Shunsuke Ogura
Juntendo University
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Featured researches published by Shunsuke Ogura.
Pacing and Clinical Electrophysiology | 1995
Yuji Nakazato; Yasuro Nakata; Teruhikoa Hisaoka; Masataka Sumiyoshi; Shunsuke Ogura; Hiroshi Yamaguchi
NAKAZATO, Y., et al.: Clinical and Electrophysiological Characteristics of Atrial Standstill. To clarify the clinical and electrophysiological characteristics of atrial standstill (AS) we studied 11 patients (7 males and 4 females), whose average age was 62 years and who were followed over a period of 4–179 months. Underlying heart disease was present in nine patients and two cases were idiopathic. Major clinical symptoms in the 11 cases included Adams‐Stokes attacks, and dyspnea on exertion. In the standard 12‐lead ECGs obtained on admission, the P wave was absent in six cases. Atrial flutter (AF) was noted in 3, atrial fibrillation (Af) in 1, and multifocal atrial tachycardia in 1. In some cases, the ECG initially showed AF or Af, and was transformed after several years into ectopic atrial tachycardia or an ectopic atrial rhythm with a markedly decreased amplitude of the P wave. Finally, the P wave disappeared over a prolonged period. When intracardiac mapping was performed, the atrial electrograms tended to diminish at the site of high, mid‐lateral right atrium (RA). Electrograms were remained present in the vicinity of the tricuspid valve (TV) annulus. A repeated mapping and pacing study conducted in two patients revealed that the “silent” area spread toward the lower site of RA. During the average follow‐up period of 64 months, four patients died. The interval until death in one patient with myocarditis was 6 months, and in another with dilated cardiomyopathy (DCM) it was 8 months. It appears that the atrial muscular lesion starts in the high lateral RA and progresses toward the lower RA, then to the vicinity of the TV annulus. A diffuse and progressive disturbance may occur not only in the atrial muscle, but also in the atrioventricular conduction system in patients with AS who had progressive myocarditis or DCM.
Pacing and Clinical Electrophysiology | 1992
Masataka Sumiyoshi; Yasuro Nakata; Takashi Tokano; Masayuki Yasuda; Yasuhiko Ohno; Teruhiko Hisaoka; Shunsuke Ogura; Yuji Nakazato; Hiroshi Yamaguchi
To clarify the clinical significance of an abnormally prolonged paced QRS duration, we studied 114 patients who had undergone pacing for atrioventricular block (AVB). Patients were divided into two groups: group I consisted of 29 patients with at least one paced QRS duration ≥ 180 msec during the follow‐up period; group II consisted of 85 patients with paced QRS durations < 180 msec. The clinical background, QRS complexes before pacing, and the echocardiographic findings were assessed. Males (P < 0.05), those with H‐V block (P< 0.05) and a wider QRS complex of conducted and escape beats (both P < 0.01) were dominant in group I. The incidence of underlying heart disease was greater in group I than in group II (83% vs 32%, P < 0.01). Reduced left ventricular ejection fraction (LVEF) and increased left ventricular end‐diastolic dimension (LVDd) were more prominent in group I than in group II (LVEF 0.49 ± 0.17 vs 0.68 ± 0.10, P < 0.01, LVDd 57.1 ± 7.9 mm vs 48.5 ± 5.6 mm, P < 0.01). The paced QRS duration correlated with LVEF (r = ‐0.61) and LVDd (r = 0.81). A paced QRS duration ≥ 180 msec was sensitive and specific for a LVEF < 0.5 (83.3% and 85.2%) and LVDd ≥ 60 mm (100% and 81.4%). We conclude that patients with a prolonged paced QRS duration have more serious heart disease, and the paced QRS duration can be a useful indicator of impaired LV function.
American Journal of Cardiology | 1995
Yuji Nakazato; Yasuro Nakata; Kaoru Nakazato; Takashi Tokano; Masayuki Yasuda; Yasuhiko Ohno; Yoshihisa Matsumoto; Masataka Sumiyoshi; Shunsuke Ogura; Hiroshi Yamaguchi; Toru Iwa
Abstract In conclusion, filtered QRS duration in time-domain analysis of SAEs was influenced by gender and body characteristics in healthy subjects; however, the parameters in spectral turbulence analysis were not.
Pacing and Clinical Electrophysiology | 1994
Yuji Nakazato; Yasuro Nakata; Takashi Tokano; Masayuki Yasuda; Yasuhiko Ohno; Teruhiko Hisaoka; Masataka Sumiyoshi; Shunsuke Ogura; Hiroshi Yamaguchi; Hiroo Ohi; Mitsuru Shimizu; Sachio Kawai; Ryozo Okada
We compared His‐bundle electrograms with pathological findings of the atrioventricular conduction system in four patients with complete atrioventricular intra‐His block with narrow QRS complexes on ECG. Split His electrograms were recorded at the time of electrophysiological study. The patients died from noncardiac causes at 10 days, 1 year, 4 years, and 9 years, respectively, after the pacemaker implantation. Serial sections through the atrioventricular conduction system revealed strictly localized more than 50% reduction of conducting cells replaced by fibrosis at the branching portion of His bundle. The proximal portions of the bundle branches also exhibited decrease of the conducting cells showing a rough positive relation with the patients age. Therefore, we considered that the H1 spikes seen on His‐bundle electrograms originated from the penetrating portion of His, which was virtually intact in our cases, and that the H2 spikes originated from the right side of the distal branching portion of His.
Japanese Heart Journal | 1993
Masataka Sumiyoshi; Yasuro Nakata; Teruhiko Hisaoka; Shunsuke Ogura; Yuji Nakazato; Sachio Kawai; Ryozo Okada; Hiroshi Yamaguchi
American Heart Journal | 1996
Masataka Sumiyoshi; Yasuro Nakata; Masayuki Yasuda; Takashi Tokano; Shunsuke Ogura; Yuji Nakazato; Hiroshi Yamaguchi
Japanese Heart Journal | 1997
Yuji Nakazato; Yasuro Nakata; Masayuki Yasuda; Kaoru Nakazato; Masataka Sumiyoshi; Shunsuke Ogura; Hiroshi Yamaguchi
Japanese Circulation Journal-english Edition | 1995
Masataka Sumiyoshi; Yasuro Nakata; Masayuki Yasuda; Takashi Tokano; Yasuhiko Ohno; Shunsuke Ogura; Yuji Nakazato; Hiroshi Yamaguchi
Japanese Heart Journal | 1994
Yuji Nakazato; Yasuro Nakata; Takashi Tokano; Yasuhiko Ohno; Teruhiko Hisaoka; Masataka Sumiyoshi; Shunsuke Ogura; Hiroshi Yamaguchi; Sachio Kawai; Ryozo Okada; Nobutane Hazato
Japanese Circulation Journal-english Edition | 1996
Yoshitaka Iwama; Masataka Sumiyoshi; Kosei Tanimoto; Shunsuke Ogura; Yuji Nakazato; Yasuro Nakata; Hiroshi Yamaguchi