Genta Osakada

Detection and evaluation of tricuspid regurgitation using a real-time, two-dimensional, color-coded, Doppler flow imaging system: Comparison with contrast two-dimensional echocardiography and right ventriculography

To detect and evaluate regurgitant flow in tricuspid regurgitation (TR) with a newly developed, realtime, 2-dimensional (2-D), color-coded, Doppler flow imaging system (Doppler 2-D echo), 27 patients (18 with suspected TR and 9 normal subjects) were examined and the findings were compared with those obtained using contrast 2-D echocardiography (contrast 2-D echo) and right ventriculography. In 16 of 18 patients with suspected TR, Doppler 2-D echo easily visualized the color-coded regurgitant flow in the right atrium and estimated the severity of TR from the distance of the visible TR jet. On the basis of the QRS synchronized appearance of contrast in the inferior vena cava by the subxiphoid approach or of the negative contrast effect above the tricuspid valve just after the contrast entered the right ventricle with its subsequent back-and-forth movements across the tricuspid valve, Doppler 2-D echo was more sensitive and specific in detecting TR (100% and 100%) than contrast 2-D echo (75% and 82% in the subxiphoid view, 56% and 100% in the 4-chamber view) when the fast Fourier transformation frequency analysis was used as the standard of TR, and it was more sensitive in detecting TR (85%) than contrast 2-D echo (69% in the subxiphoid approach, 46% in the 4-chamber view) when right ventriculography was used as the standard of TR. Additionally, the severity of TR as shown by Doppler 2-D echo correlated fairly well with that shown by right ventriculography. Thus, Doppler 2-D echo is clinically useful for detecting and evaluating TR.

Dynamic geometry of the left atrium and left ventricle in acute mitral regurgitation.

The instantaneous transverse diameter of the left atrium, left ventricular free wall segment length (SEG), and the long axis of the anterior papillary muscle (APM) length were measured throughout the cardiac cycle, using ultrasonic dimension gauges together with left atrial and left ventricular pressures in 12 open-chest dogs. During atrial contraction, left atrial diameter decreased from 19.7 to 18.7 mm, while left ventricular dimensions increased simultaneously. During ventricular ejection, percent shortening was 26% in SEG and 10% in APM, while atrial diameter increased continuously to 20.5 mm, with a concomitant rise in the v wave of left atrial pressure. After normal mitral valve opening, left atrial diameter decreased rapidly simultaneously with the y descent of atrial pressure. Graded mitral regurgitation was then produced by sectioning the chordae tendineae. With moderate mitral regurgitation, end-diastolic length of the SEG increased by 27%, while extent of shortening (delta L) was augmented by 9...

Assessment of transesophageal Doppler echography in dissecting aortic aneurysm.

To assess the clinical value of transesophageal Doppler echography in the diagnosis of dissecting aortic aneurysm, both transesophageal and conventional echograms were performed in 22 cases of dissecting aortic aneurysm. Of the 22 patients, 17 underwent angiography; 8, X-ray computed tomography; 4, both; and 12, surgery. The performance of each method was assessed in the following four segments: A, ascending aorta; B, aortic arch; C, thoracic descending aorta; and D, upper abdominal aorta. The results by angiography were presumed to be correct. In the group of 17 patients who underwent angiography, the rate of correct detection of an intimal flap using the transesophageal approach was 100% in all four segments, significantly better than detection by the conventional approach (segment A, 65%; segment B, 47%; segment C, 35%; segment D, 53%) (p less than 0.01), and the rate of correct detection of the entry sites using the transesophageal approach was 100%, significantly better than that by conventional approach (42%) (p less than 0.05). X-ray computed tomography was not capable of detecting the site of entry in all cases. The presence of thrombus, aortic regurgitation and pericardial hemorrhage were all revealed clearly by the transesophageal approach, and the results were partly proved by other methods. In conclusion, transesophageal Doppler echography provides a rapid and accurate method of diagnosing and evaluating dissecting aortic aneurysm and permits prompt initiation of appropriate treatment.

