Yoshihiro Himura

Tenri Yorozu Hospital, Тэнри, Nara, Japan

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Publications (52)204.63 Total impact

  • Journal of Cardiac Failure 12/2005; 11(9). DOI:10.1016/j.cardfail.2005.08.331
  • Journal of Cardiac Failure 12/2005; 11(9). DOI:10.1016/j.cardfail.2005.08.224
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    ABSTRACT: Intervention therapy has been recently performed on the left internal thoracic artery graft stenosis. The purpose of this study was to evaluate the natural course of the left internal thoracic artery graft stenosis at the anastomotic site and clarify whether intervention therapy should be performed early after surgery. We investigated early angiographic results of the left internal thoracic artery graft in 343 consecutive patients who underwent coronary bypass surgery. In 100 of 343 patients who underwent follow-up angiography, the graft diameter and percentage diameter stenosis at the anastomotic site were compared between early postoperative and follow-up angiography. None of these patients underwent intervention therapy on the left internal thoracic artery graft. Of 343 patients, 46 showed 50% or greater diameter stenosis, and 20 showed 70% or greater diameter stenosis at the anastomotic site. In the 100 patients with follow-up angiography, the graft diameter significantly increased (1.8 +/- 0.4 vs 2.1 +/- 0.5 mm, P < .0001) at follow-up angiography. The percentage diameter stenosis significantly decreased (69% +/- 13% vs 35% +/- 20%, P < .0001) at follow-up angiography in the patients with 50% or greater diameter stenosis at early postoperative angiography. Regression of left internal thoracic artery graft stenosis was detected in most patients with 70% or greater diameter stenosis. Our study demonstrated that left internal thoracic artery graft stenosis at the anastomotic site at early postoperative angiography might improve without intervention therapy. We should consider the natural course of the left internal thoracic artery graft stenosis in determining the indication of intervention therapy early after surgery.
    The Journal of thoracic and cardiovascular surgery 12/2005; 130(6):1661-7. DOI:10.1016/j.jtcvs.2005.07.019
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    ABSTRACT: We present a 65-year-old man with rheumatic combined valvular heart disease showing persistent fever 3 weeks after diagnostic cardiac catheterization. Infective endocarditis was strongly suspected from the clinical course, however, serial blood cultures were negative. Transesophageal echocardiography, done to investigate vegetation, revealed multiple mobile plaques in the descending aorta. Administration of both steroid and simvastatin improved both symptoms and renal function. Cholesterol embolism should be considered to be one of the possible causes of low-grade fever after cardiac catheterization especially in patients with anticoagulation.
    Internal Medicine 11/2005; 44(10):1060-3. DOI:10.2169/internalmedicine.44.1060
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    ABSTRACT: A 49-year-old man presented with fever and uremic symptoms such as general malaise, leg edema and decreased urine output. He was diagnosed as having infective endocarditis (IE) accompanied by renal failure. Although he had been receiving hemodialysis for a long time, renal function dramatically improved after heart valve replacement. This case suggests that uremia can develop as an initial manifestation of IE and removal of an infected heart valve can improve renal function despite persistent renal failure. From the perspective of recovery of renal function, early surgery should be considered in patients with renal failure following IE.
    Internal Medicine 07/2005; 44(6):598-602. DOI:10.2169/internalmedicine.44.598
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    ABSTRACT: Only a few examinations are available to critically ill patients. We assessed the efficacy of transesophageal echocardiography (TEE) in the management of patients with cardiac arrest or shock. Among a total of 2,021 patients who underwent TEE over the past 13 years at our institution, we reviewed 18 patients who underwent TEE during cardiac arrest or shock. TEE was performed in four patients with cardiac arrest and in 14 patients with shock. In 12 (67%) of 18 patients, TEE identified the following abnormalities: aortic dissection in four, ruptured thoracic aortic aneurysm in two, papillary muscle rupture in two, left ventricular free wall rupture in two, postoperative cardiac tamponade in one and ruptured chordae tendineae in one. TEE excluded suspected cardiac abnormality in two other patients. Transthoracic echocardiography could not be performed in 8 of 18 patients, and showed poor quality of images in the remaining 10 patients. Of the 12 patients with a diagnosis based on TEE, three patients died during cardiopulmonary resuscitation, whereas nine patients were treated with emergent surgery and six of these survived to hospital discharge. TEE is feasible even in patients with cardiac arrest or shock, and can play an important role in establishing the diagnosis and determining the treatment of such patients.
