H Sugihara

Kokura Memorial Hospital, Kitakyūshū, Fukuoka, Japan

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Publications (201)350.39 Total impact

  • Tatsuya Kawasaki, Hiroki Sugihara
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    ABSTRACT: An abnormal blood pressure response to exercise has been reported to be associated with left ventricular subendocardial ischemia in patients with hypertrophic cardiomyopathy (HCM), but the underlying mechanism remains unclear. We report a case of HCM with an abnormal blood pressure response and subendocardial ischemia, in which the analysis of heart rate variability revealed exercise-induced vagal enhancement. The present case highlights the possible mechanism linking abnormal blood pressure response and left ventricular subendocardial ischemia in patients with HCM.
    Annals of Noninvasive Electrocardiology 01/2014; 19(1):98-101. · 1.08 Impact Factor
  • Tatsuya Kawasaki, Hiroki Sugihara
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    ABSTRACT: Hypertrophic cardiomyopathy (HCM) patients often develop subendocardial ischemia in the left ventricle without atherosclerotic coronary stenosis. Myocardial ischemia plays an important role in the pathophysiology of HCM, but diagnostic techniques for the detection of subendocardial ischemia have not been widely available. We developed specific techniques to quantify subendocardial ischemia on stress scintigraphy, and have compared the results with various clinical features in patients with HCM. This article reviews our understanding of subendocardial ischemia in HCM based on more than 20 years of experience.
    Journal of Cardiology 11/2013; · 2.30 Impact Factor
  • Journal of Cardiology Cases 07/2013; 8(1):e57–e59.
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    ABSTRACT: AIMS: Hypertrophic cardiomyopathy (HCM) patients often develop left--ventricular subendocardial ischaemia, a cause of chest symptoms, despite normal epicardial coronary arteries. The aim of this study was to examine whether ultrasonic tissue characterization or late gadolinium enhancement on cardiac magnetic resonance imaging can detect subendocardial ischaemia in patients with HCM. METHODS AND RESULTS: Subendocardial ischaemia was quantified on exercise Tc-99m tetrofosmin myocardial scintigraphy in 29 non-obstructive HCM patients with asymmetric septal hypertrophy. Ultrasonic tissue characterization using cyclic variation of integrated backscatter (CV-IB) and late gadolinium enhancement on cardiac magnetic resonance imaging were analysed separately in the right halves and the left halves of the ventricular septum in relation to subendocardial ischaemia. Subendocardial ischaemia was identified in 17 (59%) patients. The ratio of CV-IB in the right-to-left halves of the ventricular septum was significantly higher in patients with subendocardial ischaemia (1.19 ± 0.10) than those without (0.84 ± 0.10, P = 0.04). The optimal cutoff for the detection of subendocardial ischaemia was the ratio of CV-IB >1.0, with a sensitivity of 80%, specificity of 71%, and accuracy of 76%. On the other hand, late gadolinium enhancement was not associated with subendocardial ischaemia in our cohort. CONCLUSION: Ultrasonic tissue characterization using CV-IB separately in the right and left halves of the ventricular septum, but not late gadolinium enhancement on magnetic resonance imaging, provided useful information in detecting subendocardial ischaemia in patients with HCM. Ultrasonic tissue characterization may be useful in selecting patients who will benefit from medications to relieve chest symptoms.
    European heart journal cardiovascular Imaging. 12/2012;
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    ABSTRACT: Limited data are available regarding Holter monitoring for cardiovascular events except for ventricular tachycardia as a risk marker for sudden death in hypertrophic cardiomyopathy (HCM). We aimed to examine Holter findings in relation to the long-term prognosis in patients with HCM. Ambulatory Holter monitoring was performed in 106 HCM patients with sinus rhythm. All were prospectively followed for the composite endpoint of sudden death, cardiovascular death, and hospitalization for heart failure or stroke associated with atrial fibrillation. Cardiovascular events occurred in 19 patients during a mean follow-up of 10.1 years. Neither arrhythmia information nor autonomic information as assessed by heart rate variability and turbulence significantly differed between HCM patients with and without cardiovascular events. Average heart rates were lower in HCM patients with cardiovascular events (64.7 ± 11.2 beats/min) than in those without (73.7 ± 10.2 beats/min, p = 0.001). Multivariate Cox proportional hazards regression analysis after adjustment for baseline characteristics showed that lower average heart rate remained an independent predictor of cardiovascular events (HR: 0.47 per 10 increase; 95% CI: 0.25-0.87; p = 0.016). Average heart rate on Holter monitoring predicted long-term prognosis in our cohort. Further multicenter studies are needed to confirm our results.
