Uses and limitations of transthoracic echocardiography in the assessment of atrial septal defect in the adult

Assessment of atrial septal defects using 3-dimensional transthoracic echocardiography prior to percutaneous device closure: first report from Bangladesh

BACKGROUND

Secundum atrial septal defect (ASD) is treated following trans-catheter closure in alternative to surgical treatment. Per-intervention selection of device size with balloon occlusive diameter (BOD) often cause tearing or enlarging, causing arrhythmias and hypotension. We assessed the suitability of percutaneous device closure for ASD using 3-dimensional transthoracic echocardiography (3DTTE).

OBJECTIVES

This study was conducted to investigate if 3DTTE could be an alternative of balloon sizing for selection of device size in atrial septal defect device closure.

DESIGN

It was a cross-sectional comparative study.

METHODS

This study was conducted at the department of Pediatric Cardiology, Bangabandhu Sheikh Mujib Medical University for a period of 2 years. Thirty-three purposively selected secundum ASD patients suitable for device closure were included in the study. Ethical permission was taken from the Institutional Review Board and written consent was taken from each patient's guardian. In this study, 3DTTE derived ASD diameter and BOD were compared with that of deployed device size using correlation analysis.

RESULTS

Out of 33 patients, 63.6% were female and 36.4% were males had a mean age of 18.07 ± 14.58 years (range 2-55 years). Mean diameter of ASD measured by 2-dimensional (2D) and 3-dimensional (3D) echocardiography were 17.09 ± 6.08 mm and 21.30 ± 6.56 mm, respectively, yielding a significant difference (p < 0.001). 3D echocardiography derived ASDs diameter were highly correlated with device size than BOD and 2D echocardiography derived diameter (2D echocardiography: r = 0.796, p = <0.001, 3D echocardiography: r = 0.960, p = <0.001, BOD: r = 0.840, p = <0.001).

CONCLUSION

3DTTE can accurately measure ASD diameter and can be used as an alternate, effective, and safe method to select device size.

Characterization of atrial septal defect by simultaneous multiplane two-dimensional echocardiography

AIMS

The aim of this study was to assess the value of two-dimensional (2D) transthoracic simultaneous multiplane imaging (SMPI) in the evaluation of suitability for percutaneous atrial septal secundum defect (ASD) closure compared with the golden standard 2D transoesophageal echocardiography (TEE).

METHODS AND RESULTS

Twenty-nine patients with an ASD underwent both SMPI and TEE. Ten patients (34%) were male (age 41 ± 18 years, range 20-74). SMPI assessment of ASD size and rims included xPlane and I-rotate modes. Rims were defined as suitable for ASD percutaneous closure using a cut-off value of 5 mm. There were no significant differences between SMPI in xPlane mode and TEE regarding the sizes of the anterior-posterior dimension (13.7 ± 4.5 vs. 14.5 ± 5.2 mm) and superior-inferior dimension (13.5 ± 3.9 vs. 14.1 ± 5.0 mm, respectively). Agreement for the aortic, atrioventricular, inferior, right upper pulmonary vein, and superior rims was 100, 100, 100, 96, and 96%, respectively.

CONCLUSION

The SMPI technique can reliably assess the dimensions and rim size of a secundum ASD for pre-interventional selection when compared with TEE and has thus the potential to replace TEE.

Multiple intracranial abscesses: Heralding asymptomatic venosus ASD

A case of multiple intracranial abscesses in an immune-competent young girl is reported. She had chicken pox. Two weeks later, she presented with multiple intracranial abscesses. No significant cardiac abnormality was detected on transthoracic echocardiogram (TTE). The condition was treated medically. However, one of the abscesses adjacent to the CSF pathways enlarged on treatment and caused obstructive hydrocephalus that required stereotactic aspiration. Gram stain showed gram positive cocci in chain. Pus was sterile on culture. She was treated with broad spectrum IV antibiotics based on Gram staining report for 6 weeks followed by another 8 weeks of oral antibiotics. She made good recovery and had been leading a normal life. The abscess capsules took 30 months to resolve completely on MRI. A repeat TTE done in the follow up showed enlarged right heart chambers with a suggestion of a venosus ASD. A trans-esophageal echocardiogram (TEE) confirmed the presence of sinus venosus ASD from the SVC side with mainly left to right shunt. There was also partial anomalous drainage of the pulmonary veins. The patient underwent correction of the defect and has been doing well.

