Hiroyuki Yamagishi

Osaka City University, Ōsaka-shi, Osaka-fu, Japan

Are you Hiroyuki Yamagishi?

Claim your profile

Publications (28)122.84 Total impact

  • Article: Detection of prolonged regional myocardial systolic dysfunction after exercise-induced myocardial ischemia by strain echocardiography with high frame rate tissue Doppler echocardiography
    [show abstract] [hide abstract]
    ABSTRACT: BackgroundStrain echocardiography has enabled quantification of regional myocardial systolic function objectively and is less influenced by tethering effects and cardiac translational artifact than Doppler tissue imaging. Although strain echocardiography has been applied for the detection of inducible ischemia during dobutamine stress, it has not been fully applied to exercise stress echocardiography (ESE) because of technical difficulties. Prolonged myocardial systolic dysfunction after exercise-induced ischemia has been shown previously. Thus, we designed this study to evaluate whether the myocardial strain analysis can detect myocardial ischemia by the assessment of prolonged regional left ventricular (LV) dysfunction in ESE. MethodsWe performed ESE with myocardial strain imaging system in 20 consecutive patients who had exercise Tl-201 single photon emission computed tomography (SPECT). Myocardial strain curves were obtained at six segments in mid LV walls from the apical approach before and 5min after ESE. We measured the duration from the R wave in the electrocardiogram to the timing of peak systolic strain corrected by the square root of the RR interval (TPSc). We finally calculated the differences of TPSc (ΔTPSc) before ESE and 5min after ESE. The results were compared with SPECT as a reference standard. ResultsA receiver operating characteristic curve demonstrated that a ΔTPSc cutoff value of 70ms had a sensitivity of 80% and a specificity of 84% for the detection of myocardial ischemia. ConclusionsProlonged regional LV systolic dysfunction assessed by ESE with strain analysis was useful for the detection of myocardial ischemia. KeywordsStress echocardiography–Tissue Doppler echocardiography–Ischemic heart disease–Myocardial strain analysis
    Journal of Echocardiography 04/2012; 9(3):90-96.
  • Article: Prevalence and correlates of physiological valvular regurgitation in healthy subjects.
    [show abstract] [hide abstract]
    ABSTRACT: Although echo Doppler machines have consistently advanced within a quarter of a century, age related prevalence of valvular regurgitation detected by currently available echo machines remains uncertain. The aim of this study was to investigate the prevalence and correlates of valvular regurgitation in healthy individuals. A total of 1,333 apparently healthy individuals were enrolled in this study. Echocardiographic examinations were performed using a currently available echo machine. Aortic regurgitation (AR) was detected less frequently (<10%) in younger subjects. Prevalence of aortic regurgitation increased with advancing age and reached 46% in their 9th decade. Mitral regurgitation (MR) was detected in two-thirds of the subjects >30 years old. Tricuspid regurgitation (TR) was frequently (>80%) detected in all age groups. In general, prevalence of valvular regurgitation was higher than those reported previously, except for a relatively lower prevalence of AR in the elderly population. Age was an independent correlate of AR and MR, but not of TR. The presence of AR and MR were independent correlates of TR. In healthy subjects, AR, MR or TR are commonly detected by using a current echo machine. These "physiological" valvular regurgitations should not be considered as a "pathological" valvular heart disease.
    Circulation Journal 09/2011; 75(11):2699-704. · 3.77 Impact Factor
  • Article: Cardiac and autonomic nerve function after reduced-intensity stem cell transplantation for hematologic malignancy in patients with pre-transplant cardiac dysfunction.