    Cardiology 06/2012; 122(1):44-54. · 1.52 Impact Factor
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    ABSTRACT: Intramyocardial calcification is a very rare condition. We report a case of a 72-year-old man with apical hypertrophic cardiomyopathy, who was initially suspected of having a thrombus in the left ventricular apex on echocardiography, but was finally diagnosed as having apical intramyocardial calcification on multidetector computed tomography. The mechanism of developing intramyocardial calcification remains to be elucidated, but the patient has been stable for more than 2 years.
    Internal Medicine 01/2012; 51(12):1523-6. · 0.97 Impact Factor
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    ABSTRACT: A necropsy study of patients with hypertrophic cardiomyopathy (HCM) who died at a young age exhibited marked disarray and fibrosis in the mid-wall layer of the left ventricular (LV) myocardium. We assessed ultrasonic tissue characteristics in the three layers of the ventricular septum (VS), and correlated the result with long-term prognosis in HCM. The magnitude of cyclic variation of integrated backscatter (CV-IB) was calculated in the three layers of the VS and the whole aspect of the LV posterior wall in 58 non-obstructive HCM patients and 20 healthy controls. All HCM patients were prospectively followed for an average period of 7.1 years for the occurrence of cardiac death or hospitalization due to heart failure. Each CV-IB of four regions was lower in HCM patients than in controls (all P < 0.01). CV-IB of the VS mid-wall layer was lower in 14 HCM patients with cardiac events than in patients without (5.4 ± 0.6 vs. 7.4 ± 0.5 dB, P = 0.033) although CV-IB of three other regions did not differ between the two groups. The optical cut-off point of %CV-IB <90%, i.e. the ratio of CV-IB in the VS mid-wall layer to the mean value in the layers on both sides, was an independent predictor of cardiac events (hazard ratio, 6.12; 95% confidence interval, 1.62-66.6; P = 0.013), with a positive predictive value of 44% and particularly with a high negative predictive value of 91%. Patients with non-obstructive HCM are not likely to undergo cardiac events in the near future, when the CV-IB value is not significantly lower in the VS mid-wall layer than in the layers on both sides.
    European Heart Journal – Cardiovascular Imaging 02/2011; 12(2):90-7. · 3.67 Impact Factor
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    ABSTRACT: An attenuated heart rate response to exercise, termed chronotropic incompetence (CI), has been reported to be an independent predictor of cardiovascular mortality. We examined the change in autonomic function during exercise testing and correlated the results with CI. Exercise testing using a bicycle ergometer was performed in 172 patients who had no evidence of cardiac disease. Chronotropic incompetence was defined as the failure to achieve 85% of the age-predicted maximum heart rate, heart rate reserve <80%, or chronotropic response index <0.80. We analysed the relationship between CI and the change in two components of heart rate variability during exercise testing: high-frequency (HF) component (0.15-0.40 Hz) as an index of vagal modulation and the ratio of low-frequency (LF) component (0.04-0.15 Hz) to HF component as an index of sympathovagal balance. Heart rate variability indexes before exercise were similar in patients with and without CI. Percentage changes after exercise in the ratio of LF to HF component were higher in patients with CI than in those without CI (84 +/- 15 vs. 41 +/- 16%, P < 0.05), whereas percentage changes in an HF component were similar in the two groups. Our data suggested that CI in patients without structural heart disease was mainly caused by a pathophysiological condition in which sympathetic activation was not well translated into heart rate increase. Further study is needed to determine the post-synaptic sensitivity of the beta-adrenergic receptor pathway in relation to CI.
    Europace 04/2010; 12(4):561-6. · 2.77 Impact Factor
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    Clinical Cardiology 06/2009; 32(8):E72. · 1.83 Impact Factor