Detection of intracardiac shunt flow in atrial septal defect using a real-time two-dimensional color-coded doppler flow imaging system and comparison with contrast two-dimensional echocardiography

To evaluate the noninvasive detection of shunt flow using a newly developed real-time 2-dimensional color-coded Doppler flow imaging system (D-2DE), 20 patients were examined, including 10 with secundum atrial septal defect (ASD) and 10 control subjects. These results were compared with contrast 2-dimensional echocardiography (C-2DE). Doppler 2DE displayed the blood flow toward the transducer as red and the blood flow away from the transducer as blue in 8 shades, each shade adding green according to the degree of variance in Doppler frequency. In the patients with ASD, D-2DE clearly visualized left-to-right shunt flow in 7 of 10 patients. In 5 of these 7 patients, C-2DE showed a negative contrast effect in the same area of the right atrium. Thus, D-2DE increased the sensitivity over C-2DE for detecting left-to-right shunt flow (from 50% to 70%). However, the specificity was slightly less in D-2DE (90%) than C-2DE (100%). Doppler 2DE could not visualize right-to-left shunt flow in all patients with ASD, though C-2DE showed a positive contrast effect in the left-sided heart in 9 of 10 patients with ASD. Thus, D-2DE is clinically useful for detecting left-to-right shunt flow in patients with ASD.

Recognition of regional hypertrophy in hypertrophic cardiomyopathy using thallium-201 emission-computed tomography: Comparison with two-dimensional echocardiography☆

The configuration of the hypertrophied myocardium was evaluated by thallium-201 emission-computed tomography and 2-dimensional (2-D) sector scan in 10 patients with obstructive hypertrophic cardiomyopathy (HC), 10 with nonobstructive HC with giant negative T waves and 10 with concentric left ventricular (LV) hypertrophy. Thallium-201 myocardial imaging was reconstructed into multiple 12-mm-thick slices in 3 planes. The thickness ratio of the ventricular septum and the LV posterior wall in the short-axis plane and the ratio of the ventricular septum and the apical wall in the long-axis plane were analyzed. In the patients with obstructive HC the ventricular septal wall thickness index was increased, and the ratio of septal to posterior wall thickness index (1.45 +/- 0.23) was greater than that in the patients with nonobstructive HC with giant negative T waves or in those with concentric LV hypertrophy (1.03 +/- 0.20 and 0.98 +/- 0.11, respectively; p less than 0.01 for each). In the patients with nonobstructive HC with giant negative T waves, increased apical wall thickness with apical cavity obliteration was characteristic, and the ratio of ventricular septal to apical wall thickness index (0.66 +/- 0.14) was less than that in the patients with obstructive HC or in those with concentric LV hypertrophy (1.46 +/- 0.38 and 1.04 +/- 0.09, respectively; p less than 0.001 for each). In contrast, technically satisfactory 2-D sector scanning (83%) demonstrated various configurations of the hypertrophied ventricularseptum, but could not detect apical hypertrophy in 4 of the 10 patients with nonobstructive HC with giant negative T waves whose LV cineangiograms demonstrated apical hypertrophy. Thus, thallium-201 emission-computed tomography is useful in evaluating the characteristics of LV hypertrophy and assists 2-D sector scan, especially in patients with apical hypertrophy in HC.

Influence of acute mechanical overload on dimension and dynamics of interventricular septal thickness in dogs

