Usefulness of magnetic resonance imaging in the assessment of venoatrial connections, atrial morphology, bronchial situs, and other anomalies in right atrial isomerism

Surgical management of hearts with isomeric atrial appendages

BACKGROUND AND AIM

On the basis of previously published accounts, coupled with our own experience, we have assessed the surgical approaches to patients with isomeric atrial appendages.

METHODS

We reviewed pertinent published studies on surgical treatment of individuals with isomeric atrial appendages, with the pertinent surgical details provided by most of the manuscripts.

RESULTS

Half of patients with right isomerism, and two-thirds of those with left isomerism have bilateral superior caval veins. Azygos extension of the inferior caval vein is reported in three-quarters of those with left isomerism. The coronary sinus is universally absent in right isomerism, along with totally anomalous pulmonary venous connection, and is absent in two-fifths of those with left isomerism. Univentricular atrioventricular connections are expected in up to three-quarters of those with right isomerism. Atrioventricular septal defect is reported in up to four-fifths, more frequently in right isomerism, with such patients typically having discordant ventriculoatrial connections or double outlet right ventricle. Reported mortalities extend to 85% for those with right, and 50% for those with left isomerism. In right isomerism, mortality is up to 54% for systemic-to-pulmonary arterial shunting, up to 75% for univentricular repair, and up to 95% for repair of totally anomalous pulmonary venous connection itself. No more than one-quarter had undergone Fontan completion, with reported mortalities of 21%.

CONCLUSION

Early surgical results are satisfactory in patients with left isomerism, but disappointing for those with right. Recent advances in cardiac and liver transplantation may offer improved survival.

Description of misdiagnosis and missed diagnosis of fetal complex heart malformations by prenatal echocardiography combined with postnatal cardiovascular casting

OBJECTIVE

To compare prenatal echocardiography with postnatal cardiovascular casting for detection of fetal cardiovascular malformations, and to discuss the causes of prenatal misdiagnosis and missed diagnosis.

METHODS

We retrospectively identified patients from 2013 to 2018 at our Maternal-Fetal Medicine Center who were reported to have a fetal diagnosis of severe congenital heart malformations (CHMs). Subjects had postnatal confirmation of CHMs. Prenatal and postnatal medical records, including ultrasound results and casting findings, were reviewed and analyzed.

RESULTS

Postnatal casting showed that all 35 fetuses had complex CHMs. In these 35 cases, 90 cardiovascular malformations were found by postnatal casting, and 69 were detected by prenatal echocardiography. Among the other 21 cardiovascular malformations, 7 were misdiagnosed and 14 diagnoses were missed by prenatal ultrasound.

CONCLUSION

Prenatal echocardiography may lead to misdiagnosis and missed diagnoses, especially in cases with great arterial branching anomalies. Postnatal casting can demonstrate the configuration of the great vessels and smaller branches directly. Thus, understanding of such malformations via postnatal casting may help to improve prenatal diagnostic accuracy.

Disharmonious Patterns of Heterotaxy and Isomerism: How Often Are the Classic Patterns Breached?

BACKGROUND

It is advocated that heterotaxy should be segregated into right or left isomerism according to atrial appendage morphology. However, atrial situs determination is often based on the pattern of associated findings rather than on atrial morphology itself, which can be difficult to define. The objective was to assess how often concordant patterns of isomerism classified by atrial appendage morphology, bronchopulmonary pattern, and splenic status are breached using cardiac magnetic resonance or computed tomography. The secondary objective was to determine the feasibility of defining atrial appendage morphology using cardiac magnetic resonance or computed tomography.

