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Biomedical subjects

Hiroaki Kitaoka

Publications and source records attributed to Hiroaki Kitaoka.

17 recordsLinked to original sources
PubMed2006

Left ventricular remodeling of hypertrophic cardiomyopathy: longitudinal observation in rural community.

BACKGROUND: The purpose of the present study was to assess the clinical long-term course of hypertrophic cardiomyopathy (HCM) in a rural Japanese cohort. METHODS AND RESULTS: A total of 137 consecutive HCM patients (mean age at diagnosis: 52+/-13 years) were enrolled. During a follow-up period of 11.4+/-5.7 years, 28 patients died of HCM-related causes. Eleven patients died suddenly, 10 died of progressive heart failure, 6 died of stroke associated with atrial fibrillation and 1 died of a postoperative complication of alcohol septal ablation. For the overall study group, 5-, 10- and 15-year cumulative survival rates were 91%, 88% and 79%, respectively. Although sudden death was the predominant cause of HCM-related death during the follow-up period of <10 years, heart failure death increased after follow-up period of >10 years. Fifteen (13%) of 114 patients who had follow-up echocardiography became ;end-stage' HCM and 8 patients died of severe and refractory heart failure. They already showed minimally dilated left ventricular (LV) dimension and lower LV fractional shortening at initial evaluation. CONCLUSIONS: Although HCM patients in a Japanese rural community showed relatively benign clinical course (the same as cohorts in the developed world), heart failure death because of LV remodeling became equally important to sudden death when they were followed for more than 10 years.

Adult↗
PubMed2006

Long-term prognosis of dilated cardiomyopathy revisited: an improvement in survival over the past 20 years.

BACKGROUND: Because of their favorable prognostic effects, angiotensin converting enzyme inhibitors (ACEI), angiotensin II receptor blockers (ARB) and beta blockers have become background therapy in dilated cardiomyopathy (DCM). However, there are few reports concerning the long-term prognosis of Japanese patients with DCM in relation to these treatments. METHODS AND RESULTS: One hundred and fifty patients with DCM were divided into 2 groups: group A (n=46) (diagnosis: 1982-1989) and group B (n=104) (diagnosis: 1990-2002). During follow-up period of 6.9+/-4.8 years, 62 patients died and 1 patient had a heart transplant. The survival rate at 5 and 10 years was 60.9% and 34.8%, respectively, in group A patients, and 80.9% and 65.3%, respectively, in group B patients (p=0.0079). In group A patients, ACEI/ARB or beta blockers were less frequently used (p<0.0001), whereas antiarrhythmics (class Ia or Ib) were more often used (p<0.0001). The patients treated with ACEI/ARB and beta blockers showed a better survival rate than those without (p<0.0001). The patients with antiarrhythmics showed a worse survival rate than those without (p<0.0001). CONCLUSION: The prognosis of Japanese patients with DCM has significantly improved over the past 20 years. This improvement may be explained partly through the increased use of ACEI/ARB and beta blockers and a declining use of antiarrhythmics.

Adrenergic beta-Antagonists↗
PubMed2006

Morphologic characteristics of hypertrophic cardiomyopathy of the elderly with cardiac myosin-binding protein C gene mutations.

BACKGROUND: Several morphologic distinctions between elderly and young patients with hypertrophic cardiomyopathy (HCM) have been reported. In particular, a crescent-shaped left ventricular (LV) cavity with reversed septal curvature, which is often seen in young patients, is rare in elderly patients. However, those studies were carried out before gene testing became available and heterogeneous causes or age-related changes may have been included. The purpose of this study was to determine the morphologic characteristics of elderly patients with HCM definitely caused by a mutation in the cardiac myosin-binding protein C (MyBPC). METHODS AND RESULTS: Twenty-seven patients with HCM caused by MyBPC gene abnormality were evaluated. Patients were divided into an elderly group (> or = 65 years of age, n = 8) and a young group (< 65 years of age, n = 19). LV hypertrophy was milder in the elderly than in the young for maximum LV wall thickness (18 +/- 5 mm vs 24 +/- 6 mm, p = 0.008) and Wigle score (5.7 +/- 1.5 vs 7.6 +/- 1.6, p < 0.005). However, an abnormal crescent-shaped LV was similarly prominent in both groups (75% in the elderly vs 95% in the young, p = NS). None of the elderly patients showed a proximal septal bulge. CONCLUSIONS: An abnormal crescent-shaped LV cavity was frequently present in the elderly as in the young when there are MyBPC mutations. It is possible that this morphologic feature could become useful for determining the etiology of HCM in elderly patients.

