Larry A. Latson

Accuracy of two-dimensional echocardiography in the diagnosis of congenital heart disease

To assess the accuracy of 2-dimensional (2-D) echocardiography in the evaluation of cardiac anatomy in patients with congenital heart disease, 2-D echocardiograms were performed in 126 infants and children before cardiac catheterization and angiocardiography. The segmental echocardiographic analysis included determination of intracardiac, great artery, systemic venous and pulmonary venous anatomy. The 126 patients had 259 separate cardiovascular abnormalities, of which 226 (87%) were prospectively identified by 2-D echocardiography. There were 8 false-positive diagnoses. The most common lesions and the sensitivity and specificity of echocardiography were: patent ductus arteriosus, 41 patients (83% and 100%, respectively), ventricular septal defect, 35 patients (86% and 100%); atrial septal defect, 26 patients (85% and 99%); pulmonary valve stenosis, 25 patients (77% and 97%), transposition of the great arteries, 16 patients (100% and 100%); and total anomalous pulmonary venous connection, 14 patients (85% and 100%). Less common defects and their rate of detection included coarctation of the aorta, 10 of 12 patients; atrioventricular canal, 10 of 10 patients; tetralogy of Fallot, 10 of 10 patients; aortic valve stenosis 8 of 8 patients; right aortic arch, 8 of 8 patients; interrupted aortic arch, 4 of 4 patients; and unilateral pulmonary vein atresia, 0 of 1 patient. In 33 patients (26%), the errors in echocardiographic analysis were judged to have surgical importance. Most errors were the result of overlooking or misinterpreting data that had been appropriately recorded on videotape. Pulmonary valve stenosis and patent ductus arteriosus are the lesions most likely to be misdiagnosed by ultrasound studies relying on imaging alone.

Long-term follow-up of patients with malformations for which definitive surgical repair has been available for 25 years or more☆

The results of long-term follow-up studies of patients with five common congenital heart defects are reviewed. The lesions included are ventricular septal defect, atrial septal defect, patent ductus arteriosus, pulmonary stenosis and coarctation of the aorta. A definitive, rather than palliative, operation has been available for each of these lesions for more than 25 years. Therefore many patients who have undergone operation for one of these lesions are now reaching adulthood. Although most of these postoperative patients live a normal life, many have residuae or sequelae that require close observation or treatment. Other persistent abnormalities of the physical examination, electrocardiogram and chest radiogram are obvious but call for no precaution or treatment. We have drawn on our own experience and the published experience of others to identify those findings and historical factors that best reflect the long-term prognosis of these patients. In addition, recommendations concerning the need for continued prophylaxis against infective endocarditis, and the problems of insurability and employability of these postoperative patients are discussed.

Relation of the echocardiographic estimate of left ventricular size to mortality in infants with severe left ventricular outflow obstruction

Abstract The relation of left ventricular size, as estimated with echocardiography, to mortality was evaluated in three groups of infants with severe left ventricular outflow obstruction. Group I consisted of 17 patients with combined aortic and mitral stenosis or atresia associated with definite hypoplasia of the left ventricle. Group II consisted of eight patients with the primary diagnosis of severe aortic stenosis. Group III consisted of 12 patients with severe coarctation of the aorta. The left ventricular enddiastolic dimension measured with M mode echocardiography and the cross-sectional area of the left ventricular cavity as seen in the parasternal long axis view of the two dimensional echocardiogram were used as indexes of left ventricular volume. All patients with symptomatic outflow obstruction and a left ventricular end-diastolic dimension of less than 13 mm died in infancy. However, five patients with a hypoplastic left ventricle proved at angiography or at autopsy, or both, were found to have a ventricular end-diastolic dimension of 13 mm or greater. Two dimensional echocardiography showed that the left ventricle in these patients was foreshortened and spherical in shape. The cross-sectional area of the left ventricle of each patient in group I was less than 1.6 cm 2 . This was below the range of cross-sectional areas found in a group of normal infants (1.8 to 3.5 cm 2 ± 2 standard deviations about the mean). Three patients in groups II and III had a slightly reduced left ventricular area (1.7 cm 2 ) and none of these patients survived infancy. Measurement of the cross-sectional area of the left ventricle is a useful method of determining left ventricular size in infants suspected of having the hypoplastic left ventricle syndrome. Patients who have reduced left ventricular volume as assessed by this technique are at very great risk even if surgical relief of the outflow obstruction is attempted.

