Toshiji Iwasaka

Kansai Medical University, Moriguchi, Ōsaka, Japan

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Publications (452)1774.4 Total impact

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    ABSTRACT: Visit-to-visit blood pressure variability has been shown to be an independent risk factor for cardiovascular diseases. High visit-to-visit blood pressure variability and endothelial dysfunction are observed in patients with chronic kidney disease. It is therefore assumed that high variability in visit-to-visit blood pressure measurements may be associated with endothelial dysfunction in these patients. The present study investigated the associations between visit-to-visit blood pressure variability and renal and endothelial function in patients with chronic kidney disease. We analyzed 150 consecutive patients with predialysis chronic kidney disease who visited our outpatient clinic from January 2006 to December 2010. The study examined the relationships between variability in visit-to-visit systolic blood pressure levels or mean systolic blood pressure (M SBP) and estimated glomerular filtration rate (eGFR) and flow-mediated dilation, an index of endothelial function. Variability in visit-to-visit systolic blood pressure showed a significant negative association with eGFR, independent of age, hemoglobin A1c, low-density lipoprotein (LDL) cholesterol and uric acid, whereas M SBP did not. Similarly, variability in SBP showed a significant negative association with flow-mediated dilation, independent of age, eGFR, HbA1c, LDL cholesterol and M SBP. These data indicate that variability in visit-to-visit blood pressure measurements is associated with impaired renal and endothelial function in patients with chronic kidney disease. This finding suggests that reducing blood pressure fluctuations might have beneficial effects in patients with chronic kidney disease, although this point needs to be addressed by future studies.Hypertension Research advance online publication, 4 December 2014; doi:10.1038/hr.2014.163.
    No preview · Article · Dec 2014 · Hypertension Research
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    ABSTRACT: A 73-year-old male undergoing peritoneal dialysis (PD) for end-stage renal disease due to diabetic nephropathy was diagnosed with aortic stenosis and was admitted to our hospital in September, 2009. The patient underwent replacement of the ascending aorta with an artificial blood vessel plus aortic valve replacement without any notable complications. PD was restarted 3 days after the surgery and large amounts of light red fluid from the drain placed in the pericardium were observed just after resumption of PD solution. The patient was diagnosed with peritoneopericardial communication. PD was discontinued and hemodialysis was performed only with intermittent lavage of the peritoneal cavity. The amount of drainage was spontaneously decreased, and on the 17th day after surgery, PD was resumed. The patient is undergoing PD without recurrence of peritoneopericardial communication, 59 months after the onset of symptoms. Peritoneopericardial communication in a patient with PD developing after open-heart surgery is rare because such a case has been documented in only one case report. However, since massive pericardial effusion may cause severe cardiac problems, we consider that the communication between the peritoneal cavity and the pericardium needs to be checked for in patients with PD after cardiac surgery.
    No preview · Article · Nov 2014
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    ABSTRACT: A patient without any known congenital cardiac abnormalities who suffered from ventricular tachycardia was taken to the emergency room following successful resuscitation. Transthoracic echocardiography showed diffuse left ventricle dysfunction and mild aortic regurgitation. Coronary angiography demonstrated intact coronary and suspected morphological abnormalities of the aortic valve. In addition, transesophageal echocardiography revealed a rare quadricuspid aortic valve malformation. After controlling ventricular tachycardia and congestive heart failure with optimal medical therapy, the patient had an uneventful course and was subsequently discharged 3 weeks after admission. To our knowledge, this is the first report of quadricuspid aortic valve associated with idiopathic dilated cardiomyopathy. <Learning objective: A quadricuspid aortic valve is a rare congenital anomaly. A quadricuspid aortic valve is often associated with other cardiac disorders, such as patent ductus, mitral valve malformation, hypertrophic cardiomyopathy, and coronary abnormalities. However, there have been no previous case reports of a quadricuspid aortic valve occurring in association with idiopathic dilated cardiomyopathy. This is the first report of quadricuspid aortic valve associated with idiopathic dilated cardiomyopathy.
