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Featured researches published by Riyako Shibata.


Pacing and Clinical Electrophysiology | 2006

Ventricular Fibrillation in a Patient with Prominent J Wave in the Inferior and Lateral Electrocardiographic Leads After Gastrostomy

Norihiro Komiya; Ryo Imanishi; Hiroaki Kawano; Riyako Shibata; Manabu Moriya; Satoki Fukae; Yoshiyuki Doi; Kojiro Nakao; Shinji Seto; Katsusuke Yano

We describe the case of a 39‐year‐old man who experienced a ventricular fibrillation storm related to a prominent J wave in the inferior and lateral electrocardiographic leads on the day after gastrostomy. The J wave slowly decreased after amiodarone therapy (400 mg/day) was started, and ventricular fibrillation disappeared.


Pacing and Clinical Electrophysiology | 2004

Abnormal Right Atrial Electrograms Predict the Transition to Chronic Atrial Fibrillation in Paced Patients with Sick Sinus Syndrome

Koji Miyamoto; Kojiro Nakao; Shinji Seto; Riyako Shibata; Yoshiyuki Doi; Satoki Fukae; Kiyotaka Matsuo; Norihiro Komiya; Katsusuke Yano

Although pacing therapy for sick sinus syndrome (SSS) is established, the risk of developing chronic atrial fibrillation (CAF) makes pacing therapy infeasible in some patients. We evaluated whether electrophysiological characteristics of atrial muscle can serve as predictors of the transition to CAF after pacemaker implantation in patients with SSS. Eighty‐nine patients with SSS underwent electrophysiological study before pacing therapy. Catheter mapping of 12 right atrial sites was performed during sinus rhythm during electrophysiological. An abnormal atrial electrogram was defined as having a duration of 100 ms or longer, or eight or more fragmented deflections, or both. Right atrial extrastimulation was also performed for atrial vulnerability. After electrophysiological study, all patients underwent pacemaker implantation and were followed up. During the follow‐up period of 85 ± 50 months, development of CAF was observed in 12 patients (group A). The remaining 77 patients remained in sinus rhythm (group B). There were significantly more abnormal atrial electrograms in group A than group B (2.7 ± 2.3 vs 0.8 ± 1.2; P < 0.001). The distribution of abnormal atrial electrograms was also greater in group A; patients in group A had more abnormal atrial electrograms than patients in group B in both the high and middle right atrium (P < 0.005 and P < 0.01, respectively). Kaplan‐Meier analysis showed that almost 50% of the paced patients with abnormal atrial electrograms (n = 42) developed CAF (P < 0.005). Our data suggest that the existence of abnormal atrial electrograms is predictive of the transition to CAF in paced patients with SSS. (PACE 2004; 27:644–650)


Pacing and Clinical Electrophysiology | 2006

Angiotensin‐Converting Enzyme Inhibitor Suppresses the Incidence of Prolonged and Fractionated Right Atrial Electrograms

Riyako Shibata; Kojiro Nakao; Satoki Fukae; Kiyotaka Matsuo; Katsusuke Yano

Introduction: Although prolonged and fractionated right atrial electrograms have been reported as predictors of the development of chronic atrial fibrillation in patients with paroxysmal atrial fibrillation (PAF), the effects of angiotensin‐converting enzyme inhibitor (ACEI) on these electrophysiologic abnormalities remain unknown. The purpose of this study was to evaluate whether ACEI influences these electrophysiologic abnormalities of atrial muscle in patients with PAF.


The Annals of Thoracic Surgery | 2003

A rare case of aortic tube graft occlusion 35 years after coarctectomy

Naoto Ashizawa; Hirofumi Tasaki; Riyako Shibata; Yuji Koide; Shinji Seto; Shiro Yamachika; Shiro Hazama; Kiyoyuki Eishi; Katsusuke Yano

A 52-year-old male with a history of repair of aortic coarctation by prosthetic tube graft replacement 35-years ago developed anterior spinal artery syndrome caused by acute functional occlusion of the aorta at the repair site where pseudoaneurysm formation was observed. The patient was rescued by an emergency axillofemoral bypass, and residual hypertension in upper limbs was improved by elective ascending aorta-descending aorta bypass grafting.