Usefulness of the right parasternal approach to evaluate the morphology of atrial septal defect for transcatheter closure using two-dimensional and three-dimensional transthoracic echocardiography

BACKGROUND

The aim of this study was to demonstrate the feasibility and usefulness of addition of the right parasternal approach to the conventional left parasternal and apical approaches using two-dimensional (2D) and three-dimensional (3D) transthoracic echocardiography (TTE) for morphologic evaluation in cases of transcatheter closure of atrial septal defects (ASDs).

METHODS

In 112 consecutive patients with ASDs, the morphology of the defects was evaluated for transcatheter closure in the right parasternal view in addition to the conventional left views using 2D and 3D TTE. Measurements of the maximal ASD diameter and detection of deficient rim obtained on 2D TTE were compared with those obtained by 2D transesophageal echocardiography. The shapes and locations of ASDs visualized by 3D TTE were compared with those visualized by 3D transesophageal echocardiography.

RESULTS

In 88 patients (80.0%), optimal images from the right parasternal approach for morphologic evaluation of ASDs were obtained. Although there was a significant difference in maximal ASD diameter obtained only in the conventional left approach compared with transesophageal echocardiographic measurements (P < .05), when the right parasternal approach was applied, a significant difference was not found (P = .18), and the diagnostic concordance of the rim deficiency was improved from 85.2% to 90.9%. Three-dimensional TTE from the right parasternal approach improved visualization of the shape and location of ASDs from 65.5% to 74.5%.

CONCLUSIONS

Additional use of the right parasternal approach enables detailed morphologic evaluation for transcatheter closure of ASDs. In patients with suboptimal images on 3D TTE in the left conventional approach, additional 3D TTE in the right parasternal approach can improve the feasibility of obtaining optimal 3D images to evaluate the shapes and locations of ASDs.

Multiple brain abscesses: an initial presentation in a child with an undiagnosed sinus venosus atrial septal defect

Cerebral abscess is a serious condition and in children the commonest cause is cyanotic congenital heart disease. We report a 12-year old male who presented with multiple brain abscesses. After an extensive evaluation including a transesphageal echocardiogram (TEE), we found a previously undiagnosed sinus venous atrial septal defect (ASD). He was treated medically with antibiotics. This is an unusual initial presentation of asymptomatic acynotic congenital heart disease in children. We recommended a complete cardiac evaluation including TEE with saline contrast study in the work up of an idiopathic cerebral abscess.

Immediate and late outcomes of patients undergoing transseptal left-sided heart catheterization for symptomatic valvular and arrhythmic diseases

BACKGROUND

The transseptal technique has been widely used for diagnostic and therapeutic left-sided heart catheterization. However, its differential immediate and late outcomes among patients with various valvular and arrhythmic diseases are not yet determined.

METHODS

Beginning from 1993, all patients undergoing transseptal procedures were screened and categorized into diagnosis, arrhythmia, and valvuloplasty groups according to the purposes of the catheterization. Incidences of transseptum-related acute major events (cardiac perforation, embolic stroke, and bradyarrhythmia during the procedure) and late complications (residual atrial septal defect [ASD], embolic stroke, bradyarrhythmia, and death up to 18 months) were analyzed and compared between groups.

RESULTS

From January 1993 to May 2003, a total of 176 patients underwent 184 transseptal procedures for diagnosis of valvular heart diseases (n = 8), catheter ablation of arrhythmogenic foci (n = 29), and mitral valvuloplasty (n = 147). The immediate outcome was similar among the 3 groups, with an overall acute complication incidence of 3.8%. At follow-up, the incidences of bradyarrhythmia, embolic stroke, and death were not different among the 3 groups. Patients undergoing valvuloplasty had a significantly higher prevalence of residual ASD, especially for those with more severe mitral stenosis and less valvuloplasty success. However, presence of ASD did not impose disadvantage over the 1.5-year prognosis.

CONCLUSION

Transseptal left-sided heart catheterization can be safely applied to patients with different categories of cardiac diseases with comparably good immediate and late outcomes. Although patients undergoing percutaneous valvuloplasty have a higher chance of permanent ASD creation, their prognosis is not influenced.