    [show abstract] [hide abstract]
    ABSTRACT: Recent reports have shown that cardiomyopathy caused by hemochromatosis in severe aplastic anemia is reversible after reduced-intensity allogeneic stem-cell transplantation (RIST). We comprehensively evaluated cardiac and autonomic nerve function to determine whether cardiac dysfunction due to causes other than hemochromatosis is attenuated after RIST. In five patients with cardiac dysfunction before transplant, we analyzed the changes in cardiac and autonomic nerve function after transplant, using electrocardiography (ECG), echocardiography, radionuclide angiography (RNA), serum markers, and heart rate variability (HRV), before and up to 100 days after transplant. There was no significant improvement in cardiac function in any patient and no significant alteration in ECG, echocardiogram, RNA, or serum markers. However, on time-domain analysis of HRV, the SD of normal-to-normal RR intervals (SDNN) and the coefficient of variation of the RR interval (CVRR) decreased significantly 30 and 60 days after transplant (P = 0.04 and 0.01, respectively). Similarly, on frequency-domain analysis of HRV, low and high frequency power (LF and HF) significantly and temporarily decreased (P = 0.003 and 0.03, respectively). Notably, in one patient who had acute heart failure after transplantation, the values of SDNN, CVRR, r-MSSD, LF, and HF at 30 and 60 days after transplantation were the lowest of all the patients. In conclusion, this study suggests that (a) RIST is well-tolerated in patients with cardiac dysfunction, but we cannot expect improvement in cardiac dysfunction due to causes other than hemochromatosis; and (b) monitoring HRV may be useful in predicting cardiac events after RIST.
    Annals of Hematology 02/2009; 88(9):871-9. · 2.62 Impact Factor
  • Article: Age- and gender-specific changes in the left ventricular relaxation: a Doppler echocardiographic study in healthy individuals.
    [show abstract] [hide abstract]
    ABSTRACT: Although left ventricular diastolic function has been shown to deteriorate with advancing age, its gender-specific change is unknown. The aim of this study was to investigate age- and gender-specific changes in tissue Doppler-derived left ventricular diastolic index, E'. A total of 1333 healthy individual without known heart disease or hypertension (mean age, 55 years; range, 10 to 89) were enrolled and studied. Peak early mitral annular velocity (E') and peak late mitral annular velocity (A') were recorded and measured. As an index of the left ventricular relaxation, E' was used. As an index of the left ventricular filling pressure, E/E' was calculated. Although systolic indices poorly correlated with age, diastolic indices correlated well with age. Among those aged 30 to 39 and 40 to 49 years, E' was significantly lower in males than in females. In subjects aged 50 to 59 and 60 to 69 years, E' was similar in both genders. Among those aged 70 to 79 and 80 to 89 years, E' was significantly lower in females than in males. Predictors of the lowest quartile of E' among subjects aged >50 years were age (P<0.0001; chi(2)=66.11; odds ratio, 1.08; 95% CI, 1.058 to 1.097) and female gender (P=0.002; chi(2)=9.23; odds ratio, 1.68; 95% CI, 1.202 to 2.343). Age-related changes in diastolic indices were gender specific. In the elderly population, diastolic function deteriorated more significantly in the female gender than in the male gender. These results may explain the relatively higher incidence in elderly females among patients with diastolic heart failure and higher cardiovascular mortality in the female gender.
    Circulation Cardiovascular Imaging 01/2009; 2(1):41-6. · 5.94 Impact Factor
  • Article: Coronary flow velocity reserve measurement in three major coronary arteries using transthoracic Doppler echocardiography.
    [show abstract] [hide abstract]
    ABSTRACT: Measurement of the coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography (TTDE) has been reported to be useful for the noninvasive assessment of significant coronary artery stenosis or myocardial ischemia. The purpose of this study was to evaluate the value of this method in three major coronary arteries for detecting myocardial ischemia in the clinical setting. We studied 89 consecutive patients who were referred to our outpatient clinic because of chest pain. We measured CFVR using TTDE in three major coronary arteries. We defined CFVR<2.0 in at least one vessel as being positive for myocardial ischemia. The accuracy of CFVR measurements for detecting myocardial ischemia was determined in comparison with exercise thallium-201 (Tl-201) single photon emission computed tomography (SPECT) as a reference standard. CFVR in at least one vessel was successfully measured in 87 of 89 patients (98%). The sensitivity and specificity of CFVR<2.0 in at least one coronary vessel, in any of the coronary territories, was 86% and 89%, respectively. In terms of assessing myocardial ischemia in each coronary artery territory, the agreement between CFVR<2.0 and Tl-201 SPECT for the left anterior descending coronary artery, the posterior descending coronary artery, and the left circumflex coronary artery territories was 95%, 81%, and 73%, respectively. Noninvasive CFVR measurement by TTDE may be useful for detecting myocardial ischemia, as well as for identifying ischemic territories in the clinical setting.