Pacing and Clinical Electrophysiology | 2004

Relation Between History of Paroxysmal Atrial Fibrillation and Electrophysiological Abnormalities of Atrial Muscle

Kojiro Nakao; Shinji Seto; Riyako Shibata; Yoshiyuki Doi; Satoki Fukae; Norihiro Komiya; Katsusuke Yano

Although electrophysiological abnormalities of atrial muscle have been evaluated in patients with paroxysmal atrial fibrillation (PAF), no prior study has determined the contribution of the patients history of PAF to electrophysiological abnormalities. The study population consisted of 108 patients (71 men; mean age, 57 ± 14 years) with symptomatic and idiopathic PAF who underwent electrophysiological study. Before electrophysiological study, histories of frequency, number of PAF episodes per month, and duration, a time interval from the first episode of PAF to electrophysiological study, were examined. At electrophysiological study, endocardial electrograms from 12 right atrial sites were recorded during sinus rhythm, and the right atrial effective refractory period was determined. Longest duration of atrial electrograms, maximal number of fragmented deflections, and number of abnormal atrial electrograms recorded at the right atrial sites were significantly greater in the frequent group (> 1 PAF episode per month, n = 57) than in the infrequent group (< 1 PAF episode per month, n = 51) (98 ± 18 ms vs 88 ± 16 ms, P < 0.005; 8.7 ± 2.6 vs 7.5 ± 2.6, P < 0.05; and 2.2 ± 2.2 vs 1.4 ± 1.6, P < 0.05, respectively). Indices of atrial vulnerability were also greater in the frequent group. Duration of PAF history was significantly correlated with longest duration r = 0.52, P < 0.0001), maximal number of fragmented deflections r = 0.51, P < 0.0001), and number of abnormal atrial electrograms r = 0.58, P < 0.0001). More frequent episodes and longer history of PAF significantly increased the electrophysiological abnormalities of the atrial muscle, suggesting that PAF results in gradual electrical remodeling of the atrial muscle.


Japanese Circulation Journal-english Edition | 2008

PE-137 The Atrial Vulnerability Parameters in Lone Atrial Fibrillation Pataients with Subclinical Hypothyroidism(Arrhythmia, diagnosis/Pathophysiology/EPS(06)(A),Poster Session(English),The 72nd Annual Scientific Meeting of the Japanese Circulation Society)

Norihiko Komiya; Shinji Seto; Satoki Fukae; Kojiro Nakao; Riyako Shibata; Takashi Ishimatsu; Ryoji Sakamoto


Japanese Circulation Journal-english Edition | 2008

OE-087 The Prevalence and Prognosis of Newly Onset Atrial Fibrillation : Population-Based Study of Four Decades(Preventive medicine/Epidemiology/Education(01)(H),Oral Presentation(English),The 72nd Annual Scientific Meeting of the Japanese Circulation Society)

Satoki Fukae; Masazumi Akahoshi; Norihiro Komiya; Takashi Ishimatsu; Kojiro Nakao; Riyako Shibata; Akira Tsunetoh; Daisuke Haruta; Ryoji Sakamoto; Shinji Seto


Japanese Circulation Journal-english Edition | 2008

PJ-391 Angiotensin-Converting Enzyme Inhibitors and Statins Equally Suppress the Incidence of Abnormal Atrial Electrograms in Patients with Lone Paroxysmal Atrial Fibrillation(Arrhythmia, diagnosis/Pathophysiology/EPS(14)(A),Poster Session(Japanese),The 72nd Annual Scientific Meeting of the Japanese Circulation Society)

Kojiro Nakao; Riyako Shibata; Satoki Fukae; Kiyotaka Matsuo


Japanese Circulation Journal-english Edition | 2006

PE-230 The Effect of Statin on Atrial Fibrillation Promotion in Patients with Brady-tachy Syndrome(Arrhythmia, therapy-12 (A) PE39,Poster Session (English),The 70th Anniversary Annual Scientific Meeting of the Japanese Circulation Society)

Norihiro Komiya; Shinji Seto; Satoki Fukae; Manabu Moriya; Riyako Shibata; Yoshiyuki Doi; Kojiro Nakao; Katsusuke Yano


Rev. Soc. Parag. Cardiol. (Impr.) | 2005

Efectos del envejecimiento sobre los períodos refractarios y la conducción auricular en pacientes con fibrilación auricular paroxística idiopática obtenidos mediante estimulación auricular programada

Shojiro Isomoto; Osmar Antonio Centurión; Riyako Shibata; Yoshiyuki Doi; Satoki Fukae; Kojiro Nakao; Norihiro Komiya; Katsusuke Yano

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