[Echocardiographic diagnosis of d-transposition of the great vessels by deductive analysis]. / Le diagnostic échocardiographique de la D-transposition des gros vaisseaux par analyse déductive.

The process of diagnosis by echocardiography of transposition of the great vessels is based fundamentally on the recognition of the position and relative orientation of the two ventricles and of the two vessels of the base of the heart. Traditional two-dimensional echocardiography allows us to establish the position of the left ventricle because of the atrio-ventricular (mitral) valve and its direct continuity with a sigmoid valve. If this continuity is absent, the mitral valve may be recognised because it closes after the tricuspid valve. It the tricuspid valve is on the right of and/or in front of the mitral valve, the aorta will in principle be found on the right of the pulmonary artery ("loop rule"). The orientation of the great vessels may then be determined. Two-dimensional systems are particularly useful in diagnosis of vascular disorders. If these are not available, traditional echocardiography may lead us to suspect this abnormality: 1. Provided that the orientation of the transducer is known at all times during the recording; 2. Provided the recording demonstrates simultaneously the two great vessels with their respective valves. Two other criteria are important if Van Praagh's rule or the "loop rule" is unhelpful: the diameter of the two vascular trunks, and identification of the valve by a study of the ejection times.

Ultrasonic demonstration of right ventricular myxoma.

A case of right ventricular myxoma masquerading as infundibular pulmonic stenosis with right-sided heart failure is presented. The unsuspected tumor was diagnosed with two-dimensional multicrystal real time scanning and single element echocardiography. Direct visualization of the tumor anatomy and its spatial relationships on cross-sectional images facilitates the diagnosis. On the other hand, the more accurate motion analysis form the time-motion display of the echo data yields additional functional information. Thus the two techniques are complementary to establish a diagnosis in those disorders where anatomy and function overlap. Ultrasonic examination yields a practical solution to the problem of screening patients to detect intracardiac tumors. This painless, noninvasive examination should be included in the analysis of every patient with cardiac symptoms.

Familial prevalence of asymmetric septal hypertrophy.

Echocardiography was used to detect the familial prevalence of asymmetric septal hypertrophy in relatives of patients with proven idiopathic hypertrophic subaortic stenosis. Idiopathic hypertrophic subaortic stenosis is only one clinical expression of a cardiomyopathic disease spectrum, including asymptomatic patients having asymmetric septal hypertrophy as a characteristic anatomic marker which can be detected by echo. The validity of previous proposed criteria to detect this marker was checked in our population. Therefore we examined normal subjects, patients with fixed left ventricular outflow obstruction (valvular aortic stenosis), and those with idiopathic hypertrophic subaortic stenosis who served as index cases. A septal thickness exceeding that of the free left ventricular posterior wall by 30% separates patients with a cardiomyopathy from those without this disease. 27 of 73 examined relatives of 14 index cases were found to have asymmetric septal hypertrophy. In those instances where information was available from the parents of the index cases, one parent was found to be affected. When the examined group is considered from a parent-child relationship (including the index case when appropriate), it included 78 children of affected single parents of which 20 males and 19 females had asymmetric septal hypertrophy. The history, clinical examination and electrocardiogram were not useful to detect the disease. The results suggest an autosomal dominant mode of inheritance of asymmetric septal hypertrophy with a high penetrance.

Resolution problems in echocardiology: a source of interpretation errors.

Resolution is the ability of the echocardiographic system to distinguish closely lying structures. This is usually defined in two directions: laterally (lateral resolution) and in depth (axial resolution). With use of short ultrasonic pulses, axial resolution is not a major problem. By far the more important problem is the limited lateral resolution that results from the finite beam width of current ultrasonic devices. This results in the display of echoes that originate from off-axis structures. How these off-axis or "spurious echoes" affect the display is a function of the way the echographic information is handled. In conventional M-mode tracings, spurious echoes are displayed at a site where there is no directly corresponding anatomic structure, whereas with two-dimensional imaging, these echoes may result in important distortions of structures. The underlying principles are illustrated by a clinical experiment wherein the ball of a Starr-Edwards mitral valve prosthesis serves as a target of known shape and dimensions. These data are used to elucidate some of the problems and potential errors encountered in the interpretation of clinical M-mode recordings of the aorta, mitral valve and the left ventricular endocardium as well as their cross-sectional analysis. They also explain the present limitations of quantification of left ventricular performance from cross-sectional images.

Proceedings: Echocardiology.

Any technique which allows "a look inside the body" without being invasive, affords major diagnostic possibilities. The application of ultrasound offers this possibility now. The purpose of this paper is to review the current status of this relatively new diagnostic method for the detection and quantification of many cardiac disorders and to outline its usefulness. It may be said that echocardiology offers "the ideal diagnostic method" of the future, particularly when one considers the low cost-benefit ratio in comparison with other diagnostic methods such as angiocardiography.

An improved method for the quantitative analysis of M-mode echocardiograms.

A computer-assisted system is described which speeds and extends the quantitative interpretation of M-mode echocardiographic recordings. The system consists of a digitizing tablet, minicomputer, TV monitor and a hard copy device. M-mode echocardiograms are placed on the digitizing surface and traced using the digitizing pen. The entered signal includes the endocardial surfaces of the anterior and posterior left ventricular wall for at least one cycle, and two Q waves from a simultaneously recorded ECG to identify end diastole and heart rate. End systole is determined automatically as corresponding to the minimum LV dimension. Results of analysis include continuous plots of estimated volume and circumferential fiber shortening rate (CFSR) vs time. Determinations of special interest are also displayed: enddiastolic volume (EDV) and endsystolic volume (ESV), ejection fraction, cardiac output, mean and peak CFSR. M-mode echocardiograms obtained from 25 normal volunteers are used to evaluate the system. The standard error of the estimate of the computer-assisted system is comparable to the error between observers, furthermore the computer system adds no significant systematic or random error. Comparison between M-mode estimated volumes and angiographically determined values has been described previously and Sy - x here is significantly greater. The main advantages of this system are: 1. a continuous plot of estimated LV volume and CFSR is provided; 2. beat-to-beat analyses are facilitated; 3. the automatic determination of end systole removes possible errors in judgement made previously; 4. it is time saving when one considers the amount of data obtained. With these advantages and the generally satisfactory performance in the clinical trials, this system appears to have extended the clinical quantitative capabilities of M-mode echocardiograms.