Prevalence of mitral prolapse by two dimensional echocardiography in healthy young women.

In order to establish the relative prevalence of mitral valve prolapse as diagnosed by two dimensional echocardiography, we studied 100 presumably healthy young women with two dimensional echocardiography and M-mode echocardiography, history, physical examination, electrocardiography, and phonocardiography. Two dimensional echocardiograms were obtained from parasternal, apical, and subcostal acoustic windows. Mitral valve prolapse was defined as extension of leaflet tissue cephalad to the plane of the mitral annulus into the left atrium; note was also made of any valvular thickening, redundancy, or excessive annular motion. One subject had a midsystolic click and late systolic murmur with evidence of mitral prolapse on both M-mode and two dimensional echocardiography. One subject had a midsystolic click with mitral prolapse demonstrated by two dimensional but not on M-mode echocardiography. One subject had a thick mitral valve on echocardiography but no click or murmur. Four subjects had midsystolic clicks without echocardiographic abnormalities. Mild artefactual pansystolic posterior bowing of the mitral valve on the M-mode echocardiogram could be produced in 20 subjects by incorrect transducer position. We conclude that the prevalence of mitral valve prolapse by two dimensional echocardiography is relatively low in presumably healthy young women. Use of two dimensional echocardiography may avoid overdiagnosis of mitral prolapse and identify a smaller group of individuals with true anatomical abnormalities of the mitral valve.     

Evaluation of ventricular function using two dimensional echocardiography

Two dimensional echocardiography is potentially a more accurate and reliable method for assessing ventricular function than the standard M mode echocardiographic technique. More widespread clinical application of this technique for the quantitative assessment of left ventricular systolic function has been limited by the fact that quantitation was very time-consuming. Recent advances in two dimensional instrumentation allow quantitation to be performed with less difficulty and in a shorter time period. As a result, two dimensional echocardiography should find widespread clinical use in the evaluation of global and segmental ventricular function.     

经食管二维与实时三维超声结合在风湿性二尖瓣病变成形术中的应用

目的:研究经食管二维与实时三维超声结合在风湿性二尖瓣病变成形术中的作用。方法:26例临床诊断为风湿性二尖瓣病变拟行二尖瓣成形术患者,术前联合应用经食管二维超声与实时三维超声,对二尖瓣功能不全进行分类,详细定位病变部位,测量二尖瓣前后叶厚度、长度及瓣环径。术后即刻评价疗效。结果:术前超声诊断单纯风湿性二尖瓣关闭不全10例(38.5%),单纯二尖瓣狭窄4例(15.4%),二尖瓣关闭不全重度伴狭窄轻度9例(34.6%),二尖瓣关闭不全重度伴狭窄中度3例(11.5%);瓣膜功能不全Ⅱ型4例(15.4%),ⅡAⅢa-P型18例(69.2%),Ⅲa-AⅢa-P型4例(15.4%)。术后即刻超声评价疗效,3例在超声指导下2次成形,其中2例最终选择瓣膜置换术。结论:经食管二维和实时三维超声心动图结合,在风湿性二尖瓣病变成形术前对瓣膜功能不全进行分类诊断,能准确评估二尖瓣叶厚度和长度,指导术式和人工瓣环的选择。术后即刻评价疗效,在风湿性二尖瓣成形术中有重要的应用价值。     

Determination of pressure gradient in mitral stenosis with Doppler echocardiography.

The accuracy of a non-invasive ultrasound Doppler technique for the determination of the pressure gradient in mitral stenosis was evaluated in a study of 8 adult patients. Transseptal left atrial catheterisation and retrograde left ventricular catheterisation were performed. The same diastoles were used to compare the gradient constructed from the ultrasound data (delta PU) with that constructed from the manometric data (delta PM). In the 8 patients the difference betweent he mean diastolic values of delta PU and delta PM was - 0.54 +/- 1.0 (SD) mmHg. The corresponding figure for mid-diastole was 0.01 +/- 0.9 (SD) mmHg. The results indicate that the ultrasound technique is sufficiently accurate for diagnostic purposes.     

Determination of pressure gradient in mitral stenosis with Doppler echocardiography.

The accuracy of a non-invasive ultrasound Doppler technique for the determination of the pressure gradient in mitral stenosis was evaluated in a study of 8 adult patients. Transseptal left atrial catheterisation and retrograde left ventricular catheterisation were performed. The same diastoles were used to compare the gradient constructed from the ultrasound data (delta PU) with that constructed from the manometric data (delta PM). In the 8 patients the difference betweent he mean diastolic values of delta PU and delta PM was - 0.54 +/- 1.0 (SD) mmHg. The corresponding figure for mid-diastole was 0.01 +/- 0.9 (SD) mmHg. The results indicate that the ultrasound technique is sufficiently accurate for diagnostic purposes.     