    Preview · Article · Jun 2014 · Journal of Cardiology Cases
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    ABSTRACT: Objective: Dyslipidemia is a risk factor for not only cardiovascular diseases (CVD), but also chronic kidney disease (CKD). Ezetimibe, a cholesterol absorption inhibitor, lowers cholesterol levels by inhibiting both extrinsic and intrinsic cholesterol absorption via the gastrointestinal duct. However, very few studies have examined its efficacy and safety for patients with dyslipidemia complicated with CKD. Methods: Thirty-seven dyslipidemic patients (low density lipoprotein cholesterol (LDL-C) levels ≥120 mg/dL) complicated with CKD were given ezetimibe (10 mg/day) for twenty-four weeks. The efficacy and safety of the therapy, including the anti-atherosclerotic and renal protective effects, were then examined. Results: Significant decreases were observed in the levels of LDL-C (158.9 ± 26.9 mg/dL→123.0 ± 31.8 mg/dL; p<0.0001), remnant-like lipoprotein cholesterol (9.3 ± 5.3 mg/dL→7.3 ± 3.8 mg/dL; p<0.05) and lipoprotein (a) (22.0 ± 16.1 mg/dL→16.4 ± 11.0 mg/dL; p<0.01). The estimated glomerular filtration rate did not change, but the urine protein to creatinine ratio decreased significantly (1,107.3 ± 1,454.2 mg/gCre→732.1 ± 1,237.8 mg/gCre; p<0.05). No changes were observed in the carotid intima media thickness, but the brachial-ankle pulse wave velocity decreased significantly (1,770.4 ± 590.3 cm/sec→1,702.5 ± 519.9 cm/sec; p<0.05). No adverse events were observed. Conclusion: Ezetimibe can be safely administered even to patients with CKD. The results of this study indicate that ezetimibe may provide some renal protection and suppress the complications of CVD in CKD patients.
    Full-text · Article · Feb 2014 · Internal Medicine
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    ABSTRACT: Background: Aging is an established risk factor for contrast-induced nephropathy (CIN). However, little information is available on the incidence and clinical outcome of CIN for the elderly patients in Japan. Objectives: We determined the incidence and clinical outcome of CIN in the Japanese elderly patient. Methods: We studied 292 patients who had mild renal dysfunction (estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2)) at baseline and underwent coronary angiography. Patients were divided into two groups base on their age: the elderly group (age≥75, n=108) and the control group (age<75, n=184). CIN was defined as a 25% increase in serum creatinine or an increase in serum creatinine by>0.5 mg/dl above the baseline value at or within 2 days post procedure. Results: Patients in the elderly group had a higher incidence of CIN (14%) than those in the control group (9%). In patients who developed CIN, there was no significant difference between the two groups in baseline GFR and GFR on days 1, 2, 7 and 30 after the procedure. However, the relative increase in GFR above baseline on day 7 (-4.0±6.1 vs -8.3±8.0 ml/min P=0.096) and day 30 (1.5±9.4 vs -10.1±9.6 ml/min P=0.0017) in the elderly group was higher than that in the control group. Furthermore, death occurred in 3 patients in the elderly group (20%) whereas no patient died in the control group (P=0.092). Conclusion: Aging (age≥75) is a risk factor for CIN in Japanese. CIN in the elderly patients may be associated with prolonged renal dysfunction and poor prognosis.
    No preview · Article · Aug 2013 · Nippon Ronen Igakkai Zasshi Japanese Journal of Geriatrics
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    ABSTRACT: Despite the potential benefit of granulocyte colony-stimulating factor (G-CSF) therapy in patients with acute myocardial infarction (MI), the efficacy of G-CSF in regenerating the heart after MI remains controversial. The authors hypothesize that the limited efficacy of G-CSF is related to its inhibitory effect on recruitment of bone marrow-derived cells (BMCs) to the infarcted tissue. MI was induced in rats with intrabone marrow-bone marrow transplantation from syngenic rats expressing green fluorescence protein to track BMCs. G-CSF was administered for five days after the onset of MI. G-CSF increased the number of CD45(+) cells in the peripheral circulation but did not increase their recruitment to the heart. G-CSF had no effect on myocardial stromal-derived factor-1 alpha and chemokine (C-X-C motif) receptor 4 (CXCR4) expression in mononuclear cells in the peripheral blood and CXCR4(+) cells in the heart. G-CSF had no effect on angiogenesis, myocardial fibrosis or left ventricular function four weeks after MI. These results suggest that G-CSF mobilizes BMCs to the peripheral circulation but does not increase recruitment to the infarcted myocardium despite preservation of the stromal-derived factor-1 alpha/CXCR4 axis.
