Evaluation of atrial septal defects with 4D flow MRI-multilevel and inter-reader reproducibility for quantification of shunt severity.

PURPOSE: With the hypothesis that 4D flow can be used in evaluation of cardiac shunts, we seek to evaluate the multilevel and interreader reproducibility of measurements of the blood flow, shunt fraction and shunt volume in patients with atrial septum defect (ASD) in practice at multiple clinical sites. MATERIALS AND METHODS: Four-dimensional flow MRI examinations were performed at four institutions across Europe and the US. Twenty-nine patients (mean age, 43 years; 11 male) were included in the study. Flow measurements were performed at three levels (valve, main artery and periphery) in both the pulmonary and systemic circulation by two independent readers and compared against stroke volumes from 4D flow anatomic data. Further, the shunt ratio (Qp/Qs) was calculated. Additionally, shunt volume was quantified at the atrial level by tracking the atrial septum. RESULTS: Measurements of the pulmonary blood flow at multiple levels correlate well whether measuring at the valve, main pulmonary artery or branch pulmonary arteries (r = 0.885-0.886). Measurements of the systemic blood flow show excellent correlation, whether measuring at the valve, ascending aorta or sum of flow from the superior vena cava (SVC) and descending aorta (r = 0.974-0.991). Intraclass agreement between the two observers for the flow measurements varies between 0.96 and 0.99. Compared with stroke volume, pulmonic flow is underestimated with 0.26 l/min at the main pulmonary artery level, and systemic flow is overestimated with 0.16 l/min at the ascending aorta level. Direct measurements of ASD flow are feasible in 20 of 29 (69%) patients. CONCLUSION: Blood flow and shunt quantification measured at multiple levels and performed by different readers are reproducible and consistent with 4D flow MRI.

Inferior and right-sided juxtaposition of the left atrial appendage with an unexpected type of inter-atrial communication.

We have re-investigated an unusual cardiac specimen with juxtaposition of the atrial appendages. The original description dates to 1962, when the autopsy was performed at the Children's Memorial Hospital in Chicago, now Ann & Robert H. Lurie Children's Hospital of Chicago. The heart was subsequently stored in the Farouk S. Idriss Cardiac Registry at the same institution. The specimen shows usual atrial arrangement, but with the morphologically left appendage juxtaposed in a rightward manner, passing behind the heart rather than through the transverse sinus so as to reach its location inferior to the morphologically right appendage. The heart also demonstrated an inter-atrial communication between the cavities of the juxtaposed left appendage and the morphologically right atrium. We provide a detailed description of the morphology, and provide images of this lesion, which to the best of our knowledge has not previously been described.

Defining Features of the Upper Extremity in Holt-Oram Syndrome.

PURPOSE: To investigate the distinguishing morphological characteristics of children with radial longitudinal deficiency (RLD) in Holt-Oram syndrome (HOS). METHODS: One hundred fourteen involved extremities in 62 patients with a diagnosis of HOS were identified at 3 institutions. Medical records and radiographs were evaluated. Radial longitudinal deficiency and thumb hypoplasia were classified according to the modified Bayne and Klug classification and Blauth classifications, respectively, when possible. Other unusual or distinguishing characteristics were catalogued. RESULTS: There was bilateral involvement in 84% of patients. The forearm was involved in 81% of the extremities and a shortened distal radius (Bayne and Klug type I RLD) was the most commonly identified forearm anomaly (40%). Radioulnar synostosis was present in 15% of the extremities, all in the proximal forearms with reduced radial heads. Thumb aplasia (Blauth type V hypoplastic thumb) was the most common type of classifiable thumb abnormality and occurred in 35% of involved thumbs. Twenty-seven percent of abnormal thumbs affected were not classifiable according to the Blauth classification, and 19% of involved thumbs (hypoplastic or absent) had first-web syndactyly. CONCLUSIONS: The upper extremity in HOS differs from the typical presentation of RLD. The forearm is more often involved and may demonstrate radioulnar synostosis. The thumb is frequently unclassifiable by the Blauth classification and has first-web syndactyly. The presence of radioulnar synostosis and syndactyly of the radial 2 digits in RLD should prompt the hand surgeon to obtain a cardiac evaluation and consider genetic testing for HOS. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic III.

Embryology and developmental defects of the interatrial septum.

OBJECTIVE: The various types of atrial septal defects (ASDs) can be differentiated on the basis of their imaging appearance on MDCT. CONCLUSION: It is fundamental for the cardiac imager to understand the embryologic development of the interatrial septum and the morphogenic differences of ASDs.

