Fujiwara; Atsushi Suzuki; Tomoyuki Nakanishi; Soichiro Yamashita; Akinori Matsumoto; Ken-ichi Hirata

AIMS Cardiac resynchronization therapy (CRT) improves the clinical status of patients with congestive heart failure, although left ventricular epicardial pacing may increase transmural dispersion of repolarization (TDR). The aim of this study was to investigate the time-dependent effect of CRT on ventricular repolarization and ventricular arrhythmia at mid-term follow-up. METHODS AND RESULTS The study group consisted of 84 patients treated with CRT. Twelve-lead electrocardiogram was digitally recorded and Tpeak-to-Tend interval (Tp-e) was measured at baseline, 1 week, 1 month, and 3, 6, and 12 months after device implantation. We determined the time-dependent changes in Tp-e, ventricular tachycardia and ventricular fibrillation (VT/VF) during 12 months of follow-up, in both CRT responders and non-responders. Seventeen of 84 patients (20%) had VT/VF during first year. Six of those 17 patients (35%) experienced VT/VF within 1 month of implantation and diminished over time. Tp-e decreased significantly at 6 and 12 months after implantation compared with 1 week [108 ± 14 ms at 1 week vs. 97 ± 21 ms at 6 months (P = 0.03) and 95 ± 19 ms at 12 months (P = 0.01)]. Responders demonstrated a greater time-dependent reduction of Tp-e at 6 and 12 months of CRT and had a lower rate of VT/VF compared with non-responders (log-rank test, P = 0.004). CONCLUSION Transmural dispersion of repolarization and the number of patients with VT/VF decreased over time after CRT. Patients with reverse remodelling demonstrated a lower rate of VT/VF and a greater time-dependent reduction of TDR.


Journal of Arrhythmia | 2016

Impact of esophageal temperature monitoring guided atrial fibrillation ablation on preventing asymptomatic excessive transmural injury

Kunihiko Kiuchi; Katsunori Okajima; Akira Shimane; Gaku Kanda; Kiminobu Yokoi; Jin Teranishi; Kousuke Aoki; Misato Chimura; Takayoshi Toba; Shogo Oishi; Takahiro Sawada; Yasue Tsukishiro; Tetsuari Onishi; Seiichi Kobayashi; Yasuyo Taniguchi; Shinichiro Yamada; Yoshinori Yasaka; Hiroya Kawai; Akihiro Yoshida; Koji Fukuzawa; Mitsuaki Itoh; Kimitake Imamura; Ryudo Fujiwara; Atsushi Suzuki; Tomoyuki Nakanishi; Soichiro Yamashita; Ken-ichi Hirata; Hiroshi Tada; Hiro Yamasaki; Yoshihisa Naruse

Even with the use of a reduced energy setting (20–25 W), excessive transmural injury (ETI) following catheter ablation of atrial fibrillation (AF) is reported to develop in 10% of patients. However, the incidence of ETI depends on the pulmonary vein isolation (PVI) method and its esophageal temperature monitor setting. Data comparing the incidence of ETI following AF ablation with and without esophageal temperature monitoring (ETM) are still lacking.


Journal of Arrhythmia | 2015

Topographic variability of the left atrium and pulmonary veins assessed by 3D-CT predicts the recurrence of atrial fibrillation after catheter ablation☆

Kunihiko Kiuchi; Akihiro Yoshida; Asumi Takei; Koji Fukuzawa; Mitsuaki Itoh; Kimitake Imamura; Ryudo Fujiwara; Atsushi Suzuki; Tomoyuki Nakanishi; Soichiro Yamashita; Ken-ichi Hirata; Gaku Kanda; Katsunori Okajima; Akira Shimane; Shinichiro Yamada; Yasuyo Taniguchi; Yoshinori Yasaka; Hiroya Kawai

Catheter ablation (CA) is an established therapy for atrial fibrillation (AF). However, the assessment of anatomical information and predictors of AF recurrence remain unclear. We investigated the relationship between anatomical information on the left atrium (LA) and pulmonary veins (PVs) from three‐dimensional computed tomography images and the recurrence of AF after CA.