    Preview · Article · Sep 2012 · Experimental and clinical cardiology
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    ABSTRACT: Although some atypical types of transient left ventricular apical ballooning syndrome have been reported, only a few atypical types of transient mid-ventricular ballooning have been reported. A 70-year-old female underwent surgery for urothelial carcinoma. At day 5 after the surgery, she was admitted to our department without cardiac symptoms because of ST elevation in leads I, II, III, aVF and V1–V6 indicating acute coronary syndrome. She was diagnosed with stress induced cardiomyopathy based on an angiographically normal coronary artery, newly developed extensive wall motion abnormality (hyperbasal contraction and akinesis from the mid-left ventricle to the apex without hypercontraction of the small area adjacent to the apex) based on left ventriculography, and a small elevation of myocardial enzymes incongruous with the area of contraction abnormality. Myocardial scintigraphy with 99mTc-tetrofosmin showed a severely reduced myocardial perfusion in an extensive mid-ventricular area without a left ventricular base and top of apex, in accord with a wall motion abnormality different from typical apical ballooning or typical mid-ventricular ballooning previously diagnosed in our hospital. This is the first report presenting an atypical mid-ventricular ballooning based on the myocardial atypical perfusion findings.
    Preview · Article · Sep 2012 · Journal of Cardiology Cases
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    ABSTRACT: We recently encountered a case of morning hypotension appearing after switching from a brand name to a generic version of long-acting Nifedipine. The patient was a 90-year-old male. His dropped blood pressure was pointed out in a public health check up by chance. However, his blood pressure measured in hospital was rather high. On interviewing him, we noticed that his drugs were changed from brand-name to the generic version and he felt difficulty in taking generic long-acting Nifedipin. In addition, he had crunched the tablet of long-acting Nifedipine. We concluded that unsuitable intake caused by switching from a brand name to a generic version of the drug was one of reasons for the worsening of blood pressure control. Although most generic drugs are considered to be useful, it is important to carefully observe patients to confirm that an equivalent tolerability is obtained after switching from a brand name drug to a generic drug.
    No preview · Article · Sep 2012
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    ABSTRACT: To evaluate the effects of eicosapentaenoic acid (EPA) on regional arterial stiffness assessed by strain rate using tissue Doppler imaging. Nineteen eligible patients were prospectively studied (mean age 62 ± 8 years, 68% men). Subjects with large vessel complications and/or diabetes mellitus were excluded. The strain rate of the ascending aorta was measured by tissue Doppler imaging as an index of regional arterial stiffness, and brachial-ankle pulse wave velocity (baPWV) was measured as an index of degree of systemic arteriosclerosis. These indices were compared before and after administration of EPA at 1800 mg/d for one year. The plasma concentration of EPA increased significantly after EPA administration (3.0% ± 1.1% to 8.5% ± 2.9%, P < 0.001). There were no significant changes in baPWV (1765 ± 335 cm/s to 1745 ± 374 cm/s), low-density lipoprotein cholesterol levels (114 ± 29 mg/dL to 108 ± 28 mg/dL), or systolic blood pressure (131 ± 16 mmHg to 130 ± 13 mmHg) before and after EPA administration. In contrast, the strain rate was significantly increased by administration of EPA (19.2 ± 5.6 s(-1), 23.0 ± 6.6 s(-1), P < 0.05). One year of administration of EPA resulted in an improvement in regional arterial stiffness which was independent of blood pressure or serum cholesterol levels.