    Echocardiography 05/2006; 23(4):279-86. · 1.24 Impact Factor
  • Article: Persistent high levels of plasma oxidized low-density lipoprotein after acute myocardial infarction predict stent restenosis.
    [show abstract] [hide abstract]
    ABSTRACT: Recently, elevated levels of plasma oxidized low-density lipoprotein (LDL) have been shown to relate to plaque instability in human atherosclerotic lesions. We investigated prospectively patients admitted with acute myocardial infarction (AMI) who underwent primary coronary stenting to evaluate whether the 6-month outcome could be predicted by measuring plasma oxidized LDL (ox-LDL) levels at the time of hospital discharge. Plasma ox-LDL levels were measured in 102 patients with AMI undergoing primary coronary stenting using a highly sensitive ELISA method. Measurements were taken on admission and at discharge, and the findings related to the clinical outcome. At 6-month follow-up, angiographic stent restenosis occurred in 25 (25%) of the 102 AMI patients. Plasma ox-LDL levels at discharge were significantly (P=0.0074) higher in the restenosis group than those in the no-restenosis group (1.03+/-0.65 versus 0.61+/-0.34 ng/5 microg LDL protein). Multiple regression analysis showed that only plasma ox-LDL levels at discharge were a statistically significant independent predictor for late lumen loss after stenting (beta=0.645; P<0.0001). This prospective study demonstrates that persistence of an increased level of plasma ox-LDL at discharge is a strong independent predictor of stent restenosis at 6-month follow-up in AMI patients.
    Arteriosclerosis Thrombosis and Vascular Biology 04/2006; 26(4):877-83. · 6.37 Impact Factor
  • Article: Coronary Flow Velocity Reserve Measurement in Three Major Coronary Arteries Using Transthoracic Doppler Echocardiography
    [show abstract] [hide abstract]
    ABSTRACT: Background: Measurement of the coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography (TTDE) has been reported to be useful for the noninvasive assessment of significant coronary artery stenosis or myocardial ischemia. The purpose of this study was to evaluate the value of this method in three major coronary arteries for detecting myocardial ischemia in the clinical setting. Methods: We studied 89 consecutive patients who were referred to our outpatient clinic because of chest pain. We measured CFVR using TTDE in three major coronary arteries. We defined CFVR < 2.0 in at least one vessel as being positive for myocardial ischemia. The accuracy of CFVR measurements for detecting myocardial ischemia was determined in comparison with exercise thallium-201 (Tl-201) single photon emission computed tomography (SPECT) as a reference standard. Results: CFVR in at least one vessel was successfully measured in 87 of 89 patients (98%). The sensitivity and specificity of CFVR < 2.0 in at least one coronary vessel, in any of the coronary territories, was 86% and 89%, respectively. In terms of assessing myocardial ischemia in each coronary artery territory, the agreement between CFVR < 2.0 and Tl-201 SPECT for the left anterior descending coronary artery, the posterior descending coronary artery, and the left circumflex coronary artery territories was 95%, 81%, and 73%, respectively. Conclusion: Noninvasive CFVR measurement by TTDE may be useful for detecting myocardial ischemia, as well as for identifying ischemic territories in the clinical setting.
    Echocardiography 03/2006; 23(4):279 - 286. · 1.24 Impact Factor
  • Article: Noninvasive diagnosis of restenosis by transthoracic Doppler echocardiography after percutaneous coronary intervention: comparison with exercise Tl-SPECT.
