Truncus Arteriosus Research Articles

Sirenomelia Associated with Truncus Arteriosus

Sirenomelia is a sporadic congenital anomaly caused by a disruptive vascular defect. This syndrome is characterized by fusion of the lower extremities, almost invariably associated with bilateral renal agenesis and generally absence of sacrum, rectum and bladder. In this case, the bilateral renal agenesis was present with severe oligohydramnios, in association with other anomalies as single umbilical artery and ambiguous external genitalia, which are often found in other cases publicated, and truncus arteriosus type IV. This latter association has been never described before in the revision of the literature.

Deletions in 14q24.1q24.3 are associated with congenital heart defects, brachydactyly, and mild intellectual disability

Interstitial deletions of chromosome band 14q24.1q24.3 are apparently very rare. We report on three unrelated patients with overlapping de novo deletions of sizes 5.4, 2.8, and 2.3 Mb in this region. While some clinical problems such as intestinal malrotation, cryptorchidism, and ectopic kidney were only observed in single patients, all three patients had mild intellectual disability, congenital heart defects (truncus arteriosus, pulmonary atresia, atrial septal defect, and/or ventricular septal defect), brachydactyly, hypertelorism, broad nasal bridge, and thin upper lips. Likely haploinsufficiency of one or several of the 19 genes in the common deleted interval (ACTN1, DCAF5, EXD2, GALNTL1, ERH, SLC39A9, PLEKHD1, CCDC177, KIAA0247, LOC100289511, SRSF5, SLC10A1, SMOC1, SLC8A3, ADAM21P1, COX16, SYNJ2BP, SYNJ2BP-COX16, ADAM21) was responsible for these manifestations, but apart from SMOC1, mutations in which cause autosomal recessive Waardenburg anophthalmia syndrome, and ACTN1, mutations in which are associated with congenital macrothrombocytopenia, no disease associations have so far been reported for the other genes. Functional studies and a systematic search for mutations or chromosome aberrations in this region will elucidate the role of individual genes in the clinical manifestations and will provide insight into the underlying biological mechanisms.

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Introduction: Nearly 2.9 billion passengers are transported every year in commercial airline flights, many of whom are children. When a serious medical emergency arises during flight, care is provided by crew members and passenger volunteers with a medical background, frequently in consultation with a specialized remote medical control center. Although in-flight medical emergencies and fatalities are well characterized for adults, data on pediatric subjects are lacking. Methods: We reviewed the records of all in-flight emergencies from January 2010 to June 2013 involving children (ages 0 to 18 years) treated in consultation with the world’s busiest global response center providing remote medical support to commercial airlines. This center is staffed by physicians trained in airline protocols, procedures and in-flight resources. De-identified data were abstracted by one of the authors and analyzed with descriptive statistics. Results: During the study period there were a total of 81,104 in-flight medical emergencies, including 7,573 (9.3%) involving children. There were 10 pediatric deaths (0.13% of all pediatric in-flight emergencies), or 0.025 deaths/million passengers transported. Of these, 5 were males. The overall median age was 3.5 months (range 1 month to 15 years) with 90% younger than 2 years, the age until which children are allowed to travel seated with an adult. Highest health care rank of in-flight responder was physician in 6 cases, crew in 2, nurse in 1 and EMT in 1. An AED was employed in 40% of the cases. Five patients had no previous medical history, with one arresting after developing respiratory distress and 4 found asystolic (including 3 lap infants). Five patients had pre-flight medical conditions, including 2 traveling for medical care (a 6 month-old with unspecified medical issues accompanied by a doctor and a 1 month old with cardiomegaly), a 2 month-old with truncus arteriosus, a 4 month-old with lethargy and a 12 month-old with fever, diarrhea and vomiting. An unscheduled landing (diversion) occurred in 50% of the flights in which a passenger death occurred. Conclusions: Pediatric in-flight medical emergencies rarely result in death, but death is most common in infants and those with a pre-existing medical condition. The high share of fatalities involving children under the age of 2 years (lap infants) is intriguing and warrants further study, particularly as co-sleeping has been implicated in sudden infant death syndrome.

Transposition of the great arteries with ventricular septal defect and left ventricular outflow tract obstruction: how to choose in the surgical armamentarium?