Role of Transthoracic Doppler Pulmonary Venous Flow Pattern in Large Atrial Septal Defects

OBJECTIVE

Large uncomplicated atrial septal defect (ASD) alters the pulmonary venous flow (PVF) pattern. We aimed to study the role of transthoracic echocardiography (TTE) in estimating the PVF Doppler abnormalities in ASD. By repeating the study soon after ASD closure, we correlated the hemodynamics of atrial shunting with PVF patterns.

METHODS

This study was performed in a tertiary care referral teaching hospital in 2003. The TTE PVF patterns of 34 patients with ASD were studied. TTE study was reported by two blinded investigators independently. Surgical closure of ASD was done on eleven patients and the early postoperative PVF Doppler pattern was also studied with TTE.

RESULTS

PVF patterns were adequately recorded in 34 of 38 (90%) subjects with ASD with equal male: female ratio (n = 17 each). The mean age of the study group was 21.4 +/- 8.7 years. ASD ranged from 10 to 38 mm in diameter with a mean of 18 +/- 4.2 mm. Continuous antegrade wave (CAW, mean 68.45 +/- 13.6 cm/s) replaced normally occurring S and D waves in all ASD patients. The atrial reversal wave was reduced or absent (mean 20.18 +/- 3.28 cm/sec). After ASD closure, the CAW was replaced by the S (46.18 +/- 7.5 cm/sec) and D waves (57.72 +/- 9.7 cm/sec) with increase in atrial reversal wave to 27.81 +/- 5.1 cm/sec.

CONCLUSIONS

The S and D antegrade waves normally seen in PVF are replaced by a continuous antegrade wave in ASD. Atrial reversal wave is also reduced. PVF waveform becomes normal after ASD closure. TTE PVF Doppler pattern can help estimate ASD hemodynamics.

Transthoracic three-dimensional echocardiography prior to closure of atrial septal defects in children

AIMS

Our aims were to use transthoracic three-dimensional echocardiography to assess the morphology of atrial septal defects in children prior to closure, and to compare the three-dimensional echocardiographic data with transcatheter and surgical findings.

METHODS AND RESULTS

We used transthoracic three-dimensional echocardiography in 62 consecutive patients, aged from 2 to 18 years, with atrial septal defects, measuring the maximal diameter and the extent of the rims. Subsequent to the study, we referred 42 patients for transcatheter closure, the rims being measured at greater than 4 mm. We found a good correlation between the maximal diameter of the defect as measured at transthoracic three-dimensional echocardiography and using a balloon (y = 3.45 - 0.73x; r = 0.78; p < 0.0001), the mean difference between the measurements being 2.4 +/- 2.8 mm. Successful closure with the Amplatzer septal occluder, having a mean size of 22 +/- 4 mm, was achieved in 95% of the patients. Of the original cohort, 20 patients were referred for surgical closure. In these patients, the inferior rim had been deemed insufficient in 5, the postero-superior rim in 6, and the postero-inferior rim in 9. Complete agreement was found when the deficiency of the rim as judged using transthoracic three-dimensional echocardiography was compared with intraoperative findings. The correlation between measurements of the deficiency of the rim achieved by transthoracic three-dimensional echocardiography and at surgery was excellent (y = 0.2 + 0.98x; r = 0.93; p < 0.0001), the mean difference between the measurements being no more than 0.6 +/- 0.4 mm.

CONCLUSIONS

Transthoracic three-dimensional echocardiography proved accurate in measuring the maximal diameter and rims of atrial septal defects within the oval fossa. This non-invasive method will be valuable in selecting children for transcatheter or surgical closure of such defects.

Transesophageal echocardiography (TEE) in congenital heart disease with focus on the adult

Remarkable innovations in medical and surgical approaches over the past several decades now allow for correction of major cardiac defects in children, even in early infancy. These advances have provided for survival of many pediatric patients with congenital heart disease into adulthood. Although transthoracic echocardiography remains the primary imaging technique for the characterization of simple and complex congenital cardiovascular malformations in the pediatric and adult age groups, high-resolution transesophageal imaging has markedly expanded the anatomic and hemodynamic assessment in these patients. The benefits of this imaging approach apply particularly to those with challenging or limited transthoracic examinations or poorly characterized congenital cardiovascular malformations. The utility of TEE in defining the anatomy of the usual spectrum of congenital cardiac malformations is well established. The transesophageal approach has been shown to provide additional diagnostic information over conventional transthoracic imaging for specific structural cardiac anomalies and in the perioperative setting, the opportunity for confirmation of preoperative diagnoses, and modification of the surgical plan if new or different pathology is identified. This imaging modality also may reliably provide for immediate detection of suboptimal surgical repairs and significant postoperative residua, potentially improving the efficacy of the surgical intervention. This accounts for the vital role of this technology in perioperative management and integration into the standard of care in many congenital heart centers. The usefulness of TEE also has been documented during diagnostic and therapeutic cardiac catheterizations of patients with structural cardiac anomalies, allowing for safer and more effective application of these technologies. The experience supports the use of TEE as a useful approach in the surveillance of the adult with operated and unoperated congenital heart disease.

