Diagnosis and quantitative evaluation of secundum-type atrial septal defect by transesophageal Doppler echocardiography

Accuracy of Transthoracic Echocardiography in Assessing Retro-aortic Rim prior to Device Closure of Atrial Septal Defects

OBJECTIVE

Deficient retro-aortic rim has been identified as a risk factor for device erosion following trans-catheter closure of atrial septal defects (ASDs). Transthoracic echocardiography (TTE) is the primary screening method for subjects for possible device closure of ASD, but its reliability in measuring retro-aortic rim size has not been assessed previously.

DESIGN

A single-institution cross-sectional analysis of children and adults referred for trans-catheter device closure of single ostium secundum ASD from January 1, 2005 to April 1, 2012 with reviewable TTE and trans-esophageal echocardiogram images was performed. Inter-rater reliability of measurements was tested in a 24% sample. Accuracy of TTE measurement of retro-aortic rim was assessed using a Bland-Altman plot with trans-esophageal echocardiogram measurement as the gold standard. Test characteristics of TTE detection of deficient retro-aortic rim were calculated. Risk factors for misclassification of deficient retro-aortic rim were assessed using receiver operator characteristic curves. Risk factors for measurement error were assessed through multivariate linear regression.

RESULTS

In total, 163 subjects of median age 5 years (range: 0.3-46 years) were included. Trans-thoracic echocardiography had 90% sensitivity, 84% specificity, 90% positive predictive value, and 83% negative predictive value to detect deficient retro-aortic rim. Bland-Altman plot demonstrated no fixed bias (P = .23), but errors in measurement increased on average as the aortic rim increased in size (P < .001). Prespecified patient level risk factors did not affect receiver operator characteristic curve area under the curve, nor were any patient-level risk factors independently associated with increased measurement error on TTE.

CONCLUSIONS

TTE is a sensitive and specific screening test for deficient retro-aortic rim across a range of patient ages and sizes.

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.

Blood Flow Imaging?A New Angle-Independent Ultrasound Modality for the Visualization of Flow in Atrial Septal Defects in Children

BACKGROUND

Color Doppler imaging (CDI) is the most applied method for evaluation of flow in atrial septal defects (ASD). A new real time ultrasound flow imaging modality called blood flow imaging (BFI) is able to visualize the blood flow in any direction of the image and is not limited by velocity aliasing. The method thereby overcomes the two limitations most often encountered in CDI. In this study we compared BFI with CDI for the visualization of interatrial blood flow in children.

METHODS

We studied ASD flow in 13 children using both CDI and BFI in the same examination. CDI and BFI cineloops were prepared off-line and both optimal and suboptimal (increased color artifacts) images were presented in random order to four observers. They were asked to range from 0-100 on a visual analogue scale how certain they were of interatrial blood flow. The CDI and BFI ratings were compared using the exact Wilcoxon signed rank test for paired samples.

RESULTS

All ASDs visualized with CDI were confirmed using BFI. Two of the observers ranked BFI as being significantly better than CDI when the images were optimized. When the images were suboptimal three of the observers rated BFI as being significantly better.

CONCLUSIONS

This pilot study indicates that BFI improves the visualization of interatrial blood flow in children. To include BFI in the ordinary echocardiography examination is easy and not time consuming. The method may prove to be a useful supplement to CDI in ASD imaging.

Use of non-invasive phase contrast magnetic resonance imaging for estimation of atrial septal defect size and morphology: a comparison with transesophageal echo

BACKGROUND

Transesophageal echocardiography (TEE) is a trusted method of sizing atrial septal defect (ASD) prior to percutaneous closure but is invasive, uncomfortable, and may carry a small risk of morbidity and mortality. Magnetic resonance imaging (MRI) may be useful non-invasive alternative in such patients who refuse or are unable to tolerate TEE and may provide additional information on the shape of the A0SD.

PURPOSE

To validate the accuracy of ASD sizing by MRI compared with TEE.

METHOD

Twelve patients (mean age 30 years; range 11-60 years) scheduled for ASD closure underwent TEE, cine balanced fast field echo MRI (bFFE-MRI) in four-chamber and sagittal views and phase-contrast MRI (PC-MRI) with reconstruction using the two orthogonal planes of T2-weighted images as planning. The average of the three longest measurements for all imaging modalities was calculated for each patient.