The surgical treatment of transposition of the great arteries (TGA) with ventricular septal defect (VSD) and left ventricular outflow tract obstruction (LVOTO) is currently a matter of passionate debate. Classical procedures [i.e. Rastelli and reparation a l’Etage ventriculaire (REV) operations] are still favoured by most centres. Introduced in 1984, the Nikaidoh procedure (actually a modification of an operation performed several years earlier by Bex to repair simple TGA) is gaining widespread acceptance. Kramer et al. [1] report their experience with the Nikaidoh procedure and its modification with preservation of the native pulmonary valve (en bloc rotation of the truncus arteriosus). Their results confirm those of other recent series. Despite encouraging mid-term results, the complexity of the procedure, the anatomical contraindications (mainly related to coronary anatomy) and the potential late complications (e.g. aortic regurgitation and coronary obstructions) cannot be underestimated. We, therefore, think that it is too early to endorse the authors’ conclusion that the current results ‘make the aortic translocation the procedure of choice for the treatment of this lesion (TGA/ VSD/LVOTO)’. On the contrary, we believe that all surgical options must be taken into consideration, and that the optimal repair should be chosen on an individual basis. Preoperative evaluation is essential and must be performed in close collaboration between the cardiologist and the cardiac surgeon. Careful echo-Doppler assessment is the key point, although it may be completed using new imaging techniques (particularly 3D reconstruction). Several features of a complex intracardiac anatomy must be fully delineated, including position and size of the VSD, position and size of the conal septum, potential insertions of tricuspid or mitral chordae onto the conal septum and anatomy of the obstructed left ventricular outflow tract. This last element is essential in the decisionmaking. The anatomy of the subvalvar obstruction must be analysed to determine whether it can be relieved surgically or not. Even more important, the evaluation of the valvar area (size of the annulus and anatomy of the leaflets) must ascertain whether the native pulmonary valve is subnormal and able to serve as aortic valve or abnormal but good enough to serve as pulmonary valve or severely dysplastic and not usable. At the end of the evaluation, the best surgical option can be selected, keeping in mind some simple principles: (i) the operative risk should be low, and therefore, the operation kept as simple as possible, (ii) unobstructed left and right ventricular outflow tracts must be reconstructed, (iii) some surgical manoeuvres with potential early and late deleterious consequences (e.g. transfer of the coronary arteries, translocation of the native aortic root, extensive septal resection, mobilization of tricuspid or mitral chordae) should be used with caution and (iv) prosthetic extracardiac conduits (with the inevitable need for multiple reoperations) must be avoided. Our current indications can be summarized as follows:

Perioperative mechanical circulatory support in children: An analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

Analyses of mechanical circulatory support (MCS) in pediatric heart surgery have primarily focused on single-center outcomes or narrow applications. We describe the patterns of use, patient characteristics, and MCS-associated outcomes across a large multicenter cohort. Patients (aged <18 years) in the Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (2000-2010) were included. The characteristics and outcomes of those receiving postoperative MCS were described, and bayesian hierarchical models were used to examine variations in the adjusted MCS rates across institutions. Of 96,596 operations (80 centers), MCS was used in 2.4%. The MCS patients were younger (13 vs 195 days, P < .0001) and more often had STS-defined preoperative risk factors (57.2% vs 32.7%, P < .0001). The operations with the greatest MCS rates included the Norwood procedure (17%) and complex biventricular repairs (arterial switch, ventricular septal defect, and arch repair [14%]). More than one half of the MCS patients did not survive to hospital discharge (53.2% vs 2.9% of non-MCS patients; P < .0001). MCS-associated mortality was greatest for truncus arteriosus and Ross-Konno operations (both 71%). The hospital-level MCS rates adjusted for patient characteristics and case mix varied by 15-fold across institutions, with both high- and low-volume hospitals having substantial variation in MCS rates. Perioperative MCS use varied widely across centers. The MCS rates were greatest overall for the Norwood procedure and complex biventricular repairs. Although MCS can be a life-saving therapy, more than one half of MCS patients will not survive to hospital discharge, with mortality >70% for some operations. Future studies aimed at better understanding the appropriate indications, optimal timing, and management of MCS could help to reduce the variation in MCS use across hospitals and improve outcomes.