Surgical validation and implications for transcatheter closure of quantitative echocardiographic evaluation of atrial septal defect

Accurate evaluation of secundum atrial septal defect (ASD) is important for the success of transcatheter closure. The purpose of this study was (1) to describe a quantitative evaluation by transthoracic (TTE) and transesophageal (TEE) echocardiography of the various morphologic features of ASD that might be important for patient selection for transcatheter closure, and (2) to assess the reliability of these 2 methods by surgical findings. Preoperative TTE and TEE were used to evaluate the ASD of 27 children undergoing surgical closure. Measurements included the diameters of ASD and the atrial septal lengths in the transverse and longitudinal axis, and the width of the superior, inferior, anteroinferior, and posterior septal margins. The shape and location of the ASD and the adequacy of the septal margins for anchoring occluding devices were determined. Echocardiographic data were compared with corresponding surgical measurements. No significant difference occurred in the means of all the parameters measured with the 3 methods, except for the transverse ASD diameter (p <0.05). Good agreement occurred between TTE and TEE and surgical data, except for the transverse ASD diameter, transverse atrial septal length, and the posterior septal margin on TTE. Intraclass correlations between TTE and TEE and surgical measurements of all parameters were good, except for the transverse ASD diameter. The accuracy in determining shape and location of the ASD by TTE and TEE were 100%, whereas that for determining the adequacy of septal margins was 98% and 97%, respectively. In conclusion, TTE and TEE are reliable methods for quantitative evaluation of ASD.

Secundum atrial septal defect is a dynamic three-dimensional entity

BACKGROUND

The aim of this study was to evaluate the diagnostic relevance of 3-dimensional (3D) echocardiography in the assessment of secundum atrial septum defect (ASD2).

METHODS AND RESULTS

Twenty-three patients (age 2 to 58 years) with an ASD2 were studied by transthoracic (n = 9) or transesophageal (n = 14) echocardiography for the acquisition of a 3D data set before undergoing surgical repair. Qualitative (location, shape, and structure) and quantitative (largest and smallest anteroposterior and superoinferior diameters) characteristics were analyzed and compared with surgical findings. Intraobserver and interobserver variability were assessed. The gross anatomy of the ASD2, shown by the 3D images, was confirmed by the surgeon in 21 of 23 patients, but the presence of membranous or fenestrated remnants of the valvula foramina ovalis in the defect was not optimally visualized in 7 patients. Three-dimensional echocardiography revealed changes in diameter and shape of the ASD2 during the cardiac cycle. The measured largest and smallest anteroposterior diameters and their intraobserver and interobserver agreement were 274 +/- 12 mm, r = 0. 95 (P <.001), r = 0.92 (P <.001), and 194 +/- 9 mm, r = 0.96 (P <. 001), r = 0.94 (P <.001), respectively. The measured largest and smallest superoinferior diameter and their intraobserver and interobserver agreement were 304 +/- 26 mm, r = 0.90 (P <.001), r = 0.97 (P <.001), and 204 +/- 10 mm, r = 0.83 (P <.001), r = 0.84 ( P <.001), respectively. The correlation coefficient between 2D and 3D echocardiography for the largest anteroposterior and superoinferior diameter was r = 0.69 (P <.001) and r = 0.68 (P =.05), respectively. The correlation coefficient between the measurements from 3D reconstructions and direct surgical measurements was r = 0.20 (P = not significant) and r = 0.57 (P <.05), whereas between 2D and surgery was r = 0.50 (P <.05) and r = 0.26 (P = not significant).

CONCLUSIONS

ASD2 has a complex morphology. Three-dimensional echocardiography provides better qualitative and quantitative information on its dynamic geometry, location, and extension as compared with standard 2D echocardiography and might be useful for device selection during catheter-based closure of ASD2.