Congenital mitral stenosis. Anatomical and functional assessment by echocardiography.

Digitised left ventricular echocardiograms were studied in nine children with congenital mitral stenosis to assess the severity of inflow obstruction. In six children the two prime indices of mitral stenosis were abnormal, with a prolonged time from minimum dimension to 20 per cent dimension change and a reduced peak dimension change during diastole. In three, however, these values did not suggest inflow obstruction, depsite significant gradients at cardiac catheterisation. Two-dimensional echocardiography was performed in 10 children with congenital mitral stenosis to determine the mitral annular size and the morphology of the valve and subvalvular apparatus. The annular size and number of papillary muscles could be assessed along with the detection of combined mitral abnormalities. Two-dimensional studies can reliably delineate the type of mitral abnormality, and should be performed in all cases with congenital heart disease having a high incidence of associated left ventricular inflow obstruction. Digitised M-mode left ventricular echocardiography is in general unreliable in assessing congenital obstruction, though it may be of some value in individual cases.     

Three dimensional echocardiography and aortic valve stenosis

Efforts have been made over the years to meet the challenge of three-dimensional (3D) reconstruction of cardiac structures. Succeeding in 3D reconstruction of the aortic valve and through it achieving better understanding and possibly better quantification of aortic stenosis severity is the main purpose of using such an imaging tool. The importance attached to it over the years is related mostly to the expectation of both clinicians and researchers not only for better and more complete imaging of its shape, but also for optimal demonstration of the valve motion and through it towards better understanding of valve function in health and disease. This review deals with 2 main aspects regarding 3D echocardiography: 1). three-dimensional methods and general principles and 2). the special relevance of 3D reconstruction to the stenotic aortic valve.     

Two-dimensional echocardiography in the quantification of severe mitral stenosis

The aim of the study was to evaluate the accuracy of echocardiographic quantification of mitral valve opening area in severe mitral stenosis. 31 consecutive patients with severe mitral stenosis were studied with two-dimensional echocardiography before they had complete resection of the mitral valve. The valves were examined for calcifications by x-ray. Each specimen was tensionlessly suspended in a glass cylinder, with 10 to 15 l of warm water (37 degrees C) running through it until maximal opening of the valve. Then the valvular orifice was photographed for planimetry. Now the echocardiographic results were checked again to analyse the errors of the initial assessment. In 6 out of 31 patients the size of the valvular opening area could not be assessed echocardiographically due to poor echo quality. The mean mitral opening area of the specimens was 0.92 +/- 0.32 cm2. With 1.27 +/- 0.52 cm2, the results achieved by echocardiography reached a correlation of only r = 0.44. In 9 out of 25 patients the area was assessed precisely in terms of size and anatomy. The difference between the values calculated from the specimens and echocardiograms was below 0.5 cm2 in 19 out of 25 (76%) patients and below 1 cm2 in another 4 (16%) patients. A larger difference in two patients was due to incorrect beam direction. Otherwise, false results in 10 out of 25 patients were caused by multiple inner echoes and in 2 out of 25 patients by bright reflections due to calcifications. Although the echocardiographically assessed mitral valve opening area does not correlate with the real opening area, it is possible to distinguish in most patients between severe and mild stenosis. Furthermore the valvular opening area can be exactly determined up to 0.5 cm2 in 90 percent of patients, provided that the echo beam is correctly positioned.     

Exercise Doppler echocardiography in patients with pure mitral stenosis

Exercise increases heart rate and cardiac output and is helpful in the determination of dynamic mitral gradient in patients with mitral stenosis. However exercise is difficult to perform during cardiac catheterization in a premedicated recumbent patient and is only feasible when the brachial approach is used. Therefore, in the haemodynamic laboratory, exercise has important practical limitations. In order to obtain similar information using a reproducible and non-invasive technique, we tested the feasibility of combined two-dimensional and continuous wave Doppler echocardiography during exercise in a selected number of patients with pure mitral stenosis and in sinus rhythm. Seven patients, ranging from 14 to 48 years (average: 35 +/- 13), underwent baseline two-dimensional and continuous wave Doppler examinations, repeated after 2 minutes of supine bicycle exercise at a workload of 25, 50, 75 watts. The following parameters were derived and averaged: mean velocity of flow across the mitral valve, mean mitral valve gradient, diastolic filling period and heart rate. The increase in mitral valve flow was from 1.5 +/- 0.3 to 2.2 +/- 0.5 m/s (p less than 0.001); the corresponding increase in mean pressure gradient was from 11 +/- 3 to 21 +/- 8 mmHg (p less than 0.001). The decrease in the diastolic filling period was from 424 +/- 170 to 272 +/- 73 msec (p less than 0.005). The increase in heart rate was from 60 +/- 10 to 100 +/- 18 beats/minute (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