Heparan sulfate expression in the neural crest is essential for mouse cardiogenesis

Impaired heparan sulfate (HS) synthesis in vertebrate development causes complex malformations due to the functional disruption of multiple HS-binding growth factors and morphogens. Here, we report developmental heart defects in mice bearing a targeted disruption of the HS-generating enzyme GlcNAc N-deacetylase/GlcN N-sulfotransferase 1 (NDST1), including ventricular septal defects (VSD), persistent truncus arteriosus (PTA), double outlet right ventricle (DORV), and retroesophageal right subclavian artery (RERSC). These defects closely resemble cardiac anomalies observed in mice made deficient in the cardiogenic regulator fibroblast growth factor 8 (FGF8). Consistent with this, we show that HS-dependent FGF8/FGF-receptor2C assembly and FGF8-dependent ERK-phosphorylation are strongly reduced in NDST1−/− embryonic cells and tissues. Moreover, WNT1-Cre/LoxP-mediated conditional targeting of NDST function in neural crest cells (NCCs) revealed that their impaired HS-dependent development contributes strongly to the observed cardiac defects. These findings raise the possibility that defects in HS biosynthesis may contribute to congenital heart defects in humans that represent the most common type of birth defect.

Isolated truncus arteriosus associated with a mutation in the plexin‐D1 gene

Truncus arteriosus accounts for approximately 1% of congenital heart defects and the cause of isolated non-syndromic truncus arteriosus is largely unknown. In order to identify the underlying molecular defect in a consanguineous family with recurrent tuncus arteriosus, homozygosity mapping followed by whole exome sequencing was performed. This resulted in the identification of a homozygous mutation, Arg1299Cys, in the PLXND1 gene. The mutation affected a highly conserved residue, segregated with the disease in the family and was absent from available SNP databases and ethnic matched controls. in silico comparative modeling revealed that the mutation resides in the N-terminal segment of the human plexin-D1 intracellular region which interacts with the catalytic GTPase-activating protein homology region. The mutation likely destabilizes the intracellular region, perturbing its anchoring and catalytic activity. The phenotype in human PLXND1 mutation is closely related to that of knockout mice for PLXND1, its co-receptor neuropilin-1 or its ligand SEMA3C. It is therefore suggested that SEMA3C signaling, propagated through the heterodimer receptor plexin-D1/neuropilin, is important for truncus arteriosus septation. Confirmation of this observation will require the identification of PLXND1 mutations in additional patients. Exome analysis is valuable for molecular investigation of single patients with congenital heart defects in whom chromosomal copy number variants have been excluded.

Truncus Arteriosus with Persistent Left Superior Vena Cava: Cardiac Computed Tomography Findings in an Unrepaired Adult Patient

Truncus arteriosus (TA), a rare complex congenital cardiac disease in which systemic pulmonary and coronary circulations originate from a common vessel, develops due to failure of separation of the common trunk during embryonic life. In this case report, we discuss a 24-year-old patient with TA in whom a computed tomography angiography was performed. To the best of our knowledge, no case has been reported so far where an adult had combined left superior vena cava and pulmonary vein anomaly.

CASE 10—2014Eisenmenger Syndrome: Close the Hole?

EISENMENGER SYNDROME (ES) was first referred to by Wood in 1951, further refined by him in 1958, and is currently defined as the presence of a large congenital cardiac defect permitting increased pulmonary blood flow and transmission of elevated pressures to the pulmonary circulation causing a balanced or predominant right-to-left shunt secondary to a fixed and markedly elevated pulmonary vascular resistance.1,2 ES can develop in the setting of a number of congenital cardiac defects, including a ventricular septal defect (VSD), a large atrial septal defect (ASD), a patent ductus arteriosus (PDA), an aortopulmonary window, and/or a truncus arteriosus.

The clinical study on the medium-term and late prenatal cardiac malformation screening by doppler ultrasound

Objective To investigate the role of color Doppler ultrasound in the middle and late fetal heart malformations screening and inspection methods.Methods The analysis of 38 cases of fetal malformation of the heart in our hospital from January 2010 to December 2012 and observe a variety of cardiac malformations in different facets of ultrasound performance.Results 38 cases of fetal congenital heart disease were diagnosed by color Doppler ultrasound,which included tetralogy of Fallot in 7 cases (18.42％),6 cases (15.79％) of atrioventricular septal defect,4 cases(10.53％) of single atrium single ventricle,right ventricular dysplasia 3 cases(7.89％),4 cases(10.53％)of left ventricular hypoplasia and 4 cases(10.53％) of partial endocardial cushion defect,3 cases(7.89％) of complete endocardial cushion defect,3 cases (7.89％) of the great arteries transposition,1 (2.63 ％) of pure pulmonary stenosis,2 cases(5.26％) of persistent truncus arteriosus and dextrocardia one cases(2.63％).The pregnant women with high-risk factors were 25 cases(65.79％).20 cases(52.63％) were diagnosed by single four-chamber detection,FCV + (AR-SAV) detected 24 cases(63.16％),higher than the FCV section diagnosis rate(x2 =34.61,P ＜0.05);FCV + VOTV,FCV and + 3VV and FCV + 3VVT section diagnosis rates were 30 (78.95％),37 (97.37％)and 37 (97.37％) respectively,which were significantly higher than FCV section (x2 =35.06,37.22,38.14,P ＜0.05).FCV + 3VV and FCV + 3VVT were significantly higher than the other three facets(x2 =33.97,38.10,34.24,39.02,33.89,35.63,P ＜ 0.05).Conclusion It is important for screening fetal congenital heart disease by Color Doppler ultrasound.The different ultrasonic slice can improve the diagnosis of late fetal heart malformations. Key words: Ultrasonography, doppler, color; Cardiovascular abnormalities; Fetus