Assessment of atrial septal defect morphology by transthoracic three dimensional echocardiography using standard grey scale and Doppler myocardial imaging techniques: comparison with magnetic resonance imaging and intraoperative findings

OBJECTIVE

To determine whether transthoracic three dimensional echocardiography is an accurate non-invasive technique for defining the morphology of atrial septal defects (ASD).

METHODS

In 34 patients with secundum ASD, mean (SD) age 20 (17) years (14 male, 20 female), the measurements obtained from three dimensional echocardiography were compared to those obtained from magnetic resonance imaging (MRI) or surgery. Three dimensional images were constructed to simulate the ASD view as seen by a surgeon. Measured variables were: maximum and minimum vertical and horizontal ASD dimension, and distances to inferior and superior vena cava, coronary sinus, and tricuspid valve. In each patient two ultrasound techniques were used to acquire three dimensional data: standard grey scale imaging (GSI) and Doppler myocardial imaging (DMI).

RESULTS

Good correlation was found in maximum ASD dimension (both horizontal and vertical) between three dimensional echocardiography and both MRI (GSI r = 0.96, SEE = 0.05 cm; DMI r = 0.97, SEE = 0.04 cm) and surgery (GSI r = 0.92, SEE = 0.06 cm; DMI r = 0.95, SEE = 0.06 cm). The systematic error was similar for both three dimensional techniques when compared to both MRI (GSI = 0.40 cm (27%); DMI = 0.38 cm (25%)) and surgery (GSI = 0.50 cm (29%); DMI = 0.37 cm (22%)). A significant difference was found in both horizontal and vertical ASD dimension changes during the cardiac cycle. This change was inversely correlated with age. These findings were consistent for both DMI and GSI technique. In children (age < or = 17 years), the feasibility of detecting structures and undertaking measurements was similar for both echo techniques. However, in adult ASD patients (age > or = 18 years) this feasibility was higher for DMI than for GSI.

CONCLUSIONS

Transthoracic three dimensional imaging using both GSI and DMI accurately displayed the varying morphology, dimensions, and spatial relations of ASD. However, DMI was a more effective technique than GSI in describing ASD morphology in adults.

Role of transesophageal echocardiography in the management of thromboembolic stroke

Cardiac causes of stroke account for approximately 20% of strokes occurring in the United States. Transthoracic echocardiography (TTE) remains the cornerstone of non-invasive cardiac imaging, but transesophageal echocardiography (TEE) is superior for identifying potential cardiac sources of emboli, including left atrial thrombi, valvular vegetations, thoracic aortic plaque, patent foramen ovale, and spontaneous left atrial echocardiographic contrast. The diagnostic yield of TEE for potential cardiac causes of thromboembolism exceeds 50%. The impact of TEE on the clinical management of this group, however, remains undefined for most TEE-specific diagnoses. Thus, routine use of TEE in these patients has been questioned. The diagnostic yield is highest if the clinical history/physical examination suggests a cardiac source. However, the clinical scenario often dictates patient management, and TEE data are used to "validate" the clinical impression. Data from large, prospective, randomized (aspirin/warfarin) studies, in which TEE data are obtained from patients with suspected cardiac thromboembolism, are needed. If specific TEE diagnoses can be identified in which defined therapies are beneficial, "source of embolism" will continue to be the most common indication for TEE referral. In this paradigm, TEE (without initial TTE) will probably become a more direct diagnostic pathway. However, if these studies demonstrate that all patients with suspected cardiac source benefit from one (or no) therapy, independent of TEE data, referrals for TEE will decline. Results of ongoing randomized trials to evaluate the efficacy of TEE in patients with cryptogenic stroke or transient ischemic attack are awaited.

A rare case of inferior venacaval type of atrial septal defect in an adult: echocardiographic features

We report a rare type of atrial septal defect with communication between the left atrium and the inferior vena cava. This type of defect has been referred to as a low sinus venous type of atrial septal defect because of its developmental origin, and possibly is caused by defective absorption of the left venous valve of the sinus venosus into the septum secundum. Detailed echocardiographic features are discussed.

Transesophageal echocardiography

This article presents an overview of the benefits and efficacy of transesophageal echocardiography (TEE) in the critically ill patient. The echocardiographic evaluation of ventricular function both regional and global, is discussed with special emphasis on ischemic heart disease; assessment of preload, interrogation of valvular heart disease (prosthetic and native) and its complications; endocarditis and its complications; intracardiac and extracardiac masses, including pulmonary embolism; aortic diseases (e.g., aneurysan, dissection, and traumatic tears); evaluation of patent foramen ovale and its association with central and peripheral embolic events; advancements in computer technology; and finally, the effect of TEE on critical care.