Ventricular septal defect in infancy: Detection with two dimensional echocardiography

To determine the sensitivity and specificity of two dimensional echocardiography in detecting ventricular septal defect two dimensional echocardiograms were performed on 53 infants under 1 year of age. The diagnosis of ventricular septal defect was confirmed by cardiac catheterization in 27 patients; an intact ventricular septum was confirmed by catheterization in 18 and clinically in 8. Using a 35 degree mechanical sector scanner with a 3.5 megahertz transducer, we imaged the ventricular septum in the long axis and in a four chamber view (apical or subcostal, or both). Images were recorded on videotape and reviewed independently by two observers unaware of the diagnosis. Interobserver agreement was 94 percent. Among the 27 patients with a ventricular septal defect, the lesion was correctly identified in 20 (74 percent) and was undetected in 7 (3 of whom had a defect less than 4 mm in diameter, as determined by angiography). No defect less than 4 mm in diameter was detected. Among the 26 patients with an intact septum, a defect was correctly excluded in 23 (88 percent); a false positive diagnosis was made in 3. The apical and subcostal views demonstrated the greatest number of defects (20 of 20), but also gave the highest number of false positive diagnoses (3 of 3). The long axis view was helpful when positive, but showed only 9 of 20 of the defects. In this study, two dimensional echocardiography detected approximately three fourths of ventricular septal defects large enough to warrant cardiac catheterization in the 1st year of life. False positive diagnoses were related to dropout of echoes in the membranous septum when imaged in the four chamber views.

Atrioventricular valve anular diameter: Two-dimensional echocardiographic-autopsy correlation☆

To study the accuracy of 2-dimensional echocardiography (2-D echo) in estimating mitral and tricuspid anular diameter, 2-D echo estimates were compared with autopsy measurements of anular diameter in 21 children studied by echo within 30 days of death. The mitral anulus was measured from the left parasternal long axis view and the apical or subcostal 4-chamber image and the tricuspid anulus from the 4-chamber view. Comparable measurements were made from the autopsy specimen with calipers. The correlation coefficient for echocardiographic vs autopsy measurements was 0.79 (standard error of the estimate 2.8 mm) (mitral long axis r = 0.76, mitral 4-chamber r = 0.85, tricuspid 4-chamber r = 0.76). Echo measurements exceeded the corresponding autopsy measurements by an average of 17%; this was at least partially attributed to shrinkage of the specimen during fixation. Thus, 2-D echo may be used to provide a reasonable estimate of mitral and tricuspid anular diameter.

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. Azimuthal 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 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.

Echocardiographic pulsed doppler features of absent pulmonary valve syndrome in the neonate

M mode echocardiography was used to evaluate nine neonates with absent pulmonary valve syndrome. Six were also studied with two dimensional echocardiography and two with pulsed Doppler echocardiography. M mode echocardiography demonstrated a large, overriding great artery and right ventricular dilation in all nine patients and abnormal septal motion in eight. Two dimensional echocardiography demonstrated aneurysmal dilation of the main pulmonary artery in all six patients studied. Pulsed Doppler echocardiography in the two infants studied demonstrated anterograde systolic and retrograde diastolic flow in the main pulmonary artery and right ventricular outflow tract. The echocardiographic features of absent pulmonary valve syndrome appear to be unique and allow the diagnosis to be made noninvasively, thus obviating or delaying the need for potentially high risk cardiac catheterization.

Atrioventricular valve abnormalities in infancy: Two-dimensional echocardiographic and angiocardiographic comparison

The results of two-dimensional echocardiography and biplane angiocardiography from 47 infants with congenital atrioventricular (AV) valve abnormalities were compared. Eleven patients had atresia of the right AV valve, 10 had atresia of the left AV valve, 4 had hypoplasia of the right AV valve and 5 had hypoplasia of the left AV valve. Twelve patients had endocardial cushion defect, three had single ventricle and two had straddling of the left AV valve. There was agreement between the two techniques as to the number of AV valves present in each patient. The echocardiographic estimate of valve anular diameter was below normal in seven of the eight patients thought to have a hypoplastic anulus by angiocardiography. In 10 of the 12 patients with endocardial cushion defect, there was agreement between the two techniques as to the presence or absence of atrial and ventricular septal defect. The chordal attachments of straddling valves were better visualized by echocardiography; flow patterns and effective orifice size were better demonstrated by angiocardiography. The subcostal four chamber echocardiographic views and cranially angulated oblique angiocardiographic views were comparable and provided the best images for determination of the size and number of AV valves and their relation to the atrial and ventricular septa.

Pocket calculator program to compute normal values for echocardiographic measurements in children

Abstract We have developed a pocket calculator program which computes the upper and lower limits of normal for six cardiac dimensions and two systolic time intervals frequently measured from M-mode echocardiograms. The parameters include the diameter of the left ventricle, left atrium, aorta, and right ventricle, the thickness of the septum and left ventricular posterior wall, and the preejection period and ejection time. The normal ranges are calculated from previously published regression equations relating the various parameters to a function of body weight or to heart rate. Use of the program eliminates the necessity for plotting measured values onto graphs of normals, and should increase the speed and accuracy of interpretation of these paremeters, especially in pediatric echocardiography.