Clinical Neurological, and Functional Outcomes in Patients Having Undergone Truncus Arteriosus Repair: a Cohort Study

Truncus arteriosus (TA) is an uncommon congenital cardiac lesion that portends an exceedingly poor prognosis if not repaired. The objective of this study was to assess clinical, survival and early childhood neurological and functional outcomes in a cohort who underwent TA repair and were followed prospectively.

Inactivation of Cdc42 in neural crest cells causes craniofacial and cardiovascular morphogenesis defects

Neural crest cells (NCCs) are physically responsible for craniofacial skeleton formation, pharyngeal arch artery remodeling and cardiac outflow tract septation during vertebrate development. Cdc42 (cell division cycle 42) is a Rho family small GTP-binding protein that works as a molecular switch to regulate cytoskeleton remodeling and the establishment of cell polarity. To investigate the role of Cdc42 in NCCs during embryonic development, we deleted Cdc42 in NCCs by crossing Cdc42 flox mice with Wnt1-cre mice. We found that the inactivation of Cdc42 in NCCs caused embryonic lethality with craniofacial deformities and cardiovascular developmental defects. Specifically, Cdc42 NCC knockout embryos showed fully penetrant cleft lips and short snouts. Alcian Blue and Alizarin Red staining of the cranium exhibited an unfused nasal capsule and palatine in the mutant embryos. India ink intracardiac injection analysis displayed a spectrum of cardiovascular developmental defects, including persistent truncus arteriosus, hypomorphic pulmonary arteries, interrupted aortic arches, and right-sided aortic arches. To explore the underlying mechanisms of Cdc42 in the formation of the great blood vessels, we generated Wnt1Cre-Cdc42-Rosa26 reporter mice. By beta-galactosidase staining, a subpopulation of Cdc42-null NCCs was observed halting in their migration midway from the pharyngeal arches to the conotruncal cushions. Phalloidin staining revealed dispersed, shorter and disoriented stress fibers in Cdc42-null NCCs. Finally, we demonstrated that the inactivation of Cdc42 in NCCs impaired bone morphogenetic protein 2 (BMP2)-induced NCC cytoskeleton remodeling and migration. In summary, our results demonstrate that Cdc42 plays an essential role in NCC migration, and inactivation of Cdc42 in NCCs impairs craniofacial and cardiovascular development in mice.

Morphological and molecular bases of cardiac development

The heart is a mesoderm-derived organ, whose formation is regulated by various genes. Initially, the most important is expression of Nkx2.5, CR1, pitx2, anf and mhc2a, which are responsible for differentiation of cardiomyocytes. In a later phase activation of mhc2b, pitx2c, mesp1, pcmf1, vmhc, xin, mcl2v, mlc2a, mlc2a, mef2, hand1 and hand2 was revealed. Their expression is regulated by various molecules, including transcription (XIN, GATA, MEF, Tbx5, Baf60c, PECAM, tie-2, MEF2) and growth (VEGF, FGF, PDGF) factors, as well as proteins (i.e., dickkopf-1, cerberus, cytotactin, fibrillin, nodal, thrombomodulin, Wnt, bone morphometric ones - BMP2, BMP 4, BMP5, BMP7) and other substances, such as retinoid and folic acid. Crucial steps in cardiac organogenesis are development of the ventricle and atrial formation, as well as septation and valve formation. Any disturbances of such processes may lead to various congenital heart diseases and defects that could be initiated by various genetic, epigenetic or environmental factors. The most common heart malformations are: stenosis (coarctation) of the aorta and pulmonary trunk, bicuspid aortic valve, atrial and/or ventricular septal defect, persistent truncus arteriosus (Botallo duct), transposition of the great vessels, tricuspid atresia, hypoplastic left and right heart, as well as syndrome of Lutembachera, Cantrell, Ebstein, Eisenmenger and Shone and trilogy, tetralogy, pentalogy of Fallot.