Diagnosis of sinus venosus atrial septal defect with transesophageal echocardiography

BACKGROUND

Sinus venosus atrial septal defect (SVD) is underdiagnosed with transthoracic echocardiography because of its posterior (far field) location. Transesophageal echocardiography (TEE) should be ideally suited to diagnose SVD, given the proximity of the transducer to the defect.

METHODS AND RESULTS

A retrospective study was undertaken that used the medical history, echocardiographic findings, and surgical data of patients identified from computer records as having the diagnosis of SVD during the period in which TEE has been in use (1987 to 1995). Twenty-five patients (14 females and 11 males; median age, 45 years; range, 10 to 75 years) with SVD had TEE between 1987 and 1995. Prior transthoracic echocardiography clearly defined the SVD in 3 of these patients, and it was suspected in another 11 on the basis of color-flow imaging. Ten patients had unexplained dilatation of the right side of the heart, which prompted TEE examination. SVD was visualized with TEE in all 25 patients and ranged in size from 1 to 3 cm. Thirty-seven right-sided anomalous pulmonary venous connections were identified in 23 patients. No left-sided anomalous pulmonary venous connections were detected. Anatomic confirmation was obtained in all 23 surgical patients. No patient required preoperative cardiac catheterization for diagnosis.

CONCLUSIONS

TEE is accurate for the diagnosis of SVD and should be undertaken in any patient with unexplained dilatation of the right side of the heart. The associated pulmonary venous abnormalities can be identified with TEE. Cardiac catheterization for diagnostic purposes should not be required before surgical correction.

Intracardiac shunts

Unsuspected intracardiac shunts can be a cause of acute deterioration in critically ill patients. Shunts can be acquired or congenital conditions that become symptomatic only with changed physiologic conditions. Transesophageal echocardiography is an excellent tool for the diagnosis of intracardiac shunts.

Imaging and sizing of atrial septal defects by magnetic resonance

BACKGROUND

Development of techniques for percutaneous closure of atrial septal defects (ASDs) makes accurate noninvasive sizing of ASDs important for appropriate patient selection.

METHODS AND RESULTS

Magnetic resonance (MR) images of ASDs were obtained in 30 patients (mean age, 41 +/- 16 years) by both spin-echo and phase-contrast cine MR imaging. Spin-echo images were obtained in two orthogonal views (short-axis and four-chamber) perpendicular to the plane of the ASD. Spin-echo major and minor diameters were measured, and spin-echo defect area was calculated. Phase-contrast cine MR images were obtained in the plane of the ASD, and cine major diameter and defect area were measured from the region of signal enhancement or phase change due to shunt flow across the defect. MR measurements were compared with templates cut during surgery to match the defect or with ASD diameter determined by balloon sizing at catheterization. ASD size measured from cine MR images (y) agreed closely with catheterization and template standards (x). For major diameter, y = 0.78x + 5.7, r = .93, and SEE = 3.4 mm. On average, spin-echo measurements overestimated major diameter and area of secundum ASDs by 48% and 125%, respectively.

CONCLUSIONS

Phase-contrast cine MR images acquired in the plane of an ASD define the defect shape by the cross section of the shunt flow stream and allow noninvasive determination of defect size with sufficient accuracy to permit stratification of patients to closure of the defect by catheter-based techniques versus surgery. Spin-echo images, on the other hand, are not adequate for defining ASD size, because septal thinning adjacent to a secundum ASD may appear to be part of the defect.

