Transoesophageal echocardiographic assessment of fixed subaortic obstruction in children.

OBJECTIVE--To evaluate the clinical usefulness of transoesophageal echocardiography in the assessment of children with fixed left ventricular outflow tract stenosis. PATIENTS AND METHODS--Eight consecutive children, aged over 5 years, with fixed subaortic stenosis and one child with fixed subpulmonary left ventricular outflow tract stenosis were prospectively assessed by precordial and transoesophageal echocardiography. RESULTS--Transoesophageal images of the left ventricular outflow tract were much clearer than precordial images in all patients except one with a prosthetic mitral valve. Improved visualisation provided further information on the nature of the lesion (additional chordal attachment of the mitral valve in one, accessory atrioventricular valve tissue with aneurysm formation in one), on the extent of the lesion (circumferential in three), and on the very close relation of a ridge to the aortic valve leaflets in one. Transoesophageal Doppler did not provide any additional information on aortic regurgitation and was unreliable for gradient estimation across the left ventricular outflow tract. CONCLUSIONS--Transoesophageal imaging provides an excellent means of visualising lesions in the left ventricular outflow tract and can be useful in a few children and adolescents in whom precordial echocardiography does not provide adequate information. The technique can also be used intraoperatively to define the full extent of the obstructive lesion and to assess residual lesions after surgery.     

Transoesophageal echocardiographic evaluation of atrial morphology in children with congenital heart disease.

In a prospective study, atrial morphology was evaluated by both transoesophageal and precordial echocardiography in 86 unoperated children with congenital heart disease (age range = 0.2 to 14.8 years, mean = 3.8 years) to determine what advantages, if any, might be inherent in the transoesophageal approach. The information derived from both ultrasound approaches was correlated and compared to information obtained during subsequent cardiac catheterization (78 patients) and, or, surgical inspection (53 patients). Atrial appendage morphology and hence atrial situs was determined by transoesophageal echocardiography in every case (82 solitus, two right atrial isomerism, two left atrial isomerism). In addition, the transoesophageal approach indicated left juxtaposition in four patients, compared to only one by precordial examination. Probe patency of the foramen ovale was correctly predicted in 21 patients by transoesophageal imaging, but in only 10 by precordial imaging. In two children significant secundum defects, undetected by the precordial route, were identified. Multiple atrial septal defects were correctly defined in four patients by transoesophageal study but in only one by precordial study. Sinus venosus defects were documented in four by the transoesophageal approach, but in only one by the precordial. Primum defects were equally well documented (nine patients) by either technique, but the associated valve leaflet morphology was better documented by transoesophageal study in 5/9. A subtotal cor triatriatum was diagnosed in one child only by transoesophageal investigation. Transoesophageal echocardiography allows a much more detailed evaluation of atrial morphology than precordial imaging even in infants. It provides direct diagnosis of atrial situs, detection of juxtaposed atrial appendages and improved demonstration or definitive exclusion of atrial septal defects.     

Transoesophageal echocardiographic assessment of primum, secundum and sinus venosus atrial septal defects

We compared the ability of transthoracic and transoesophageal echocardiography to determine the presence and site of an atrial septal defect and associated anomalous pulmonary venous connexions in 13 school age children (aged 5 to 15 years) and 12 adults (aged 25 to 68 years). Transthoracic echocardiography detected atrial septal defects in 12 children and 6 adults. Transoesophageal echocardiography confirmed the position of 16 (13 secundum, 3 primum) of these 18 defects but altered the diagnosis from a secundum defect to a sinus venosus defect in one and from a sinus venosus defect to a high secundum defect in another. In addition to these 18, transoesophageal echocardiography diagnosed a defect in 5 adults (3 secundum and 2 sinus venosus defects) and 1 child (secundum defect). In an adult with inconclusive transthoracic findings, transoesophageal echocardiography enabled clear visualisation of the atrial septum and excluded an atrial septal defect. Transoesophageal echocardiography showed anomalous attachment of a pulmonary vein into the region of a sinus venosus defect (n = 3) but did not show anomalous connexions to the superior caval vein (n = 3) or the inferior caval vein (n = 1). Transoesophageal echocardiography provides a reliable method of diagnosing or excluding an atrial septal defect in patients with inconclusive transthoracic findings and is of particular diagnostic value in sinus venosus defects.     