    Full-text · Article · Aug 2012 · World Journal of Cardiology (WJC)
  • Takanao Ueyama · Kazuya Takehana · Hirofumi Maeba · Toshiji Iwasaka
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    ABSTRACT: Background: Patients with a normal stress image on technetium-99m (Tc-99m) single-photon emission computed tomography (SPECT) have a good prognosis for diagnosing coronary artery disease. However, current guidelines recommend stress and rest imaging to confirm that a stress image is normal. Methods and results: We determined all-cause of cardiac events (acute coronary syndrome and sudden death) in 1,939 patients undergoing stress myocardial perfusion SPECT with Tc-99m radiotracers. Patients with an abnormal stress image were excluded, so we focused on 1,125 patients in whom the stress SPECT study was interpreted as normal. A stress-only protocol was used in 726 patients (adenosine=339; exercise=387), whereas 399 had both stress and rest imaging (adenosine=294; exercise=105). Mean follow-up was 1,252 days. At the end of follow-up, there were 39 cardiac events in the stress-only cohort and 19 in the stress-rest cohort. Kaplan-Meier analysis revealed that there were no differences for the entire cohort of cardiac events not only between the stress-only and stress-rest protocols but also for stressor modality, despite the fact that the stress-rest cohort showed higher coronary risk factors. Conclusions: Patients determined as having a normal SPECT on the basis of stress imaging alone have a similar cardiac event rate as those who have a normal SPECT on the basis of evaluation of both stress and rest images. This imaging strategy will significantly reduce radiation exposure in a substantial number of patients.
    No preview · Article · Jul 2012 · Circulation Journal
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    ABSTRACT: Background: Both obesity and left ventricular (LV) diastolic dysfunction are associated with an increased risk of cardiovascular morbidity and mortality. There is a paucity of data as to whether obesity is independently associated with LV diastolic dysfunction. Methods: Adult patients with sinus rhythm referred for a transthoracic echocardiography between July, 2007, and December, 2007, were prospectively included. Exclusion criteria were patient who had a history of congenital or valvular heart disease, treatment with pacemaker implantation or implantable cardioverter defibrillator, myocardial infarction, or impaired LV systolic function. Diastolic function was classified by an algorithm incorporating data from mitral and pulmonary venous flow indices, and Doppler tissue imaging. Body mass index (BMI) was evaluated as a categorical variable (normal weight <25.0 kg/m(2); overweight 25.0 to <30.0 kg/m(2); and obese ≥30 kg/m(2)). Logistic models were used to assess the risk of abnormal LV diastolic function associated with BMI categories. Results: Of a total number of 692 patients who met all study criteria (mean 59 ± 15 year-old; 50% women, 48% hypertension, 16% diabetes, 26% overweight, 8% obese), 538 (78%) had abnormal LV diastolic function. In multivariate analyses adjusting for age, sex, and cardiovascular risk factors, obesity was independently associated with LV diastolic dysfunction (odds ratio [OR]: 2.98, 95% confidence interval [CI]: 1.12-7.88; P = 0.03) compared to normal weight. LV mass did not weaken this association (OR: 2.88, 95% CI: 1.08-7.68; P = 0.04). Overweight was not independently associated with LV diastolic dysfunction. Conclusion: Obesity was associated with LV diastolic dysfunction independent of cardiovascular risk factors and LV mass.
    No preview · Article · Jul 2012 · Obesity Research & Clinical Practice
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    ABSTRACT: It is often difficult to noninvasively differentiate a post-infarction left ventricular (LV) pseudoaneurysm from a post-infarction true aneurysm. A 66-year-old woman with a past history of inferior acute myocardial infarction was admitted to our hospital because of acute decompensated heart failure. Two-dimensional transthoracic echocardiography showed an aneurysm with a narrow orifice in the inferoposterior basal area. The pulmonary to systemic flow ratio (Q p/Q s) was 2.2:1, which corresponded to moderate left–right shunting. Three-dimensional transesophageal echocardiography (3D-TEE) showed the orifice in the perforated right ventricular basal area with a color jet through the orifice from the LV to the right ventricle. Collectively, based on the 3D-TEE findings, we diagnosed the case as inferoposterior pseudoaneurysm with a left-to-right shunt caused by myocardial infarction.
