CArdiac MagnEtic resonance assessment of bi-Atrial fibrosis in secundum atrial septal defects patients: CAMERA-ASD study.

AIMS: Atrial septal defects (ASD) are associated with atrial arrhythmias, but the arrhythmia substrate in these patients is poorly defined. We hypothesized that bi-atrial fibrosis is present and that right atrial fibrosis is associated with atrial arrhythmias in ASD patients. We aimed to evaluate the extent of bi-atrial fibrosis in ASD patients and to investigate the relationships between bi-atrial fibrosis, atrial arrhythmias, shunt fraction, and age. METHODS AND RESULTS: Patients with uncorrected secundum ASDs (n = 36; 50.4 ± 13.6 years) underwent cardiac magnetic resonance imaging with atrial late gadolinium enhancement. Comparison was made to non-congenital heart disease patients (n = 36; 60.3 ± 10.5 years) with paroxysmal atrial fibrillation (AF). Cardiac magnetic resonance parameters associated with atrial arrhythmias were identified and the relationship between bi-atrial structure, age, and shunt fraction studied. Bi-atrial fibrosis burden was greater in ASD patients than paroxysmal AF patients (20.7 ± 14% vs. 10.1 ± 8.6% and 14.8 ± 8.5% vs. 8.6 ± 6.1% for right and left atria respectively, P = 0.001 for both). In ASD patients, right atrial fibrosis burden was greater in those with than without atrial arrhythmias (33.4 ± 18.7% vs. 16.8 ± 10.3%, P = 0.034). On receiver operating characteristic analysis, a right atrial fibrosis burden of 32% had a 92% specificity and 71% sensitivity for predicting the presence of atrial arrhythmias. Neither age nor shunt fraction was associated with bi-atrial fibrosis burden. CONCLUSION: Bi-atrial fibrosis burden is greater in ASD patients than non-congenital heart disease patients with paroxysmal AF. Right atrial fibrosis is associated with the presence of atrial arrhythmias in ASD patients. These findings highlight the importance of right atrial fibrosis to atrial arrhythmogenesis in ASD patients.

Preliminary Assessment of Tricuspid Valve Annular Velocity Parameters by Cardiac Magnetic Resonance Imaging in Adults with a Volume-Overloaded Right Ventricle: Comparison of Unrepaired Atrial Septal Defect and Repaired Tetralogy of Fallot.

The aim is to compare tricuspid valve (TV) atrioventricular junction (AVJ) annular motion parameters in unrepaired atrial septal defect (ASD) and repaired Tetralogy of Fallot (TOF) by cardiac magnetic resonance (CMR) imaging. We retrospectively reviewed CMR studies performed between November 2007 and November 2013 in patients 16-45 years of age with unrepaired ASD (with or without partial anomalous pulmonary venous return) and with repaired TOF, who had previous infundibulotomy, but have not undergone pulmonary valve replacement. Longitudinal motion of lateral TV in four-chamber view cine image was tracked through the cardiac cycle with custom software. Twenty TOF patients and 12 ASD patients were included, and values were compared with 80 controls. Right ventricular end-diastolic volume index and right ventricular end-systolic volume index were similar in the ASD and TOF groups and were significantly higher in both groups than in controls. Maximum displacement of the TV in systole, velocity at half-maximal displacement during systole, and velocity at half-maximal displacement during early diastole were all significantly lower in the TOF group than the ASD group [1.39 ± 0.47 vs. 2.21 ± 0.46 (cm, p < 0.01), 5.9 ± 2.1 vs. 10.1 ± 2.3 (cm/s, p < 0.01), and 7.7 ± 2.6 vs. 10.9 ± 3.1 (cm/s, p < 0.05)]. TOF patients have diminished early diastolic TV AVJ velocity compared to patients with an unrepaired ASD, despite similar RV volumes. This observation could suggest diastolic dysfunction or cardiac mechanics unique to the postoperative, volume-overloaded right ventricle in patients with repaired TOF.

Assessment of atrial septum morphology by live three-dimensional echocardiography.

To evaluate the morphology of atrial septum by the live three-dimensional echocardiography (L3DE) and its value of clinical application, L3DE was performed in 62 subjects to observe the morphological characteristics and dynamic change of the overall anatomic structure of atrial septum. The study examined 49 patients with atrial septal defect (ASD), including 3 patients with atrial septal aneurysm, and 10 healthy subjects. ASD in the 35 patients was surgically confirmed. The maximal diameters of ASD were measured and the percentages of area change were calculated. The parameters derived from L3DE were compared with intraoperative measurements. The results showed that L3DE could directly and clearly display the morphological features of overall anatomic structure of normal atrial septum, repaired and artificially-occluded atrial septum, atrial septal aneurysm. The defect area in ASD patients changed significantly during cardiac cycle, which reached a maximum at end-systole and a minimum at end-diastole, with a mean change percentage of 46.6%, ranging from 14.8% to 73.4%. The sizes obtained from L3DE bore an excellent correlation with intraoperative findings (r=0.90). It is concluded that L3DE can clearly display the overall morphological features and dynamic change of atrial septum and measure the size of ASD area accurately, which is important in the decision to choose therapeutic protocols.

