Keijirou Nakamura
Toho University
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Publication
Featured researches published by Keijirou Nakamura.
Pacing and Clinical Electrophysiology | 2015
Mahito Noro; Xin Zhu; Takahito Takagi; Naohiko Sahara; Yuriko Narabayashi; Hikari Hashimoto; Naoshi Ito; Yoshinari Enomoto; Keijirou Nakamura; Shingo Kujime; Tuyoshi Sakai; Takao Sakata; Kaoru Sugi
Pacemaker generators are routinely implanted in the anterior chest. However, where to place the generator may need to be considered from the mental, functional, and cosmetic standpoints.
Circulation | 2016
Mahito Noro; Xin Zhu; Yoshinari Enomoto; Masako Asami; Rina Ishii; Yasutake Toyoda; Naohiko Sahara; Takahito Takagi; Yuriko Narabayasi; Hikari Hashimoto; Naoshi Ito; Shingo Kujime; Yasuhiro Oikawa; Hiroyuki Tatsunami; Tsuyoshi Sakai; Keijirou Nakamura; Takao Sakata; Kaoru Sugi
BACKGROUND Subcutaneous implantable cardiac defibrillator (S-ICD) systems have a lower invasiveness than traditional ICD systems, and expand the indications of ICD implantations. The S-ICD standard defibrillation shock output energy, however, is approximately 4 times that of the traditional ICD system. This raises concern about the efficacy of the defibrillation and myocardial injury. In this study, we investigated the defibrillation efficacy and myocardial injury with S-ICD systems based on computer simulations. METHODS AND RESULTS First, computer simulations were performed based on the S-ICD system configurations proposed in a previous study. Furthermore, simulations were performed by placing the lead at the left or right parasternal margin and the pulse generator in the superior and inferior positions (0-10 cm) of the recommended site. The simulated defibrillation threshold (DFT) for the 4 S-ICD system configurations were 30.1, 41.6, 40.6, and 32.8 J, which were generally similar to the corresponding clinical results of 33.5, 40.4, 40.1, and 34.3 J. CONCLUSIONS The simulated DFT were generally similar to their clinical counterparts. In the simulation, the S-ICD system had a higher DFT but relatively less severe myocardial injury compared with the traditional ICD system. Further, the lead at the right parasternal margin may correspond to a lower DFT and cause less myocardial injury.
Circulation | 2016
Mahito Noro; Xin Zhu; Yoshinari Enomoto; Yasuhiro Oikawa; Hiroyuki Tatsunami; Rina Ishii; Yasutake Toyoda; Masako Asami; Naohiko Sahara; Takahito Takagi; Yuriko Narabayashi; Hikari Hashimoto; Naoshi Ito; Shingo Kujime; Tsuyoshi Sakai; Keijirou Nakamura; Takao Sakata; Haruhiko Abe; Kaoru Sugi
BACKGROUND To reduce myocardial damage caused by implantable cardioverter defibrillator (ICD) shock, the left axilla was studied as an alternative pulse generator implantation site, and compared with the traditional implantation site, the left anterior chest. METHODSANDRESULTS Computer simulation was used to study the defibrillation conduction pattern and estimate the simulated defibrillation threshold (DFT) and myocardial damage when pulse generators were placed in the left axilla and left anterior chest, respectively; pulse generators were also newly implanted in the left axilla (n=30) and anterior chest (n=40) to compare the corresponding DFT. On simulation, when ICD generators were implanted in the left axilla, compared with the left anterior chest, the whole heart may be defibrillated with a lower defibrillation energy (left axilla 6.4 J vs. left anterior chest 12.0 J) and thus the proportion of cardiac myocardial damage may be reduced (2.1 vs. 4.2%). Clinically, ventricular fibrillation was successfully terminated with a defibrillation output ≤5 J in 86.7% (26/30) of the left axillary group, and in 27.5% (11/40) of the left anterior group (P<0.001). CONCLUSIONS Clinically and theoretically, the left axilla was shown to be an improved ICD implantation site that may reduce DFT and lessen myocardial damage due to shock. Lower DFT also facilitates less myocardial damage, as a result of the lower shock required.
Journal of Atherosclerosis and Thrombosis | 2010
Hirofumi Noike; Keijirou Nakamura; Yuukou Sugiyama; Takuo Iizuka; Kazuhiro Shimizu; Mao Takahashi; Keiichi Hirano; Masayo Suzuki; Hiroshi Mikamo; Takahiro Nakagami; Kohji Shirai
Japanese Circulation Journal-english Edition | 2011
Mahito Noro; Shingo Kujime; Naoshi Ito; Yoshinari Enomoto; Keijirou Nakamura; Tsuyoshi Sakai; Takao Sakata; Kaoru Sugi
Circulation | 2011
Mahito Noro; Shingo Kujime; Naoshi Ito; Yoshinari Enomoto; Keijirou Nakamura; Tsuyoshi Sakai; Takao Sakata; Kaoru Sugi
Journal of Cardiology | 2006
Hirofumi Noike; Shin Satoh; Kawana H; Hirano K; Takeshi Sakurai; Yuko Sugiyama; Takuo Iizuka; Mao Takahashi; Kazuhiro Shimizu; Keijirou Nakamura; Hidefumi Ohsawa; Kawashima T
Choonpa Igaku | 2008
Yuko Sugiyama; Masayo Suzuki; Keiichi Hirano; Keijirou Nakamura; Mao Takahashi; Kazuhiro Shimizu; Hirofumi Noike; Tsuyoshi Tabata; Takanobu Tomaru
Journal of Cardiology | 2005
Hirofumi Noike; Takashi Hitsumoto; Yuko Sugiyama; Takeshi Sakurai; Shin Satoh; Takuo Iizuka; Mao Takahashi; Kazuhiro Shimizu; Keijirou Nakamura; Hidefumi Ohsawa
Journal of Cardiology | 2004
Takashi Hitsumoto; Takuo Iizuka; Mao Takahashi; Keijirou Nakamura; Kazuhiro Shimizu; Shin Satoh; Yuko Sugiyama; Takeshi Sakurai; Hirofumi Noike; Hidefumi Ohsawa; Hitoshi Watanabe; Kohji Shirai