Atrial Septal Defect.

Atrial septal defects are common congenital heart defects, characterized by insufficient/absent tissue at the interatrial septum. An unrepaired defect may be associated with right heart volume overload, atrial arrhythmia or pulmonary arterial hypertension. The 3 major types of atrial septal defect are: ostium secundum defect, ostium primum defect, and sinus venosus. Characteristic physical findings include a midsystolic pulmonary flow or ejection murmur, accompanied by a fixed split-second heart sound. Small defects may spontaneously close; larger defects may persist and result in hemodynamic and clinical sequelae requiring percutaneous or surgical intervention. Severe pulmonary arterial hypertension is a contraindication to closure.

Device closure of diverse layout of multi-hole secundum atrial septal defect: different techniques and long-term follow-up.

BACKGROUND: There are no unanimous reports on different layouts and classifications of multi-hole secundum atrial septal defects (MHASD) and subsequent standardized occlusion techniques. The MHASD can be isolated or cribriform with variable inter-defects distance. In this retrospective study, experience-based classification and two approaches-based occlusion results are presented. METHODS: We retrospectively collected and analyzed data of 150 MHASD patients from 1320 patients who underwent atrial septal defect occlusion in our institute. The MHASD patients were categorized into 4 types; type A, B, C and D and occluded under exclusive transesophageal echocardiographic guidance. According to different types, 122 patients were occluded using peratrial approach and 28 patients via percutaneous approach. In type A, single device implantation is performed to occlude the large hole and squeeze the small one. For type B single or double-device deployment was performed depending on an inter-defects distance. In type C and D, a patent foramen-ovale (PF) device was selectively positioned to the central defect to occlude the central defect and cover the peripheral ones. In peratrial approach, 8 patients underwent inter-defects septal puncture technique to achieve single-device occlusion. The intracardiac manipulation time, procedural time, double device deployment, redeployment rate, residual shunt, and proportions were analyzed between (and within peratrial technique) two techniques. RESULTS: Successful occlusion was achieved in all 150 patients. Single device occlusion was applied in 78/84 type A and 22/37 type B patients (p < 0.05). Double device occlusion was more applicable to type B than A patients (p < 0.01). Sixteen of 21 type C and all type D patients used PF device for a satisfactory occlusion. Redeployment of the device occurred frequently in type B patients than A (p < 0.01). The intracardiac manipulation time and procedural time were shorter in type A than B (p < 0.05). The intracardiac manipulation time was also shortened in type A peratrial than type A percutaneous group (p < 0.05). Complete occlusion rate for all patients at discharge was 70% and rose to 82% at 1 year follow up. CONCLUSIONS: The diverse layouts and classification of MHASDs can help to choose different techniques and proper devices of different kinds to achieve better occlusion results.

Fate of atrial septal defect in children with end-stage liver disease undergoing living donor liver transplantation.

BACKGROUND AND OBJECTIVE: The course of atrial septal defects (ASD) in children undergoing liver transplantation is poorly described. Our objective was to present our experience in living donor liver transplantation (LDLT) in children with type II ASD. PATIENTS AND METHODS: Between June 1994 and December 2006, 18/140 (12.8%) pediatric LDLT were diagnosed to have both type II ASD and end-stage liver disease. We reviewed the records of these patients. The median follow-up was 48.7 months. Data were analyzed using descriptive statistics. RESULTS: There were 8 male and 10 female patients whose overall mean age was 12 months. There were 15 biliary atresia and 3 neonatal hepatitis patients. The median Child score was 9. The mean Pediatric Model End-stage Liver Disease score was 14. There were 13 with small (< or =4 mm), 4 with medium (5 to 9 mm), and 1 large (>10 mm) ASD. Six small ASD closed spontaneously pretransplant. Seven small ASD closed posttransplant. The medium and large ASD persisted or increased in size posttransplant. Only one patient showed hemodynamically significant ASD based on cardiac echocardiography and catheterization. This patient underwent Amplatzer closure of the ASD at 10 months posttransplant. All patients are surviving with their original grafts to date. There were no perioperative cardiac or neurologic complications. CONCLUSION: This series demonstrated that LDLT can be safely performed in hemodynamically stable patients with small- to large-sized ASD. Small ASD may close pre- or posttransplant.

Echocardiographic assessment of secundum-type atrial septal defects in the adult: role in treatment decisions.

