Partial atrioventricular canal defect and aortic coarctation associated with variants in GDF1 and NOTCH1 genes: A case report.

BACKGROUND: A peculiar subgroup of patients with partial or complete atrioventricular canal defect exhibits a spectrum of left-sided obstructions including right ventricular dominance and aortic coarctation. The association of atrioventricular canal defect with left-sided obstructions is found in several genetic syndromes; however, the molecular basis of nonsyndromic atrioventricular canal defect with aortic coarctation is still poorly understood. Although some candidate genes for nonsyndromic atrioventricular canal defect are known, a complex oligogenic inheritance determined in some cases by the co-occurrence of multiple variants has also been hypothesized. CASE REPORT: We describe a nonsyndromic infant with mesocardia with viscero-atrial situs solitus, partial atrioventricular canal defect, mild right ventricular dominance, and coarctation of the aorta. Next generation sequencing genetic testing revealed variants in two genes, GDF1 and NOTCH1, previously reported in association with atrioventricular canal defect and left-sided obstructive lesions, respectively. CONCLUSION: The present report could support the hypothesis that the co-occurrence of cumulative variants may be considered as genetic predisposing risk factor for specific congenital heart defects.

Human Genetics of Atrioventricular Septal Defect.

Atrioventricular septal defects (AVSD), also known as a common atrioventricular canal (CAVC), are clinically severe heart malformations that affect about 1 out of every 2100 live births. AVSD makes up about 5% of all congenital heart defects. AVSD is associated with cytogenetic disorders such as Down syndrome and numerous other rare genetic syndromes, but also occurs as a simplex trait. Studies in mouse models have identified over 100 genetic mutations that have the potential to cause an AVSD. However, studies in humans indicate that AVSD is genetically heterogeneous, and that the cause in humans is very rarely a single-gene defect. Familial cases do occur albeit rarely, usually with autosomal dominant inheritance and variable expression. In addition, the frequent occurrence of AVSD in some syndromes with known genetic causes such as heterotaxy syndrome points to additional genes/pathways that increase AVSD risk. Accordingly, while the genetic underpinnings for most AVSD remain unknown, there have been advances in identifying genetic risk factors for AVSD in both syndromic and nonsyndromic cases. This chapter summarizes the current knowledge of the genetic basis for AVSD.

Clinical Presentation and Therapy of Atrioventricular Septal Defect.

Atrioventricular septal defects (AVSDs) consist of a number of cardiac malformations that result from abnormal development of the endocardial cushions. AVSDs occur in 0.19 of 1000 live births and constitute 4-5 % of congenital heart defects. AVSDs can be categorized as incomplete (or partial) or complete, and intermediate or transitional.

Molecular Pathways and Animal Models of Atrioventricular Septal Defect.

The development of a fully functional four-chambered heart is critically dependent on the correct formation of the structures that separate the atrial and ventricular chambers. Perturbation of this process typically results in defects that allow mixing of oxygenated and deoxygenated blood. Atrioventricular septal defects (AVSD) form a class of congenital heart malformations that are characterized by the presence of a primary atrial septal defect (pASD), a common atrioventricular valve (cAVV), and frequently also a ventricular septal defect (VSD). While AVSD were historically considered to result from failure of the endocardial atrioventricular cushions to properly develop and fuse, more recent studies have determined that inhibition of the development of other components of the atrioventricular mesenchymal complex can lead to AVSDs as well. The role of the dorsal mesenchymal protrusion (DMP) in AVSD pathogenesis has been well-documented in studies using animal models for AVSDs, and in addition, preliminary data suggest that the mesenchymal cap situated on the leading edge of the primary atrial septum may be involved in certain situations as well. In this chapter, we review what is currently known about the molecular mechanisms and animal models that are associated with the pathogenesis of AVSD.

Predictors of post-operative left atrioventricular valve regurgitation in pediatric patients with complete atrioventricular canal defects.