METHODS AND RESULTS

Retrospective review of 114 pediatric patients (median, 2.4 years; range, 1 day-17.9 years) with heterotaxy who underwent cardiac magnetic resonance or computed tomography was performed to evaluate atrial appendage, bronchopulmonary, and visceral organ arrangements. Atrial appendage and splenic anatomy were not definable in 17 of 114 (15%) and 4 of 114 (3.5%) patients, respectively. In the remaining 93 patients, 39% had classic right isomerism (bilateral right atrial appendages, right bronchopulmonary pattern, and asplenia) and 40% had classic left isomerism (bilateral left atrial appendages, left bronchopulmonary pattern, and polysplenia). Classic pattern of isomerism was breached in 20 of 93 (21.5%) patients: 13 (65%) displayed incongruent abdominal situs, 5 (25%) incongruent bronchial situs, 1 (5%) had discrepant appendage morphology, and 1 (5%) incongruent situs at all levels.

CONCLUSIONS

Atrial appendage morphology is difficult to assess and not always indicative of bronchopulmonary or abdominal situs. Discordance between bronchopulmonary branching, atrial appendage arrangement, and splenic status was identified in >20% patients with heterotaxy. Independent description of each organ system is required when arrangements are disharmonious among different organ systems.

Severe bacterial infection in patients with heterotaxy syndrome

OBJECTIVE

To determine the incidence of sepsis in patients with heterotaxy syndrome.

STUDY DESIGN

From our institutional database, we identified patients with heterotaxy syndrome and other complex congenital heart disease (CHD) born between 2001 and 2011. Severe bacterial infection was defined as sepsis with positive culture result or infection with abscess formation.

RESULTS

We enrolled 95 patients with heterotaxy syndrome (88 with right atrial isomerism and 7 with left atrial isomerism) and 142 patients with complex CHD. With 1026 person-years follow-up, the 5-year survival was 52% and 65.7% in heterotaxy and complex CHD groups, respectively (P = .239). Community-acquired severe bacterial infection occurred only in heterotaxy syndrome (13 episodes in 10 patients, 3 of whom had spleen noted at imaging study) with 2- and 5 years cumulative severe bacterial infection rate of 9.6% and 14.5%, respectively. The overall mortality rate of those with community-acquired severe bacterial infection was 31%. Pneumococcus and Citrobacter freundii were the most common pathogens. Nosocomial severe bacterial infection occurred in 33.3% of all patients and 12.5% of all procedures. The rates (0.59 and 0.52/100 hospitalization days in heterotaxy and complex CHD group) and the pathogens of nosocomial severe bacterial infection were similar between heterotaxy and complex CHD groups.

CONCLUSIONS

Patients with heterotaxy syndrome are at high risk for community-acquired severe bacterial infection and also have high mortality rate whether the spleen is present or not. The risk of nosocomial severe bacterial infection seems similar to that of patients with other complex CHD.

A suggested new surgical classification for mixed totally anomalous pulmonary venous connection

The morphologic variations of mixed totally anomalous pulmonary venous connection are many and varied. In this review, we give an account of all cases previously described as mixed totally anomalous pulmonary venous connection, analyzing in detail those cases where an accurate anatomical description was provided. We identified 182 suitable cases, from 54 investigations, and reviewed the clinical presentation, anatomic variations, diagnostic features, and management of the patients described.Cross-sectional echocardiography, and cardiac catheterization, provided the necessary diagnostic information, and defined the anatomy before surgery in 139 patients. Magnetic resonance imaging and computerized tomographic angiography had been used for further clarification of the pulmonary venous anatomy. An obstructive pattern of drainage, involving one or more pulmonary veins, had been described in over half of the patients. We then grouped the lesions into categories that have a bearing on the appropriate surgical approach, discussing the appropriate repair for each group. For the overall group, the operative mortality remains high, at 22.9%. We submit that an increased appreciation of various types of mixed totally anomalous pulmonary venous connection may well contribute to improved future surgical management.

Clinical investigations over 13 years to establish the nature of the cardiac defects in patients having abnormalities of lateralization

INTRODUCTION

The first step in diagnosing congenital cardiac malformations is to assess the arrangement of the atrial appendages. In patients with abnormal lateralization of the organs of the body, the arrangement of atrial appendages is neither normal, nor a mirror image of normal. There are 2 categories of abnormal arrangement based on the morphology of the atrial appendices, namely right isomerism and left isomerism, and in almost all instances these are found in the setting of so-called heterotaxy syndromes.