RESULTS

Mean maximum ASD length on TEE was 18.8 +/- 4.6 mm, mean length by bFFE-MRI was 20.0 +/- 5.0 mm, and mean length by PC-MRI was 18.3 +/- 3.6 mm. The TEE measurement was significantly correlated with the bFFE-MRI and PC-MRI measurements (Pearson r = 0.69, p = 0.02 and r = 0.59, p = 0.04, respectively). The mean difference between TEE and bFFE-MRI measurements was -1.2mm (95% CI: -3.7, 1.3) and between TEE and PC-MRI was 0.5 mm (95% CI: -1.9, 2.9). Bland-Altman analysis also determined general agreement between both MRI methods and TEE. The ASDs were egg-shaped in two cases, circular in 1 patient and oval in the remaining patients.

CONCLUSION

ASD sizing by MRI using bFFE and phase-contrast protocols correlated well with TEE estimations. PC-MRI provided additional information on ASD shapes and proximity to adjacent structures.

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.

Balloon sizing and transcatheter closure of acute atrial septal defects guided by magnetic resonance fluoroscopy: Assessment and validation in a large animal model

PURPOSE

To quantitatively assess atrial septal defects (ASDs) with small shunts using MRI followed by transcatheter closure monitored by MR fluoroscopy.

MATERIALS AND METHODS

Acute ASDs were created in 14 pigs under x-ray fluoroscopy. Six animals were studied in order to select MR-compatible delivery systems and imaging strategies. ASDs in eight animals were examined with balloon sizing under MR fluoroscopy, flow measurements, and contrast media injections, after which transcatheter closure was performed under MR fluoroscopy. The delivery system was assembled from commercially available materials.

RESULTS

The ratio of pulmonary to systemic flow (Qp/Qs) was reduced from 1.23 +/- 0.15 before ASD closure to 1.07 +/- 0.11 after ASD closure (P < 0.001). In two out of eight animals Qp/Qs was close to 1.0 before closure despite the presence of defects >15 mm. The ASDs were measurable with MR balloon sizing in all of the animals. Balloon sizing was identical with MR (16.9 +/- 2.3 mm) and x-ray fluoroscopy (17.1 +/- 1.3 mm). The in-house-assembled delivery system allowed successful placement of closure devices under MR guidance.

CONCLUSION

Assessment and closure of small shunts with MR fluoroscopy is feasible. A barrier to the rapid implementation of transcatheter closure in patients is uncertainty about the MR safety of guidewires and device delivery systems.

Transesophageal echocardiographic guidance of blade atrial septostomy in children

Transesophageal echocardiography (TEE) was used to guide blade atrial septostomy in children requiring decompression of right or left atrium. In conjunction with biplane fluoroscopy, TEE was used to position the blade septostomy catheter and to monitor the pullback from left atrium to right atrium. Subsequent balloon dilatation of atrial septum was also carried out under TEE control. The use of TEE monitoring facilitated the procedure by providing optimal views of intracardiac structures while also limiting the total radiation exposure.

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.

The role of echocardiography in transcatheter closure of atrial septal defects

Closure of so-called "secundum" atrial septal defects with a device inserted on a catheter necessitates precise delineation of their morphology. Echocardiography is the diagnostic method of choice to demonstrate this morphology, and to differentiate such defects located within the oval fossa from the other variants producing an interatrial communication. Precordial echocardiography usually allows selection of cases likely to be suitable for closure in this fashion. This selection is based on the localisation and the size of the deficiency in the oval fossa, the length of the interatrial septum, and the adequacy of the infolded rims surrounding the defect. Suitability for closure is reevaluated by transesophageal echocardiography, either as a separate investigation or at the start of the interventional catheterisation. This investigation requires a multiplane transesophageal echocardiographic probe, since only oblique planes will demonstrate the entrance of the systemic and pulmonary veins and their relationship to the defect. Transesophageal echocardiography serves as an important monitoring tool during the interventional procedure. As such, it is a necessary adjunct to fluoroscopy. The stretched diameter of the defect measured with a balloon is the main determinant of the choice of the type and size of the device. This diameter can be measured fluoroscopically, as well as on echo. Colorflow mapping serves to rule out residual shunting during the occlusion of the defect with the balloon. During deployment of the device, constant echocardiographic visualisation of the device and its position relative to the atrial septum facilitates proper placement. Such constant visualisation can only be provided by repeated quick acquisitions of multiple planes. Once the device is released, the investigator should continue to record the position of the device, and assess the potential for residual shunting. Most of the devices show some subtle change in position during the first 20 minutes after implantation.

