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Dive into the research topics where Haruhiko Onaka is active.

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Featured researches published by Haruhiko Onaka.


Journal of the American College of Cardiology | 1994

Left ventricular wall motion abnormalities in patients with subarachnoid hemorrhage: Neurogenic stunned myocardium☆

Tatsuji Kono; Hiroshi Morita; Toshihiko Kuroiwa; Haruhiko Onaka; Hiroyuki Takatsuka; Akira Fujiwara

OBJECTIVES The purpose of this study was to determine whether a relation exists between electrocardiographic (ECG) abnormalities and left ventricular wall motion in patients with subarachnoid hemorrhage. BACKGROUND Although ECG changes simulating acute myocardial infarction are frequently seen in patients with subarachnoid hemorrhage, their relation to left ventricular wall motion has not been established. METHODS Twelve patients with subarachnoid hemorrhage were classified according to the presence of ST segment elevation in at least two consecutive leads on admission: seven patients with ST segment elevation (group I) and five patients without ST segment elevation (group II). No patients had a previous history of heart disease. Left ventricular regional wall motion was evaluated by the centerline method. The mean (+/- SEM) duration from onset of subarachnoid hemorrhage to left ventriculography was 9 +/- 3 h in group I and 10 +/- 1 h in group II. Coronary angiography was performed to rule out wall motion abnormalities due to coronary artery disease while the ST segment was still elevated. Two-dimensional echocardiography was used to evaluate wall motion thereafter. RESULTS All patients in group I showed ST segment elevation in ECG leads V4 to V6. Wall motion of the left ventricular apex was significantly reduced in group I compared with group II (-2.48 +/- 0.41 vs. -0.45 +/- 0.72, p < 0.02). No patients showed organic stenosis or vasospasm, or both, of epicardial coronary arteries. Wall motion abnormalities decreased echocardiographically in all patients, but one patient in group I died in hospital at 2 or 3 weeks after the onset of subarachnoid hemorrhage, when the T wave was inverted in leads V4 to V6. CONCLUSIONS These findings suggest that patients with subarachnoid hemorrhage and ST segment elevation may demonstrate transient corresponding regional wall motion abnormalities. The mechanism of neurogenic stunned myocardium was not clearly elucidated in the present study.


American Journal of Cardiology | 1996

Natural History and Left Ventricular Response in Chronic Aortic Regurgitation

Katsuhisa Ishii; Yuzo Hirota; Michihiro Suwa; Yoshio Kita; Haruhiko Onaka; Keishiro Kawamura

This study was aimed at clarifying the natural history and left ventricular response in aortic regurgitation using M-mode echocardiography. We analyzed the history and echocardiographic data on 94 patients, who were divided into 4 stages according to symptoms. The duration of the asymptomatic period, which represents pure volume overload, is long, and the period of minimal symptoms, combined volume and pressure overload, is relatively short. Patients with overt heart failure due to impaired contractility can survive longer than is usually believed, and the factor that predicted the onset of heart failure was a decrease in fractional shortening > 3.8 percentage points.


Journal of the American College of Cardiology | 1996

Clinical observation of spontaneous anginal attacks and multivessel spasm in variant angina pectoris with normal coronary arteries: evaluation by 24-hour 12-lead electrocardiography with computer analysis

Haruhiko Onaka; Yuzo Hirota; Satoshi Shimada; Yoshio Kita; Yasuhiko Sakai; Yoshihide Kawakami; Shuji Suzuki; Keishiro Kawamura

OBJECTIVES Using a new, computerized 24-h 12-lead electrocardiographic (ECG) recording and analysis system (the EAGLE system), we sought to evaluate the clinical manifestations of ischemic episodes in patients with variant angina and normal coronary arteries. BACKGROUND Although the prognosis of variant angina without significant organic stenosis is generally good, the incidence of multivessel spasm, a major prognostic factor, is surprisingly high in provocation tests. METHODS A total of 122 patients with suspected variant or unstable angina underwent 24-h examination with the EAGLE system and two-channel Holter monitoring. Thirty patients in this group were diagnosed as having variant angina with normal or nearly normal coronary arteries. Twenty-two (73%) of these 30 patients developed anginal attacks with ST segment elevation during monitoring and were enrolled in the study. RESULTS The 22 patients had a total of 138 episodes of transient ST segment elevation and 13 episodes of ST segment depression. No arrhythmias were observed during ST segment depression, but 26 episodes of ST segment elevation (19%) were associated with arrhythmias: 7 with premature ventricular contractions, 3 with ventricular bigeminy, 3 with complete atrioventricular (AV) block, 1 with complete AV block and couplets of premature ventricular contractions and 12 with marked sinus bradycardia (< 45 beats/min). Ten (45%) of the 22 patients had multivessel spasm. We observed three different patterns of multivessel spasm: 1) spasm at a different site on different occasions (migratory spasm); 2) spasm that sequentially affected two different sites; 3) simultaneous spasm at more than one site. The duration of ST segment elevation was much longer in patients with sequential and simultaneous spasm than in those with single-vessel spasm, and arrhythmias were more frequent during these two types of multivessel spasm. CONCLUSIONS Although the prognosis of multivessel spasm is believed to be poor, this may not necessarily be so. Anginal attacks due to sequential and simultaneous multivessel spasm seem to be more dangerous than those involving single-vessel spasm or migratory multivessel spasm.