    Journal of Cardiology 12/2004; 44(5):189-94.
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    ABSTRACT: Stenosis of the left internal thoracic artery (LITA) graft, which usually occurs at the site of the anastomosis, can be noninvasively evaluated by the flow pattern in the proximal graft, but the flow pattern is influenced by several other factors. In the present study, LITA graft flow was investigated by high-frequency transthoracic Doppler echocardiography in 75 consecutive patients who underwent postoperative angiography of the LITA graft. The flow velocity was measured at both the anastomosis and proximal to it, and compared with the quantitative angiographic results. Flow at both sites was detected in 61 (81%) of the 75 patients. The diastolic velocity ratio of the anastomosis to the proximal site correlated with the percent diameter stenosis at the anastomosis. A diastolic velocity ratio >2.0 had a high sensitivity, specificity, positive predictive value and negative predictive value for the presence of significant stenosis at the anastomosis of a LITA graft. High-frequency transthoracic Doppler echocardiography can be used for the noninvasive diagnosis of LITA graft stenosis.
    Circulation Journal 09/2004; 68(9):845-9. DOI:10.1253/circj.68.845
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    ABSTRACT: We reported recently that inhibition of neuronal reuptake of norepinephrine (NE) by desipramine prevented the reduction of sympathetic neurotransmitters in the failing right ventricle of right heart failure animals. In this study, we studied whether desipramine also reduced the sympathetic neurotransmitter loss in animals with left heart failure induced by rapid ventricular pacing (225 beats/min) or after chronic NE infusion (0.5 microg. kg(-1). min(-1)). Desipramine was given to the animals for 8 wk beginning with rapid ventricular pacing or NE infusion. Animals receiving no desipramine were studied as controls. We measured myocardial NE content, NE uptake activity, and sympathetic NE, tyrosine hydroxylase, and neuropeptide Y profiles by histofluorescence and immunocytochemical techniques. Effects of desipramine on NE uptake inhibition were evidenced by potentiation of the pressor response to exogenous NE and reduction of myocardial NE uptake activity. Desipramine treatment had no effect in sham or saline control animals but attenuated the reduction of sympathetic neurotransmitter profiles in the left ventricles of animals with rapid cardiac pacing and NE infusion. In contrast, the panneuronal marker protein gene product 9.5 profile was not affected by either rapid pacing or NE infusion, nor was it changed by desipramine treatment in the heart failure animals. The study confirms that excess NE contributes to the reduction of cardiac sympathetic neurotransmitters in heart failure. In addition, it shows that the anatomic integrity of the sympathetic nerves is relatively intact and that the neuronal damaging effect of NE involves the uptake of NE or its metabolites into the sympathetic nerves.
    AJP Heart and Circulatory Physiology 06/2003; 284(5):H1729-36. DOI:10.1152/ajpheart.00853.2002
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    ABSTRACT: Right heart failure (RHF) is characterized by chamber-specific reductions of myocardial norepinephrine (NE) reuptake, beta-receptor density, and profiles of cardiac sympathetic nerve ending neurotransmitters. To study the functional linkage between NE uptake and the pre- and postsynaptic changes, we administered desipramine (225 mg/day), a NE uptake inhibitor, to dogs with RHF produced by tricuspid avulsion and progressive pulmonary constriction or sham-operated dogs for 6 wk. Animals receiving no desipramine were studied as controls. We measured myocardial NE uptake activity using [(3)H]NE, beta-receptor density by [(125)I]iodocyanopindolol, inotropic responses to dobutamine, and noradrenergic terminal neurotransmitter profiles by glyoxylic acid-induced histofluorescence for catecholamines, and immunocytochemical staining for tyrosine hydroxylase and neuropeptide Y. Desipramine decreased myocardial NE uptake activity and had no effect on the resting hemodynamics in both RHF and sham animals but decreased myocardial beta-adrenoceptor density and beta-adrenergic inotropic responses in both ventricles of the RHF animals. However, desipramine treatment prevented the reduction of sympathetic neurotransmitter profiles in the failing heart. Our results indicate that NE uptake inhibition facilitates the reduction of myocardial beta-adrenoceptor density and beta-adrenergic subsensitivity in RHF, probably by increasing interstitial NE concentrations, but protects the cardiac noradrenergic nerve endings from damage, probably via blockade of NE-derived neurotoxic metabolites into the nerve endings.