Transesophageal echocardiographic predictors for successful transcatheter closure of defects within the oval fossa using the CardioSEAL septal occlusion device

OBJECTIVES

To define the utility of transesophageal echocardiography in predicting the likelihood of a successful procedure and residual shunting in patients undergoing transcatheter closure of defects within the oval fossa using the CardioSEAL device.

BACKGROUND

Transesophageal echocardiography is used to monitor transcatheter closure of interatrial defects within the the oval fossa, but predictors of successful closure and residual shunting have yet to be determined.

METHODS

We reviewed transesophageal echocardiograms obtained from 26 consecutive patients undergoing attempted transcatheter closure of interatrial defects within the oval fossa between January, 1997 and May, 1998. Assessment of the atrial septum, the septal defect, and the rims of the oval fossa bordering the defect was performed in 3 planes: longitudinal, 4-chamber, and basal short-axis.

RESULTS

Closure proved successful in 24 patients (92%). The defect was significantly larger, and the anterosuperior rim of the defect smaller, in the 2 patients in whom occlusion was not successful. Residual shunting 24 hrs after closure was detected in 14 patients. Significant predictors of leakage included smaller posterior and superior rims, a larger shunt prior to closure, and herniation of a one left atrial arm of the device into the right atrium. In all cases, the sites of leakage were the superior rim of the defect at the superior cavo-atrial junction, and the anterosuperior rim behind the aortic root. Herniation of a left atrial arm into the right atrium was seen in 7 patients (29%). In all, it was the anterosuperior arm which herniated Doppler color flow was suboptimal in detecting residual leaks, and was enhanced substantially with the use of contrast echocardiography.

CONCLUSIONS

Transesophageal echocardiography allows excellent assessment of the oval fossa and deficiencies of its floor in all of their dimensions. It is an important tool for guiding the deployment of the occlusion device in patients undergoing attempted transcatheter closure of defects within the fossa. Contrast echocardiography should be used for optimal detection of residual shunting.

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.

A new technique for sizing of atrial septal defects

This article evaluates a new compliant balloon catheter for sizing of Atrial Septal Defects (ASDs) in vitro and in vivo using X-ray and echo measurements. A phantom consisting of a plastic plate with 17 circular holes varying from 8 to 30 mm was used to determine the accuracy of the measurements. The catheter has a 7 Fr shaft with a double lumen. The balloon is made from a 0.002" plastic membrane. Four platinum marker bands on the shaft of the catheter allow radiographic measurements. The balloon catheter was placed through various holes of the phantom and inflated with 38% contrast medium. X-ray measurement by video and cine recording were performed and compared with the true measurement of the model. The study was carried out in a double blind fashion. For echo measurements, the plastic model was immersed in a water bath. The balloon was inflated with water and measured in a long-axis view. The actual diameters were compared with the measurements obtained by video, cine, and echo recordings. One young pig with a surgically created ASD was used for in vivo measurement. The balloon catheter was passed through the ASD over an exchange wire, inflated with diluted contrast medium until a waist was observed, which was measured by video and cine techniques. The animal was euthanized, and the defect was measured by a tapered measuring probe. The difference between the actual size and measurements obtained by video recordings was 0.54 +/- 0.30 mm, by cine 0.62 +/- 0.20 mm, and by echo measurements 0.60 +/- 0.43 mm. All measurements were less than 1 mm in error except for four measurements (<1.5 mm). A strong correlation was present between each two groups (r = 0.99, P < 0.0001). In the in vivo study, the size of the video and cine recordings (14.2 and 13.9 mm, respectively) were very closer to the actual size (14 mm) as measured by a probe in the postmortem specimen. The new balloon catheter provides a more rapid and precise determination of the stretched diameter of atrial septal defects. It eliminates the error of pulling a catheter through the communication. This new technique should be of benefit to all investigators using septal occlusion devices and will facilitate the selection of the properly sized Amplatzer septal occluder.