    [show abstract] [hide abstract]
    ABSTRACT: Noninvasive methods that have the ability to accurately detect restenosis have been desired in the selection of patients requiring further angiographic evaluation. The present study sought to evaluate the diagnostic potential of transthoracic Doppler echocardiography (TTDE), a noninvasive method for evaluating coronary flow velocity reserve (CFVR), in detecting restenosis after percutaneous coronary intervention (PCI). We studied 107 consecutive patients 6 months after undergoing successful PCI on the left anterior descending coronary artery (LAD) lesions for relief of angina pectoris. The flow velocity in the distal LAD was measured by TTDE both at rest and during intravenous infusion of adenosine triphosphate. CFVR was calculated as the ratio of hyperemic to basal mean diastolic flow velocities. We defined a reversible perfusion defect in exercise Tl-201 single-photon emission computed tomography (SPECT) as restenosis. The CFVR measurements by TTDE were compared with the results of SPECT. Complete TTDE data were acquired for 105 of the 107 study patients. A contrast agent was used to obtain adequate Doppler signals in 29 patients. Of the 105 patients, there were 18 patients with abnormal perfusion (group A) and 87 patients with normal perfusion (group B) in the LAD territories on Tl-201 SPECT. CFVR was greater in group B than in group A (1.7 +/- 0.5 vs. 3.7 +/- 0.8, P < 0.0001, respectively). There were 17 patients with CFVR < 2 and 88 patients with CFVR > or = 2. CFVR < 2 predicted restenosis determined by Tl-201 SPECT, with a sensitivity of 94% and a specificity of 100%. Noninvasive measurement of CFVR by TTDE accurately reflects the physiological severity of coronary narrowing due to restenosis after PCI. This method has possibility of reducing the number of unnecessary coronary angiographies after PCI.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 02/2006; 19(2):165-71. · 2.98 Impact Factor
  • Article: Acute myocardial infarction: clinical characteristics and plaque morphology between expansive remodeling and constrictive remodeling by intravascular ultrasound.
    [show abstract] [hide abstract]
    ABSTRACT: According to recent intravascular ultrasound (IVUS) studies, expansive remodeling (ER) at the culprit lesion has been observed in almost 50% of patients with acute coronary syndrome and constrictive remodeling (CR) in 30%. The purpose of this study is to investigate the difference between ER and CR at the culprit lesion in patients with acute myocardial infarction (AMI). Preinterventional IVUS images of 73 patients with AMI were identified. The remodeling index (RI) was defined as the ratio of the external elastic membrane (EEM) areas at the culprit lesion to the EEM areas at the proximal reference site. Expansive remodeling was defined as an RI > 1.05; CR, as an RI < 0.95. In patients with AMI, 40 patients (55%) showed ER on IVUS, whereas CR was observed in 18 patients (25%). Patients with ER were significantly older than those with CR (P < .005). The frequency of the presence of calcifications was higher in patients with ER than in those with CR (P < .0005). In patients with AMI with ER, soft plaque with small calcium was the most frequent (58%). Multivariate analysis revealed that age and the presence of calcifications remained as independent predictors of ER. These findings suggest that ER relates to old age and calcification, and CR may contribute to early plaque progression than ER in patients with AMI.
    American heart journal 02/2006; 151(2):332-7. · 4.65 Impact Factor
  • Article: Protective effect of high diastolic blood pressure during exercise against exercise-induced myocardial ischemia.
    [show abstract] [hide abstract]
    ABSTRACT: Hypertension is one of the risk factors for coronary artery disease. However, because most coronary blood flow to the left ventricle occurs during diastole, high diastolic blood pressure during exercise may have a protective effect against exercise-induced myocardial ischemia. The aim of the present study was to test this hypothesis. We identified 469 patients with sinus rhythm and known or suspected coronary artery disease who underwent exercise thallium-201 myocardial single-photon emission computed tomography and coronary arteriography. High diastolic blood pressure during exercise was defined as diastolic blood pressure at peak exercise > or = 90 mm Hg. There was no significant difference in medications, number of diseased vessels, or Gensini score between patients with high (n = 228) and normal (n = 241) diastolic blood pressure during exercise, whereas patients with high diastolic blood pressure during exercise exhibited a higher pressure-rate product during exercise than patients with normal diastolic blood pressure during exercise. The reversibility score on thallium-201 myocardial scan was significantly smaller in patients with high diastolic blood pressure during exercise than in patients with normal diastolic blood pressure during exercise (P = .021). High diastolic blood pressure during exercise has a potential protective effect against exercise-induced ischemia, although the mechanism of such effects remains to be determined.
    American heart journal 10/2005; 150(4):790-5. · 4.65 Impact Factor
  • Article: Physiologic assessment of coronary artery stenosis without stress tests: noninvasive analysis of phasic flow characteristics by transthoracic Doppler echocardiography.