The purpose of this study is to evaluate morphologic patterns of ostium secundum-type atrial septal defects (osASD) in the adult, analyzing their role in treatment decisions. The population was composed of 155 adults (age 43.3 +/- 18.9 years) consecutively diagnosed with osASD in our center, and confirmed by transthoracic and transesophageal echocardiography, between January 2000 and December 2007. Of these, 83 (53.5%) underwent successful percutaneous closure. Surgical closure was used in 31 patients (20.0%). The remaining 42 patients (27.1%) received conservative medical treatment. The mean diameter of the defects was 15.8 +/- 8.5 mm. The prevalence of mitral valve prolapse and severe pulmonary hypertension was also assessed. Based on the criteria in the literature, we detected 14 different morphologic patterns of osASD. There was a central defect in 45/155; 40/155 had a short rim and 20/155 two short rims, 24/155 were multifenestrated and 15/155 PFO-like, and 12/155 had three or more short rims. The different morphologic patterns in each treatment arm, as well as the criteria leading to their inclusion in each, are described. While percutaneously closed defects had a simpler morphology, those that were surgically closed were normally larger and had a more complex shape (with two or more deficient rims or multifenestrated, and thus not suitable for percutaneous closure).

A Misclassification of Pulmonary Stenosis Using Conventional Echocardiographic Methods.

BACKGROUND: The classification of pulmonary stenosis (PS) severity based on the transpulmonary pressure gradient, which is affected by flow rate. CASE REPORT: We report the first case of a pregnant patient with atrial septal defect (ASD) and pulmonary stenosis that was misclassified by conventional echocardiographic methods. Most importantly, three-dimensional transoesophageal echocardiographic assessment of pulmonary stenosis changed the entire treatment strategy. CONCLUSION: The planimetric calculation of the pulmonary valve (PV) opening area using three-dimensional transoesophageal echocardiographic may be helpful, especially in encounters with specialized conditions such as ASD and/or pregnancy, which can cause inaccurate recordings of the transvalvular peak gradient.

Prevalence of Semicircular Canal Hypoplasia in Patients With CHARGE Syndrome: 3C Syndrome.

Importance: CHARGE syndrome refers to a syndrome involving coloboma, heart defects, atresia choanae, retardation of growth and development, genitourinary disorders, and ear anomalies. However, Verloes revised the characteristics of CHARGE syndrome in 2005 to define this syndrome more broadly. Deficiency of the semicircular canals is now a major criterion for CHARGE syndrome. Objective: To characterize patients with CHARGE syndrome at our center using Verloes' criteria and to reevaluate the nomenclature for this condition. Design, Setting, and Participants: We performed a medical chart review of patients with CHARGE syndrome and reviewed their temporal bone imaging studies at a tertiary care children's hospital affiliated with Washington University in St Louis. Two authors independently reviewed each imaging study (A.W. and K.H.). Radiologic studies, physical findings, genetic tests, and other diagnostic tests were included. Patients with no temporal bone imaging studies were excluded. Results: Eighteen children were included in this study; 13 children (72%) were male, and the mean (median; range) age of patients at the time of inner ear imaging studies was 2 years (4.5 years; 8 months to 8 years). Coloboma was present in 13 patients (72%) and choanal atresia in 5 (28%); semicircular canal anomalies were present in all patients. Additionally, 13 patients (72%) were diagnosed as having hindbrain anomalies, 17 (94%) as having endocrine disorders, 17 (94%) as having mediastinal organ malformations, and all as having middle or external ear abnormalities and development delay. Cleft lip and cleft palate were found in 6 of 14 patients (43%) who did not have choanal atresia. We tested 16 patients for mutations in the CHD7 gene; 10 were positive (63%) for mutations, 4 (25%) were negative, and 2 (13%) were inconclusive. Conclusions and Relevance: Semicircular canal anomalies were the most consistent finding in our patients with CHARGE syndrome. Given the high prevalence of semicircular canal hypoplasia and importance of imaging for diagnosing CHARGE syndrome, we propose changing the term CHARGE syndrome to 3C syndrome to emphasize the importance of the semicircular canals and to recall the 3 major criteria for diagnosis: coloboma, choanal atresia, and semicircular canal anomaly. The nomenclature would also reference the 3 semicircular canals in each ear. This new name for CHARGE syndrome would provide a mnemonic and focus the disease on the most important clinical criteria for diagnosis.

[Atrial septal defect. A morphopathological and embryological study]. / Defecto septal atrial. Estudio morfopatológico, embriológico.