Visualization of Secundum Atrial Septal Defect Using Transthoracic Three-Dimensional Echocardiography in Children: Implications for Transcatheter Closure

BACKGROUND: The objective of this study was to evaluate the efficacy of quantitative measurements of secundum atrial septal defect (ASD) with dynamic transthoracic three-dimensional (3-D) echocardiography. METHODS: Twenty-six patients (age, 13 months to 14 years; mean age, 37 months) with secundum ASDs underwent 3-D echocardiographic imaging generated from transthoracic echocardiographic interrogation before surgery. Four specific cut planes were defined: four-chamber view, transverse view, en face view from right and left atrial side. The images obtained from 16 patients clearly demonstrated all four defined cut planes for the quantitative measurement. RESULTS: The defect sizing determined by the 3-D images correlated well with surgical findings. These images may be interactively manipulated to optimize visualization of the defect to allow the cardiologist to perform transcatheter occlusion. A significant correlation was demonstrated to the limbic band tissue assessment by four-chamber and transverse views. Unusual atrial structures such as muscle bands and the fore-shortening of the en face view might induce biased measurements. CONCLUSIONS: The transthoracic approach was successful in capturing sufficient data to create 3-D images, which can provide an accurate assessment of secundum ASD. The possibility of underestimation should always be taken into account with the en face view. Multiple cut planes were essential to ensure correct sizing for adequate selection of the occluder.

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.

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.

Quantification of pulmonary and systemic blood flow by magnetic resonance velocity mapping in the assessment of atrial-level shunts

The objective of this study was to asses the feasibility and accuracy of magnetic resonance (MR) velocity mapping to calculate pulmonary-to-systemic flow ratio (Qp:Qs) in patients with a suspected or diagnosed atrial-level shunt. During a one-year period, all patients referred to our department for further evaluation of an atrial-level shunt underwent the same imaging protocol. Multiphase-multisection gradient-echo MR image sets of the heart were acquired to measure left and right ventricular stroke volumes for validation. Ascending aorta and main pulmonary artery volume flow were measured with MR velocity mapping. Qp:Qs ratios were calculated from both stroke volume data and flow data. Twelve patients, including 6 children, were studied. Six patients had an established diagnosis of atrial septal defect, and the other 6 patients were suspected to have an atrial-level shunt. Measurements of left and right ventricular stroke corresponded closely with those of aortic (r = 0.98) and pulmonary flow (r = 0.99) respectively, and Qp:Qs flow ratios agreed with stroke volume ratios (r = 0.92). In 5 patients with a suspected shunt, the diagnosis could be rejected. Shunts were demonstrated in the other 7 patients. M(r) velocity mapping offers an accurate method to measure aortic and pulmonary artery volume flow that can be useful in the evaluation of atrial-level shunts, in order to establish a definite diagnosis and/or to quantify the Qp:Qs ratio.

"Crochetage" (notch) on R wave in inferior limb leads: a new independent electrocardiographic sign of atrial septal defect

OBJECTIVES

This study sought to determine the clinical significance of a "crochetage" pattern--a notch near the apex of the R wave in electrocardiographic (ECG) inferior limb leads--in secundum atrial septal defect.

BACKGROUND

Atrial septal defect is often overdiagnosed on the basis of classical clinical features. Thus, more specific signs on the ECG for screening are needed. Methods. We searched for a crochetage pattern in 1,560 older children and adults: 532 with secundum atrial septal defect, 266 with ventricular septal defect, 146 with pulmonary stenosis, 110 with mitral stenosis, 47 with cor pulmonale and 459 normal subjects.

RESULTS

This pattern was observed respectively in 73.1%, 35.7%, 23.3%, 6.4%, 10.6% and 7.4% of these groups (p<0.001). In atrial septal defect, its incidence increased with larger anatomic defect (p<0.0001) or greater left-to-right shunt (p<0.0001), even in the presence of pulmonary hypertension. By multiple regression analysis, only shunt size (p<0.0006) and defect location (p<0.0001) were the determinants of its presence. In all groups, the specificity of this sign for the diagnosis was remarkably high when present in all three inferior limb leads (> or = to 92%), even when comparison was limited to patients with an incomplete right bundle branch block (> or = 95.2%). Early disappearance of this pattern was observed in 35.1% of the operated-on patients although the right bundle branch block pattern persisted.

CONCLUSIONS

A crochetage pattern of the R wave in inferior limb leads is frequent in patients with atrial septal defect, correlates with shunt severity and is independent of the right bundle branch block pattern. Sensitivity and specificity of this sign are remarkably high when it is associated with an incomplete right bundle branch block or present in all inferior limb leads.

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.