Adult↗
PubMed2006

[Arrhythmogenic right ventricular cardiomyopathy with pulmonary embolism: a case report].

A 50-year-old man complained of dyspnea on exertion. Electrocardiography showed frequent premature ventricular contraction and inverted T wave in leads V1-V6. Echocardiography and right ventriculography showed dilation and systolic dysfunction of the right ventricle. The diagnosis was arrhythmogenic right ventricular cardiomyopathy. In addition, thrombus was also observed in the pulmonary artery on chest computed tomography and pulmonary artery angiography. The final diagnosis was arrhythmogenic right ventricular cardiomyopathy complicated by pulmonary embolism. Pulmonary embolism should be considered in patients with arrhythmogenic right ventricular cardiomyopathy with dyspnea.

Arrhythmias, Cardiac↗
PubMed2005

Lifelong left ventricular remodeling of hypertrophic cardiomyopathy caused by a founder frameshift deletion mutation in the cardiac Myosin-binding protein C gene among Japanese.

OBJECTIVES: We studied the longitudinal evolution of hypertrophic cardiomyopathy (HCM) caused by a founder frameshift mutation in the cardiac myosin-binding protein C (MyBPC) gene. BACKGROUND: Mutations in the MyBPC gene have been associated with delayed expression of HCM and a good prognosis. Few studies, however, demonstrated the phenotype-genotype correlations in the longitudinal study. METHODS: We studied long-term evolution of clinical features of 15 unrelated families who were found to have an identical frameshift mutation in the MyBPC gene: a one-base deletion of a thymidine at nucleotide 11645 (V592fs/8). RESULTS: Thirty-nine individuals in 15 families were genotype-positive. Thirty of the 39 individuals with the mutation were phenotype-positive. The disease penetrance was 100% in subjects > or =50 years and 65% in those <50 years. "End-stage" HCM (ejection fraction <50%) was observed in 7 (18%) of the 39 genotype-positive individuals (7 [23%] of the 30 phenotype-positive patients); 6 of them were 60 years or older. Seven patients were hospitalized for treatment of repeated congestive heart failure, and four patients died or had implantable cardioverter-defibrillator discharge (13%; incidence, 1.4%/year) during a mean follow-up period of 9.2 +/- 5.5 years. CONCLUSIONS: Elderly patients with a V592fs/8 mutation in the MyBPC gene may evolve into the "end-stage" HCM, characterized by left ventricular systolic dysfunction, cavity dilation, and irreversible heart failure. The clinical course in patients with this mutation is not benign in the long run, with progressive left ventricular remodeling with advancing age.

Adolescent↗
PubMed2005

Functional assessment by myocardial performance index (Tei index) correlates with plasma brain natriuretic peptide concentration in patients with hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) might exhibit not only diastolic, but also latent systolic dysfunction. Therefore combined assessment of both systolic and diastolic function using myocardial performance index (Tei index) can be useful in HCM. Plasma brain natriuretic peptide (BNP) level is reported to be elevated in HCM, but the mechanism of BNP elevation in HCM remains to be established. METHODS AND RESULTS: The value of Tei index in 45 HCM patients was compared with that of 20 normal control subjects. The HCM patients showed a higher value of Tei index (0.55+/-0.12 vs 0.36+/-0.08, p < 0.0001) and longer isovolumic relaxation and contraction times than control subjects. The plasma BNP level correlated with Tei index in non-obstructive HCM (n = 35, r = 0.61, p < 0.0001), although the correlation was mild when overall HCM patients were included (r = 0.34, p = 0.02). The correlation was still significant after adjusting for age, or the extent and severity of left ventricular hypertrophy. Multiple stepwise regression analysis identified mitral E/A ratio (r = 0.49, F = 13.1) and Tei index (r = 0.37, F = 7.6) as independent predictors of higher plasma BNP level in non-obstructive HCM. CONCLUSIONS: Myocardial performance index was abnormal in HCM, reflecting both systolic and diastolic dysfunction in this disorder. Plasma BNP level correlated with functional assessment by Tei index in non-obstructive HCM.