To contribute to a better understanding of the morphopathology of atrial septal defects (ASD), we describe and classify topographically a series of hearts obtained from necropsies. We performed an anatomo-embryological correlation to gain insight on the pathogenesis of this type of congenital heart disease. Seventy-one hearts with ASD and twenty-three normal hearts with patent foramen ovale from the collection at the Instituto Nacional de Cardiologia lgnacio Chavez were studied morphologically; segmental sequential analysis was used. The topography of the interatrial septum was determined on the basis of the structures related to it in order to classify the ASD. The FS area was projected on the right septal surface using pins. To stablish the anatomo-embryological correlation, the ASD's anatomy was compared with the embryological processes that take place in atrial septation. The most frequent ASD was the OO type (FS) with 64.78%, followed by common atrium, true FS, FP, superior and inferior sinus venosus, types each one with 2.81% and one coronary sinus venosus type (1.40%). The FS area was projected below the superior vena cava. The morphologically and topographically knowledge of atrial septal defect is useful to interpret the imaging studies of this cardiopathy and is basic for the surgeon and the interventionist cardiologist. Abnormal apoptosis and retarded developmental growth are proposed as pathogenic mechanisms.

Improvement in exercise capacity in asymptomatic and mildly symptomatic adults after atrial septal defect percutaneous closure.

BACKGROUND: Controversy exists as to whether secundum atrial septal defects (ASDs) in asymptomatic or mildly symptomatic New York Heart Association (NYHA) class I or II adult patients should be closed. METHODS AND RESULTS: Thirty-seven patients (24 females; mean age 49.4 years, range 19 to 76) with a mean pulmonary to systemic flow ratio (Qp:Qs) of 2.1 (1.2 to 3.4) had a maximal oxygen uptake (VO2max) determination and echocardiographic measurement of right ventricular dimensions before and 6 months after elective percutaneous closure of ASD. At baseline, mean VO2max was 23.5+/-6.4 mL/kg per minute and was higher in the 15 NYHA I patients than in the 22 NYHA II patients (27+/-6.9 versus 20.8+/-4.6 mL/kg per minute; P=0.0015). VO2max increased significantly at 6 months (23.5+/-6.4 to 26.9+/-6.9 mL/kg per minute; P<0.0001). Improvement was as marked in NYHA I (+22%; P<0.0001) as in NYHA II patients (+12%; P<0.0001), in patients with Qp:Qs 1.2 to 2.0 (+16%; P<0.0001) as in those with Qp:Qs >2 (+12%; P<0.0001), and in patients > or =40 years of age (+14%; P<0.0001) as in those <40 years of age (+16%; P<0.0001). Compared with 15 of 37 patients before closure, 35 of 37 patients were in NYHA I at 6 months. Right ventricular dimensions decreased significantly (P<0.0001). CONCLUSIONS: Adult ASD patients significantly increase their functional capacity after percutaneous defect closure. This is observed even in patients classified as asymptomatic, in those with lesser shunts, and in older patients. These findings suggest that ASD closure in an adult population should be considered even in the absence of symptoms.

Diagnosis and classification of atrial septal aneurysm by two-dimensional echocardiography: report of 80 consecutive cases.

Atrial septal aneurysms have been related (either by association or as potential causes) to systolic clicks, atrial arrhythmias, systemic and pulmonary embolism, atrioventricular valve prolapse and atrial septal defect. To study these associations and the incidence of atrial septal aneurysm, we reviewed 80 consecutive patients (female to male ratio 1.9:1, mean age 47 years, range 1 day to 89 years) who had been identified prospectively as having an atrial septal aneurysm. These were found in 36,200 two-dimensional echocardiographic studies (incidence: 0.22% overall; 0.29% in the last year of the study done between 1978 and 1984). Three types of fossa ovalis aneurysm and one type of aneurysm involving the entire atrial septum were observed; a fossa ovalis aneurysm with leftward projection and excursion of less than 5 mm or an aneurysm involving the entire atrial septum with rightward projection was not observed. Atrial septal aneurysm occurred more often as an isolated abnormality than in association with other cardiac malformations, although all patients with an aneurysm involving the entire atrial septum had complex congenital cardiac anomalies of the hypoplastic right heart type. The reported associations between atrial septal aneurysms and atrial septal defect, atrioventricular valve prolapse, midsystolic clicks, atrial arrhythmias and cerebral ischemic events were examined. A hypothesis based on interatrial pressure gradients is proposed to explain the different motions and configurational characteristics of fossa ovalis aneurysms observed in these patients. All patients in whom atrial septal aneurysm is demonstrated should undergo examination for atrial septal defect. Atrial septal aneurysm should be specifically looked for in patients who have these associations and who undergo two-dimensional echocardiography, especially if these abnormalities are unexplained.

