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Biomedical subjects

Satoshi Nakatani

Publications and source records attributed to Satoshi Nakatani.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of transmural distribution of viable muscle by myocardial strain profile and dobutamine stress echocardiography.

Transmural distribution of viable myocardium in the ischemic myocardium has not been quantified and fully elucidated. To address this issue, we evaluated transmural myocardial strain profile (TMSP) in dogs with myocardial infarction using a newly developed tissue strain imaging. TMSP was obtained from the posterior wall at the epicardial left ventricular short-axis view in 13 anesthetized open-chest dogs. After control measurements, the left circumflex coronary artery was occluded for 90 min to induce subendocardial infarction (SMI). Subsequently, latex microbeads (90 microm) were injected in the same artery to create transmural infarction (TMI). In each stage, measurements were done before and after dobutamine challenge (10 microg.kg(-1).min(-1) for 10 min) to estimate transmural myocardial viability. Strain in the subendocardium in the control stage increased by dobutamine (from 53.6 +/- 17.1 to 73.3 +/- 21.8%, P < 0.001), whereas that in SMI and TMI stages was almost zero at baseline and did not increase significantly by dobutamine [from 0.8 +/- 8.8 to 1.3 +/- 7.0%, P = not significant (NS) for SMI, from -3.9 +/- 5.6 to -1.9 +/- 6.0%, P = NS for TMI]. Strain in the subepicardium increased by dobutamine in the control stage (from 23.9 +/- 6.1 to 26.3 +/- 6.4%, P < 0.05) and in the SMI stage (from 12.4 +/- 7.3 to 27.1 +/- 8.8%, P < 0.005), whereas that in the TMI stage did not change (from -1.0 +/- 7.8 to -0.7 +/- 8.3%, P = NS). In SMI, the subendocardial contraction was lost, but the subepicardium showed a significant increase in contraction with dobutamine. However, in TMI, even the subepicardial increase was not seen. Assessment of transmural strain profile using tissue strain imaging was a new and useful method to estimate transmural distribution of the viable myocardium in myocardial infarction.

Animals↗
PubMed2006

Impact of blockade of histamine H2 receptors on chronic heart failure revealed by retrospective and prospective randomized studies.

OBJECTIVES: The goal of this work was to determine whether the blockade of histamine H2 receptors is beneficial for the pathophysiology of chronic heart failure (CHF). BACKGROUND: Because CHF is one of the major life-threatening diseases, we need to find a novel effective therapy. Intriguingly, our previous study, which predicts the involvement of histamine in CHF, suggests that we should test this hypothesis in patients with CHF. METHODS: We selected 159 patients who received famotidine among symptomatic CHF patients for the retrospective study. We blindly selected age- and gender-matched CHF patients receiving drugs for gastritis other than histamine H2 receptor blockers as a control group. For the prospective study, 50 symptomatic CHF patients were randomly divided into 2 groups. One group received famotidine of 30 mg/day for 6 months, and the other group received teprenone. RESULTS: In the retrospective study, famotidine of 20 to 40 mg decreased both left ventricular end-diastolic and end-systolic lengths (LVDd and LVDs, respectively) and the plasma B-type natriuretic peptide (BNP) levels (182 +/- 21 vs. 259 +/- 25 pg/ml, p < 0.05) with unaltered fractional shortening (FS). In a randomized, open-label study, compared with teprenone, famotidine of 30 mg prospectively decreased both New York Heart Association functional class (p < 0.05) and plasma BNP levels (183 +/- 26 pg/ml vs. 285 +/- 41 pg/ml, p < 0.05); this corresponded to decreasing both LVDd (57 +/- 2 mm vs. 64 +/- 2 mm, p < 0.05) and LVDs (47 +/- 2 mm vs. 55 +/- 2 mm, p < 0.05) with unaltered FS (15 +/- 1% vs. 17 +/- 1%). The frequency of readmission because of worsening of CHF was lower in the famotidine group (4% and 24%, p < 0.05). On the other hand, teprenone had no effects on CHF. CONCLUSIONS: Famotidine improved both cardiac symptoms and ventricular remodeling associated with CHF. Histamine H2 receptor blockers may have therapeutic benefits for CHF.