Adult↗
PubMed2005

Hypertrophic cardiomyopathy with progression from apical hypertrophy to asymmetrical septal hypertrophy: a case report.

A 41-year-old man was referred to our hospital for further examination because of abnormal electrocardiography findings at a health-check examination. Transthoracic echocardiography showed left ventricular hypertrophy confined to the most distal portion of the left ventricle, which is a typical feature of apical hypertrophic cardiomyopathy. Ten years later, he was again admitted for the evaluation of chest pain. Echocardiography showed asymmetrical septal hypertrophy in addition to apical hypertrophy. These findings demonstrate morphologic evolution in hypertrophic cardiomyopathy from apical hypertrophy to asymmetrical septal hypertrophy.

Adult↗
PubMed2005

[Aortic stenosis and mitral regurgitation complicated by hemolytic anemia and positive Direct Coombs test: a case report].

A 83-year-old man was admitted because of heart failure due to severe aortic stenosis and mitral regurgitation secondary to chordal rupture of the anterior leaflet. Mild anemia and elevated serum lactate dehydrogenase were present with reticulocytosis and haptoglobinemia. Direct Coombs test was positive. Coexistence of autoimmune hemolytic anemia was identified, but the main cause of his hemolysis was thought to be mechanical hemolysis due to stenotic valve and/or ruptured chordae because of the presence of red cell fragmentation. The patient successfully underwent double valve replacement. Improvement of anemia was coupled with reduction of the serum lactate dehydrogenase level. Valvular shear stress on the red cells and reduction of red cell deformability secondary to autoimmune hemolytic anemia were thought to be responsible for his hemolysis.

Aged↗
PubMed2005

[Discrete subaortic stenosis with pressure recovery: a case report].

A 54-year-old woman with subvalvular aortic stenosis was admitted to our hospital. The pressure gradient across the left ventricular outflow tract was estimated as 88 mmHg (peak) and 45 mmHg (mean) by Doppler echocardiography, but only 14 mmHg (peak to peak) and 31 mmHg (mean) by cardiac catheterization. We considered this discrepancy attributable to the presence of moderate aortic regurgitation and the pressure recovery phenomenon. Pressure recovery has clinical relevance particularly in a patient with tunnel-like stenosis, with gradual lumen re-expansion beyond the limiting orifice. Therefore, if Doppler echocardiography shows significant left ventricular outflow tract gradient, precise evaluation of the stenosis geometry is required to investigate the effect of pressure recovery.

Blood Pressure↗
PubMed2003

Comparison of prevalence of apical hypertrophic cardiomyopathy in Japan and the United States.

The morphologic apical form of hypertrophic cardiomyopathy (HC), in which left ventricular (LV) wall thickening is confined to the most distal region at the apex, has been regarded as a phenotypic expression of nonobstructive HC largely unique to Japanese patients. To investigate this question further, we directly compared unselected and regional hospital-based cohorts of adult patients with HC ( > or =18 years of age) from Japan (Kochi; n=100) and from the United States (US) (Minneapolis; n=361). Japanese and American patients with HC had similar clinical features and did not differ significantly with regard to the severity of symptoms and frequency of outflow obstruction. Although Japanese and American patients also showed similar maximum LV thickness, they differed significantly with respect to the distribution of LV hypertrophy. In particular, the segmental form of HC, with hypertrophy confined to the LV apex, was more frequent in Japanese patients (i.e., apical HC, 15% in Japan vs 3% in US, p<0.0001). Giant negative T waves were also more common in Japanese patients with HC (26% vs 2%, p<0.001), including those with the apical form (64% vs. 30%, p<0.05). Each patient with apical HC had either no or only mild symptoms, and all survived. The morphologic form of nonobstructive HC with hypertrophy limited to the LV apex (apical form of HC) was 5 times more common in an unselected Japanese population. These findings document variability in the phenotypic expression of HC between countries and races, which may be due to differences in environmental factors or genetic background. Patients with the apical form of HC had a benign clinical course.

Adult↗
PubMed2003

Heart failure in the elderly.