Can transcranial Doppler discriminate between solid and gaseous microemboli? Assessment of a dual-frequency transducer system.

BACKGROUND AND PURPOSE: Transcranial Doppler ultrasound can reliably detect both gaseous and solid cerebral emboli. However, conventional equipment is unable to discriminate between gaseous and solid emboli. This is a major limitation in situations in which the 2 coexist, because they may have very different clinical relevance. Recently, a novel Embo-Dop system, using insonation at 2 ultrasound transducer frequencies, has been developed. An initial study with a small sample size suggested it provided excellent discrimination. We performed a validation study in subjects with embolic signals of known nature. METHODS: Gaseous embolic signals were obtained in 7 patients with known patient foramen ovale by intravenous injection of agitated saline injections. Solid embolic signals were obtained in patients with symptomatic carotid stenosis (N=23). Discrimination of the 2 using the Embo-Dop system dual-frequency system was assessed. It was compared with discrimination using embolic signal maximum intensity with an intensity threshold. RESULTS: One hundred forty-five solid embolic signals were recorded from carotid stenosis patients. Seventy-three were classified as solid and 72 as gaseous by the Embo-Dop system. Six hundred forty-eight gaseous embolic signals were recorded from 7 patients with patent foramen ovale. Six hundred twenty-five were classified as gaseous and 23 as solid. This gave a sensitivity of 50.3% and specificity of 96.5% for detecting solid embolic signals. Discrimination was better than using a simple intensity threshold. CONCLUSIONS: The Embo-Dop dual-frequency system allows better discrimination than a simple intensity threshold but it is not accurate enough for use in clinical or research studies. Further work is needed to develop reliable clinical systems for discrimination of emboli.

Cross-sectional echocardiographic assessment of atrioventricular septal defect: basic morphology and preoperative risk factors.

Accurate evaluation of an atrioventricular septal defect is readily achieved by echocardiography. A sound understanding of the basic morphology and associated lesions is key to this approach. This article first details the features that are common to all hearts with an atrioventricular septal defect, irrespective of the presence or absence of an interatrial or interventricular communication. These common features are: (1) inlet outlet disproportion; (2) absence of the atrioventricular muscular septum; (3) abnormal position of the left ventricular papillary muscles; (4) abnormal configuration of the atrioventricular valves and, (5) cleft in the left atrioventricular valve. These are all predicated by a sprung atrioventricular junction. Second, is a detailed outline of the associated risk factors that must be identified by the echocardiographer prior to presenting the patient for surgical management, with the most important ones being abnormalities of the left atrioventricular valve and left ventricular outflow tract obstruction. Indeed, in this current era it is rarely necessary to perform other investigations prior to surgical repair.

Influence of atrial septal defect anatomy in patient selection and assessment of closure with the Cardioseal device; a three-dimensional transoesophageal echocardiographic reconstruction.

BACKGROUND: The maximal diameter of the defect and the dimensions of the septal rims are essential parameters for the selection of optimal cases for device closure. Neither two-dimensional echocardiography nor balloon catheter sizing provide optimal data. Unique three-dimensional echocardiography might help to improve patient selection and assessment of results. Our aim was to optimize transcatheter closure of secundum type atrial septal defects using three-dimensional echocardiography. METHODS: Sixteen patients enrolled in a protocol for atrial septal defect transcatheter closure with the Cardioseal device underwent transoesophageal two- and three-dimensional echocardiography. Maximal diameter and tissue rim of the atrial septal defect were measured and compared by both methods. In the 12 patients selected for closure, the balloon stretched diameter was compared to three-dimensional echocardiography measurements. Device placement was assessed by two- and three-dimensional echocardiography. RESULTS: The shape of the atrial septal defect appeared variable on three-dimensional views: round in nine patients but complex (oval, raquet-shaped, multiple) in seven patients. The surface area of the atrial septal defect varied by 68+/-15% during the cardiac cycle. The correlation between atrial septal defect maximal diameters measured by two-dimensional transoesophageal echocardiography and three-dimensional echocardiography was better in round defects (y=1 x +1.6, r=0.99) than in complex defects (y=0.7 x -0.5, r=0.88). The antero-superior rim could only be properly assessed by three-dimensional echocardiography. In 12 patients the correlation between stretched diameter and three-dimensional echocardiography maximal diameter was poor (y=0.3 x +13, r=0.41). After placement of the device, three-dimensional echocardiography enabled the mechanism of residual shunting to be understood in three patients. CONCLUSIONS: Dynamic three-dimensional echocardiography enhances the understanding of the anatomy and physiology of atrial septal defect and should be an important process in future initiatives for device closures.

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.

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.

Doppler color-flow imaging assessment of shunt size in atrial septal defect.