Malignant Hyperthermia-Like Manifestations in a Two-Month-Old Child With Holt-Oram Syndrome Undergoing Cardiac Surgery

HOLT-ORAM SYNDROME (HOS) is a rare congenital disorder associated with limb abnormalities, structural cardiac defects, and cardiac arrhythmias due to various abnormalities in TBX5, a member of the T-box gene family. Children with this disorder frequently present for orthopedic and congenital cardiac surgery. HOS may manifest with minor structural cardiac defects such as atrial septal defects or ventricular septal defects, though more complex defects such as hypoplastic left heart or truncus arteriosus have been reported. In addition, abnormal TBX5 gene products are implicated in the abnormal development of the cardiac conduction system, resulting in various cardiac arrhythmias. The genetic basis of the cardiac abnormalities associated with HOS is incompletely understood at present though abnormalities in ion conduction, particularly potassium conduction, may lead to atrial tachyarrhythmia. The authors present the case of an infant with HOS who underwent congenital cardiac surgery, developed intraoperative findings suspicious for malignant hyperthermia (MH), and responded favorably to standard MH treatment.

Tricuspid Atresia Associated with Truncus Arteriosus versus Aortopulmonary Window: Combining Fetal and Postnatal Echocardiography to Make the Diagnosis

The coincident occurrence of tricuspid atresia and aortopulmonary window (APW) is exceedingly rare, with one previous case reported in the literature. We present a patient with tricuspid atresia, pulmonary atresia, and APW. Postnatal echocardiograms demonstrated no visible pulmonary valve, and additional defects including a bicuspid aortic valve, right aortic arch and anomalous coronary arteries raised suspicion for tricuspid atresia with persistent truncus arteriosus. However, fetal echocardiography and direct visualization of the anatomy confirmed the alternate diagnosis. The patient underwent successful palliation consisting of APW repair, atrial septectomy and a 3.5mm modified Blalock-Taussig shunt, followed by a bidirectional cavopulmonary connection.

Risk and protective factors in the origin of conotruncal defects of heart—a population‐based case–control study

Congenital heart defect (CHD) cases have been evaluated together as a group in some previous epidemiological studies. However, different CHD entities have different etiologies, and the underlying causes are unclear in the vast majority of patients. Thus the aim of this study was to analyze the possible association of different maternal diseases with the risk of four types of conotruncal defects (CTD), that is, truncus arteriosus, d-transposition of the great arteries, tetralogy of Fallot, and double-outlet right ventricle based on autopsy or surgical report diagnosis. Acute and chronic diseases with related drug treatments and peri-conceptual folic acid or multivitamin supplementations were compared in mothers of 598 CTD cases, of 902 matched controls, and 38,151 population controls without any defects, and with 20,896 malformed controls with other isolated non-cardiac defects in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities. Mothers who had medically recorded influenza and the common cold with secondary complications in the prenatal maternity logbook during the second and/or third gestational months were associated with a higher risk of CTD (OR with 95% CI: 2.22, 1.19-3.88). The common denominator of these maternal diseases may be high fever, which could be prevented by antifever therapies. On the other hand, high doses of medically recorded folic acid in early pregnancy were able to reduce the birth prevalence of CTD (OR with 95% CI: 0.54, 0.39-0.73), and this reduction was significant in transposition of the great arteries (0.46, 0.29-0.71) as well. In conclusion, high fever related maternal diseases may have a role in the origin of CTD, while high doses of folic acid in early pregnancy were able to reduce of CTD, particularly transposition of great vessels.