Cost-effectiveness of echocardiography for evaluation of children with murmurs

Echocardiography is widely accepted as an accurate diagnostic test to evaluate heart murmurs in children, however its costs, and the ubiquity of murmurs in children, discourage its universal application. The purpose of this article is to identify some clinical circumstances in which the cost of echocardiography is justified for the evaluation of heart murmurs in infants and children. Eight common clinical problems were selected in which a heart murmur is present and a diagnosis is called for. Effectiveness of echocardiography and less costly clinical diagnostic methods in these settings were compared. In some circumstances, echocardiography is worth the cost, because clinical evaluation is unacceptably insensitive to important disease (the premature infant with a murmur which might represent a patent ductus arteriosus, the infant with a dysmorphic syndrome and a murmur). In others, the expert clinical examination is highly accurate (the asymptomatic child with a heart murmur) and is preferred over the echocardiogram as the initial diagnostic approach on the grounds of cost. When the expert clinical examination suggests minor structural heart disease, a continuum of echocardiographic cost-effectiveness relative to the expert clinical examination exists between these extremes depending on the working diagnosis. A threshold has not yet been defined at any point on this continuum above which the public will demand the greater diagnostic detail available echocardiographically, and below which the public will refuse to accept its greater cost. Quantitative formal cost-effectiveness analysis of echocardiography for evaluation of heart murmur in infants and children is not yet feasible because the benefits of echocardiography are indirect, dependent upon the as yet unmeasured benefits of correct management of congenital heart defects. To go beyond simple comparison of efficacy of echocardiography with less costly methods, further work is required in outcomes research in congenital heart disease.

Three-dimensional reconstruction of ventricular septal defects: validation studies and in vivo feasibility

OBJECTIVES

The purpose of this study was to demonstrate the feasibility of in vivo three-dimensional reconstruction of ventricular septal defects and to validate its quantitative accuracy for defect localization in excised hearts (used to permit comparison of three-dimensional and direct measurements without cardiac contraction).

BACKGROUND

Appreciating the three-dimensional spatial relations of ventricular septal defects could be useful in planning surgical and catheter approaches. Currently, however, echocardiography provides only two-dimensional views, requiring mental integration. A recently developed system automatically combines two-dimensional echocardiographic images with their spatial locations to produce a three-dimensional construct.

METHODS

Surgically created ventricular septal defects of varying size and location were imaged and reconstructed, along with the left and right ventricles, in the beating heart of six dogs to demonstrate the in vivo feasibility of producing a coherent image of the defect that portrays its relation to surrounding structures. Two additional gel-filled excised hearts with defects were completely reconstructed. Quantitative localization of the defects relative to other structures (ventricular apexes and valve insertions) was then validated for seven defects in excised hearts. The right septal margins of the exposed defects were also traced and compared with their reconstructed areas and circumferences.

RESULTS

The three-dimensional images provided coherent images and correct spatial appreciation of the defects (two inlet, two trabecular, one outlet and one membranous Gerbode in vivo; one inlet and one apical in excised hearts). The distances between defects and other structures in the excised hearts agreed well with direct measures (y = 1.05x-0.18, r = 0.98, SEE = 0.30 cm), as did reconstructed areas (y = 1.0x-0.23, r = 0.98, SEE = 0.21 cm2) and circumferences (y = 0.97x + 0.13, r = 0.97, SEE = 0.3 cm).

CONCLUSIONS

Three-dimensional reconstruction of ventricular septal defects can be achieved in the beating heart and provides an accurate appreciation of defect size and location that could be of value in planning interventions.

Detection of left-to-right shunt in atrial septal defect by negative contrast echocardiography: a comparison of transthoracic and transesophageal approach

The occurrence of a right atrial negative contrast effect as an indicator of left-to-right shunt was studied in 101 patients with atrial septal defect by peripheral venous contrast injection during transthoracic and transesophageal echocardiography. Confirmation of the diagnosis was provided by cardiac catheterization or by autopsy in 72 (72%) patients. The defect could be visualized directly in 57 (57%) patients during the transthoracic and in 93 (93%) during the transesophageal examination (p < 0.001). A negative right atrial echo contrast effect was observed in 53 of 92 (58%) patients from the transthoracic and in 86 of 92 (93%) patients from the transesophageal approach (p < 0.001). Among these were seven (7%) patients with an aneurysmal interatrial septum but no directly visible defect during conventional transesophageal imaging. Appearance of contrast in the left atrium indicating right-to-left shunting was seen in 70 of 92 (76%) patients from the transthoracic and in 91 of 92 (99%) patients from the transesophageal approach (p < 0.001). Contrast injection during transesophageal imaging also helped identify additional malformations in 12 (12%) patients. Thus transesophageal echocardiography with echo contrast injection is a very reliable diagnostic method in patients with suspected atrial septal defect.