Two-dimensional echocardiography and pulsed-Doppler studies have not proved to be reliable methods of assessing left-to-right shunt size in atrial septal defect. Doppler color-flow imaging displays the transatrial jet, providing a new dimension with the potential capability of quantifying left-to-right shunt size. Twenty-three patients with atrial septal defect were studied by color-flow imaging and cardiac catheterization. The defect size measured by two-dimensional echocardiography, the maximal color-flow jet width in the atrial septum, and the maximal color-flow jet area in the right atrium were correlated with cardiac catheterization-derived left-to-right shunt size. Correlation coefficients were 0.57 (p less than 0.01), 0.67 (p less than 0.001), and 0.65 (p less than 0.01), respectively. Atrial septal color-flow jet width distinguished patients with less than a 2:1 left-to-right shunt size ratio (eight patients, jet width less than 15 mm in in all) from patients with greater than a 2:1 left-to-right shunt size ratio (15 patients, jet width greater than 15 mm in all). These results indicate that Doppler color-flow imaging can distinguish left-to-right shunt size in atrial septal defect accurately enough to influence decisions with regard to subsequent patient management.

Usefulness of echocardiographic assessment of right ventricular and pulmonary trunk size for estimating magnitude of left-to-right shunt in children with atrial septal defect.

M-mode and 2-dimensional echocardiographic studies were performed in 42 patients, aged 1 to 16 years (mean 6), with a secundum or sinus venosus type atrial septal defect (ASD) and normal pulmonary artery pressure. Twenty normal children served as a control group. In patients with ASD the echocardiographic variables were correlated with the magnitude of the left-to-right shunt (Qp/Qs) calculated by the Fick principle. Although M-mode echocardiograms showed increased right ventricular (RV) dimension in 69% of the patients, the correlation between RV dimension index (RV dimension/body surface area) and Qp/Qs was weak (r = 0.49). When RV dimension was related to left ventricular (LV) dimension and expressed by the RV/LV ratio, 90% of the patients were found to have an abnormally large right ventricle. The correlation between the RV/LV ratio and Qp/Qs was fairly good (r = 0.64). In 33 patients (78%), the pulmonary trunk (PT) was adequately visualized and measured on 2-dimensional echocardiograms. The dimension of the PT was related to the aortic root dimension and expressed by the PT dimension/aortic dimension ratio. This ratio was 0.99 +/- 0.06 in normal children and 1.35 +/- 0.23 in patients with ASD (p less than 0.001). The PT/aortic ratio exceeded the upper limit of normal (the normal mean value + 2 standard deviations) in each of the 27 patients with a Qp/Qs of 1.5 or greater. In 5 of the 6 patients with a Qp/Qs of less than 1.5 the PT/aortic ratio was close to 1 and within the normal range. An excellent correlation (r = 0.89) was found between the PT/aortic ratio and Qp/Qs.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of atrioventricular septal defects by two dimensional echocardiography.

Ninety-six patients with an atrioventricular septal defect were assessed by two dimensional echocardiography. Forty-eight patients were judged as having two discrete valve orifices. In this group, 37 had an intact ventricular septum and 11 a ventricular septal defect. Two patterns of attachment of the valve leaflets to the interventricular septum were noted. Forty-eight patients had a common valve orifice. In 29 patients there was absence of tethering of the anterior bridging leaflet to the interventricular septum. A further 19 had varying degrees of tethering of the anterior bridging leaflet. A ventricular septal defect was identified under the anterior bridging leaflet in all cases. In 58 cases where the posterior bridging leaflet was identified, a ventricular septal defect was visualised in eight and missed in two. Seventy-eight patients had an ostium primum defect, 12 a common atrium, and a further six an intact interatrial septum. Two dimensional echocardiography provides in depth morphological information about the type of atrioventricular defect and can correctly identify the presence of a ventricular septal defect beneath the anterior or posterior bridging leaflet, unless it exists between short crowded chordae.

Secundum atrial septal defect and significant mitral regurgitation: incidence, management and morphologic basis.

To better understand the association between mitral regurgitation and secundum atrial septal defect and to clarify the evaluation and management of these patients, the records of 235 adult patients with atrial septal defect were reviewed. Ten patients (4 percent) had significant mitral regurgitation defined by clinical, hemodynamic and angiographic criteria. Three patients required mitral valve replacement at the time of closure of the atrial septal defect and four patients had closure alone, one of whom required mitral valve replacement after five years. Three patients did not undergo closure of the atrial septal defect or mitral valve replacement because of severe coexisting medical problems. In six patients, the mitral valves were studied pathologically and all had thick, fibrotic leaflets and short, thick, fibrotic chordae tendineae. Three of these valves also had scattered areas of patchy myxomatous degeneration and three had areas of vascular ingrowth suggestive of rheumatic disease. Although both invasive and noninvasive studies have high-lighted the coincidence between atrial septal defect and mitral regurgitation, particularly the frequent association of mitral valve prolapse, our data indicate that this association rarely has clinical significance. Furthermore, the morphologic basis for mitral regurgitation in patients with atrial septal defect consists of leaflet and chordal thickening fibrosis and deformity rather than attenuation and ballooning as would be expected in mitral valve prolapse.