The use of echocardiography in pediatric interventional cardiac catheterization procedures

The last decade saw a dramatic change in the management of congenital heart defects. The introduction and development in echocardiography and Doppler modalities enable definitive diagnosis of congenital lesions without cardiac catheterization. At the same time, new therapeutic procedures for congenital defects using the catheter as a channel for different procedures were developed. These therapeutic procedures have replaced cardiac surgery in many types of defects. The new developments in echocardiography and Doppler modalities provide accurate imaging and visualization of the transcatheter devices and brought these two imaging modalities into a close marriage. The use of echocardiography and Doppler in the catheterization laboratory became a must, especially when used in atrial (ASD) and ventricular septal defect (VSD) closure. In this article we will detail the role of echocardiography in the different transcatheter interventional procedures in the catheterization laboratory. Those include atrial septostomy, blade atrial septectomy, balloon dilation, ASD closure, VSD closure, patent ductus anterior closure, and pericardiocentesis.

Transoesophageal echocardiography in congenital heart disease

The development of paediatric transoesophageal ultrasound imaging represents an important advance in the diagnosis and management of the patient with congenital heart disease. Although primary diagnostic transoesophageal studies are seldom indicated in infants and unoperated children, they have an important role in the older child, especially where there has been prior cardiac surgery. Diagnostic studies are most appropriate for abnormalities of venous return, the atria, atrioventricular valves and the left ventricular outflow tract. Two other important areas in which transoesophageal imaging is playing an increasing role in the management of the paediatric patient is in monitoring of surgical repair.

Assessment of right-to-left shunt flow in atrial septal defect by transesophageal color and pulsed Doppler echocardiography

To investigate the clinical significance and problems of right-to-left (R-L) shunt flow dynamics in atrial septal defects, we performed transesophageal color and pulsed Doppler echocardiography in 30 patients with atrial septal defects of the ostium secundum type. The 30 patients consisted of 20 with a pulmonary artery systolic pressure of less than 40 mm Hg, four with a pressure of 40 to 60 mm Hg, three with a pressure of 90 mm Hg or more, two patients with pulmonic stenosis, and one patient with Ebstein's anomaly. R-L shunting was determined by the presence of a shunt flow signal across the defect during each cardiac cycle. The time of R-L shunt flow was compared with the various parameters obtained by echocardiography and cardiac catheterization. R-L shunt flow signals were detected at the following times: (1) at the onset of ventricular contraction or the closing phase of the tricuspid valve in five patients with isolated atrial septal defect. These patients showed an increase of mean right atrial pressure but had no severe pulmonary hypertension; (2) during ventricular systole in five of 26 patients with tricuspid regurgitation and one patient with Ebstein's anomaly. The tricuspid regurgitant signal was directed toward the ostium of the defect in three patients and was massive in the other patients; (3) during middiastole in three patients without pulmonary hypertension. These patients showed massive left-to-right shunt flow from end systole to early diastole; and (4) during atrial systole in three patients with severe pulmonary hypertension and two patients with pulmonic stenosis. The former, in particular, showed the aliasing signal as a high-speed shunt flow. In two of the three patients with severe pulmonary hypertension, R-L shunting continued from atrial systole to early ventricular systole and was also observed in early diastole. R-L shunt flow was detected in patients with atrial septal defects not only with pulmonary hypertension but also without pulmonary hypertension and was influenced by the right atrial pressure in the phase of tricuspid valve closing, the volume or direction of tricuspid regurgitation, rebound flow caused by massive left-to-right shunt flow, the grade of right ventricular distensibility or the complication of pulmonary hypertension, and complications with other cardiac anomalies. Thus R-L shunt flow in patients with atrial septal defects was detected easily by transesophageal color and pulsed Doppler echocardiography because of the high efficiency of this method for its detection.

Routine use of transesophageal echocardiography and color flow imaging in the evaluation and treatment of children with congenital heart disease

We reviewed our experience with transesophageal echocardiography (TEE) and color flow imaging in 157 consecutive patients with known or suspected heart disease to ascertain the impact of this technology on patient care. TEE was performed for diagnostic purposes (22/157), during interventional cardiac catheterizations (13/157), and during operative procedures (122/157). Diagnostic studies were performed after transthoracic echocardiography (TTE) in 21 of 22 patients. TEE was performed because TTE was inconclusive (15/21) or failed to provide sufficient detail of an abnormality (6/21). TEE detected an abnormality in 6 of 15 inconclusive TTEs. TEE was helpful during interventional cardiac catheterizations, particularly during umbrella closure of septal defects and in patients with complex venous and atrial anatomy undergoing transseptal puncture. TEE studies performed before cardiac operations significantly changed the diagnosis in only 5 of 122 (4%) patients, but the information changed the surgical approach in 4 of 5 of these patients. Postoperative TEE assessment more frequently changed care and resulted in further surgical management in 9 of 122 (7%) or a change in medical management in 6 of 122 (5%) patients. TEE was discontinued because of complications before studies were completed in only 4 of 157 (3%) patients. TEE and color flow imaging is a useful adjunct to care of children with known or suspected congenital heart disease.