Aged↗
PubMed2006

Myocardial strain changes in Duchenne muscular dystrophy without overt cardiomyopathy.

BACKGROUND: Patients with Duchenne muscular dystrophy (DMD) are at risk of the development of dilated cardiomyopathy and heart failure, thus making early identification of high-risk patients necessary. Myocardial strain imaging (MSI) can be used for quantitative analysis of wall motion of the left ventricle (LV). The aim of this study was to determine whether MSI could detect early changes in myocardial properties in presymptomatic DMD patients with normal LV function. METHODS AND RESULTS: Two-dimensional echocardiographic and tissue Doppler examinations were performed in 13 DMD patients (age range, 11 to 20 years) with normal LV function and in 10 healthy controls. MSI was obtained from tissue Doppler information. In control subjects, strain values in both inner and outer layers of the myocardium were positive at the short-axis image showing the radial systolic thickening. In 10 of the 13 DMD patients, however, myocardial strain showed a negative strain value in systole in the outer layer of the posterolateral wall at the parasternal short-axis image for each cardiac cycle. In 5 of these 10 patients, the timing of the peak systolic velocity at the inferoposterior wall was delayed more than 60 ms than that at the posterolateral wall (mean 80.0+/-17.5 ms). CONCLUSIONS: In some DMD patients with normal LV function, myocardial strain profiles at the posterolateral wall of the LV were different from those in healthy controls, suggesting abnormal myocardial contraction. MSI appears to detect early changes in myocardial features in DMD patients before the onset of overt cardiomyopathy.

Adolescent↗
PubMed2006

Impaired systolic torsion in dilated cardiomyopathy: reversal of apical rotation at mid-systole characterized with magnetic resonance tagging method.

Left ventricular (LV) torsion plays an important role in squeezing the blood out of the heart. To characterize the systolic torsion in LV dysfunction, we studied using magnetic resonance imaging myocardial tagging method in 26 subjects: 17 patients with dilated cardiomyopathy (DCM, LV ejection fraction [EF], 27 +/- 8%) and 9 healthy control subjects. Grid-tagged LV short-axis cine images were acquired at base, mid and apex levels. Tag-intersections were tracked during the systole, thereby determining rotation angle (positive indicated clockwise from the apex). Peak torsion was defined as the maximum difference in rotation angle between the base and apex. Time to peak torsion was expressed as % systole by dividing the time by a total systolic time. Amplitude of the rotation at peak was less in DCM than in controls at both the base (0.1 +/- 2.9 vs. 2.6 +/- 1.6 degrees , P < 0.05) and apex (-5.9 +/- 5.3 vs. -11.2 +/- 2.5 degrees , P < 0.01). Amplitude of peak torsion was then less in DCM than in controls (6.1 +/- 3.4 vs. 13.6 +/- 2.5 degrees , P < 0.001), and the timing of peak was earlier (66 +/- 22 vs. 104 +/- 16% systole, P < 0.001). The amplitude of peak torsion was correlated with LVEF (r=0.74, P < 0.001). In conclusion, amplitude of systolic torsion was impaired in proportion to LV function. Systolic torsion in LV dysfunction was characterized by the discontinuing counter-rotation of the apex to the base before end-systole.

Adult↗
PubMed2006

Unusual appearance of mitral annular calcification mimicking intracardiac tumor prompting early surgery.

Although mitral annular calcification (MAC) is usually easy to diagnose by transthoracic echocardiography, we experienced a rare case with MAC which looked like an intracardiac tumor. The patient who had been on chronic hemodialysis for 20 years was admitted to our hospital because of dyspnea. Transthoracic echocardiography showed a mass with severe calcification on the anterior mitral annulus and mean mitral gradient of 20 mm Hg. Because of the suspicion of the intracardiac calcified tumor that restricted mitral valve motion causing mitral obstruction, she underwent resection of the mass and mitral valve replacement. Pathological findings showed that the mass had a calcified envelope containing liquefied necrotic eosinophilic material with lympocytic infiltrate inside consistent with MAC. We should consider a possibility of MAC when we see a severe calcified mass attached to the mitral annulus in a patient on long-term hemodialysis.

