Arata Miwa

Cross-sectional echocardiographic study on persistent left superior vena cava

Abstract Twelve patients with persistent left superior vena cava (PLSVC) were studied using high speed cross-sectional echocardiography with mechanical sector scanning. The majority of the examined patients had other associated congenital heart diseases. A circular echo with an echo-free space was demonstrated at the posterosuperior region of the posterior mitral leaflet (PML) in the cross-section of the long cardiac axis. It was also recognized as a narrow tubular cavity echo posterior to the left atrium and the left ventricle in the cross-section of the sagittal plane of the chest. This abnormal echo was gradually enlarged during systole and the unusual cavity was largest in early diastole at the E point of the anterior mitral leaflet (AML), and its anterior margin moved back in middiastole. This abnormal echo seems to be correspond to the left atrioventricular sulcus. By the injection of indocyanine green at the left median cubital vein, the positive contrast echo appeared in the cavity which was considered to be PLSVC, whereas it appeareed neither in the left atrium nor in the left ventricle. This abnormal echo was not recognized in normal subjects and other cardiac diseases without PLSVC. In M-mode echocardiography, the unusual linear echo was recorded behind the AML. It moved anteriorly during systole and went back posteriorly in diastole. Consequently, because of the direction of the echo beam, the movement and the location of the unusual echo, it seems to emanate from the lower part of the PLSVC. High speed cross-sectional echocardiography has proved to be useful for noninvasive diagnosis of the PLSVC.

Real-time observation of cardiac movement and structures in congenital and acquired heart diseases employing high-speed ultrasonocardiotomography

Echocardiography has proved useful for cardiac diagnosis during the past several years; however, the conventional one-dimensional ultrasound pulse echo method cannot easily visualize the anatomical relationships of the various cardiac structures. To overcome the limitation, the authors attempted a real-time observation of cardiac structures and introduced high-speed ultrasonocardiotomography with a Sonolayergraph Model SSL-51H (Toshiba) having a logarithmic amplifier. Thirty sector images are produced per second by a mechanically operated, single flat or 75 mm. focus transducer measuring 10 mm. in diameter. The angle of a sector image composed of about 120 scanning lines is arbitrarily changeable from null to 65 degrees. The fast succession of images produced enables clear observation of the movement of cardiac structures in real time. Study of 230 patients by means of the proposed system suggests that it is advantageous as a quick method to provide two-dimensional echocardiograms for cardiac diagnosis and assessment, especially in noninvasive diagnosis.

Clinical study on the flow murmurs at the defect area of atrial septal defect by means of intracardiac phonocardiography.

In order to study flow murmurs through atrial septal defects, right heart catheterization was performed on 48 patients of secundum type, four of primum type, and five of probe-patent foramen ovale, with the double-lumen phonocatheter of Lewis, at the tip of which barium titanate was mounted. The flow murmurs at the defect area were classified into three patterns: v murmur, atriosystolic murmur, and mid-diastolic murmur. V murmur was continuous, extending from late systole to diastole, of low to medium pitch, closely related to atrial v wave and augmenting with expiration. It had no significant correlation to the ratio of left-to-right shunt. It was recorded in 32 out of 48 cases of secundum type and one of primum type, but not observed in probe-patent foramen ovale. Atriosystolic murmur was noted in 17 of 48 cases of secundum type and one of primum type. It was connected with atrial a wave. Mid-diastolic murmur was found at the defect area in four subjects of secundum type. It was thought to be an independent entity from v murmur and to be another one due to shunt flow through the septal defect, since it had no relation to v wave but it was localized between v and a waves in the pressure curve of the right atrium. It is different in localization from mid-diastolic murmur due to relative tricuspid stenosis at the inflow tract of right ventricle.

Origin of the basal systolic murmurs in mitral stenosis. A study with intracardiac phonocardiography

In order to study the origin of the basal systolic murmurs in mitral stenosis, left and right heart catheterization was performed in 18 patients with mitral stenosis using intracardiac phonocardiography. Our data revealed that the basal systolic murmurs originated in the aorta, the pulmonary artery, and the outflow tract of the right ventricle. In 14 cases, we noted the maximal ejection systolic murmur in the aorta near the aortic valve. However, in two cases, there was a loud systolic murmur in the pulmonary artery. These murmurs occurred in early to mild-systole and were crescendo-decrescendo in configuration. The pitch of the murmur ranged from low to medium frequency in the majority of cases. They are produced by the turbulence of blood flow in the aorta and the pulmonary artery. A late systolic murmur was also recorded in the outflow tract of the right ventricle in two patients. This is thought to occur due to functional or relative infundibular stenosis of the right ventricle. It differs in location and timing from those in the aorta and the pulmonary artery. The outflow tract of the right ventricle is regarded as the third origin of the basal systolic murmur in mitral stenosis.