Yasuhiko Orita

Left atrial ball thrombus diagnosed by two-dimensional echocardiography

The diagnosis of the ball thrombus in the left atrium has been very difficult by conventional clinical techniques. In the present case, two-dimensional echocardiography successfully demonstrated a spherical tumor moving in unpredictable directions in the left atrium. M-mode echocardiography did not clearly identify the tumor because of the limited visual width and spatial orientation of the technique; however, simultaneous recordings of the M-mode echocardiogram with phonocardiogram, carotid pulse wave, and electrocardiogram provided some diagnostic clues to the occlusive left atrial tumor. In the absence mitral valve occlusion by the tumor, a logarithmic correlation between the ejection time and the preceding R-R interval, and a negative lines correlation between Q to the first sound interval and the preceding R-R interval were found. In the beat following the appearance of the tumor in the mitral orifice, the sudden shortening of the ejection time and the prolongation of Q to the first sound interval were noted. Both of these findings are indirect evidence of decreased left ventricular filling associated with an elevated left atrial pressure resulting from the sudden mitral orifice obstruction by the tumor. Detailed analysis of the data obtained by the conventional noninvasive techniques could provide critical clues for the diagnosis of the occlusive left atrial tumor.

Baroreflex sensitivity in patients with Takayasu's aortitis.

Takayasus aortitis is an arterial inflammatory disease of arteries of unknown etiology. Fainting is a common symptom and has been attributed to hypersensitivity of the baroreflex. We studied baroreflex sensitivity in 11 patients with Takayasus aortitis and compared it with that of eight control subjects of comparable age. Baroreflex sensitivity was assessed by determining the slope of a regression line relating the rise of systolic arterial pressure to the prolongation of the R-R interval of the electrocardiogram during a transient rise of arterial pressure induced by an intravenous injection of phenylephrine. The average baroreflex slope of patients with Takayasus arteritis (4.0 ± 0.8 msec/mm Hg) was signiffcantdy less than that of control subjects (10.7 ± 0.8 msec/mm Hg, P < 0.001). Reduced baroreflex sensitivity in patients with Takayasus aortitis may be due to the hardening of the arteries where baroreceptors lie, or to hypertension and/or cardiac disease which was present in most of the patients included in the study. Patients with Takayasus aortitis who complained of fainting also showed the reduced baroreflex sensitivity. This indicates that fainting in this disease is not likely to be caused by the hyperreactivity of the baroreceptors as is commonly postulated.

Hypertensive Crisis Induced by Metoclopramide in Patient with Pheochromocytoma

A hypertensive crisis associated with evidence of catecholamine release was induced following intravenous administration of 10 mg metoclopramide in a woman with pheochromocytoma and in whom the tyramine test was nega tive. After removal of the tumor, blood-pressure and plasma catecholamine concentrations were not influenced by the administration of metoclopramide. It is suggested that the mechanism of hypertensive crises induced by metoclo pramide may not be due to a direct catecholamine releasing effect from the tumor or sympathetic nerve endings, but rather to its presynaptic dopaminer gic blocking effect which would indirectly release catecholamines.

Coronary arterial spasm in single coronary artery.

A 48-year-old man developed severe chest pain and became unconscious. Coronary cineangiography revealed single coronary artery of the type LZb by Sharbaugh and White. Ergonovine, 0.2 mg i.v., produced coronary arterial spasm in the right coronary artery.This case suggests that coronary arterial spasm might be a cause of sudden death in patients with single coronary artery. However, an association of single coronary artery and coronary arterial spasm might be coincidental.

Quantitation of myocardial dyssynergy in closed-chest dogs by two-dimensional echocardiography

Myocardial infarction was produced in 29 anaesthetized mongrel dogs by a closed-chest coronary occlusion technique. A two-dimensional echocardiographic examination (2-D echo) was carried out just before occlusion and again 48 h after occlusion. Many cross-sectional images were recorded by a video-tape recorder. The applied site of the probe was fixed in an intercostal space and the direction of the ultrasonic beam was tilted stepwise from the basis to the apex. The animals were sacrificed at 49 hours after occlusion. The hearts were removed, quick frozen, sliced into radiating sections and stained with nitroblue tetrazolium (NBT). The outline of dyssynergy, including dyskinesis, akinesis or extreme hypokinesis, was traced with a tablet digitizer by two specialists. The three-dimensional image of dyssynergy in the left ventricular wall was reconstructed by a computer in spherical co-ordinates and assumed to be made of numerous triangular pyramids. The volume of dyssynergy was calculated quantitatively as the sum of volumes of these numerous triangular pyramids. The volume of dyssynergy seen in 2-D echo correlated well over a wide range with the volume of infarction determined by NBT staining.

Congenital Mitral Stenosis Associated with Ventricular Septal Defect, Patent Ductus Arteriosus and Tubular Hypoplasia of the Ascending Aorta

A 28-year-old female was discovered to have mitral stenosis associated with ventricular septal defect, patent ductus arteriosus and tubular hypoplasia of the ascending aorta. The diagnosis of such complex anomalies was con firmed by an echocardiographic and cardiac catheterization study. Congenital mitral stenosis is a rare cardiac malformation and usually results in early death. This patient is a relatively long survival case in spite of many complications.