    [show abstract] [hide abstract]
    ABSTRACT: We evaluated the significance of the diastolic-to-systolic blood flow velocity ratio (DSVR) determined by transthoracic Doppler echocardiography, for a physiologic assessment of the severity of coronary stenosis without stress tests, as compared with thallium 201 single photon emission computed tomography. In 95 patients undergoing thallium 201 single photon emission computed tomography for coronary artery disease, the flow velocity in the distal left anterior descending coronary artery was obtained with transthoracic Doppler echocardiography. The mean and peak DSVR values were calculated using mean and peak coronary flow velocity. DSVR was successfully measured for 82 patients (86.3%), including 33 patients with reversible perfusion defects in the left anterior descending coronary artery territories. For predicting reversible perfusion defects in thallium 201 single photon emission computed tomography, the best cut-off points were 1.5 for mean DSVR (sensitivity 81.8%, specificity 85.7%) and 1.6 for peak DSVR (sensitivity 75.7%, specificity 83.6%). Noninvasive measurement of DSVR with transthoracic Doppler echocardiography provides physiologic estimation of the left anterior descending coronary artery stenosis severity at high success rate, without stress tests.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 10/2005; 18(9):949-55. · 2.98 Impact Factor
  • Article: Non-invasive assessment of myocardial ischaemia using new real-time three-dimensional dobutamine stress echocardiography: comparison with conventional two-dimensional methods.
    [show abstract] [hide abstract]
    ABSTRACT: Although two-dimensional-dobutamine stress echocardiography (2D-DSE) is useful for the diagnosis of myocardial ischaemia, it requires the acquisition of multiple cross-sections at each stage. The introduction of new real-time three-dimensional echocardiography (RT3DE) offers rapid acquisition and 3D display of the entire left ventricle (LV). The purpose was to evaluate real-time three-dimensional-dobutamine stress echocardiography (RT3D-DSE) for the diagnosis of ischaemia using exercise (201)Tl single-photon emission computed tomography (SPECT) as the reference standard, in comparison with 2D-DSE. We performed DSE in 56 consecutive patients who had undergone SPECT because of suspected ischaemia. 3D images by RT3DE were acquired from the apical window after the acquisition of cross-sectional images at every stage of 2D-DSE. Wall motion analysis in RT3DE was performed from anatomical images by cropping the acquired full volume data sets. Mean scanning time for adequate image acquisition at peak stress by RT3D-DSE was shorter than that by 2D-DSE (29+/-4 vs. 68+/-6 s, P<0.0001). RT3DE provided adequate images at success rate of 92% at rest and 89% at peak stress, whereas two-dimensional echocardiography did at 94 and 90%, respectively. The sensitivity, specificity, and accuracy of RT3D-DSE for the detection of coronary artery disease are 86, 80, and 82%, respectively. Those of 2D-DSE are 86, 83, and 84%, respectively. There were no significant differences in the sensitivity, specificity, and accuracy between these two methods (P=1.000). RT3D-DSE offers rapid and simple acquisition of the entire LV wall motion and provides feasible and accurate assessment of myocardial ischaemia.
    European Heart Journal 08/2005; 26(16):1625-32. · 10.48 Impact Factor
  • Article: Freehand three-dimensional echocardiography with rotational scanning for measurements of left ventricular volume and ejection fraction in patients with coronary artery disease.
    [show abstract] [hide abstract]
    ABSTRACT: Measurement of left ventricular (LV) volumes and ejection fraction (EF) is important in managing patients with coronary artery disease (CAD). Introduction of free-hand three-dimensional echocardiography (3DE) system which is equipped with small magnetic tracking system and average rotational geometry for LV volumes may provide easy and accurate quantification of LV systolic function in CAD patients. To evaluate the feasibility and accuracy of LV volumes and EF measurement by free-hand 3DE with rotational geometry in patients with CAD. The study subjects consisted of consecutive 25 patients with CAD who were scheduled for quantitative gated single-photon emission computed tomography (QGS). LV end-diastolic volume (EDV), end-systolic volume (ESV), and EF were determined by conventional two-dimensional echocardiography (2DE), 3DE, and QGS. Three-dimensional echocardiography data acquisition and analysis were possible in 22 of 25 subjects (feasibility 88%). In this 3DE system, image acquisition time was 2 minutes, and 5 minutes were needed for off-line analysis of LV volumes and EF. Correlations and the limits of agreement between 3DE and QGS (r = 0.97, 0.0 +/- 9.1 ml for EDV, r = 0.99, 0.0 +/- 5.0 ml for ESV, and r = 0.97, 0.5 +/- 3.3% for EF, respectively) were superior to those between 2DE and QGS (r = 0.85, 12.6 +/- 26.8 ml for EDV, r = 0.85, 9.7 +/- 26.1 ml for ESV, and r = 0.90, -1.3 +/- 6.9% for EF, respectively). Inter- and intra-observer variabilities of 3DE were smaller than that of 2DE (5% vs 10%, 5% vs 10% for EDV, 6% vs 13%, 5% vs 9% for ESV, and 4% vs 11%, 4% vs 6% for EF, respectively). Three-dimensional echocardiography using magnetic tracking system and average rotational geometry offered a feasible and accurate method for quantification of LV volumes and EF in patients with CAD.