    AJP Heart and Circulatory Physiology 12/2002; 283(5):H1863-72. DOI:10.1152/ajpheart.01131.2001
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    ABSTRACT: A 51-year-old man with a primary angiosarcoma of the right atrium is reported. The angiosarcoma was not detected by transthoracic echocardiography or computed tomography, but magnetic resonance imaging and transesophageal echocardiography did show the tumor of the right atrial free wall. We performed a transvenous endomyocardial biopsy of the tumor under the guidance of transesophageal echocardiography and made the pathological diagnosis. This case demonstrates the advantage of magnetic resonance imaging and transesophageal echocardiography for tumor detection over transthoracic echocardiography and computed tomography and the usefulness of transesophageal echocardiography for guiding the right atrial endomyocardial biopsy procedure.
    Internal Medicine 06/2001; 40(5):391-5. DOI:10.2169/internalmedicine.40.391
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    ABSTRACT: Mitral valve replacement (MVR) with chordal preservation in patients with chronic mitral regurgitation (MR) has been reported to maintain systolic function of the left ventricle. However, the benefits of MVR with chordal preservation are not always predictable. The study aim was to ascertain the influence that papillary muscle (PM) size has on cardiac function after MVR with chordal preservation. Postoperative regional shortening and its relationship with PM size were investigated by two-dimensional echocardiography in 18 patients who underwent MVR with chordal preservation, and nine patients without chordal preservation between 1986 and 1998 at Tenri Hospital. The PM cross-sectional area was measured in each patient, as well as postoperative fractional shortening (FS) of the septolateral, anteroposterior and vertical dimensions of the left ventricle. The technique of preserving all chordae tendineae involved reattaching the anterior leaflet chordae to the mitral annulus near each commissure. Postoperative FS of the septolateral and anteroposterior dimensions was better in patients with chordal preservation than in those without. In the former subgroup, a larger PM was associated with better FS of the left ventricle in the septolateral dimension (anterior PM, p <0.001, r = 0.78; posterior PM, p = 0.0010, r = 0.69), but not in the anteroposterior or vertical dimensions. This discrepancy in the relationship between PM size and functional benefits among the three dimensions may be related to the direction in which the PMs are suspended in our technique, or its effect on regional left ventricular function. The present study indicated that PM size may be used as a factor to better predict the outcome of MVR with chordal preservation.
    The Journal of heart valve disease 01/2001; 10(1):57-64.
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    ABSTRACT: The present study analyzed the clinical backgrounds of 9 patients with fresh left ventricular thrombus (LVT) detected by two-dimensional echocardiography during the past 5 years. Patients with acute myocardial infarction were excluded. Left ventricular systolic function was disturbed either diffusely or segmentally in all patients with a mean ejection fraction of 33%. In 7 patients, echocardiography was performed shortly after furosemide therapy for New York Heart Association class IV congestive heart failure; echocardiography was also performed just before treatment in 4 of the 7 patients and LVT was not detected in any of them. Two patients died of underlying disorders within 2 months of detection of the thrombus. However, the LVT disappeared in the other 7 patients without any thromboembolic episodes during the 6 months after starting anticoagulant therapy. As fresh LVT developed shortly after diuretic therapy in patients with severe congestive heart failure associated with left ventricular systolic dysfunction, concomitant anticoagulant therapy is recommended.