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 follow-up of atrial septal defect after catheter closure by double-umbrella device

BACKGROUND

Transcatheter device occlusion of atrial septal defects is an attractive approach, but its efficacy and place in patient management remain to be determined.

METHODS AND RESULTS

To evaluate the medium-term results of atrial septal defect device occlusion and factors influencing residual shunting, transesophageal and transthoracic echocardiograms of 49 patients were reviewed. Transesophageal echocardiograms on 48 patients immediately following surgical closure revealed residual shunting in 2% compared with 91% after device occlusion; this proportion decreased to 53% after a mean follow-up of 10 months. The actuarial analysis suggests a progressive resolution of shunting with time. One patient had residual shunting by transesophageal echocardiography immediately after surgical closure compared with 29 after a mean follow-up of 10 months after device occlusion. Residual shunting was not influenced by (1) dimension, location, or position with relation to the device as assessed by transesophageal echocardiography; (2) location of the defect; or (3) device size relative to the stretched dimension of the defect. In 15 patients, a poor correlation existed between transesophageal and transthoracic echocardiographic findings. Variability in serial transthoracic echocardiographic findings was observed in 14. Right ventricular dimension, heart size, and presence of a murmur at follow-up did not correlate with the presence or size of residual shunting after device occlusion.

CONCLUSIONS

These results suggest that ongoing spontaneous resolution of residual shunting occurs after device insertion. Factors related to the defect or device could not predict eventual resolution of residual shunting. Transthoracic echocardiography in the follow-up of these patients may not be reliable in determining presence of residual shunting.

Usefulness of transesophageal echocardiography in the pediatric catheterization laboratory

Transesophageal echocardiography was performed in 51 children (aged 2 to 14 years, mean 4; weight 9 to 50 kg, mean 21) undergoing elective diagnostic or therapeutic cardiac catheterization. The interventional procedures were percutaneous balloon dilation of pulmonary (n = 8) and aortic (n = 2) valve stenosis, percutaneous closure of patent ductus arteriosus (n = 8), and attempted occlusion of Pott's anastomosis by the double umbrella device (n = 1). The diagnostic catheterizations were performed on preoperative children of whom 5 had undergone previous palliative procedures. Precise placement of the balloon across the valve, timing of balloon inflation and deflation according to real-time monitoring of ventricular function and immediate evaluation of results and complications were accomplished with transesophageal monitoring. The exact position of distal and proximal umbrellas of patent ductus occlusive devices was checked on transesophageal imaging and completeness of occlusion controlled on color Doppler. The only relevant information in the preoperative cases was the detection of a septic thrombus in a severely ill patient. With more experience and smaller probes, transesophageal echocardiography may become a new method of monitoring cardiac catheterization also in smaller children where it may reduce duration of the procedure and amount of contrast material.

Biplane transesophageal echo-Doppler studies of atrial septal defects: quantitative evaluation and monitoring for transcatheter closure

Forty-four patients with atrial septal defects, aged 7 months to 18 years (median 8.9), underwent biplane transesophageal (TEE) and transthoracic (TTE) echocardiography. The size of the defect and the shunt flow volume were measured by TEE and compared with the actual size at surgery (N = 14) or the shunt volume measured by the Fick method (N = 34), respectively. In all cases the location and morphology of the defect were clearly demonstrated by TEE; on the other hand, two patients with sinus venosus-type and multiple-type defects, respectively, and one with a small ostium primum defect did not have a complete diagnosis by TTE. The defect size determined by TEE correlated well with the surgical measurement. Similarly a significant correlation was demonstrated between the shunt volume measured by TEE and that obtained by the Fick method. In three patients transcatheter closure of the atrial septal defect by means of a clamshell device was accomplished successfully with TEE monitoring. We conclude that biplane TEE provides a better appreciation of cardiac anatomy and hemodynamic evaluation than TTE in this setting, and TEE is essential for monitoring during transcatheter closure.