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    ABSTRACT: Acute inferior myocardial infarction (MI) often induces transient sinus bradycardia through vagal enhancement, known as Bezold-Jarisch reflex, which is explained by preferential distribution of vagal nerve in the inferior wall. We examined vagal activity in relation to the occurrence of residual ischemia in patients with old inferior MI and assessed its diagnostic usefulness. Exercise myocardial scintigraphy was performed in 15 patients with old inferior MI, 19 angina pectoris (AP) patients with inferior ischemia but no MI, and 32 control subjects who had no evidence of cardiac disease. We analyzed the connection of residual ischemia in old MI with ST-segment response to exercise and with vagal activity as determined by coefficient of component variance of high frequency (CCV(HF)). Exercise-induced percentage change in CCV(HF) was higher in patients with old MI and residual ischemia (18.8 +/- 13.5%) and AP (5.5 +/- 9.7%) than old MI but no residual ischemia (-24.1 +/- 4.9%) or control (-22.8 +/- 4.5%, P = 0.006). Percentage change in CCV(HF) > -5% had a good diagnostic value for the detection of residual ischemia in patients with old inferior MI with sensitivity of 83%, specificity of 89%, accuracy of 87%, and positive likelihood ratio of 7.50, which was higher than that of ST-segment depression (67%, 50%, 56%, and 1.33). Vagal enhancement was associated with residual ischemia in old inferior MI as well as inferior AP. Measurement of CCV(HF) is useful in improving the diagnostic reliability of exercise electrocardiography in patients with old inferior MI.
    Pacing and Clinical Electrophysiology 01/2009; 32(1):52-8. · 1.75 Impact Factor
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    ABSTRACT: Small Q waves in the left lateral leads are termed septal q waves, and their response to exercise has been reported to be a marker of septal ischemia in coronary artery disease. Patients with hypertrophic cardiomyopathy (HCM) sometimes develop septal ischemia in the absence of coronary stenosis, but little data are available concerning the association of the septal q wave response with septal ischemia. Exercise electrocardiography and Tc-99m-tetrofosmin myocardial scintigraphy were recorded to detect myocardial ischemia in 29 HCM patients with asymmetric septal hypertrophy. The septal q wave amplitude was summed up in V(5) and V(6) during exercise testing, and the results were correlated with septal ischemia defined as a regional septal ischemia or a part of diffuse subendocardial ischemia. A decrease in the sum of the septal q wave amplitude during exercise testing yielded a sensitivity of 100% and specificity 33% for regional septal ischemia, and a sensitivity of 100% and specificity of 43% for diffuse subendocardial ischemia, although an absent septal q wave at rest provided a low sensitivity for the detection of regional septal ischemia (43%) and diffuse subendocardial ischemia (33%). The septal q wave response to exercise is a useful marker of septal ischemia in HCM with asymmetric septal hypertrophy.
    Circulation Journal 07/2008; 72(6):953-7. · 3.58 Impact Factor
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    Clinical nuclear medicine 07/2008; 33(6):416-8. · 3.92 Impact Factor
  • Internal Medicine 02/2008; 47(2):121. · 0.97 Impact Factor
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    ABSTRACT: R-wave amplitude change during exercise has been reported to enhance diagnostic value for myocardial ischemia in coronary heart disease. We summed up R-wave amplitude in all the 12 leads during exercise testing and correlated the results with regional myocardial ischemia or diffuse subendocardial ischemia as detected by scintigraphy in 49 patients with hypertrophic cardiomyopathy (HCM) and 16 controls. The sum of R-wave amplitude decreased during exercise in patients with HCM (mean, 12.4 mV to 11.7 mV, P < .01) as well as in controls (8.0 mV to 7.7 mV, P < .05). Percent changes in the sum of R-wave amplitude did not differ between 4 subgroups of patients with HCM: one having both regional and subendocardial ischemia, one only the former, one only the latter, and one neither of them (mean, 6.5%, 7.7%, 4.6%, and 5.1%; P = .79). R-wave amplitude response to exercise failed to demonstrate myocardial ischemia in our patients with HCM.
    Journal of electrocardiology 01/2008; 41(1):68-71. · 1.08 Impact Factor
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    ABSTRACT: We report a case of biventricular noncompaction in whom magnetic resonance imaging revealed prominent trabeculations in the right ventricle as in the left ventricle. A 58-year-old man was referred to our hospital complaining of appetite loss and leg edema. Chest radiography showed cardiomegaly without pulmonary congestion. The diagnosis was right ventricular heart failure with congestive liver causing elevated liver enzyme. Transthoracic echocardiography showed prominent trabeculations and deep recesses in the inferolateral wall and apex of the left ventricle with the end-diastolic dimension of 64mm and ejection fraction of 29%. Magnetic resonance imaging demonstrated right ventricular noncompaction which remained unclear on echocardiography. Prominent trabeculations in the dilated right ventricle were confirmed by right ventriculography. The ejection fraction was 23%.