Surgical repair of uncomplicated atrial septal defect without "routine" preoperative cardiac catheterization.

Whether all patients with atrial septal defect should undergo cardiac catheterization before surgical correction is controversial. Of 152 patients of all ages with surgically documented isolated atrial septal defect (ostium secundum, ostium primum and sinus venosus types) who underwent preoperative two-dimensional echocardiography between January 1978 and December 1983, there were 55 (36%) (group 1) who did not have preoperative cardiac catheterization. These 55 patients are compared with the 97 patients (64%) who did have preoperative catheterization studies (group 2). Group 1 patients were younger (mean age 22 versus 36 years) and did not have clinical evidence of other associated cardiac disorders. Forty-four (80%) of the group 1 patients had typical findings for atrial septal defect on cardiac examination, chest radiograph and electrocardiogram compared with 16 (16%) of group 2 patients (p less than 0.001). The most frequent reasons for cardiac catheterization in group 2 patients were documentation of diagnosis, usually because of atypical clinical findings, and exclusion of associated cardiac abnormalities. Contrast echocardiography, radionuclide shunt studies and Doppler echocardiography were used as additional confirmatory tests in 36 patients (65%). In 19 patients (35%), two-dimensional echocardiography was the only confirmatory test. There were no false positive two-dimensional echocardiographic studies. There were no operative deaths or significant perioperative complications in any of the patients. At a mean follow-up of 28 months (range 6 to 64), there was one late death (3 1/2 years postoperatively) in a 61 year old man with chronic congestive heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Need for closure of secundum atrial septal defect in infancy.

OBJECTIVES: Closure of isolated secundum atrial septal defect is generally recommended at the age of 4 to 5 years. However, there are children with isolated secundum atrial septal defect in whom early closure should be performed. We aimed to assess the underlying conditions that led to earlier closure in this special patient group and to analyze the outcome. METHODS AND RESULTS: From January 1990 through August 2002, 24 infants with isolated secundum atrial septal defect underwent surgical closure within the first year of life. All children were symptomatic. Signs of pulmonary hyperperfusion, such as tachydyspnea, failure to thrive, recurrent respiratory infections, or heart failure, were present. Four infants required artificial ventilation. Ten patients had additional problems, such as prematurity with chronic lung disease, hepato-omphalocele and congenital diaphragmatic hernia, which were present in 1 patient each. Eleven patients had defined dysmorphic syndromes. All but 1 infant underwent preoperative invasive hemodynamic evaluation. Thirteen patients had pulmonary hypertension preoperatively. The follow-up time was 46 +/- 33 months (range, 4-125 months). At follow-up, pulmonary artery pressure proved to be normal in 11 of the 13 children who had pulmonary hypertension previously. One patient died of persistent pulmonary hypertension. Clinical performance, growth, and development improved in nearly all patients. All ventilator-dependent children could be weaned shortly after atrial septal defect closure. CONCLUSIONS: If lungs are compromised, even a minor left-to-right shunt might be poorly tolerated in infancy. In these children early surgical closure of an isolated secundum atrial septal defect should be performed to support thrive and growth and to prevent the onset of irreversible changes of the pulmonary vasculature.

Comprehensive assessment of morphology and severity of atrial septal defects in adults by CT.

BACKGROUND: Cardiac CT is an excellent tool for evaluating the anatomy of a secundum atrial septal defect (ASD). However, a comprehensive assessment of its usefulness, including measurement of the pulmonary to systemic blood flow ratio in secundum ASD patients, has not been performed. OBJECTIVE: Therefore, this study was designed to evaluate the usefulness of CT for assessing the hemodynamics of secundum ASD in adults compared with transesophageal echocardiography (TEE), transthoracic echocardiography, and invasive catheterization. METHODS: Fifty adult patients with secundum ASD were enrolled. Cardiac CT scans (128-slice multidetector CT instrument) were acquired. These were followed by 2-dimensional reconstruction of the secundum ASDs to determine the defect size, the rim length between the outer edge of the defect, and the pulmonary to systemic blood flow (Qp/Qs) ratio. RESULTS: The maximum sizes of the secundum ASDs derived from CT and TEE studies were comparable (21.2 ± 8.0 vs. 20.0 ± 7.3 mm; P = .41; r = 0.960; P < .001). The rim lengths for the aortic, mitral, and tricuspid valves; the inferior vena cava; and posterior atrium were also comparable between CT and TEE measurements. The mean Qp/Qs ratio that was derived from CT measurements was comparable with that found by invasive catheterization (2.3 ± 0.7 vs. 2.3 ± 0.8; P = .73; r = 0.786; P < .001). CONCLUSION: Cardiac CT is feasible for assessing pathology and the severity of secundum ASD in adults.