Calcinosis↗
PubMed2006

Visualization of three-dimensional cardiac electrical excitation using standard heart model and anterior and posterior magnetocardiogram.

Our aim in this study is to obtain novel three-dimensional (3-D) images of cardiac electrical excitation that include morphological information on the whole heart. We obtain these 3-D images by projecting anterior and posterior two-dimensional (2-D) current-arrow maps (CAMs) onto a 3-D standard heart model. This standard heart model is adjusted to the individual subject's heart position by using the coordinates of the sinus node, which are obtained from magnetocardiogram (MCG) signals. The anterior and posterior CAMs are calculated by taking the orthogonal partial derivatives of the normal component of the anterior and posterior MCGs. After adjusting the base current values of the anterior and posterior CAMs, the adjusted CAMs are projected onto the standard heart model. We generated the projected CAMs (PCAMs) of the six phases (atrial, and ventricular, excitation) for seven healthy subjects. The validity of PCAM was evaluated by extracting the maximal current directions and positions from the PCAMs. The maximal current directions and positions during each excitation phase were almost in the same in the seven healthy subjects. Therefore, the PCAMs give us a clear view of the anterior and posterior myocardial excitation for the respective electrophysiological phases.

Adult↗
PubMed2006

Determinants of rapid progression of aortic root dilatation and complications in Marfan syndrome.

BACKGROUND: Progressive aortic dilatation has prognostic significance in the Marfan syndrome. METHODS: To identify which patients were at high risk of rapid progression, we echocardiographically studied 43 patients (age 22 +/- 14 years) with the mean follow-up period of 5.2 +/- 3.2 years. Aortic diameters, left ventricular (LV) size, fractional shortening, and the severity of aortic and mitral regurgitation were assessed. Transmitral peak early and atrial flow velocities, their ratio and the deceleration time of peak early velocity were also obtained. RESULTS: Mean annual increases of aortic diameters were 0.4 +/- 0.3 mm at the annulus, 1.5 +/- 1.3 mm at the sinuses of Valsalva, 0.7 +/- 0.6 mm at the supraaortic ridge and 0.4 +/- 0.4 mm at the proximal ascending aorta. Patients were divided into 2 groups according to the aortic growth rate at the sinuses of Valsalva level: rapid (R, >3% per year, 15 patients) or slow (S, < or =3% per year, 28 patients) progression groups. Measured variables did not show significant differences between the 2 groups except older age, higher blood pressure and more severe aortic regurgitation in group R. Multiple regression analysis identified prolonged deceleration time as the most important variable predicting aortic complications. Aortic dissection occurred more frequently in group R (7 patients, 47%) than in group S (0%, P < 0.001). CONCLUSIONS: Marfan patients at older age, with higher blood pressure, and with significant aortic regurgitation were at high risk of progression of aortic dilatation, with the most remarkable increase at the sinuses of Valsalva. Prolonged deceleration time may relate to an increased risk for aortic complications.

Adolescent↗
PubMed2006

Circadian variation of endothelial function in idiopathic dilated cardiomyopathy.

This study measured flow-mediated dilation (FMD) of the brachial artery 3 times a day (6:30 a.m., 11:30 a.m., and 9 p.m.) in 7 normal subjects and 14 patients with idiopathic dilated cardiomyopathy (7 in New York Heart Association [NYHA] functional class I or II and 7 in NYHA functional class III or IV). FMD in normal subjects and patients in NYHA class I or II showed a circadian variation, being lowest in the morning and highest at night. Compared with them, FMD in patients in NYHA class III or IV was lower and almost constant during the day, showing loss of significant circadian variation in endothelial function in patients with congestive heart failure.

Adult↗
PubMed2006

Acute improvement in myocardial function assessed by myocardial strain and strain rate after aortic valve replacement for aortic stenosis.