Transoesophageal echocardiographic visualization of renal cyst mimicking aortic aneurysm.

We report a tricky case of a 63-year-old man with previous coronary artery bypass graft surgery in whom transoesophageal echocardiography revealed a voluminous echolucent cavity simulating aortic ectasia but that proved to be of nephrogenic origin.     

Transoesophageal echocardiographic monitoring of left ventricular function

Summary Technical advances in echocardiography, especially the introduction of oesophageal probes, have led to the extension of its indications to the field of anaesthesia and intensive care. Transoesophageal echocardiography (TEE) provides high quality imaging of the left ventricle in patients on ventilators [12]. In addition, manipulation of the probe is performed near the patient's head and so does not interfere with the surgeon's job. This enables echocardiographic monitoring of left ventricular function throughout the operation. The information so obtained not only provides data about anatomical changes which is sometimes invaluable, but also allows quantification of left ventricular function which is the main advantage for anaesthetists. The images allow study of regional and global left ventricular contraction and the deduction of certain parameters of ventricular performance. The ability to perform real time monitoring of ventricular function throughout anaesthesia and the immediate postoperative period is all the more valuable in patients with limited cardiac and coronary reserve. This new method of monitoring gives a better understanding of the physiopathology of peroperative cardiac events and provides information which may guide the conduct of the anaesthesia and postoperative care.     

Echocardiographic evaluation of fixed left ventricular outlet obstruction in children. Pre and postoperative outlet obstruction in children.

Rencently, several investigators have utilized the echographically determined magnitude of relative left ventricular posterior wall hypertrophy as a reflection of normalized systolic wall stress to estimate left ventricular systolic pressure noninvasively. In this study, relative wall thickness determined echographically was compared to peak systolic pressure measured at catheterization in 20 children without obstruction to left ventricular outflow and with normal left ventricular function. From these data a relationship, pressure = 225 X left ventricular systolic wall thickness/left ventricular end-systolic internal dimension, was derived. The relationship was then applied to 57 children with fixed aortic stenosis. Left ventricular pressure estimated echographically compared well with that demonstrated at cardiac catheterization (r = 0.89). Twenty-one patients had further echographic studies following surgical relief of outlet obstruction. Estimated left ventricular pressure fell to normal values within two months following surgery in over half the patients with good surgical relief of obstruction, and was normal at subsequent studies up to 22 months postoperatively in all but one patient with good surgical relief. In patients in whom outlet obstruction was not adequately relieved at surgery, echographically estimated left ventricular pressure remained persistently elevated.     

Transoesophageal echocardiographic diagnosis of aortico-left atrial fistula in aortic valve endocarditis.

Intra-cardiac fistulas are rarely seen and they are estimated to account for <1% of all cases of infective endocarditis. Fistulization of paravalvular abscesses has been found in 6% to 9% of cases. This is a report of an unusual communication between the abscess region in the aortic root and the left atrium. A 44-year-old patient diagnosed with infective endocarditis had continuous fevers despite antibiotic therapy. Transoesophageal echocardiography revealed multiple vegetations on aortic valve, fistulization of an aortic root abscess to the left atrium and mitral regurgitation and moderate aortic regurgitation. At surgery, multiple vegetations on the aortic valve and a large abscess cavity establishing direct communication between aortic root and the left atrial cavity through a fistulous tract were discovered. This experience demonstrates the improved sensitivity and specificity of transoesophageal echocardiography in defining periannular extension of infective endocarditis.     

Pre- and postoperative echocardiographic features of discrete subaortic stenosis.