Journal of the American College of Cardiology | 1996

Aortic Counterpulsation May Improve Late Patency of the Occluded Coronary Artery in Patients With Early Failure of Thrombolytic Therapy

Tatsuji Kono; Hiroshi Morita; Takuya Nishina; Masashi Fujita; Haruhiko Onaka; Yuzo Hirota; Keishiro Kawamura; Akira Fujiwara

OBJECTIVES Using a prospective, randomized design, we tested our hypothesis that the augmentation of diastolic pressure by intraaortic balloon counterpulsation (IABP) would improve the late patency of the occluded coronary artery in patients with early failure of thrombolytic therapy. BACKGROUND Rescue angioplasty is often performed in patients in whom thrombolysis has failed, although 30% to 60% of the infarct-related arteries that are closed early after thrombolytic therapy will open later with conservative therapy. METHODS The study included 45 patients in whom thrombolysis had failed, despite treatment with intravenous tissue-type plasminogen activator (alteplase 0.75 mg/kg body weight) delivered over 60 min within 12 h of the onset of symptoms. All patients underwent coronary angiography 60 min after initiation of thrombolytic therapy (baseline), and Thrombolysis in Myocardial Infarction (TIMI) grade 0, 1 or 2 flow was defined as failed thrombolysis. The patients were randomized to groups receiving IABP for 48 h (n = 23) or conservative therapy (n = 22, control subjects) at the end of cardiac catheterization. The late patency of the infarct-related artery, the primary end point of the study, was evaluated 3 weeks after myocardial infarction. Stenosis of the infarct-related artery was measured using a computer-assisted quantitative angiographic system in blinded manner. Data are expressed as mean value +/- SEM. RESULTS There was no difference with regard to the baseline value for TIMI flow grade between the groups. However, 3 weeks after myocardial infarction, the patients treated with IABP had a significantly higher frequency of TIMI flow grade 3, lower residual percent stenosis and larger minimal lumen diameter of the infarct-related artery than did the control subjects (74% vs. 32%, p < 0.05; 42 +/- 5% vs. 68 +/- 6%, p < 0.01; and 1.6 +/- 0.1 vs. 0.9 +/- 0.2 mm, p < 0.01, respectively). CONCLUSIONS These findings suggest that in patients with early failure of thrombolytic therapy, IABP may improve late patency of the occluded coronary artery, probably due to augmented perfusion pressure.


American Journal of Cardiology | 1998

Circadian Variation of Myocardial Ischemia in Patients With Unstable Angina Pectoris Secondary to Fixed and/or Spastic Coronary Narrowing

Haruhiko Onaka; Yuzo Hirota; Satoshi Shimada; Takayuki Mishima; Hisashi Shimoyama; Yasuhiko Sakai; Keishiro Kawamura

We investigated the circadian variation of myocardial ischemia in patients with unstable angina using a 24-hour 12-lead electrocardiographic monitoring system with computer analysis. The circadian variation of ischemic attacks in patients who had ST elevation showed a similarity to that of the onset of acute myocardial infarction and most of these patients had vasospasm without organic stenosis; no similarity was seen in patients with organic stenosis.


Japanese Circulation Journal-english Edition | 1993

Usefulness of serum CA125 measurement for monitoring pericardial effusion.

Toshihiko Seo; Yoshihiro Ikeda; Haruhiko Onaka; Takahiro Hayashi; Keizo Kawaguchi; Chikao Kotake; Tsunenori Toda; Katsuya Kobayashi


Japanese Circulation Journal-english Edition | 1999

Prognostic Significance of the Pattern of Multivessel Spasm in Patients With Variant Angina

Haruhiko Onaka; Yuzo Hirota; Satoshi Shimada; Syuji Suzuki; Tatuji Kono; Jyoji Suzuki; Yasuhiko Sakai; Keishiro Kawamura


Japanese Circulation Journal-english Edition | 1998

Detection of Myocardial Ischemia With a Computer-Assisted 12-lead 24-hour ECG Monitoring System (EAGLE) in Patients With Suspected Unstable Angina

Satoshi Shimada; Yuzo Hirota; Haruhiko Onaka; Takayuki Mishima; Shuji Suzuki; Yoshihide Kawakami; Yasuhiko Sakai; Yoshio Kita; Keishiro Kawamura


Japanese Circulation Journal-english Edition | 1997

Comparison of Immediate and Long-Term Outcome of Percutaneous Transvenous Mitral Commissurotomy in Patients Who Have and Have not Undergone Previous Surgical Commissurotomy

Takahide Ito; Michihiro Suwa; Yuzo Hirota; Yoshio Kita; Yoshiaki Otake; Ayaka Moriguchi; Haruhiko Onaka; Keishiro Kawamura


Japanese Journal of Nephrology | 1993

Significance of endothelial deposition of von Willebrand factor in thrombotic thrombocytopenic purpura: Autopsy findings of a case complicated with systemic lupus erythematosus.

Takahiko Ono; Keizo Kawaguchi; Haruhiko Onaka; Satoshi Ueda; Toshihiko Inui; Hiroyuki Nagai; Takahiko Matsuo; Takashi Kuwahara

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