A critical appraisal of M-mode echocardiography in mitral stenosis

The reliability of M-mode echocardiography in confirming mitral stenosis and in assessing its severity was tested in 39 patients with mitral stenosis. None of the conventional echocardiographic signs of mitral stenosis is absolutely reliable. Unless at least 2 signs are combined, the diagnosis is not conclusive (sensitivity = 0.97, specificity = 1.00). Of a number of echocardiographic parameters and equations recommended (as tools) to determine the severity of mitral stenosis, the early diastolic velocity of anterior leaflet opening (EF) is the only one with a statistically significant relationship to the mitral valve area (MVA) calculated by Gorlin (r = 0.712, p less than 0.001), and this only in uncomplicated unoperated mitral stenoses, but not in mitral restenoses and combined mitral defects. Even the recently published Seitz's equation for calculating MVA from echocardiographic data is not reliable. M-mode echocardiography is an excellent technique for the primary diagnosis of mitral stenosis. However, it is not suitable to even an approximate assessment of its haemodynamic severity.     

二尖瓣狭窄的四维超声心动图初步研究

为显示狭窄二尖瓣的动态立体结构，采用四维超声心动图对５例正常人、１４例二尖瓣狭窄病人应用该技术进行研究，建立二尖瓣的长轴、短轴立体剖面图，分别从侧面、左房面、左室面观察二尖瓣的形态结构及活动状况。结果表明，二尖瓣的四维重建能更直观地显示瓣膜的解剖结构，综合评估狭窄二尖瓣的病变程度。     

Role of exercise Doppler echocardiography in isolated mitral stenosis

This study reports the role of Doppler ultrasound during exercise for assessment of patients with mitral stenosis. Doppler echocardiography was performed at rest and during symptom-limited supine bicycle exercise in ten patients with isolated mitral stenosis. The mean mitral valvular gradient was calculated using modified Bernoulli's equation, and the mitral valvular area was estimated from the equation, 220/pressure half-time. During exercise the heart rate increased from 74 +/- 14 beats per minute (mean +/- SD) at rest to 110 +/- 8 beats per minute (p less than 0.001) during exercise. The mean mitral gradient increased from 9 +/- 5 mm Hg at rest to 18 +/- 7 mm Hg (p less than 0.01) during exercise. The mitral pressure half-time decreased from 225 +/- 62 msec at rest to 190 +/- 42 msec during peak exercise (p less than 0.005). This corresponded to a reduction of 15 percent. The estimated mitral valvular area increased from 1.0 +/- 0.4 sq cm at rest to 1.2 +/- 0.3 sq cm at peak exercise (p less than 0.005). In conclusion, Doppler echocardiography can be used to evaluate patients with mitral stenosis, with the response of the mitral valvular gradient being the index of obstruction; however, caution should be used in applying the mitral pressure half-time for estimation of the mitral valvular area at high heart rates and flows.     

Resolution and accuracy in two dimensional echocardiography

The resolution and accuracy of commercially available two dimensional echocardiographic systems were tested by Imaging two types of in vitro test objects. One consisted of a series of fine parallel threads spaced at known intervals and the other was a tissue phantom in which a series of holes of known size had been cut. The echocardiographic systems tested included a mechanical single element sector scanner, a three element rotary sector scanner and a phased array system. Azlmuthal resolution, lateral resolution and accuracy of horizontal distance measurements were assessed at depths of 2 and 6 cm.For each system, azimuthal resolution was better than lateral resolution, especially when assessed with use of the parallel threads. When the tissue phantom was imaged, the best resolution (2 mm in azimuthal and lateral directions) was obtained with the highest frequency transducer tested (3.5 MHz). The apparent size of a tissue defect was sensitive to gain settings, especially at a depth of 2 cm with lower frequency transducers; at a depth of 6 cm, echographic measurements of defect size were accurate to within 2.5 mm. Recent applications of two dimensional echocardiography require resolution near the apparent limits of current equipment. It Is recommended that the highest frequency transducer and lowest possible gain settings be used in these situations.     

Cardiac anatomy viewed systematically with two dimensional echocardiography.