    Echocardiography 03/2005; 22(2):111-9. · 1.24 Impact Factor
  • Article: Spotty calcification typifies the culprit plaque in patients with acute myocardial infarction: an intravascular ultrasound study.
    [show abstract] [hide abstract]
    ABSTRACT: Calcification is a common finding in human coronary arteries; however, the relationship between calcification patterns, plaque morphology, and patterns of remodeling of culprit lesions in a comparison of patients with acute coronary syndromes (ACS) and those with stable conditions has not been documented. Preinterventional intravascular ultrasound (IVUS) images of 178 patients were studied, 61 with acute myocardial infarction (AMI), 70 with unstable angina pectoris (UAP), and 47 with stable angina pectoris (SAP). The frequency of calcium deposits within an arc of less than 90 degrees for all calcium deposits was significantly different in culprit lesions of patients with AMI, UAP, and SAP (P<0.0001). Moreover, the average number of calcium deposits within an arc of <90 degrees per patient was significantly higher in AMI than in SAP (P<0.0005; mean+/-SD, AMI 1.4+/-1.3, SAP 0.5+/-0.8). Conversely, calcium deposits were significantly longer in SAP patients (P<0.0001; mean+/-SD, AMI 2.2+/-1.6, UAP 1.9+/-1.8, and SAP 4.3+/-3.2 mm). In AMI patients, the typical pattern was spotty calcification, associated with a fibrofatty plaque and positive remodeling. In ACS patients showing negative remodeling, no calcification was the most frequent observation. Conversely, SAP patients had the highest frequency of extensive calcification. Our observations show that IVUS allows the identification of vulnerable plaques in coronary arteries, not only by identifying a fibrofatty plaque and positive remodeling, but also by identifying a spotty pattern of calcification.
    Circulation 11/2004; 110(22):3424-9. · 14.74 Impact Factor
  • Article: Detecting viable myocardium and predicting functional improvement: comparisons of positron emission tomography, rest-redistribution thallium-201 single-photon emission computed tomography (SPECT), exercise thallium-201 reinjection SPECT, I-123 BMIPP SPECT and dobutamine stress echocardiography.
    [show abstract] [hide abstract]
    ABSTRACT: Low-dose dobutamine stress echocardiography (LDDE) has become a useful and safe method for identifying hibernating or stunned myocardium and for predicting improvement in wall motion after coronary revascularization. In the present study, fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), rest-redistribution thallium-201 ((201)Tl) single-photon emission computed tomography (RR-Tl SPECT), (123)I-15-(p-iodophenyl)-3-(R,S)-methyl pentadecanoic acid (BMIPP) and LDDE were performed in 30 patients with acute myocardial infarction (AMI) at 10+/-3 days after the onset of AMI. Also, exercise (201)Tl reinjection SPECT (RI-Tl SPECT) was performed at 14+/-2 days. Follow-up echocardiography was performed 5+/-3 months later in all patients after interventional therapy for the assessment of functional recovery. Of the 390 segments analyzed by echocardiography, 110 (28%) had abnormal wall motion. There were no significant differences between RR-Tl SPECT and LDDE in sensitivity, specificity, positive predictive value and negative predictive value using the chi(2)-test; however, in akinetic segments, there was a significant difference in sensitivity. Among FDG-PET, RI-Tl SPECT, BMIPP and LDDE, there were significant differences in 3 variables. In akinetic segments, LDDE is superior to RR-Tl SPECT in sensitivity and to FDG-PET in specificity. In hypokinetic segments, LDDE is superior to RI-Tl SPECT and BMIPP in sensitivity, and to FDG-PET and BMIPP in specificity. LDDE could detect functional recovery of viable myocardium in the early period of AMI and can be performed easily and safely.