OBJECTIVES: We investigated whether Doppler tissue imaging (tissue velocity, strain, and strain rate) could be useful to detect subtle left ventricular (LV) dysfunction in patients with aortic stenosis and changes in regional myocardial function after aortic valve replacement (AVR). METHODS: We studied 34 patients (age 69.2 +/- 10.4 years) with severe aortic stenosis, 21 of whom underwent AVR. Tissue velocity, systolic strain, strain rate, time to peak strain, and time to peak systolic and diastolic strain rates of basal and midsegments were measured in the apical 4-, 3-, and 2-chamber views before and 2 weeks after AVR. RESULTS: Strain and systolic strain rate showed the best correlation with LV ejection fraction (r = 0.80 and r = 0.70, respectively, both P < .0001). Early and late diastolic strain rates showed significant correlations with LV mass index (r = 0.45, P < .01; and r = 0.64, P < .0001, respectively) and time to peak strain, to peak systolic strain rate, and to peak early diastolic strain rate with aortic pressure gradient (r = 0.45, P < .01; r = 0.44, P < .01; and r = 0.56, P < .001, respectively) before AVR. Although LV mass index and LV systolic function did not change significantly after 2 weeks (LV mass index, 137 +/- 54 vs 125 +/- 36 g/m2; LV ejection fraction, 60 vs 58%, both P = not significant), peak strain and strain rates increased (P < .001) and time to peak strain and strain rate shortened after AVR (P < .001). Tissue velocities did not change significantly after AVR. CONCLUSIONS: Strain and strain rate parameters seemed to relate to LV function and aortic stenosis severity. Further, they seemed to be superior to tissue velocity and conventional echocardiography in detecting subtle changes in myocardial function after AVR before LV mass and LV function showed improvement.

Aged↗
PubMed2006

[Echocardiography].

Advancement of echocardiography has been remarkable recently and has been useful to diagnose and manage chronic heart failure. Tissue Doppler echocardiography can measure myocardial motion velocity thereby enabling us to assess global and regional myocardial function. Mitral annular velocity in early diastole has been reported to correlate with left ventricular diastolic relaxation. The ratio of pulsed Doppler mitral flow velocity to the mitral annular velocity in early diastole is used to assess pulmonary capillary wedge pressure or left ventricular end-diastolic pressure. Comparison of time to peak of myocardial systolic velocity among various segments provides us important information on ventricular dyssynchrony, which is crucial for the success of cardiac resynchronization therapy. Finally, real-time three-dimensional echocardiography has emerged as a new modality to assess cardiac anatomical abnormalities. It is also promising to measure ventricular volume accurately.

Echocardiography↗
PubMed2005

Prevention of left ventricular remodeling by long-term corticosteroid therapy in patients with cardiac sarcoidosis.

Forty-three patients with cardiac sarcoidosis were studied echocardiographically before and after (mean follow-up 88 months) steroid therapy to determine the effectiveness of corticosteroids to prevent left ventricular (LV) remodeling and improve LV contractility. In patients with initial LV ejection fractions (LVEFs) >or=55%, long-term steroid therapy showed preventive effects for LV remodeling and LV function. Patients with LVEF <54% showed significant reductions of LV volumes and LVEF improvement. However, in patients with LVEFs <30%, steroid therapy resulted in neither LV volume reductions nor improved LVEFs. In the early or middle stage of the disease, steroid therapy may be protective or therapeutic in preventing LV remodeling and preserving LV function. However, it may not be as effective in the late stage.

Adult↗
PubMed2005

Impact of preoperative and postoperative atrial fibrillation on outcome after mitral valvuloplasty for nonischemic mitral regurgitation.