In two patients with discrete membranous subaortic stenosis, partial early systolic closure of the aortic valve was noted on the preoperative record. Postoperatively, this abnormality was found to be less pronounced. Narrowing of the left ventricular outflow tract was seen in the preoperative tracing in each patient. Echocardiograms taken after resection of the subaortic membrane showed widening of the left ventricular outflow tract as compared with the preoperative tracing. Thus, echocardiography may be of value in distinguishing between discrete subaortic stenosis and other forms of left ventricular outflow tract obstruction.     

An echocardiographic study of localized subaortic hypertrophy

A prospective echocardiographic investigation was undertakento determine the prevalence and significance of localized subaortichypertrophy in WOO consecutive patients presenting for a routineechocardiographic examination. Localized septal hypertrophywas diagnosed when the subaortic septum was hypertrophied (<l.4cm)and was 50% thicker than the mid-point of the septum. Patientswith hypertrophic cardiomyopathy and fixed subvalvular aorticstenosis were excluded. Eight cases of localized subaortic hypertrophywere identified. In 7 the appearances of the left side of theinterventricular septum were similar with an apparently sigmoidshape (reversed S on its side) and in 1 with associated mitralstenosis the septum was a tapered wedge. All patients with localizedsubaortic hypertrophy had left ventricular hypertrophy (leftventricular mass or posterior wall thickness >2 SD from normal)with a normal size cavity due to aortic valve disease (2 patientswere also hypertensive). Of the 180 patients with aortic valvedisease, localized subaortic hypertrophy was found in 10% ofthose with left ventricular hypertrophy and 33% of those withasymmetrical-septal hypertrophy (septum to posterior wall ratioof >l.5:1). There was no evidence of subaortic stenosis bypulsed and continuous wave doppler echocardiography (8 cases)and cardiac catheterization (6 cases). The aetiology of thisdiscrete localized muscular bulge is unclear but is presumablydue to change in shape of the septum with left ventricular hypertrophy.However, this finding has important implications as a causeof asymmetrical septal hypertrophy and because of the possiblefalse diagnosis of subvalvular stenosis and its effect on ultrasoundmeasurements.     

Long-term echocardiographic assessment of dilated cardiomyopathy in children

Left ventricular (LV) dimensions and function were assessed by echocardiography in 22 children with dilated cardiomyopathy. They had survived an initial episode of congestive heart failure in infancy for greater than or equal to 2 years. At the time of echocardiography, when they were 3 to 16 years old, 8 patients (Group 1) still had signs of dilated cardiomyopathy and 14 (Group 2) had lost all roentgenographic and electrocardiographic evidence of heart disease. All 8 patients in Group 1 (average follow-up 4.5 years) had significantly increased LV dimensions. The end-diastolic dimension averaged 144 +/- 18% of the normal value. Fractional LV shortening with systole was significantly reduced and averaged 23 +/- 3%. The E point-septal separation ranged from 7 to 17 mm (mean 12 +/- 4) and was far above the normal limit in all. Of the 14 patients in Group 2, seven (average follow-up 7 years) had normal ventricular dimensions and 7 (average follow-up 10 years) had LV dimensions larger than the upper range of the 95% prediction limit. In 6 of the latter patients the fractional LV shortening with systole was less than or equal to 31% and the E point-septal separation in excess of the upper limit of normal. These findings indicate that about half of the patients who had apparently recovered still had residual lesions as judged from the echocardiogram. In 6 patients in group 1, two-dimensional echo-cardiography allowed the visualization of a thickened endocardium. One of these 6 patients died. The echocardiographic image correlated well with the process of LV endocardial fibroelastosis found at necropsy.     

Regional myocardial function in idiopathic hypertrophic subaortic stenosis. An echocardiographic study.