    Circulation Journal 11/2004; 68(10):950-7. · 3.77 Impact Factor
  • Article: Accuracy of measurement of left ventricular volume and ejection fraction by new real-time three-dimensional echocardiography in patients with wall motion abnormalities secondary to myocardial infarction.
    [show abstract] [hide abstract]
    ABSTRACT: Three-dimensional echocardiography is an ideal tool for the measurement of left ventricular (LV) volume because no geometric assumptions about LV shape are needed. The introduction of new real-time 3-dimensional echocardiography (RT3DE) has allowed rapid acquisition of a 3-dimensional dataset with good image quality. The purpose of this study was to examine the accuracy of RT3DE for the measurement of LV volume and ejection fraction in patients with wall motion abnormalities by using quantitative gated single-photon emission computed tomography (QGSPECT) as a reference standard. The study population consisted of 25 consecutive patients with wall motion abnormalities who underwent LV volume measurement by 2-dimensional echocardiography and by QGSPECT. LV volume and ejection fraction by RT3DE were measured offline by using the average rotation method. In 23 of 25 patients (92%), it was possible to measure 3-dimensional volume with RT3DE. RT3DE correlated well with QGSPECT in the measurement of end-diastolic volume and end-systolic volume (r = 0.97, mean difference 3.4 ml; r = 0.98, mean difference 2.0 ml, respectively), 2-dimensional echocardiography also correlated with QGSPECT but underestimated LV volume (r = 0.98, mean difference 21.1 ml; r = 0.98, mean difference 15.6 ml, respectively). Ejection fraction obtained by RT3DE had better agreement with that obtained by QGSPECT than that obtained by 2-dimensional echocardiography (r = 0.92, mean difference -0.2%; r = 0.89, mean difference -2.7%, respectively). RT3DE allows convenient and accurate estimation of LV volume and ejection fraction in patients with wall motion abnormalities.
    The American Journal of Cardiology 10/2004; 94(5):552-8. · 3.37 Impact Factor
  • Source
    Article: New noninvasive diagnosis of myocardial ischemia of the left circumflex coronary artery using coronary flow reserve measurement by transthoracic Doppler echocardiography: comparison with thallium-201 single photon emission computed tomography.
    [show abstract] [hide abstract]
    ABSTRACT: The usefulness of coronary flow reserve measurement in the left circumflex coronary artery by transthoracic Doppler echocardiography to detect myocardial ischemia was compared with exercise thallium-201 single photon emission computed tomography (SPECT). Transthoracic Doppler echocardiography was performed in 110 patients with suspected coronary artery disease. Color Doppler signals of the left circumflex coronary artery flow in the apical four-chamber view were identified, and the velocities at rest and during hyperemia recorded for calculation of coronary flow reserve by the pulsed Doppler method. All patients underwent SPECT within 1 week of the transthoracic Doppler echocardiographic study. Coronary flow reserve in the left circumflex coronary artery was measured in 79 (72%) of 110 patients. SPECT revealed reversible perfusion defect in the left circumflex coronary artery territories in 12 of 69 patients excluding those with multivessel disease. Coronary flow reserve < 2.0 had a sensitivity of 92% and specificity of 96% for reversible perfusion defect detected by SPECT. Noninvasive coronary flow reserve measurement in the left circumflex coronary artery by transthoracic Doppler echocardiography can estimate myocardial ischemia in the left ventricular lateral regions.
    Journal of Cardiology 03/2004; 43(3):109-16. · 1.28 Impact Factor
  • Article: Rapid and accurate noninvasive assessment of global left ventricular systolic function using biplane advanced automated contour tracking method.