The details of three-dimensional cardiac anatomy are complex, and structure recognition is difficult in tomograms produced with recently developed two-dimensional ultrasonic sector scanners. This article presents a method we have found useful for systematic inclusion of most cardiac structures during such echocardiographic examinations. Orthogonal planes, aligned parallel and perpendicular to the long or major left ventricular axis, are obtained from each of three transducer positions on the body surface. Moving this X-Y image plane through the heart perpendicular to the plane (z axis) allows the viewer to integrate the images into a mental picture of the whole structure. The illustrations are oriented as they are displayed by ultrasonic sector scanners so they aid rapid recognition of cardiac structures.     

Clinical uses of two dimensional echocardiography

The added advantages of two dimensional over M mode echocardiography in the diagnosis of cardiac disorders occurring in adults are reviewed. In patients with coronary artery disease, left ventricular aneurysm, wall motion abnormalities and ventricular dysfunction can be reliably evaluated with two dimensional echocardiography. Preliminary studies have demonstrated that two dimensional echocardiography is useful for assessing regional cardiac dilatation and prognosis after acute myocardial infarction, detecting left main coronary stenosis and predicting operability in patients with ventricular aneurysm. Determination of mitral valve area by two dimensional echocardiography in patients with mitral stenosis has shown good correlation with measurements of mitral valve area and size performed at the time of operation or calculated from cardiac catheterization data. The cause of mitral regurgitation can be more reliably elucidated by the differentiation of valvular and myocardial pathologic conditions. In addition, precise anatomic cardiac detail can be obtained in the localization of left and right ventricular and aortic outflow obstruction. Tricuspid valve disorders are particularly apparent because all three leaflets of the tricuspid valve can be visualized in real time studies and the detection of tricuspid regurgitation can be readily accomplished. Two dimensional echocardiography appears to be more reliable than M mode echocardiography in the detection of complications occurring as a result of bacterial endocarditis. Bioprosthetic valve function and localization and site of pericardial effusions as well as aortic aneurysms can be determined with two dimensional echocardiography. Two dimensional echocardiography can provide an accurate appreciation of the size, shape, mobility and origin of an intracardiac mass. With the use of contrast echocardiography, right to left shunting or the negative contrast effect can be demonstrated in patients with an atrial septal defect. Thus, the precision, accuracy and sensitivity of two dimensional echocardiography affords the clinician a valuable noninvasive instrument in the detection of cardiac disease.     

Localisation and direction of mitral regurgitant flow in mitral orifice studied with combined use of ultrasonic pulsed Doppler technique and two dimensional echocardiography.

Regurgitant flow was analysed in 40 cases of mitral regurgitation, using combined ultrasonic pulsed Doppler technique and two dimensional echocardiography. Abnormal Doppler signals indicative of mitral regurgitant flow were detected in reference to the two dimensional image of the long axis view of the heart and the short axis view at the level of the mitral orifice. The overall direction of regurgitant flow into the left atrium was clearly seen in 28 of 40 cases, and the localisation of regurgitant flow in the mitral orifice in 38 cases. In cases with mitral valve prolapse of the anterior leaflet or posterior leaflet the regurgitant flow was directed posteriorly or anteriorly, respectively. The prolapse occurred at the anterolateral commissure or posteromedial commissure and resulted in regurgitant flow located near the anterolateral commissure or posteromedial commissure of the mitral orifice, respectively. In cases with rheumatic mitral regurgitation the regurgitant flow is usually towards the central portion of the left atrium and is sited in the mid-part of the orifice. The Doppler findings were consistent with left ventriculography and surgical findings. The ultrasonic pulsed Doppler technique combined with two dimensional echocardiography is useful for non-invasive analysis and preoperative assessment of mitral regurgitation.     

四维超声心动图评价二尖瓣脱垂

采用经胸壁与经食管检查途径获取二维数据，对１０例正常人及２０例二尖瓣脱垂患者的二尖瓣装置及返流束进行了四维（动态三维）超声心动图重建。结果显示，正常二尖瓣装置呈＂马鞍＂形结构，瓣膜附着于瓣环前后缘处靠近左房，位置较高，内外侧结合部附着处靠近左室，位置较低。收缩期二尖瓣前后叶对合良好，四维超声心动图可从左房、左室侧及四腔切面等多个方位显示二尖辩脱垂病变的立体结构关系，脱垂部位、形状、程度及活动情况均可清晰显示，并可对返流束进行四维重建，显示其立体形态及动态变化。对全面理解二尖瓣脱垂的病理改变、提高诊断率、协助制定治疗方案及评价疗效有重要价值。