OBJECTIVE

To evaluate the various congenital cardiac malformations those are associated with abnormalities of lateralization, and to discuss the diagnostic tools, therapeutic options, and outcome for these patients.

PATIENTS AND METHODS

We studied 134 patients, who had been admitted to our department of paediatric cardiology with known abnormalities of lateralization and congenital cardiac defects between 1990 and 2003. The data relating to each patient was evaluated retrospectively. The arrangement of the atrial appendages was established echocardiographically, and/or angiographically, and/or on the basis of morphologic investigations during the operation. These studies showed that 43 (32.1%) of the patients had right isomerism, and 88 (65.7%) had left isomerism. In 2 (1.5%), there was mirror-imaged arrangement, while in the final patient (0.07%), we were unable to determine sidedness with certainty. The median age at diagnosis was 0.66 years, and the females outnumbered the males in a ratio of 3 to 1. Patients in the 2 isomeric groups were compared with regard to age, cardiac defects, diagnostic tools and outcomes.

RESULTS

The difference in mean ages of the two groups of patients was statistically significant, those with right isomerism being 1.0 minus or plus 1.5 years, as opposed to those with left isomerism being 3.3 minus or plus 4.7 years (P is less than 0.005). Of the patients with right isomerism, 32 (74.4%) had left-sided, and 11 (25.6%) right-sided hearts, whereas in those with left isomerism, the hearts were left-sided in 65 (73.9%), and right-sided in 21 (23.9%), with 2 (2.2%) positioned in the midline. Extracardiac totally anomalous pulmonary venous connection was more common in those with right isomerism, being found in 13 patients (30.2%) as opposed to 5 patients (5.7%) with left isomerism. In only 8 of those with right isomerism did we find two perforate atrioventricular valves (18.6%), this arrangement being found in 34 (38.6%) of those with left isomerism. Pulmonary atresia and stenosis were present in 40 (93.0%) of those with right isomerism, but also in 41 (46.6%) of the patients with left isomerism. Angiographic and echocardiographic investigations were concordant in about three-quarters of patients with both right and left isomerism. All patients with extracardiac totally anomalous pulmonary venous connection died. Overall, 22 of the patients with right isomerism died (51.2%), as opposed to 20 (22.7%) of those with left isomerism.

CONCLUSION

Our experience confirms that patients with right isomerism have more complex cardiac defects than those with left isomerism. Overall, the presence of isomerism carries a poor prognosis, the more so for right isomerism, with this related to the complex cardiac abnormalities. In our cohort, extracardiac totally anomalous pulmonary venous connection with pulmonary arterial obstruction was always a fatal combination. The mapping of cardiac and abdominal morphologies is still essential for proper diagnosis of these syndromes, especially in fetal life.

Noninvasive diagnostics in congenital heart disease: echocardiography and magnetic resonance imaging

The ability to noninvasively diagnose even the most complex congenital heart disease is one of the greatest advances in the care of children with cardiac defects. Initially, two-dimensional echocardiography displayed anatomy; later, Doppler allowed the quantitation of pressure and flow. Using these modalities, cardiac catheterization is unnecessary for most children with cardiac defects. Echocardiography also is routinely used for intraoperative and fetal cardiac imaging. Three-dimensional magnetic resonance imaging can now quantitate volumes of irregular shaped heart chambers (eg, the right ventricle) and blood flow (eg, as from a leaking valve). As technology moves further into the digital age, developments will continue to facilitate noninvasive diagnosis and treatment of children with congenital heart disease.

Sudden death in patients with right isomerism (asplenism) after palliation

OBJECTIVE

To define the risk of sudden death in patients with right isomerism (asplenia) after palliation.

STUDY DESIGN

A total of 154 patients with right isomerism was identified from 1980 to 1999. Sudden death was defined as acute cardiovascular collapse from which death occurred within 24 hours.