    [show abstract] [hide abstract]
    ABSTRACT: The advanced automated contour tracking (AACT) method has been newly developed for automated detection of the left ventricular endocardial boundary. Left ventricular ejection fraction (LVEF) may be estimated by applying the AACT method to 2 orthogonal planes of patients even when regional wall-motion abnormalities exist. The purpose of this study was to examine the reliability of the biplane AACT method in the measurement of LVEF in patients with suggested ischemic heart disease with use of quantitative gated single photon emission computed tomography (QGS) as a reference standard. The study population consisted of 47 consecutive patients with suggested ischemic heart disease. All patients underwent 2-dimensional echocardiography and QGS. Biplane LVEF from apical 4- and 2-chamber views was measured offline by the AACT method using disk summation method. The accuracy of the AACT method for LVEF measurement was determined in comparison with QGS. In 41 (29 with and 12 without regional wall-motion abnormalities) of 47 patients (87%), automated tracing of the endocardial border was adequately achieved with the AACT method. LVEF measured by the AACT method correlated well with that measured by QGS (y = 0.97x +2.4, r = 0.91). The mean difference between AACT and QGS was 0.6 +/- 5.5% (mean +/- SD). The mean time required for analysis of 1 set of images during 1 cardiac cycle by the AACT method was much shorter than that required by manual tracing method (7 +/- 1 vs 37 +/- 4 seconds, P <.0001). The biplane AACT method provides accurate and quick measurement of LVEF in patients even with regional wall-motion abnormalities.
    Journal of the American Society of Echocardiography 12/2003; 16(12):1237-43. · 3.71 Impact Factor
  • Article: Noninvasive assessment of myocardial ischemia in the left ventricular inferior regions by coronary flow reserve measurement using transthoracic Doppler echocardiography.
    [show abstract] [hide abstract]
    ABSTRACT: The purpose of this study was to evaluate the potential of noninvasive measurement of coronary flow reserve (CFR) by transthoracic Doppler echocardiography (TTDE) for the assessment of myocardial ischemia in the left ventricular (LV) inferior regions. Although coronary flow assessment by TTDE has been determined for the assessment of perfusion abnormality in the LV anterior regions, the usefulness of this method has not been well investigated in the LV inferior regions. We studied 50 patients (43 men; mean age 60 +/- 9 years) with suggested coronary artery disease. CFR in the posterodescending coronary artery (PDA) was calculated as a ratio of hyperemic to basal peak (peak CFR) and mean (mean CFR) flow velocities in the PDA, which were measured by TTDE. CFR values were compared with the results of exercise 201-thallium single photon emission computed tomography. CFR was successfully measured in 43 of 50 patients (86%). Mean and peak CFR < 2 were shown in 10 of 12 patients with abnormal perfusion in the LV inferior regions, whereas CFR > or = 2 were shown in 30 of 31 patients with normal perfusion. Thus, CFR < 2 in the PDA by TTDE had a sensitivity of 83% and a specificity of 97% for the assessment of perfusion abnormality in the LV inferior regions by 201-thallium single photon emission computed tomography. CFR in the PDA measured by TTDE provides data equivalent to those obtained by 201-thallium single photon emission computed tomography for myocardial ischemia in the LV inferior regions.
    Journal of the American Society of Echocardiography 12/2003; 16(12):1252-7. · 3.71 Impact Factor
  • Article: Impact of diabetes mellitus on worsening of the left ventricular ejection fraction in exercise-gated 201Tl myocardial single photon emission computed tomography in patients with coronary artery disease.
    [show abstract] [hide abstract]
    ABSTRACT: It remains uncertain whether factors other than the severity of coronary artery disease (CAD) are associated with the worsening of the left ventricular ejection fraction (LVEF) by exercise. In the present study the impact of coronary risk factors on the worsening of LVEF by exercise was investigated in 391 patients with known or suspected CAD using exercise-gated (201)Tl scanning to calculate the LVEF. Significant worsening of the LVEF by exercise was defined as >4.7% (mean plus 1 SD of the value in 116 patients without CAD). Multivariate analysis revealed that diabetes mellitus (DM) was an independent risk factor for the worsening of LVEF by exercise in patients with multivessel (2- or 3-vessel) CAD with an odds ratio (95% confidence interval) of 2.2 (1.1-4.5, p=0.037). In 157 patients with 2- or 3-vessel CAD, 20 (23.5%) of 85 nondiabetic patients and 31 (43.1%, p=0.009 vs nondiabetic patients) of 72 diabetic patients showed significant worsening of LVEF by exercise. In patients with 2- or 3-vessel CAD, there was no significant difference in Gensini score or reversibility of perfusion defects between nondiabetic and diabetic patients. Thus, DM is a risk factor for worsening LVEF by exercise in addition to the severity of CAD.
    Circulation Journal 10/2003; 67(10):839-45. · 3.77 Impact Factor