OBJECTIVE: We sought to determine the impact of preoperative or postoperative atrial fibrillation on survival, stroke, and cardiac function after mitral valvuloplasty for mitral regurgitation. METHODS: Between 1991 and 2003, 1026 patients with nonischemic/noncardiomyopathy mitral valve regurgitation underwent mitral valve plasty in 3 centers; 663 patients remained in sinus rhythm (group A), and 363 patients had atrial fibrillation or flutter preoperatively (group B) with concomitant maze procedures (group BM, n = 163) or without maze procedures (group BN, n = 200). RESULTS: Eight-year freedom from cardiovascular-related death was better in group A (99.3%) than group B (BM: 96.9%, BN: 81.6%) ( P < .001) and also better in group BM than group BN ( P = .007). The adjusted hazard ratio of group B versus group A for preoperative differences was 5.1 (95% confidence interval: 1.8-14.8). Eight-year freedom from stroke was better in group A (99.2%) than group B (BM: 98.2%, BN: 82.6%) ( P < .001) and also better in group BM than group BN ( P < .001). Patients with preoperative atrial fibrillation had larger left atria and left ventricular systolic dimensions. The adjunct maze procedure improved left ventricular systolic dimensions over mitral repair alone (group A vs B: P = .359; group BM vs BN: P = .001). CONCLUSION: Preoperative permanent/persistent atrial fibrillation was associated with a dilated left atrium and reduced left ventricular function in patients with mitral regurgitation. Including the maze procedure with mitral repair improved survival, late cardiac function, and freedom from late stroke.

Actuarial Analysis↗
PubMed2005

Cardiac tumor as an initial manifestation of acquired immunodeficiency syndrome.

A cardiac tumor was the first manifestation of acquired immunodeficiency syndrome (AIDS) in a female patient in a state of severe immunodeficiency caused by human immunodeficiency virus (HIV) infection. The extensive cardiac and extracardiac involvement shown by various imaging modalities, including echocardiography and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), suggested that she was in the critical stage of non-Hodgkin's lymphoma (NHL). AIDS was treated by highly active-antiretroviral therapy and the NHL was treated by a combination of rituximab-cyclophosphamide-vincristine-doxorubicine-predonisolone. After 6 cycles of chemotherapy, she was in complete remission. Her cardiac tumor dramatically reduced in size and FDG-PET showed no positive uptake on whole body imaging. Generally, an AIDS-related cardiac tumor tends to be diagnosed at the late stage of the disease because of its nonspecific clinical findings, resulting in an extremely poor prognosis. In the present case, the cardiac tumor was detected by echocardiography and treated with appropriate chemotherapy. Early diagnosis and prompt treatment may improve a patient's prognosis.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Clinical implications of assessing coronary flow velocity reserve and plasma endothelin-1 in hypertensive patients.

Previous reports have indicated that hypertensive patients who have angina-like chest pain and normal coronary arteriograms have reduced coronary flow velocity reserve (CFVR) levels. In addition, elevated plasma endothelin-1 (ET-1) levels have been reported to be associated with microvascular angina. The purpose of this study was to evaluate the plasma ET-1 levels and CFVR in patients with chest pain but without coronary artery disease (CAD). A total of 66 patients were included in this study. CAD was ruled out by exercise stress test or coronary angiogram. Plasma ET-1 and CFVR measurements were performed in patients with (n=35) and without (n=31) a history of angina-like chest pain. CFVR was measured using adenosine-triphosphate stress transthoracic Doppler echocardiography. The mean ET-1 level was significantly higher and the CFVR was significantly lower in patients in the symptomatic group than in those in the asymptomatic group (ET-1: 3.85 +/- 1.24 pg/ml vs. 2.98 +/- 1.27 pg/ml, CFVR: 2.26 +/- 0.48 vs. 2.77 +/- 0.11, respectively). Plasma ET-1 level and CFVR were significantly correlated with each other (-r = 0.265, p = 0.033). Age, blood pressure, cardiovascular risk factors, and left ventricular mass index were similar between the two groups. The results of multiple regression analysis indicate that age (p = 0.008) and plasma ET-1 concentration (p = 0.031) had statistically independent associations with CFVR. Attenuated CFVR in the symptomatic hypertensive patients was associated with endothelial dysfunction, which results in elevated plasma ET-1 levels. The link between these two parameters may play a role in the genesis of chest pain in hypertensive patients without CAD.

Aged↗