RESULTS

A total of 620 patient-years were evaluated. The 1-year and 5-year survival was 72% and 50%, respectively. There were 22 sudden unexpected deaths (14%, 35 events/1000 patient-years). Sudden death tended to occur in infancy or early childhood (12 +/- 9 months; median, 9 months). The mechanisms were classified as sudden tachyarrhythmic in 2 (9%), sudden cardiac but nontachyarrrhythmic (sudden onset severe cyanosis) in 15 (68%), and sudden noncardiac in 5 (23%)(fulminant sepsis with positive blood culture: streptococcus pneumonia (3), Escherichia coli (1), and yeast-like organism (1)). The incidence of sudden death steadily decreased with age until the age of 3 years.

CONCLUSION

The incidence of sudden death in patients with right isomerism after initial palliation remained high. Sudden death was related to complex cardiac anomalies, a susceptibility to fulminant infection, and arrhythmia.

Efficacy of MRI in complicated congenital heart disease with visceral heterotaxy syndrome

PURPOSE

The authors' goal was to assess the diagnostic accuracy and clinical effect of MRI compared with echocardiography and catheterization in the evaluation of cardiac defects with situs ambiguous.

METHOD

Twenty-two patients with visceral heterotaxy syndrome were included.

RESULTS

Because situs determined by the relation between the pulmonary artery and bronchi showed most predominantly a tendency toward lateralization, this was regarded as the standard reference of situs determination. For the purpose of this study, patients were classified as having right isomerism (n = 13) or left isomerism groups (n = 9). MRI has several advantages compared with echocardiography or cardiac angiography for examining patients with situs ambiguous. (1) The bronchial, pulmonary arterial, and splenic situs can be readily determined, and discrepancies (n = 2) can be assessed easily. (2) Venoatrial connections are adequately imaged. In particular, all types of total and partial anomalous pulmonary venous return are delineated, regardless of whether restrictions of pulmonary blood flow or pulmonary venous obstructions are involved (n = 4). The courses of vertical veins were easily identified, and the prearterial position was revealed in only one of seven right isomerisms with total anomalous pulmonary venous return. The drain pattern of the hepatic vein can be visualized using three-dimensional spatial information and is useful for total cavopulmonary connection design. (3) Associated complicated cardiac anomalies, particularly the size or peripheral stenosis of the pulmonary arteries, may be evaluated, and this information is useful for palliative shunt operations.

CONCLUSION

Because of its wide field of view and imaging, which is not restricted by associated anomalies, a thorough understanding of the cardiovascular anatomy of the situs ambiguous can be achieved using MRI, which is of considerable value in the surgical correction of this complicated anomaly. MRI can obviate or facilitate catheterization in these critically ill patients.

Supraventricular tachycardia in patients with right atrial isomerism

OBJECTIVES

To clarify the prevalence and mechanism of supraventricular tachycardia in patients with right atrial isomerism.

BACKGROUND

Paired SA and dual atrioventricular (AV) nodes have been described in patients with right atrial isomerism. However, the clinical significance remains unclear.

METHODS

From 1987 to 1996, a total of 101 patients (61 male, 40 female) and four fetuses were identified with right atrial isomerism. The diagnosis of supraventricular tachycardia exclude the tachycardia with prolonged QRS duration or AV dissociation, and primary atrial tachycardia.

RESULTS

The median follow-up duration was 38 months (range 0.2-270 months). Supraventricular tachycardia was documented in 25 patients (24.8%) and one fetus (25%) (onset age ranged from prenatal to 14 years old; median 4 years old). Actuarial Kaplan-Meier analysis revealed that the probability of being free from tachycardia was 67% and 50% at 6 and 10 years of age, respectively. These tachycardias could be converted by vagal maneuvers in one, verapamil in seven, propranolol in four, digoxin in two, procainamide in one, and rapid pacing in five. Spontaneous conversion was noted in six (including the fetus). Seven cases had received electrophysiological studies. Reciprocating AV tachycardia could be induced in five and echo beats in one. The tachycardia in three patients was documented as incorporating a posterior AV node (antegrade) and an anterior or a lateral AV node (retrograde). Two of them received radiofrequency ablation. Successful ablation in both was obtained by delivering energy during tachycardia, aimed at the earliest retrograde atrial activity and accompanied by junctional ectopic rhythm. The patient with echo beats developed tachycardia soon after operation.