To assess regional contractility in idiopathic hypertrophic subaortic stenosis (IHSS), a primary myopathic disorder with documented hyperdynamic ventricular contractions, systolic wall thickening and velocity of contraction of the septum and left ventricular posterior wall were measured in echocardiograms from 16 patients with IHSS and 16 normal subjects. The average thickening of the normal septum and posterior wall was 75.9+/-8.8% and 84.8+/-6.3%, respectively. The posterior wall in IHSS thickened by 75.1+/-6.8%. None of these values differed significantly. However, the increase in thickness of the IHSS septum averaged 22.5+/-2.4%, significantly less than that of either the IHSS posterior wall or the normal septum. Velocity measurements confirmed the impression of diminished septal function. The mean velocity of normal septal contraction averaged 37.0+/-2.3 mm/sec, normal posterior wall 42.3+/-2.0 mm/sec and IHSS posterior wall 55.7+/-3.5 mm/sec, whereas the septum in IHSS contracted at the rate of 26.0+/-2.5 mm/sec. Thus, the IHSS septum contracted significantly more slowly than the normal septum or IHSS posterior wall. However, the posterior wall velocity in IHSS was significantly more rapid than that measured in normal ventricles--perhaps to compensate for the septum. Normalization of all velocities for left ventricular end-diastolic internal diameter did not alter the sifnificance of the results. Consideration of IHSS as an asymmetric myopathy based on prior observations of predominantly septal hypertrophy and distorted septal cellular architecture is now supported by the above evidence of functional left ventricular asymmetry. Although the total left ventricular function in IHSS may be hyperdynamic, regional function is not uniform. The septum appears to be hypodynamic, while the contractile capacity of the posterior wall is increased.     

Transoesophageal Doppler echocardiographic measurement of cardiac output by the mitral annulus method.

OBJECTIVE--To compare cardiac output measured by the transoesophageal Doppler and thermodilution techniques. DESIGN--Prospective direct comparison of paired measurements by both techniques in each patient. SETTING--Intensive care unit in a cardiovascular centre. PATIENTS--65 patients after open heart surgery (mean (SD) age 53 (12) years). INTERVENTIONS--Cardiac output was measured simultaneously by the transoesophageal Doppler and thermodilution techniques. Cardiac output was measured again after a mechanical intervention or volume loading. RESULTS--The limits of agreement were -2.53 to +0.83 1.min-1 for cardiac output measured by the Doppler and thermodilution techniques. This suggests that the Doppler method alone would not be suitable for clinical use. The second measurement of cardiac output by thermodilution was compared with cardiac output estimated from the first and second Doppler measurements and the first thermodilution measurement. The limits of agreement (-0.55 to +0.51 1.min-1) were good enough for clinical use. CONCLUSIONS--After cardiac output had been measured simultaneously by both the Doppler and thermodilution techniques, subsequent transoesophageal Doppler alone gave a clinically useful measurement of cardiac output.     

Balloon dilation of postsurgical subaortic obstruction

Two children aged 10 and 5.5 years underwent balloon dilation for postsurgical subaortic obstruction. The outcome and the role of this procedure are discussed.     

Two-dimensional echocardiographic assessment of left atrial size in children

The ability of 2-dimensional echocardiography (2-D echo) to estimate end-systolic left atrial (LA) size and volume was assessed in 140 infants and children. These subjects were divided into 2 groups. Group A included 91 patients with normal LA volume and Group B included 49 patients with LA volume overload. Five echocardiographic views (left parasternal long-axis, left parasternal short-axis, apical 4-chamber, apical 2-chamber and subcostal 4-chamber) were used. From these views, the LA long-axis and minor-axis lengths were measured and the area was planimetered. These echocardiographically derived measurements were compared with angiographically calculated LA volume. Although all echocardiographic measurements correlated well with angiographic LA volume measurements, the echocardiographic area tracked better than length measurements. Echo LA volume was calculated using 5 single-plane and 3 biplane area-length methods. LA volume calculated from either single- or biplane methods correlated well with angiographically determined LA volume. The degree of correlation depended on the method used. Echocardiographic area and estimated LA volume measured from the parasternal long-axis and apical 2-chamber views best separated patients with LA volume overload from normal. Two-dimensional echo using these views accurately segregated all patients with a LA volume >180% of normal and 15 of 21 patients (71%) with an LA volume between 138% and 179% of normal. Thus, 2-D echo is useful in the evaluation of LA size and volume in Infants and children.