Novel Coronary Artery Anomaly in an English Bulldog with Pulmonic Stenosis

Novel Coronary Artery Anomaly in an English Bulldog with Pulmonic Stenosis

Bmp signaling repressesVegfato promote outflow tract cushion development

Congenital heart disease (CHD) is a devastating anomaly that affects ∼1% of live births. Defects of the outflow tract (OFT) make up a large percentage of human CHD. We investigated Bmp signaling in mouse OFT development by conditionally deleting both Bmp4 and Bmp7 in the second heart field (SHF). SHF Bmp4/7 deficiency resulted in defective epithelial to mesenchymal transition (EMT) and reduced cardiac neural crest ingress, with resultant persistent truncus arteriosus. Using a candidate gene approach, we found that Vegfa was upregulated in the Bmp4/7 mutant hearts. To determine if Vegfa is a downstream Bmp effector during EMT, we examined whether Vegfa is transcriptionally regulated by the Bmp receptor-regulated Smad. Our findings indicate that Smad directly binds to Vegfa chromatin and represses Vegfa transcriptional activity. We also found that Vegfa is a direct target for the miR-17-92 cluster, which is also regulated by Bmp signaling in the SHF. Deletion of miR-17-92 reveals similar phenotypes to Bmp4/7 SHF deletion. To directly address the function of Vegfa repression in Bmp-mediated EMT, we performed ex vivo explant cultures from Bmp4/7 and miR-17-92 mutant hearts. EMT was defective in explants from the Bmp4/7 double conditional knockout (dCKO; Mef2c-Cre;Bmp4/7(f/f)) and miR-17-92 null. By antagonizing Vegfa activity in explants, EMT was rescued in Bmp4/7 dCKO and miR-17-92 null culture. Moreover, overexpression of miR-17-92 partially suppressed the EMT defect in Bmp4/7 mutant embryos. Our study reveals that Vegfa levels in the OFT are tightly controlled by Smad- and microRNA-dependent pathways to modulate OFT development.

Morbidity in children and adolescents after surgical correction of truncus arteriosus communis

Studies of outcome after operative correction of truncus arteriosus communis (TA) have focused on mortality and rates of reintervention. We sought to investigate the clinical status of children and adolescents with surgically corrected TA. A cross-sectional study of subjects with TA was performed. Subjects underwent concurrent genetic testing, electrocardiogram, cardiac magnetic resonance imaging, cardiopulmonary exercise testing, and completed questionnaires assessing health status and health-related quality of life. Review of their medical history provided retrospective information on cardiac reintervention and use of medical care. Twenty-five subjects with a median age of 11.8 (8.1-18.99) years were enrolled. The prevalence of 22q11.2 deletion was 32%. Incidence of hospitalization, cardiac reintervention, and noncardiac operations was highest in the first year of life. Combined catheter-based and operative reintervention rates were 52% on the conduit and 56% on the pulmonary arteries. Right ventricular ejection fraction and end-diastolic volume were normal. Moderate or greater truncal valve insufficiency was seen in 11% of subjects, and truncal valve replacement occurred in 8% of subjects. Maximal oxygen consumption (P = .0002), maximal work (P < .0001), and forced vital capacity (P < .0001) were all lower than normal for age and sex. Physical health status and health-related quality of life were both severely diminished. Patients with TA demonstrate significant comorbid disease throughout childhood, significant burden of operative and catheter-based reintervention, and deficits in exercise performance, functional status, and health-related quality of life.

Microcomputed Tomography Provides High Accuracy Congenital Heart Disease Diagnosis in Neonatal and Fetal Mice

Mice are well suited for modeling human congenital heart disease (CHD), given their 4-chamber cardiac anatomy. However, mice with CHD invariably die prenatally/neonatally, causing CHD phenotypes to be missed. Therefore, we investigated the efficacy of noninvasive microcomputed tomography (micro-CT) to screen for CHD in stillborn/fetal mice. These studies were performed using chemically mutagenized mice expected to be enriched for birth defects, including CHD. Stillborn/fetal mice obtained from the breeding of N-ethyl-N-nitrosourea mutagenized mice were formalin-fixed and stained with iodine, then micro-CT scanned. Those diagnosed with CHD and some CHD-negative pups were necropsied. A subset of these were further analyzed by histopathology to confirm the CHD/no-CHD diagnosis. Micro-CT scanning of 2105 fetal/newborn mice revealed an abundance of ventricular septal defects (n=307). Overall, we observed an accuracy of 89.8% for ventricular septal defect diagnosis. Outflow tract anomalies identified by micro-CT included double outlet right ventricle (n=36), transposition of the great arteries (n=14), and persistent truncus arteriosus (n=3). These were diagnosed with a 97.4% accuracy. Aortic arch anomalies also were readily detected with an overall 99.6% accuracy. This included right aortic arch (n=28) and coarctation/interrupted aortic arch (n=12). Also detected by micro-CT were atrioventricular septal defects (n=22), tricuspid hypoplasia/atresia (n=13), and coronary artery fistulas (n=16). They yielded accuracies of 98.9%, 100%, and 97.8%, respectively. Contrast enhanced micro-CT imaging in neonatal/fetal mice can reliably detect a wide spectrum of CHD. We conclude that micro-CT imaging can be used for routine rapid assessments of structural heart defects in fetal/newborn mice.