Transesophageal echocardiographic diagnosis of right to left shunting across the foramen ovale in adults without prior stroke

OBJECTIVES

The purpose of this study was to estimate the prevalence of potential right to left interatrial shunting and to quantify the morphologic characteristics of the fossa ovalis in adults without a prior history of stroke or systemic embolism.

BACKGROUND

Paradoxic embolization through a patent foramen ovale is an important cardiac mechanism for embolic stroke. Although anatomic and physiologic data obtained by transesophageal echocardiography increase the frequency of demonstration of potential cardiac sources of systemic embolism and occasionally can conclusively demonstrate the mechanism for embolic stroke, the prevalence and prognostic implications of these findings in neurologically healthy persons are still being actively investigated.

METHODS

Intraoperative transesophageal saline contrast echocardiography was performed on 50 adult patients without prior history of stroke or systemic embolism who were undergoing elective cardiovascular surgery.

RESULTS

No patient had a manifest atrial septal defect by right heart oximetric measurements or transesophageal Doppler echocardiographic examination. Eleven of the 50 patients demonstrated right to left atrial passage of saline contrast medium during apnea or after release of 20-cm H2O positive airway pressure, signifying patency of the foramen ovale. These 11 patients with a patent foramen ovale had increased total excursion of the flap valve (septum primum) of the fossa ovalis (1.3 +/- 0.7 cm) compared with findings in the 39 patients without a patent foramen ovale (0.3 +/- 0.5 cm, p < 0.001). All patients with a patent foramen ovale exhibited some mobility of the septum primum and 73% of these patients had > or = 1 cm total excursion of the septum primum. In contrast, 56% of patients without a patent foramen ovale exhibited no motion of the septum primum out of the plane of the atrial septum. The maximal diameter of the fossa ovalis was greater in patients with (1.4 +/- 0.4 cm) than in patients without (1.0 +/- 0.3 cm, p < 0.003) a patent foramen ovale.

CONCLUSIONS

Hypermobility of the septum primum and enlargement of the fossa ovalis are morphologic findings that occur in the presence of a patent foramen ovale.

Comparison of color flow imaging and peripheral venous saline contrast during transesophageal echocardiography to evaluate right-to-left shunt at the atrial level

Intravenous injections of agitated saline (contrast) are used to identify right-to-left atrial shunt during transesophageal echocardiography (TEE). Color flow imaging (CFI) with TEE can be used to detect left-to-right atrial shunt but its application to detect right-to-left shunt is not known. We performed CFI and contrast during TEE in 72 patients for detection of right-to-left shunt. Frame-by-frame review of CFI demonstrated discrete laminar jets of the left side of the atrial septum at the lower or upper margin of the fossa ovalis (FO) in 41 (57%) of 72; only 22 had positive contrast. Timing of shunts was late diastolic or early systolic and not related to pulmonary venous inflow. The length of the FO at end-systole was greater in those with positive CFI compared to negative CFI (13.5 +/- 5 vs 11 +/- 4 mm, P = 0.02). CFI was positive for right-to-left shunt in ten of 14 with atrial septal aneurysms. Contrast was positive for right-to-left shunt in 29 (40%) of 72; all but six had positive CFI. The degree of left atrial opacification was minimal in 19 and moderate to severe in ten. FO size was greater in positive versus negative contrast (14 +/- 4 vs 11 +/- 5 mm, P = 0.02). Contrast was positive for shunt in ten of 14 with septal aneurysms. Thus, right-to-left atrial shunt more often occurs with increased FO size and septal aneurysms.(ABSTRACT TRUNCATED AT 250 WORDS)

Transesophageal echocardiography: procedures and clinical application

In existence for more than a decade, transesophageal echocardiography has gained renewed interest because of technologic advances including high resolution transducers, multiple imaging planes and Doppler color flow mapping. The heart is imaged from within the esophagus with a gastroscope-mounted transducer, obviating technical difficulties encountered in transthoracic echocardiography. Transesophageal echocardiography is utilized intraoperatively to monitor patients undergoing open heart surgery or high risk cardiac patients undergoing noncardiac surgery. In the ambulatory patient, the procedure facilitates imaging of many structures (including the left atrium and appendage, mitral and aortic native and prosthetic valves and thoracic aorta), with better resolution than that obtained by routine transthoracic echocardiography. Technical aspects of transesophageal echocardiography as well as its indications and limitations are reviewed.