Heart failure is common in the elderly population. Approximately 6 to 10 percent of the population 65 years or older have heart failure. Heart failure is the most common reason for hospitalization in elderly patients. Etiology of heart failure is often multifactorial in the elderly. The common causes of heart failure include ischemic heart disease, valvular heart disease, hypertensive heart disease, and cardiomyopathy. Exacerbation of heart failure in the elderly is often accompanied by precipitating factors which include arrhythmia, renal failure, anemia, infection, adverse effect of drugs and non-compliance with medication and/or diet. Diagnosis of heart failure may be difficult in the elderly because symptoms of heart failure are often atypical or even absent. Heart failure with preserved systolic function is common in the elderly because aging has a greater impact on diastolic function. It is important to recognize that very old patients with heart failure are underrepresented in clinical trials.

Aged↗
PubMed2003

Prognostic significance of post-exercise blood pressure response in patients with dilated cardiomyopathy.

BACKGROUND AND OBJECTIVES: The occurrence of an abnormal cardiovascular response during exercise in patients with chronic heart failure is well known. Post-exercise blood pressure response is also useful in assessing the severity of heart failure and impaired exercise capacity. This study evaluated the prognostic significance of post-exercise blood pressure response in patients with dilated cardiomyopathy. METHODS: Thirty patients with dilated cardiomyopathy (left ventricular ejection fraction: 32 +/- 9%) were studied and the relationship between post-exercise blood pressure response and cardiac events (sudden death, heart failure death and readmission for heart failure) were evaluated. The post-exercise blood pressure response was defined as PBP3 (systolic blood pressure at 3 min after exercise divided by peak systolic blood pressure during exercise). RESULTS: Seven cardiac events (one sudden death, two deaths for heart failure and four readmissions from heart failure) were observed during the follow-up period (3.3 +/- 1.8 years). The PBP3 in patients with these cardiac events was higher than that in patients without cardiac events (0.95 +/- 0.09 vs 0.84 +/- 0.10, p < 0.05). The area under the curve for the receiver-operating characteristic curve with PBP3 used to predict the cardiovascular events was 0.79 (95% confidence interval: 0.62-0.97, p = 0.02). CONCLUSIONS: Post-exercise blood pressure response is a simple and useful predictor of adverse cardiac events in patients with dilated cardiomyopathy.

Aged↗
PubMed2002

Photochemical behavior of sitafloxacin, fluoroquinolone antibiotic, in an aqueous solution.

Sitafloxacin (STFX) hydrate, an antimicrobial agent, is photo-labile in aqueous solutions. The photodegradation rates (k) in neutral solutions were higher than those observed in acidic and alkaline solutions and maximum at the maximum absorption wavelength of STFX. The structures of photodegradation products were elucidated as 7-[7-amino-5-azaspiro[2.4]heptan-5-yl]-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid and 1-(1-amino-2-[16-fluoro-1-(2-fluoro-1-cyclopropyl)-1,4-dihydro-4-oxo-3-quinolin-7-yl]-amino]ethyl)cyclopropanecarbaldehyde. This implies that dechlorination is the key step in the photodegradation of STFX. The effect of halide ions on the photodegradation of STFX was estimated by observing the increments in the photostability of STFX with the addition of chloride ions. In contrast, in the presence of bromide ions, instead of increased photostability of the STFX rate, a new photodegradation product in the presence of bromide ion was observed. The structure of this new photodegradation product was an 8-bromo form of STFX, which was substituted for chlorine at the 8-position, so the dissociation of C-Cl bond at the 8-position of STFX was the rate-limiting step in the initial process of the photodegradation. STFX generated .C (carbon centered radical) and .OH (hydroxyl radical) in the process of photodegradation in a pH 4.0 buffer. On the contrary, STFX did not generate C in the presence of chloride ion in a pH 4.0 buffer. The .C was generated and then degraded into the above degradation products by photoirradiation in the absence of chloride ion, but the .C immediately reacted with chloride when it was present. As a result, the C-Cl bond was recovered leading to a possible increase in the apparent photostability.

Anti-Infective Agents↗
PubMed2002

Long-term prognosis of patients with mildly dilated cardiomyopathy.