    Japanese Circulation Journal 05/2000; 64(4):254-6. DOI:10.1253/jcj.64.254
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    ABSTRACT: In order to evaluate coronary flow response to 2 different vasodilators, nicorandil and papaverine, in patients with myocardial infarction, we measured coronary flow reserve using a Doppler guide wire in infarct-related and non infarct-related arteries. The study group consisted of 28 patients with first acute myocardial infarction 3 weeks after successful coronary angioplasty within 6 hr after symptom onset. Twelve patients with atypical chest pain served as the control group. Coronary flow reserve induced by intracoronary papaverine(12 mg) was lower in infarct-related arteries than in non infarct-related arteries, but there were no differences in coronary flow reserve induced by intracoronary nicorandil(1 mg) between infarct-related and non infarct-related arteries. Coronary flow reserve induced by nicorandil was lower than that by papaverine in non infarct-related arteries and the control group. However, there were no differences between coronary flow reserve induced by nicorandil and papaverine in infarct-related arteries. Vasodilatory response induced by nicorandil was relatively preserved in infarct-related arteries compared with papaverine. These results suggest that impairment of coronary microvascular response in infarct myocardium varies in the different sites acted on by different vasodilator agents.
    Journal of Cardiology 04/2000; 35(3):175-80.
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    ABSTRACT: The pulmonary venous flow signal measured by transesophageal echocardiography is generally recorded from the left upper pulmonary vein in the left lateral decubitus position, whereas that by transthoracic echocardiography is from the right upper pulmonary vein in the left semi-lateral decubitus position. The purpose of this study was to evaluate the influence of the postural change on the peak flow velocities of the left and right pulmonary veins and whether the parameters of the left and right pulmonary venous flow can be used interchangeably. The study group consisted of 37 patients with normal left ventricular filling pressure and in whom the systolic forward flow signals from both pulmonary veins recorded in the left and right lateral decubitus positions were clear enough to differentiate as biphasic. The peak early systolic (peak S1) and diastolic velocities were significantly increased when the pulmonary vein was on the recumbent subject's upper side, whereas the peak late systolic velocity (peak S2) was significantly increased when the pulmonary vein was on the recumbent subject's lower side. The peak S1 was higher than the peak S2 when the pulmonary vein was on the recumbent subject's upper side, whereas the reverse relation was seen when the pulmonary vein was on the recumbent subject's lower side. We should take into consideration the body position and the side on which the pulmonary vein is situated in evaluating the peak flow velocities of the pulmonary veins.
    American Heart Journal 04/1999; 137(3):419-26. DOI:10.1016/S0002-8703(99)70486-2
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    ABSTRACT: The right-to-left shunt at the atrial level is responsible for arterial hypoxemia in patients with atrial septal defect. This study investigated the mechanism of arterial hypoxemia in patients with atrial septal defect by measuring the P(O2) in both the right and left upper pulmonary veins. We prospectively measured the P(O2) in the femoral artery and the right and left upper pulmonary veins during cardiac catheterization in 13 adults (median age, 53 years) and 7 children (median age, 7 years) with secundum atrial septal defect. The adults and children were studied consecutively. Contrast echocardiography was performed to evaluate right-to-left shunt in all adults. Among the children, there were no patients showing arterial hypoxemia, and there was no difference in the P(O2) (+/-SD) between the right and left upper pulmonary veins (right, 100+/-3.8 mm Hg vs left, 100+/-7.8 mm Hg; p = 0.92). However, arterial hypoxemia was present in 11 of the 13 adult patients, although contrast echocardiography showed more than a moderate degree of right-to-left shunt in only four adults. The P(O2) was lower in the left upper pulmonary vein than it was in the right upper pulmonary vein in all adult patients (right, 91.6+/-13.8 mm Hg vs left, 73.0+/-11.5 mm Hg; p < 0.0001). The P(O2) was lower in the left upper pulmonary vein than it was in the right upper pulmonary vein in adults with atrial septal defect. Care must be taken in measuring pulmonary blood flow if the P(O2) in the left upper pulmonary vein is low enough to influence oxygen content. The decreased P(O2) in the left upper pulmonary vein may contribute to arterial hypoxemia in addition to right-to-left shunt at the atrial level in adults with atrial septal defect.
    Chest 03/1999; 115(3):679-83.
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    ABSTRACT: A 55-year-old man with tetralogy of Fallot underwent corrective surgery. Left ventricular filling pressure increased markedly with increased left ventricular volume one month after surgery, then decreased over the next 7 months, presumably due to increased left ventricular compliance.
    Japanese Circulation Journal 03/1999; 63(2):145-7.