    Journal of Cardiology 09/2007; 50(2):149-54. · 2.30 Impact Factor
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    ABSTRACT: Patients with hypertrophic cardiomyopathy (HCM) often develop myocardial ischemia in association with abnormal blood pressure response to exercise. Vagal nerves mediate cardioinhibitory stimuli, with little knowledge regarding vagal response to myocardial ischemia in patients with HCM. Exercise Tc-99m-tetrofosmin myocardial scintigraphy was performed in 59 HCM patients and 39 controls who had no evidence of cardiac disease. We examined how reversible regional perfusion abnormality and transient left ventricular cavity dilation, a parameter of subendocardial ischemia, are related to vagal modulation as assessed by coefficient of high frequency component variance (CCV(HF)) on heart rate variability. We then correlated the results with abnormal blood pressure response to exercise, defined as failed increase >or=25 mm Hg during exercise. Regional perfusion abnormality and left ventricular cavity dilation were observed in 26 and 21 HCM patients, respectively. The percentage change of CCV(HF) from before to after exercise was higher in HCM patients with left ventricular cavity dilation than without or controls (5.2+/-9.8%, -23.5+/-5.7%, -14.5+/-5.5%, P=0.004). By contrast, the change of CCV(HF) was similar in HCM patients with regional perfusion abnormality, those without, and controls. The change of CCV(HF) was correlated with exercise-induced increase in systolic blood pressure (rho=-0.64, P<0.001); HCM patients with abnormal blood pressure response were characterized by a higher percentage change in CCV(HF) (50.0+/-18.3%). Subendocardial ischemia provoked vagal enhancement in patients with HCM, which may be related to the development of abnormal blood pressure response to exercise.
    International journal of cardiology 07/2007; 129(1):59-64. · 6.18 Impact Factor
  • Journal of Cardiology 07/2007; 49(6):367-8. · 2.30 Impact Factor
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    ABSTRACT: Patients with hypertrophic cardiomyopathy (HCM) sometimes develop subendocardial ischemia (SEI) in the left ventricle (LV). In the present study it was examined whether volumetric variables obtained by gated single-photon emission computed tomography (SPECT) are useful in detecting exercise-induced SEI in patients with HCM. Exercise 99mTc-tetrofosmin myocardial scintigraphy was performed in 26 HCM patients having non-obstruction and mild hypertrophy with a ventricular septal thickness < or = 20 mm. SEI was quantified using software developed previously, and the results were correlated with volumetric variables obtained using Quantitative Gated SPECT software. Exercise-induced percentage change in LV end-systolic volume was higher in 9 HCM patients with SEI (25.8+/-3.1%) than in 17 patients without (10.0+/-2.5%, p=0.009), although the percentage change in LV end-diastolic volume was similar in the 2 groups. The receiver-operator characteristics curve of the percentage changes in LV end-systolic volume for the detection of SEI showed that the optimal cutoff was 17%. This cutoff point yielded a good diagnostic value for the presence of SEI with a sensitivity of 89%, specificity 82%, and likelihood ratio 5.04. Gated SPECT technique is useful in detecting SEI during exercise in a select population of HCM patients.
    Circulation Journal 03/2007; 71(2):256-60. · 3.58 Impact Factor
  • Internal Medicine 02/2007; 46(2):67. · 0.97 Impact Factor
  • Anesthesia and analgesia 01/2007; 103(6):1602-3. · 3.08 Impact Factor

Publication Stats

765 Citations
350.39 Total Impact Points

Institutions

  • 2002–2013
    • Kokura Memorial Hospital
      • Department of Cardiology
      Kitakyūshū, Fukuoka, Japan
  • 1997–2012
    • Tsukuba Memorial Hospital
      Tsukuba, Ibaraki, Japan
  • 1986–2008
    • Kyoto Prefectural University of Medicine
      • • Department of Cardiovascular Medicine
      • • Division of Cardiology and Vascular Regenerative Medicine
      • • Department of Radiology
      Kyoto, Kyoto-fu, Japan
  • 1996–2003
    • Asahi University
      Gihu, Gifu, Japan
  • 1993–2003
    • Kyoto Daini Red Cross Hospital
      Kioto, Kyōto, Japan
  • 1995
    • Nagoya Second Red Cross Hospital
      Nagoya, Aichi, Japan
  • 1992
    • Kyoto City Hospital
      Kioto, Kyōto, Japan