Pacing and Clinical Electrophysiology | 2014

Discrepancy between electrical and mechanical dyssynchrony in patients with heart failure and an electrical disturbance.

Ryudo Fujiwara; Akihiro Yoshida; Koji Fukuzawa; Asumi Takei; Kunihiko Kiuchi; Mitsuaki Itoh; Kimitake Imamura; Atsushi Suzuki; Tomoyuki Nakanishi; Soichiro Yamashita; Akinori Matsumoto; Hidekazu Tanaka; Ken-ichi Hirata

Cardiac resynchronization therapy (CRT) improves the survival rates of patients with heart failure, but 30–40% of them do not respond to CRT, partially because of the position of the left ventricular (LV) lead. The relationship between the electrical and mechanical activation of the left ventricle is unknown. The aim of this study was to compare the electrical and mechanical dyssynchrony.


Journal of Cardiology | 2016

Optical coherence tomography study of chronic-phase vessel healing after implantation of bare metal and paclitaxel-eluting self-expanding nitinol stents in the superficial femoral artery.

Amane Kozuki; Toshiro Shinke; Hiromasa Otake; Yoichi Kijima; Tomoya Masano; Ryoji Nagoshi; Kimitake Imamura; Ryudo Fujiwara; Hiroyuki Shibata; Ryo Takeshige; Yoshiro Tsukiyama; Kenichi Yanaka; Shinsuke Nakano; Yusuke Fukuyama; Seinosuke Kawashima; Ken-ichi Hirata; Junya Shite

BACKGROUND This study aimed to assess chronic-phase suppression of neointimal proliferation and arterial healing following paclitaxel-coated (PTX) and bare metal stent (BMS) implantation in the superficial femoral artery using optical coherence tomography (OCT). METHODS Twenty-five patients with 68 stents underwent an 8-month OCT follow-up. Besides standard OCT variables, neointimal characterization and frequencies of peri-strut low-intensity area (PLIA), macrophage accumulation, and in-stent thrombi were evaluated. RESULTS The mean neointimal thickness was significantly less with PTX stents (544.9±202.2 μm vs. 865.0±230.6 μm, p<0.0001). The covered and uncovered strut frequencies were significantly smaller and larger, respectively, in the PTX stent group vs. the BMS group (93.7% vs. 99.4%; p<0.0001, 4.0% vs. 0.4%; p<0.0001, respectively). Heterogeneous neointima was only observed in the PTX stent group (12.5% vs. 0%, p=0.017). The frequencies of PLIA and macrophage accumulation were significantly greater in the PTX stent group (87.2% vs. 67.6%, p=0.001 and 46% vs. 9.1%, p=0.003, respectively). CONCLUSION After 8 months, reduced neointimal proliferation was observed with PTX stent implantation. On the other hand, delayed arterial healing was observed compared with BMS.


Journal of Arrhythmia | 2015

Prophylactic catheter ablation of ventricular tachycardia before cardioverter-defibrillator implantation in patients with non-ischemic cardiomyopathy: Clinical outcomes after a single endocardial ablation

Atsushi Suzuki; Akihiro Yoshida; Asumi Takei; Koji Fukuzawa; Kunihiko Kiuchi; Kaoru Takami; Mitsuaki Itoh; Kimitake Imamura; Ryudo Fujiwara; Tomoyuki Nakanishi; Soichiro Yamashita; Akinori Matsumoto; Akira Shimane; Katsunori Okajima; Ken-ichi Hirata

Outcomes related to prophylactic catheter ablation (PCA) for ventricular tachycardia (VT) before implantable cardioverter‐defibrillator (ICD) implantation in non‐ischemic cardiomyopathy (NICM) are not well characterized. We assessed the efficacy of single endocardial PCA in NICM patients.