    No preview · Article · Jul 2012 · Journal of Medical Ultrasonics
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    ABSTRACT: To investigate the luminal esophageal temperature (LET) at the time of delivery of energy for pulmonary vein isolation (PVI). This study included a total of 110 patients with atrial fibrillation who underwent their first PVI procedure in our laboratory between March 2010 and February 2011. The LET was monitored in all patients. We measured the number of times that LET reached the cut-off temperature, the time when LET reached the cut-off temperature, the maximum temperature (T max) of the LET, and the time to return to the original pre-energy delivery temperature once the delivery of energy was stopped. Seventy-eight patients reached the cut-off temperature. It took 6 s at the shortest time for the LET to reach the cut-off temperature, and 216.5 ± 102.9 s for the temperature to return to the level before the delivery of energy. Some patients experienced a transient drop in the LET (TDLET) just before energy delivery. Ablation at these sites always produced a rise to the LET cut-off temperature. TDLET was not observed at sites where the LET did not rise. Thus, the TDLET before the energy delivery was useful to distinguish a high risk of esophageal injury before delivery of energy. Sites with a TDLET before energy delivery should be ablated with great caution or, perhaps, not at all.
    Full-text · Article · May 2012 · World Journal of Cardiology (WJC)
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    ABSTRACT: BACKGROUND: Myocardial injury during elective percutaneous coronary intervention (PCI) is associated with higher subsequent cardiac events and mortality. β-Blockers have been used to reduce myocardial injury during ischemia and reperfusion. We investigated whether intracoronary followed by intravenous administration of the short-acting β-blocker landiolol prevents myocardial injury in the face of elective PCI. METHODS AND RESULTS: Patients undergoing elective PCI (n=70) were randomly assigned to the landiolol (n=35) or control (n=35) group. Landiolol or saline was administered into target vessels through a balloon catheter for 1min before and after first balloon inflation followed by continuous intravenous administration for 6h after PCI. The incidence of myocardial injury defined by cardiac troponin-I (cTnI) ≧0.05ng/ml was 79% of the patients in the control group compared to 56% in the landiolol group (p=0.04). The cTnI level at 24h after PCI tended to be lower in the landiolol group (0.57±1.14 versus 1.27±2.48ng/ml; p=0.07), while the CK-MB level was not significantly different between the landiolol and control groups. The incidence of peri-procedural myocardial infarction defined by cTnI ≧0.12ng/ml was significantly (p=0.02) lower in the landiolol group (41%) compared to the control group (70%). There was no incidence of coronary spasm, hypotension, bradycardia or heart failure during and after PCI in the two groups. CONCLUSIONS: Brief intracoronary followed by continuous intravenous administration of landiolol is safe and effective for myocardial protection in the face of elective PCI.
    No preview · Article · May 2012 · International journal of cardiology
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    ABSTRACT: A 73-year-old female patient with a past history of right ventricular infundibular stenosis was admitted to our intensive care unit because of right ventricular dysfunction. On the fifth day of hospitalization, she suddenly experienced dyspnea without chest pain despite the improvement of her condition by initial medical treatment. Although electrocardiography revealed no ST-segment elevation, echocardiography and myocardial perfusion using 99mTc-MIBI revealed new development of severe symmetrical akinesia and reduced perfusion of the left ventricular (LV) apex and mid-ventricle. LV apical ballooning syndrome was diagnosed based on the minimal elevation of cardiac enzymes (peak cardiac troponin I 0.18 ng/ml) despite the presence of large regions of focal myocardial damage in the myocardium and the absence of positive ECG diagnosis and urgent coronary angiography. Previous coronary angiography revealed normal coronary arteries and the left anterior descending artery without full irrigation around the apex making apical ballooning. On the 12th day of hospitalization, despite the use of positive inotropic treatment, it was impossible to maintain hemodynamic stability, and the patient died prior to the functional recovery of the left ventricle.