Subdivided left atrium: an expanded concept of cor triatriatum sinistrum.

Twenty-four hearts with cor triatriatum were studied. On the basis of this material and a review of the literature a new classification of "subdivided left atrium" is proposed. Tye A, the most common form of subdivided left atrium, is the classic cor triatriatum with its multiple variations of partial anomalous pulmonary venous drainage; the fossa ovalis can be related to the proximal left atrial chamber (type A, a) or the distal left atrial chamber (type A, b). Type B hearts are related to (but not identical with) total anomalous pulmonary venous drainage into the coronary sinus; the coronary sinus opening is atretic in these hearts; abnormal defects connect the proximal left atrial chamber usually with the right atrium only, rarely also with the distal left atrial chamber. The Type C heart, first reported in this paper, has a superiorly and medially situated proximal chamber, located between the right and distal left atrium; it does not receive any pulmonary veins; the coronary sinus is normally formed. Current morphogenetic hypotheses that satisfactorily explain the Type A b and B heart fail to account for the Type A a and C heart.

Further observations on the morphology of atrioventricular septal defects.

Certain morphologic aspects of atrioventricular septal defects ("endocardial cushion defects," "atrioventricular canal malformations") remain controversial. It is still not clear which precise lesions should not be placed in this category. For example, is an "isolated" cleft of the mitral valve or a perimembranous inlet ventricular septal defect to be so described? It is also not fully accepted that the left atrioventricular valve in these lesions bears little resemblance to a morphologically mitral valve. We have investigated these problems by both observation and mensuration. We determined the junctional circumference of the left atrioventricular valve leaflets and the ventricular dimensions in 130 atrioventricular septal defects (95 with common valve orifice and 35 with separate right and left atrioventricular orifices); in 50 hearts with perimembranous ventricular septal defects (20 extending into the inlet septum and 30 with outlet or trabecular extensions); in seven hearts with isolated cleft of the mitral valve, and in 10 normal hearts. All specimens came from the cardiopathological collection of Children's Hospital of Pittsburgh. The measurements showed conclusively that the atrioventricular septal defects were all directly comparable irrespective of the detailed morphology of the atrioventricular valve or valves. The group of atrioventricular septal defects was totally discrete as compared with all the other specimens that had normal atrioventricular septation. The left atrioventricular valve in atrioventricular septal defects is basically a three-leaflet valve which differs from the normal mitral valve in terms of its leaflet, its chordal support, and the arrangement of its papillary muscle. Its only similarity with the normal mitral valve is that it resides in the morphologically left ventricle and guards the left atrioventricular junction.

Of clefts, commissures, and things.

A full understanding of the morphology of atrioventricular septal defects ("endocardial cushion defects," "atrioventricular canal malformations") demands knowledge of the exact nature of three specific breaches in the skirt of valve leaflet tissue guarding the atrioventricular junction. One of these is the space between the left ventricular components of the two leaflets that are enclosed in both the right and left ventricles (the bridging leaflets). Traditionally described as a cleft, it has been suggested more recently that this gap functions as a commissure. The second space is that which is found anteriorly and superiorly in the so-called Rastelli type A malformation. This is also called a cleft in a common anterior leaflet, but it has been suggested that it too is a commissure. The final breach is that produced by the surgeon when he divides the free-floating superior bridging leaflet if repairing the so-called Rastelli type C malformation with a one-patch technique. It is generally agreed that this breach be considered a division. To adjudicate the nature of the other breaches, it is necessary to compare them with commissures in atrioventricular and arterial valves and with the isolated cleft that exists in the aortic leaflet of a normal mitral valve. These considerations show that the gap between the left ventricular components of the bridging leaflets functions as a commissure even though it is not supported by a papillary muscle. This would not be expected, since the commissural attachments of the leaflets are in the left and right ventricle, respectively. The gap seen anteriorly in the Rastelli type A malformation is also a commissure, being supported in typical fashion by the medial papillary muscle of the right ventricle.

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.