Publications by authors named "Shizukuda Y"

Hereditary hemochromatosis with the homozygous C282Y HFE mutation (HH-282H) is a genetic condition which causes iron overload (IO) and elevated reactive oxygen species (ROS) secondary to the IO. Interestingly, even after successful iron removal therapy, HH-282H subjects demonstrate chronically elevated ROS. Raised ROS are also associated with the development of multiple cardiovascular diseases and HH-282H subjects may be at risk to develop these complications.

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A 62-year-old man was treated for castration-resistant prostate cancer (CRPC) ; however, his condition progressed. The patient planned to visit our department for treatment, including palliative care. However, he visited the emergency room with a complaint of a persistent nose bleed just before visiting our department.

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The prevalence of iron overload cardiomyopathy (IOC) is increasing. Patients with transfusion-dependent anemias or conditions associated with increased iron absorption over time are at a significant risk for the development of iron-overloaded states such as IOC. Current guidelines regarding the diagnostic evaluation and follow-up of patients at risk for IOC exist, and are composed of multiple components, including such as echocardiography, genetic testing, magnetic resonance imaging of liver, and cardiac magnetic resonance imaging (CMR).

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Arrhythmias as a cardiac complication of iron overload (IO) have been well described for decades in the clinical literature. They are assumed to be directly associated with the myocardial accumulation of iron. However, the influence of heart failure and elevated oxidative stress, which are major arrhythmogenic confounding factors associated with IO on arrhythmias, has not been critically reviewed in the published literature.

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Hereditary hemochromatosis (HH) is a genetic disorder which affects the heart due to systemic iron overload and concomitant elevated oxidative stress. Increasing numbers of patients are diagnosed at an asymptomatic stage due to genetic testing. Subclinical abnormal left ventricular diastolic function (LVDF) and increased arrhythmias are noted in this population; however, the mechanism leading to these observances has not been well understood.

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A 63-year-old male with past medical history of type II diabetes mellitus, hypertension, hyperlipidemia, stroke, and permanent pacemaker implant for poor chronotropic response to exercise underwent coronary computed tomography angiography (CCTA) for worsening atypical chest pain. The patient had normal myocardial perfusion by nuclear stress testing 3 months prior to this test. A rare variation of dual left anterior descending coronary artery (LAD) was identified by CCTA and subsequent coronary angiography confirmed a dual LAD and revealed no significant stenosis of the coronary arteries.

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Single ostium coronary artery is a rare coronary artery anomaly. It is reported to occur in only 0.0448% of cases who underwent invasive coronary angiography.

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Background: Left atrial volume (LAV) is surgically kept enlarged in heart transplant (HT) recipients. On the other hand, LAV has been known an independent predictor of various cardiovascular diseases and is associated with exercise capacity of HT recipients. Thus, we evaluated the hypothesis that LAV is still associated with clinical outcomes in HT recipients whose left atria are artificially enlarged.

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Background: Atrial function plays an important role in many cardiac conditions, how recipient and donor compartments of left atrium (LA) of transplanted hearts differentially contribute to overall LA function in transplanted hearts has not been described. We tested whether three-dimensional transthoracic echocardiography (3DE) could be used to calculate these compartment-specific atrial functions.

Methods And Results: We analyzed 3DE images of 22 consecutive transplant patients who had diagnostic imaging quality (ages 59 ± 16 years) using TomTec Research Arena.

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Objective: A long-term effect of hereditary hemochromatosis (HH) on aerobic exercise capacity (AEC) has not been well described.

Design: Forty-three HH and 21 volunteer control subjects who were asymptomatic underwent cardiopulmonary exercise testing using the Bruce protocol. AEC was assessed with minute ventilation (V(E)), oxygen uptake (V(O)(2)), and carbon dioxide production (V(CO)(2)) at baseline and at a follow-up assessment after 5 yrs.