Europace | 2015

Reduction in coronary microvascular resistance through cardiac resynchronization and its impact on chronic reverse remodelling of left ventricle in patients with non-ischaemic cardiomyopathy

Mitsuaki Itoh; Toshiro Shinke; Akihiro Yoshida; Amane Kozuki; Asumi Takei; Koji Fukuzawa; Kunihiko Kiuchi; Kimitake Imamura; Ryudo Fujiwara; Atsushi Suzuki; Tomoyuki Nakanishi; Soichiro Yamashita; Akinori Matsumoto; Hiromasa Otake; Ryoji Nagoshi; Junya Shite; Ken-ichi Hirata

AIMS Left bundle branch block (LBBB) induces mechanical dyssynchrony, thereby compromising the coronary circulation in non-ischaemic cardiomyopathy. We sought to examine the effects of cardiac resynchronization therapy (CRT) on coronary flow dynamics and left ventricular (LV) function. METHODS AND RESULTS Twenty-two patients with non-ischaemic cardiomyopathy (New York Heart Association class, III or IV; LV ejection fraction, ≤35%; QRS duration, ≥130 ms) were enrolled. One week after implantation of the CRT device, coronary flow velocity and pressure in the left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCx) were measured invasively, before and after inducing hyperemia by adenosine triphosphate administration, with two programming modes: sequential atrial and biventricular pacing (BiV) and atrial pacing in patients with LBBB or sequential atrial and right ventricular pacing in patients with complete atrioventricular block (Control). We assessed hyperemic microvascular resistance (HMR, mean distal pressure divided by hyperemic average peak velocity) and the relationship between the change in HMR and mid-term LV reverse remodelling. Hyperemic microvascular resistance was lower during BiV than during Control (LAD: 1.76 ± 0.47 vs. 1.54 ± 0.45, P < 0.001; LCx: 1.92 ± 0.42 vs. 1.73 ± 0.31, P = 0.003). The CRT-induced change in HMR of the LCx correlated with the percentage change in LV ejection fraction (R = -0.598, P = 0.011) and LV end-systolic volume (R = 0.609, P = 0.010) before and 6 months after CRT. CONCLUSION Cardiac resynchronization therapy improves coronary flow circulation by reducing microvascular resistance, which might be associated with LV reverse remodelling.


Pacing and Clinical Electrophysiology | 2014

Visualization of the Antegrade Fast and Slow Pathway Inputs in Patients with Slow-Fast Atrioventricular Nodal Reentrant Tachycardia

Atsushi Suzuki; Akihiro Yoshida; Asumi Takei; Koji Fukuzawa; Kunihiko Kiuchi; Satoko Tanaka; Mitsuaki Itoh; Kimitake Imamura; Ryudo Fujiwara; Tomoyuki Nakanishi; Soichiro Yamashita; Akinori Matsumoto; Hiroki Konishi; Hirotoshi Ichibori; Ken-ichi Hirata

Mapping of the antegrade fast pathway (A‐FP) exact sites and antegrade slow pathway (A‐SP) input locations has not been well described.


Journal of the American College of Cardiology | 2015

CIRCULATING INTERMEDIATE CD14++CD16+ MONOCYTES ARE INCREASED IN PATIENTS WITH ATRIAL FIBRILLATION AND REFLECT FUNCTIONAL REMODELING OF LEFT ATRIUM

Atsushi Suzuki; Koji Fukuzawa; Tomoya Yamashita; Akihiro Yoshida; Naoto Sasaki; Takuo Emoto; Asumi Takei; Ryudo Fujiwara; Tomoyuki Nakanishi; Soichiro Yamashita; Akinori Matsumoto; Hiroki Konishi; Hirotoshi Ichibori; Nobutaka Inoue; Ken-ichi Hirata

Recent large clinical study demonstrated association of intermediate CD14++CD16+monocytes (IM) with cardiovascular events. We investigated the possible role of IM in pathophysiology of atrial fibrillation (AF). This case-control study included 30 AF patients (17 paroxysmal and 13 persistent AF

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Atsushi Suzuki

National Institute of Advanced Industrial Science and Technology

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