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Biomedical subjects

M Akaishi

Publications and source records attributed to M Akaishi.

60 records · Page 4Linked to original sources
PubMed1982

Evaluation of combined valvular prolapse syndrome by two-dimensional echocardiography.

The patterns of aortic and tricuspid valve motion in 50 patients with mitral valve prolapse were analyzed by wide-angle, phased-array, two-dimensional echocardiography. Twelve patients (24%) had redundant aortic leaflets bulging into the left ventricular outflow tract during diastole. Eight of 12 patients had aortic regurgitation and seven of 12 had M-mode echocardiographic evidence of aortic valve prolapse. One patient underwent mitral and aortic valve replacement, and the excised valves revealed marked myxomatous degeneration. Eight of 15 patients undergoing contrast echocardiography had tricuspid regurgitation (systolic reflux of contrast material into the inferior vena cava persisting for more than 10 beats), and prolapse in the septal leaflet of the anterior leaflet or both. A similar tricuspid valve pattern was noted in three of seven patients without tricuspid regurgitation. Tricuspid valve prolapse was identified in 20 patients (40%). Nine patients (18%) had combined prolapse of the mitral, aortic and tricuspid valves. In five patients with middiastolic high-pitched murmurs recorded along the left sternal border, tricuspid valve prolapse was demonstrated. In one of these patients, the presence of pulmonary regurgitation was confirmed by intracardiac phonocardiography. We conclude that two-dimensional echocardiography is useful for evaluating patients with combined valvular prolapse syndrome.

Adolescent↗
PubMed1982

[Echocardiographic findings of a patient with cardiac amyloidosis and left ventricular outflow obstruction].

This report described 56-year-old male with cardiac amyloidosis, whose echocardiographic and hemodynamic findings suggested hypertrophic obstructive cardiomyopathy. M-mode echocardiography demonstrated asymmetric septal hypertrophy (2.1 cm/1.6 cm), systolic anterior motion of the mitral valve, and pericardial effusion. Two-dimensional echocardiography revealed marked hypertrophy of the septum and papillary muscles with characteristic fine grannular sparkling appearance of the myocardium. Bilateral heart catheterization showed normal hemodynamics except a pressure gradient of 35 mmHg within the left ventricular outflow tract. Moreover, no hemodynamic evidence of restrictive cardiomyopathy was observed. Myocardial biopsy was performed at the time of pericardiectomy, and diffuse amyloid deposits were identified between myocardial fibers. It is of particular interest that cardiac amyloidosis presented the form of ventricular hypertrophy associated with left ventricular outflow obstruction, probably due to uneven deposition of amyloid.

Amyloidosis↗
PubMed1980

A new approach to visualize the left main coronary artery using apical cross-sectional echocardiography.

Patients undergoing coronary arteriography were studied to evaluate the feasibility of use of cross-sectional echocardiography to detect the left main coronary artery. Visualization of the left main coronary artery from the cardiac apex was attempted using a cranial transducer angulation. With this approach, the left main coronary artery was adequately visualized in 27 of 35 consecutive patients (77 percent) who were prospectively evaluated; in 12 of the 27 the bifurcation was clearly seen. In 26 of the 27 patients cross-sectional echocardiography correctly assessed the patency of the left main coronary artery as judged with coronary angiography. One patient had a false positive echocardiographic study; there were no false negative studies. A comparison of the short axis versus apical cross-sectional techniques in another group of 30 patients revealed the superiority of the apical approach in visualization of the left main coronary artery and its bifurcation; combined use of both techniques allowed for a 93 percent (rate of) success. Thus, apical cross-sectional echocardiography permits visualization of the left main coronary artery and its bifurcation and, therefore, has the potential for detecting left main coronary obstructive lesions.

Adult↗
PubMedDate not supplied

Variations in myocardial contraction sequence under various hypoxic conditions.

Hypokinetic myocardial segment motion is observed in various pathophysiologic conditions. The aim of this study was to clarify the mechanisms involved in differences in segment motion of hypokinesis. Nineteen open-chest dogs were studied with regard to myocardial segment length, left ventricular pressure, and internal minor-axis diameter. Sequential instantaneous myocardial elastance [alpha(t) curve] was calculated under 4 different hypoxic conditions: complete coronary occlusion and reperfusion, partial coronary occlusion, coronary microembolization, and anoxic perfusion. The alpha(t) curve peaked at end-systole in the case of normal contraction; but it was almost totally flat when complete bulging occurred. The hypokinesis which occurred during development of the complete systolic bulge immediately after complete coronary occlusion had an earlier alpha(t) peak curve than the hypokinesis resulting from partial coronary stenosis (209.5 +/- 35.6 ms after end-diastole vs. 261.9 +/- 18.2 ms; p less than 0.02), microsphere injection into the coronary artery (243.2 +/- 24.5 ms vs. 289.3 +/- 15.4 ms; p less than 0.05), or anoxic perfusion (213.4 +/- 40.2 vs. 275.6 +/- 28.3 ms; p less than 0.05). The early alpha(t) peak resulted in a late-systolic bulge in segment length motion. In conclusion, hypokinetic segment motion differed depending on whether the coronary blood flow was present or not. A late-systolic bulge only developed immediately after complete coronary occlusion, and resulted from an abrupt decrease in myocardial stiffness during the cardiac cycle, which is closely related to the abrupt cessation of coronary blood flow.

Animals↗