Atrial septal aneurysm and stroke: a transesophageal echocardiographic study

The prevalence and morphologic characteristics of atrial septal aneurysms identified by transesophageal echocardiography in 410 consecutive patients are described. Two groups of patients were compared: Group I consisted of 133 patients referred for evaluation of the potential source of an embolus and Group II consisted of 277 patients referred for other reasons. An atrial septal aneurysm was diagnosed by transesophageal echocardiography in 32 (8%) of the 410 patients. Surface echocardiography identified only 12 of these aneurysms. Atrial septal aneurysm was significantly more common in patients with stroke (20 [15%] of 133 vs. 12 [4%] of 277) (p less than 0.05); right to left shunting at the atrial level was demonstrated in 70% of patients in Group I and 75% of patients in Group II by saline contrast echocardiography. Four patients in Group I had an atrial septal defect with additional left to right flow. There was no difference between the two groups in aneurysm base width, total excursion or left atrial or right atrial excursion. However, Group I patients had a thinner atrial septal aneurysm than did Group II patients. It is concluded that an atrial septal aneurysm occurs commonly in patients with unexplained stroke, is more frequently detected by transesophageal echocardiography than by surface echocardiography and is usually associated with right to left atrial shunting. Treatment (anticoagulant therapy vs. surgery) of atrial septal aneurysm identified in stroke patients can be determined only by long-term follow-up studies.

Color Doppler echocardiographic assessment of atrial septal defect size: correlation with surgical measurements

In patients with atrial septal defect (ASD), color flow Doppler echocardiography provides visualization of the transseptal jet, the maximal dimension of which can be assumed to correspond to the maximal dimension of the true orifice. To test whether color flow Doppler echocardiography can provide an alternative method for measurement of ASD size, we studied 63 consecutive patients with echocardiographic evidence of ASD. In 48 patients the maximal dimension of the jet was measured in the parasternal, apical, or subcostal four-chamber view or in the parasternal short-axis view. In the remaining 15 patients transesophageal echocardiography was performed because of transthoracic views were inadequate. The transesophageal studies also measured, from two-dimensional images, the maximal transverse discontinuity in the atrial septum. All patients underwent surgical repair, during which the surgeon directly measured the maximal dimension of ASD. Linear regression equations were performed to compare transthoracic and transesophageal dimensions to those measured at operation. Correlation coefficients were as follows for transthoracic versus surgical measurements: r = 0.745, standard error = 4.35, p less than 0.001. Transesophageal measurements derived from both two-dimensional images and echocardiographic jet width showed similar excellent correlation with surgical measurements (n = 0.91, standard error = 4.33, p less than 0.001; and r = 0.919, standard error = 4.42, p less than 0.001, respectively). We conclude that ASD size derived from color flow Doppler echocardiography shows a good correlation with the anatomic maximal dimension observed at operation. Both transesophageal color flow Doppler echocardiography of jet width and direct surgical measurement of the defect provide an accurate estimation of ASD size.

Double-umbrella device for transvenous closure of patent ductus arteriosus and atrial septal defect: first experience

A new device for transcatheter closure of heart defects was constructed and used to close a patent ductus arteriosus (PDA) in seven adult patients and an atrial septal defect (ASD) in six adult patients. The device consisted of two self-opening umbrellas and a piece of Ivalon. A Dacron patch was sewn on the "male" umbrella for the ASD closure. The device required a 9 Fr introducing venous sheath for PDA and a 14 Fr sheath for the ASD. The venoarterial (right femoral vein-PDA or ASD-left femoral artery) long wire track was arranged. The "male" umbrella and the Ivalon were inserted transvenously one after another, advanced over the long wire across the PDA or ASD and extruded into the aorta or left atrium, respectively. The "female" umbrella was advanced transvenously over the long wire into the pulmonary artery (for PDA) or into the right atrium (for ASD). The metal conus on the long wire was used to pull the "male" umbrella while a special stiff pusher was used to bring the "female" umbrella to the "male" umbrella along the long wire. By these means the umbrellas interlocked at the defect level and closed it. The long wire was then removed through the left femoral artery. Protrusion of the interlocked device through the PDA occurred in one patient and through the ASD in two patients. In all three patients the device was kept on the wire until surgery and an early postrelease device embolization was avoided. In all other patients the defects were successfully closed. The follow-up of 3-27 months was uneventful in all patients. These results indicate that the described procedure is effective and safe, and warrants further clinical trial.