To evaluate directly septal thickness and related dynamic changes, miniature ultrasonic crystals were Implanted across the Interventricular septum and left ventricular free wall and In the circumferential endocanNal segments of the left and right ventricles In 12 open chest dogs. In the control resting state, end-dlastollc wall thickness of the septum and the left ventricular free wall was 9.4 ± 2.1 and 9.6 ± 2.6 mm, respectively (mean ± standard deviation). Wall thickness Increased during systole by 15 percent In the septum and by 17 percent in the free wall. With constriction of the ascending aorta, left ventricular end-dlastollc segment Increased by 13 percent with reciprocal thinning In the end-dlaslollc thickness of the septum (by −8.5 percent) and the left ventricular free wall (by −5.2 percent); there were decreases in percent shortening of the left ventricular segment (from 21.0 to 15.5 percent) and In percent thickening of both the septum (from 14.6 to 11.8 percent) and the free wall (from 16.9 to 13.1 percent). Pulmonary arterial constriction resulted In significant right ventricular chamber enlargement; however, there was no direct change In dimension and dynamics of the septum. When mitral regurgitation was produced by sectioning the chordae tendlneae, left ventricular end-dlastollc segment length Increased (by 23.5 percent) with reciprocal thinning of the enddlastollc thickness of the septum (by −8.6 percent) and the free wall (by −6.9 percent). The left ventricular segment shortening and wall thickening of the septum and the free wall were equally augmented (from 18.6 to 37.5, from 16.1 to 31.0 and from 19.8 to 29.3 percent, respectively). Wtth the onset of acute tricuspld regurgitation, right ventricular end-dlastollc segment and its shortening Increased markedly, but there were no direct changes in the septum. Thus, the interventrlcular septum can be regarded as a functional part of the left ventricle, and any form of mechanical loading on the left ventricle will ultimately Induce proportionate changes in the septum and left ventricular free wall.

Transesophageal echocardiography in the diagnosis of thoracic saccular aortic aneurysm The value of transesophageal echocardiography during the course of treatment

Transesophageal echocardiography (TEE) was performed in 17 cases of aortic aneurysms referred to our hospital for further examination and treatment. All 17 cases were treated surgically and TEE was performed as a preoperative examination. In nine of the 17 cases, there were already some signs of bleeding upon admission and in all of these nine cases, rupture of the aneurysm was confirmed during surgery. Measurement on cross-sectional TEE imaging disclosed large aneurysmal diameters in eight of these nine cases, suggesting a close relationship between diameter and rupture. Moreover, observation of the lesions by TEE suggested a relationship between the risk of rupture and morphological characteristics of the thrombus. In seven of the nine bleeding cases, TEE imaging revealed destructive features of the aneurysmal thrombus, such as exfoliation from the aortic wall and/or tearing-off, suggesting expansion of the aortic diameter.Detailed findings of the aneurysm and thrombus on TEE corresponded with surgical findings. Thus, we concluded that TEE is a useful method of obtaining information about aortic aneury sms not only as a preoperative examination but also as an independent examination to determine treatment options and prognosis.

Dynamic changes in left ventricular regional wall thickness during premature ventricular contraction in conscious dogs

The contractile pattern of the regional left ventricular wall during premature ventricular contraction was analyzed in conscious dogs instrumented with an ultrasonic dimension gauge across the anterior and posterior left ventricular walls. Aortic flow was measured with an electromagnetic flow probe. A single premature ventricular contraction was induced by stimulating either the anterior or posterior wall with varied coupling intervals from 380 to 650 msec. Stroke volume of premature ventricular contraction was significantly smaller than that of premature atrial contraction with identical coupling intervals. In premature contractions, stroke volume was linearly related to coupling intervals. Though there was no isovolumic wall thickening in premature atrial contraction, the wall started to thicken during isovolumic ventricular systole in premature ventricular contraction. There was a clear inverse correlation between the ratio of the isovolumic wall thickening to the total wall thickening and coupling intervals. In premature ventricular contractions with identical coupling intervals, the deformation of thickening characteristics was more pronounced in regions with closer proximity to the ectopic focus. Thus it is concluded that the pump function is depressed in premature ventricular contraction, in part due to the increased ratio of wall thickening during isovolumic systole before the opening of the aortic valve. Isovolumic wall thickening increases along with the shorter coupling intervals and closer proximity to the ectopic focus. These alterations in left ventricular mechanical function due to ectopic contraction might induce serious sequelae, depending upon the ectopic focus in the presence of already depressed regional function.