The long-term prognosis of patients with mildly dilated cardiomyopathy (MDCM) was investigated in 21 patients. MDCM was defined as left ventricular ejection fraction < or = 40% and left ventricular end-diastolic volume < or = 120 ml/m2 by left ventriculography. During a follow-up period of 6.8+/-3.7 years, there were 9 cardiac events (5 heart failure deaths, 2 sudden deaths, and 2 re-hospitalizations for heart failure). Only in the patients without cardiac events was there a significant decrease in left ventricular size (end-diastolic dimension decreased from 58+/-6 mm to 50+/-8 mm, p<0.001) and an improvement in systolic function (fractional shortening increased from 17+/-5% to 26+/-11%, p=0.007). However, left atrial dilation was observed in the patients with an event (from 39+/-5 mm to 43+/-5 mm, p=0.02). Based on proportional hazard analysis, left ventricular end-diastolic pressure and mean pulmonary artery pressure at diagnosis and left atrial dimension at the time of follow-up were significant predictors of poor outcome. A subset of patients with MDCM has impaired hemodynamics at diagnosis, left atrial dilation at follow-up and a poor prognosis, and must be followed carefully even if the left ventricular dilatation is mild.

Age of Onset↗
PubMed2002

Myocardial enhancement on magnetic resonance imaging with gadolinium-diethylenetriamine pentaacetic acid and improvement of left ventricular function in patients with dilated cardiomyopathy.

OBJECTIVES: This study evaluated the significance of myocardial gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) enhancement on magnetic resonance imaging for the improvement of left ventricular function in patients with dilated cardiomyopathy. METHODS: Twenty-seven patients with dilated cardiomyopathy (mean age 59 +/- 11 years) were studied. The magnitude of myocardial Gd-DTPA enhancement was quantitatively assessed using signal intensity ratio and compared to changes in left ventricular function and adverse cardiac events during a relatively long follow-up period. RESULTS: Regional high signal intensity ratio, defined as > or = mean + 2SD in seven normal subjects, was found in 14 patients: in three or more regions out of five myocardial regions analyzed in six patients (extensive enhancement) and in only one or two regions in eight patients (limited enhancement). The remaining 13 patients had no high signal ratio in any of the five regions analyzed (no enhancement). During the follow-up period of 3.9 +/- 1.9 years, four patients died of cardiac causes. The incidence of cardiac death was 33.3% in patients with extensive enhancement, 12.5% in those with limited enhancement and 7.7% in those without enhancement, but there was no statistical difference. Mild improvement in fractional shortening was observed in patients without enhancement during the follow-up (19 +/- 4%-->27 +/- 10%, p = 0.03). CONCLUSIONS: Evaluation of myocardial Gd-DTPA enhancement on magnetic resonance imaging may provide useful prognostic information for patients with dilated cardiomyopathy.

Adult↗
PubMed2002

Thallium scintigraphy for the prognosis of idiopathic dilated cardiomyopathy.

OBJECTIVES: This study evaluated the significance of perfusion defects demonstrated by thallium-201 and age in the prognosis of patients with idiopathic dilated cardiomyopathy. METHODS: Seventy-four dilated cardiomyopathy patients underwent thallium scintigraphy as well as clinical and hemodynamic examination. RESULTS: Abnormal perfusion defects were present in 23 of 38 patients aged < 60 years (61%) and in 26 of 36 elderly patients aged > or = 60 years (72%; NS). Univariate analysis showed that such perfusion defects were a significant predictor of cardiac death only in patients aged < 60 years (p = 0.015). Stepwise discriminant analysis also revealed that perfusion defects were a significant predictor in patients aged < 60 years (Wilks' lambda 0.499, chi-square test 20.2, p = 0.003). Perfusion defects were not more important than the history of syncope or stroke in elderly dilated cardiomyopathy patients. Twenty-one patients died of disease-related causes during 58 +/- 43 months. The five-year survival rate was better in patients aged < 60 years without than in those with perfusion defects (100% vs 58.4%, respectively), but not affected in patients aged > or = 60 years (66.7% vs 62.2%). CONCLUSIONS: Thallium scintigraphy is valuable for the prognosis of patients with dilated cardiomyopathy aged < 60 years who are usually candidates for heart transplantation. Absence of thallium perfusion defects may indicate good long-term prognosis.

Cardiomyopathy, Dilated↗