CONCLUSIONS

Supraventricular tachycardia is common in patients with right atrial isomerism and can occur during the prenatal stage. Drugs to slow conduction through the AV node may help to terminate the tachycardia. Radiofrequency ablation is a safe and effective treatment alternative to eliminate tachycardia.

MRI and echocardiography in children: how do they compare?

Clearly, both echocardiography and MRI play vital roles in the diagnosis and management of children with congenital heart defects. 2-D Doppler echocardiography is very easy to use in a vast array of clinical situations. The accuracy of the anatomic and hemodynamic findings are well accepted. In comparative studies, 2-D Doppler echocardiography appears preferable for intracardiac anatomy, whereas MRI appears preferable for extracardiac anatomy. In certain patients, Doppler echocardiography may not be able to optimally obtain the anatomic or hemodynamic information, and MRI should be used in these particular cases.

Usefulness of electron beam computed tomography in children with heterotaxy syndrome

Children with heterotaxy syndrome frequently have complex cardiac and noncardiac malformations requiring detailed diagnostic evaluation for management planning. Direct delineation of these structures by electron beam computed tomography (EBCT) is validated as a means of diagnosis. From July 1995 to March 1997, 32 patients (16 girls, 16 boys) with clinically impressed heterotaxy syndrome were enrolled in this study. After evaluation by echocardiography, EBCT studies were performed. Interpretation of cardiac anomalies was performed by sequential analysis based on these cross-sectional images. The diagnoses were subsequently confirmed by angiocardiography and surgical findings. Twenty-eight patients had bilateral trifurcated bronchi, and most of these (24 of 28) did not have a spleen. Four patients had bilateral bifurcated bronchi, 2 patients had polysplenia, and the other 2 patients had a lobulated single spleen. We found that laterality could be identified by EBCT in all patients. Comparison of diagnostic yield between echocardiography, catheterization, and EBCT showed that EBCT is superior to echocardiography and catheterization in demonstration of pulmonary venous anatomy and presence of a very small rudimentary ventricle. In addition, associated visceral, bronchopulmonary, mediastinal, and intracardiac anomalies could all be clearly delineated by EBCT at the same time. Thus, EBCT is a promising complementary modality for an overall understanding of heterotaxy syndrome.

Mixed total pulmonary venous drainage: still a surgical challenge

OBJECTIVE

The aim of this report is to review the surgical experience of a single institution with a relatively large series of patients with mixed total pulmonary venous drainage.

PATIENT POPULATION

Between January 1, 1971, and December 31, 1994, 232 patients with total pulmonary venous drainage underwent surgical correction. Twenty of these patients (8.6%) had mixed type total pulmonary venous drainage. Ages at operation ranged from 1 day to 46 months, with a median of 2.3 months.

RESULTS

Both cardiac catheterization and echocardiography were performed before operation in 12 patients. Four patients underwent only cardiac catheterization, and another four patients underwent only echocardiography. The sensitivity and specificity for catheterization were 94% and 99%, respectively; they were 31% and 100%, respectively, for echocardiography. Severe pulmonary venous obstruction was present in three patients, all of whom underwent emergency operation. Three patients (15%), all of whom had preoperative pulmonary venous obstruction, died after operation. There were two late deaths, one of pulmonary vein stenosis and the other of probable pulmonary hypertension. The actuarial survival at 10 years was 73% for all patients; patients who survived the initial operation had a 10-year survival of 87%.

CONCLUSION

The diagnosis of mixed total pulmonary venous drainage can be difficult to establish by echocardiography or at the time of operation. For patients in stable condition, cardiac catheterization may be considered if fewer than three pulmonary veins are identified by echocardiography. Pulmonary venous obstruction is relatively infrequent in this group of patients but when present impacts patient survival significantly. The long-term results with this lesion are excellent.

Defects in the determination of left-right asymmetry

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