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It is not well known whether systemic iron overload per se in hereditary hemochromatosis (HH) is associated with cardiac arrhythmias before other signs and symptoms of cardiovascular disease occur. In the present study, we examined the incidence of cardiac arrhythmia in cardiac asymptomatic subjects with HH (New York Heart Association functional class I) and compared it to that in age- and gender-matched normal volunteers. The 42 subjects with HH and the 19 normal control subjects were recruited through the National Heart, Lung, and Blood Institute-sponsored "Heart Study of Hemochromatosis.

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We have previously reported that left ventricular (LV) diastolic function in those with cardiac asymptomatic hereditary hemochromatosis (HH) is similar to that of volunteer control (VC) subjects, despite a presence of augmented left atrial contractile function. However, concern still exists that those with HH might gradually develop LV diastolic dysfunction despite receiving conventional phlebotomy treatment. To address this concern, we prospectively monitored the LV diastolic function of those with HH and VCs during a 5-year period.

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Article Synopsis
  • The study aimed to evaluate the effectiveness of computed tomography angiography (CTA) for distinguishing between ischemic and nonischemic causes of cardiomyopathy, even though earlier guidelines labeled it "appropriate" without large-scale evidence.
  • Researchers conducted a meta-analysis of six studies involving 452 patients with significant left ventricular function impairment to assess CTA's diagnostic accuracy against the gold standard of invasive coronary angiography.
  • Findings showed that CTA had a high sensitivity of 98% and specificity of 97% for diagnosing ischemic cardiomyopathy, making it a reliable tool for effectively ruling out ischemic causes in patients.
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Future cardiology practice will be increasingly individualized, and thus to maintain its central role, echocardiography must keep pushing to expand the boundaries of real-time data acquisition from tissue and fluid motion, and yet still provide efficient and timely data analysis that leads to succinct, clear clinical recommendations tailored to each person in our care. In this article, recent efforts to expand echocardiography techniques into an era of increasingly personalized cardiology, including advances in color-coded tissue Doppler, 3D echocardiography and complex exercise stress echocardiography are described. The common metric for success in each of these efforts is the development of robust and institutionally supportable echocardiography protocols for specific cardiology disease populations that currently may be underdiagnosed and/or undertreated.

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Background: Heart transplant (HT) recipients demonstrate limited exercise capacity compared to normal patients, very likely for multiple reasons. In this study we hypothesized that left atrial volume (LAV), which is known to predict exercise capacity in patients with various cardiac pathologies including heart failure and hypertrophic cardiomyopathy is associated with limited exercise capacity of HT recipients.

Methods: We analyzed 50 patients [age 57 ±2 (SEM), 12 females] who had a post-HT echocardiography and cardiopulmonary exercise test (CPX) within 9 weeks time at clinic follow up.

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Dynamic appearance of intrapulmonary arteriovenous fistula (AVF) during exercise may be associated with unexplained exertional dyspnea (UED) and can be diagnosed with an agitated saline contrast study during exercise echocardiography. However, the occurrence of AVF during exercise in patients with UED has not been well described. Thus, the frequency of exercise-induced intrapulmonary AVF in the outpatients with UED was retrospectively analyzed.

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The prevalence of iron overload cardiomyopathy (IOC) is increasing. The spectrum of symptoms of IOC is varied. Early in the disease process, patients may be asymptomatic, whereas severely overloaded patients can have terminal heart failure complaints that are refractory to treatment.

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Exercise echocardiography has been established as a reliable diagnostic tool for assessment of myocardial ischemia. However, more recent advances in its technique have expanded its routine clinical use to include quantification of exercise-induced diastolic dysfunction, exercise-induced pulmonary hypertension, and dynamic assessment of mitral and aortic valve function. The indications for exercise echocardiography have increased to include cardiac symptoms such as exertional dyspnea, fatigue, and limited exercise capacity.

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Background: Little is known about the early mechanisms mediating left ventricular (LV) diastolic dysfunction in patients with hereditary hemochromatosis (HH). However, the increased oxidative stress related to iron overload may be involved in this process, and strain rate (SR), a sensitive echocardiography-derived measure of diastolic function, may detect such changes.

Aim: we evaluated the relationship between left ventricular diastolic function measured with tissue Doppler SR and oxidative stress in asymptomatic HH subjects and control normal subjects.

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