    Preview · Article · Apr 2012 · Journal of Cardiology Cases
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    Preview · Article · Mar 2012 · Journal of the American College of Cardiology
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    Preview · Article · Mar 2012 · Journal of the American College of Cardiology
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    Preview · Article · Mar 2012 · Nihon Naika Gakkai Zasshi
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    ABSTRACT: Pioglitazone has been shown to reduce the occurrence of fatal and nonfatal myocardial infarction (MI) in type 2 diabetes mellitus (DM). However, the mechanisms of such favorable effects remain speculative. The aim of this study was to investigate the effect of pioglitazone on arterial baroreflex sensitivity (BRS) and muscle sympathetic nerve activity (MSNA) in 30 DM patients with recent MI. Patients were randomly assigned to those taking pioglitazone (n = 15) and those not taking pioglitazone (n = 15) at 4 weeks after the onset of MI. BRS, MSNA, calculated homeostasis model assessment of insulin resistance index (HOMA-IR), and plasma adiponectin were measured at baseline and after 12 weeks. Pioglitazone increased plasma adiponectin (from 6.9 ± 3.3 μg/dL to 12.2 ± 7.1 μg/dL) and reduced HOMA-IR (from 4.0 ± 2.2 to 2.1 ± 0.9). In the pioglitazone group, MSNA decreased significantly (from 37 ± 7 bursts/min to 25 ± 8 bursts/min) and BRS increased significantly (from 6.7 ± 3.0 to 9.9 ± 3.2 ms/mm Hg) after 12 weeks. Furthermore, a significant relationship was found between the change in MSNA and HOMA-IR (r = 0.6, P = 0.042). Thus, pioglitazone decreased the sympathetic nerve traffic through the improvement of insulin resistance in DM patients with recent MI, which indicate that the sympathoinhibitory effects of pioglitazone may, at least in part, have contributed to the beneficial effects of pioglitazone.
    No preview · Article · Feb 2012 · Journal of cardiovascular pharmacology
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    ABSTRACT: In hemodialysis (HD) patients, obesity has been recognized as a serious risk factor for mortality and morbidity for cardiovascular diseases. In addition, abnormalities of lipid profiles exist in these patients. In patients undergoing maintenance HD, incidences of abnormality of lipid profiles and visceral obesity determined by computed tomography scans were compared. In addition, the relationship between visceral fat area (VFA) and brachial-ankle pulse wave velocity (baPWV), an index of arterial stiffness, or carotid intima-media thickness (IMT), an index of atherosis, was examined. The incidence of high VFA (27.0%) was significantly greater than that of high body mass index (BMI) (9.7%), high low-density-lipoprotein cholesterol (LDL-C) (4.8%), and high triglyceride (12.7%). In patients with diabetes mellitus (DM), waist circumference and VFA showed a significant positive relationship with baPWV. baPWV was significantly higher in patients with high VFA and DM than in patients with low VFA without DM, those with high VFA without DM, and those with low VFA and DM. Carotid IMT was significantly greater in patients with high VFA and DM than in those with low VFA without DM and those with low VFA and DM. The incidence of high VFA was much greater than that of high BMI, high LDL-C, or high triglyceride. Visceral fat accumulation may be related to both arterial stiffness and atherosis in diabetic patients on maintenance HD.
    No preview · Article · Feb 2012 · Clinical and Experimental Nephrology

Publication Stats

9k Citations
1,774.40 Total Impact Points


  • 1987-2014
    • Kansai Medical University
      • • Second Department of Internal Medicine
      • • Cardiovascular Center
      • • Department of Internal Medicine
      Moriguchi, Ōsaka, Japan
  • 2012
    • Takeda Hospital Group
      Kioto, Kyoto, Japan
  • 2009
    • Hirakata General Hospital For Developmental Disorders
      Ōsaka, Ōsaka, Japan
  • 2007
    • Mayo Clinic - Rochester
      • Department of Cardiovascular Diseases
      Rochester, Minnesota, United States
    • Himeji Dokkyo University
      Himezi, Hyōgo, Japan
  • 1998
    • Harvard Medical School
      Boston, Massachusetts, United States
  • 1985
    • Saint Vincent Hospital
      • Department of Medicine
      Worcester, Massachusetts, United States