  • Japanese Circulation Journal 01/1999; 63(2):145-147. DOI:10.1253/jcj.63.145
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    ABSTRACT: To address the problems of pharmacological evaluation in paroxysmal atrial fibrillation (PAf), we interviewed 108 consecutive patients with documented PAf regarding symptoms, frequency and trigger factors of PAf and analyzed the 24-hour ambulatory electrocardiographic monitoring (Holter monitoring) records in relation to symptoms. Twenty-nine patients were totally asymptomatic, while 79 patients were symptomatic of which 49 patients had obvious trigger factors. PAf was documented by Holter monitoring in 22 of 79 symptomatic patients. On analysis of PAf-documented 25 Holter monitoring records, the patients checked event marks as PAf in only 20 of 155 PAf episodes. Six episodes of 26 event marks that patients thought to be PAf proved to be premature atrial or ventricular contractions. Nine patients in whom PAf persisted for more than 24 hours became asymptomatic. Patients suitable for pharmacological evaluation constituted about one-fifth of the PAf patients in our consecutive study. Even with the selection of these patients, pharmacological evaluation based on symptoms is difficult because disappearance of PAf may be associated with persistent atrial fibrillation.
    Internal Medicine 01/1999; 37(12):1005-8. DOI:10.2169/internalmedicine.37.1005
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    ABSTRACT: Chest pain in patients with hypertrophic cardiomyopathy seems to be caused by relative myocardial ischemia due to the left ventricular outflow pressure gradient and myocardial hypertrophy. However, in 2 cases of hypertrophic cardiomyopathy chest pain was associated with coronary vasospasm. Thus, chest pain in these cases was decreased not by a beta-blocker but by isosorbide dinitrate and a calcium antagonist. Because beta-blockers are commonly used for hypertrophic obstructive cardiomyopathy and chest pain may be aggravated by beta-blockers in patients with coronary vasospasm, a combination of beta-blocker, isosorbide dinitrate and calcium antagonist was necessary for this hypertrophic cardiomyopathy with variant angina.
    Japanese Circulation Journal 12/1998; 62(11):854-7. DOI:10.1253/jcj.62.854
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    ABSTRACT: Thrombin-antithrombin III complex (TAT) is a marker of thrombin generation, indicating increased coagulability. To investigate whether paroxysmal atrial fibrillation (PAf) is associated with an increased coagulation system, we measured TAT within 24 h after the documentation of PAf in 50 patients with structurally normal hearts. The mean age of the study population was 62 years old. In 32 patients, PAf was documented during routine physical examinations, electrocardiograms or echocardiograms and in the remaining 18 patients, it was reproducibly documented on more than two Holter electrocardiograms. Group I consisted of 38 TAT data sets from 38 patients who did not receive anticoagulant therapy during PAf episodes. At least one week after starting anticoagulant therapy, TAT was measured again in ten patients in whom there was evidence of PAf on the day of measurement. In the remaining 12 patients, PAf occurred while the patients were receiving anticoagulation. Group II consisted of 22 TAT data sets from 22 patients who received anticoagulation during PAf episodes. The average TAT value was 5.8 ng/ml in group I, while it was 2.8 ng/ml in group II (P<0.0001). TAT was greater than 5 ng/ml in 15 of the 38 patients in group I, and in four of the 22 patients in group II. In 20 symptomatic patients, we measured TAT again when the patients maintained sinus rhythm under the same anticoagulant therapy; four patients were receiving and 16 patients were not receiving anticoagulation therapy. TAT decreased from 6.4 to 2.3 ng/ml on average when PAf disappeared and sinus rhythm was maintained (P=0.0009). Increase in the coagulation system occurred transiently during or shortly after PAf episodes in about 40% of PAf patients. As patients with prior anticoagulation had a relatively low TAT value, anticoagulant therapy might be useful in patients with PAf.
    International Journal of Cardiology 10/1998; 66(2):153-6. DOI:10.1016/S0167-5273(98)00211-3

Publication Stats

415 Citations
204.63 Total Impact Points


  • 1995–2005
    • Tenri Yorozu Hospital
      Тэнри, Nara, Japan
  • 1994–1997
    • University Center Rochester
      • Department of Medicine
      Rochester, Minnesota, United States
    • University of Rochester
      • Department of Medicine
      Rochester, New York, United States
  • 1988–1992
    • Kyoto University
      Kioto, Kyōto, Japan