Echocardiographic assessment of atrial septal defects

Echocardiography has become the method of choice for the assessment of patients with a known or suspected atrial septal defect. The majority of patients with defects can be identified by this method. In patients with inconclusive transthoracic studies, transesophageal echocardiography is useful for identification or exclusion of a defect. Echocardiography is useful for quantification of left-to-right shunting, identification of associated anomalies, and estimation of pulmonary pressure. Cardiac catheterization can be reserved for patients who require measurement of pulmonary vascular resistance, those who have a significant risk of coronary artery disease, and those with complex congenital heart disease.

Echocardiography in the evaluation of cardiac sources of emboli: the role of transthoracic echocardiography

Cardioembolism is responsible for a significant number of systemic emboli including approximately 15% of all ischemic strokes. Transthoracic echocardiography has contributed to the understanding of cardioembolism and has been used to detect specific and potential cardiac sources of systemic emboli and risk stratify patients with specific clinical findings for subsequent cardiovascular events. Findings from transthoracic echocardiography indicate that stasis is an important prerequisite for intracardiac thrombosis while reversal of stasis and thrombolysis appear operative in embolism of existing thrombus. Transthoracic echocardiography allows a sensitive and specific noninvasive means to detect left ventricular thrombus, valvular vegetation, and intracardiac tumor, lesions that are directly responsible for cardioembolism. Transthoracic echocardiography can also detect lesions that could potentially contribute to cardioembolism but are not specific causes. Examples of these potential lesions include mitral valve prolapse, patent foramen ovale, and interatrial septal aneurysm. Finally, population-based studies and prospective clinical trials have indicated that the results of transthoracic echocardiography have predictive value for subsequent cardiovascular events and hence provide a means for stratification of patients at risk for cardioembolism. The latter is most notable for the group of patients with nonvalvular atrial fibrillation where left ventricular dysfunction and increased left atrial size are independent predictors for subsequent stroke.

Value of transesophageal color Doppler echocardiography for detection of different types of atrial septal defect in adults

In 121 adults, the value of transthoracic and transesophageal color Doppler echocardiography for detection of different types of atrial septal defect (ASD) or of partial anomalous pulmonary venous return was analyzed. The 121 patients had a total of 129 defects with left-to-right atrial shunting (including eight patients with two types of defects). All of six cases with primum-type ASD were diagnosed correctly by both echocardiographic methods. Ninety-seven patients showed a secundum-type ASD during transesophageal echocardiography: by transthoracic echocardiography, only eight (20%) of the 40 small defects (diameter < 5 mm) were detected as compared with 15 (83%) of the 18 defects with a diameter of 5 to 10 mm and all 39 defects with a diameter > 10 mm. A sinus venosus--type ASD was evident by transesophageal echocardiography in 11 patients, of which only one (9%) was demonstrated by the transthoracic approach. Partial anomalous pulmonary venous return was seen by transesophageal echocardiography in 13 patients but missed in two other patients in whom anomalous pulmonary venous return was subsequently identified by surgery (both with anomalous return of the upper right pulmonary vein into the superior vena cava). By use of the transthoracic technique, partial anomalous venous return was detected in only two cases, both of which had "scimitar syndrome." Compared with transthoracic echocardiography, the transesophageal approach is clearly superior in the detection of small secundum-type ASD, sinus venosus--type ASD, and partial anomalous pulmonary venous return.

Value and limitations of color Doppler echocardiography in the evaluation of percutaneous balloon mitral valvuloplasty for isolated mitral stenosis

The limitations of 2-dimensional and pulsed Doppler echocardiography in patients undergoing mitral valvuloplasty are well known. This study was undertaken to assess the value of color Doppler flow imaging in 36 symptomatic mitral stenosis patients who subsequently underwent successful balloon mitral valvuloplasty by comparing the results to those obtained at cardiac catheterization. Color Doppler-guided conventional Doppler assessment agreed well with cardiac catheterization results in classifying mitral stenosis as mild, moderately severe and severe, both before and after valvuloplasty. Color Doppler was also useful in identifying patients who had moderate to severe mitral regurgitation before and after valvuloplasty. Color Doppler flow mapping was more sensitive than oximetry in the detection of iatrogenic atrial septal defects, which were noted in 25 patients. The defects of those patients with smaller defects by color Doppler (diameter less than 0.7 cm) or echocardiographic shunt volume less than 0.7 liters/min tended to close, usually within 6 months, as opposed to those with larger defects or higher shunt volumes, which tended to persist. Echocardiographic shunt volumes revealed a fair correlation with oximetric results.