BACKGROUND: In infants with complete atrioventricular canal (CAVC) defects, post-operative left atrioventricular valve regurgitation (LAVVR) is a known major cause of morbidity and mortality and a common indication for re-operation. However, there is scarce data to identify risk factors for poor outcomes. Our study aims to find echocardiographic characteristics that predict post-operative LAVVR at discharge and 1-year follow-up. METHODS: Retrospective cohort study of patients with initial CAVC repair at our hospital who were followed for 1 year between 2013 and 2022. Patients with major co-morbid conditions were excluded. Serial echocardiograms were reviewed. Anatomic details, quantitative and qualitative measure of LAVVR including the number of regurgitant jets, regurgitant jet length and vena contracta width, and ventricular function were collected. The time points measured include pre-operative transthoracic echocardiogram (TTE), post-operative transesophageal echocardiogram (PO-TEE), routine protocol based post-operative day 1 (POD1) TTE, discharge TTE and 1-year post-operative (1yPO) TTE. Paired t-tests, chi-square analysis, and linear regression analysis were performed comparing measured variables to LAVVR outcomes. RESULTS: Fifty-two patients were included; 92% had Trisomy 21. The majority were classified as Rastelli A (71%), others Rastelli C (29%). Only two patients had moderate or greater LAVVR pre-operatively. The mean age at repair was 125 ± 44 days. Pre-operative LAVVR was the only significant predictor of LAVVR severity at 1 year after backward stepwise regression. Of those with < moderate LAVVR on PO-TEE, 20% had worsening to ≥ moderate at discharge, but only 9% remained that way at 1 year. Of those with ≥ moderate LAVVR on PO-TEE, 40% improved to < moderate by 1 year. Two patients who worsened at 1 year, both secondary to likely cleft suture dehiscence. Only one patient required reoperation in the immediate post-operative period secondary to severe LAVVR due to suture dehiscence. Routine protocol-based POD1 echo did not have any association with altered outcomes. CONCLUSION: Pre-operative LAVVR was the only significant predictor of LAVVR severity at 1 year. A significant percentage (40%) of patient with ≥ moderate LAVVR on PO-TEE improved to < moderate by 1 year. Furthermore, routine protocol-based POD1 echo did not have any association with altered outcomes.

Fetal left and right ventricular strain parameters using speckle tracking in congenital heart diseases.

Assessment of fetal ventricular function is mostly subjective, and currently, for the objective assessment left ventricular shortening fraction is obtained. However, this by itself is not very reliable. Hence, more tools that can provide an objective assessment are needed to increase the confidence of functional assessment. Speckle tracking imaging can provide one such tool. In this study we sought to establish the normative value of global longitudinal and circumferential strain for our fetal patients and for two major forms of congenital heart diseases, namely atrioventricular canal defects (AVC) and uncorrected dextro-transposition of the great arteries (dTGA) to act as a benchmark. The study was completed via a single center retrospective analysis on 72 fetal echocardiograms (26 normal, 15 dTGA, and 31 AVC). Tomtec Arena™ echocardiography analysis software was used for analysis. In normal fetuses, mean left ventricular (LV) global longitudinal strain (GLS) was - 22.6% (95% CI -24, -21.1) and mean right ventricular (RV) GLS was - 22.1% (95% CI -23.6, -20.6). In AVC patients LV GLS was-26.6% (95% CI -28,-25.3) and mean RV GLS was - 26.5% (95% CI -27.9,-25.2). In dTGA patients LV GLS was - 22.9% (95% CI of -24.8, -21) and RV GLS was - 21.3% (95% CI was - 23.4, -20.8). There was good intra-rater reliability though poor to fair inter-rater reliability. Notwithstanding its current limitations, strain imaging can provide useful information that can increase confidence of cardiac functional assessment in fetal patients. However, to be reliable across the board, further automation and standardization is required.

Revisiting Atrioventricular Septal Defects: Exploring Chromosomal Abnormalities, Cardiac and Extracardiac Anomalies in a Contemporary Prenatal Cohort.

To estimate if there is an association between partial AVSD with chromosomal abnormalities, cardiac and extracardiac malformations, and to report the outcomes of prenatally diagnosed AVSD in a large, contemporary cohort. This is a retrospective cohort study of 190 prenatally diagnosed fetal AVSD between 2014 and 2023. Type of AVSD (complete vs partial), additional cardiac findings, extracardiac findings, presence of a heterotaxy, results of prenatal karyotype, and pregnancy outcomes were documented and analyzed. A total of 190 cases of fetal AVSD were analyzed. Complete AVSDs comprised 141 (74.2%) of the cohort, while partial AVSDs comprised 49 (25.7%). Karyotype was completed in 131 cases, and in 98 (74.8%) cases chromosomal abnormalities were identified, with trisomy 21 being the most common (53/131, 40.5%). Complete AVSDs were associated with trisomy 21 (45.5%, p = 0.04), Isolated cases of complete AVSDs (p = 0.03). Partial AVSDs were associated with trisomy 18 (53.1%, p < 0.001). In cases of partial AVSDs with aneuploidies, 7 (70%) had an ostium primum defect and 20 (90.9%) of AV canal type VSD. Isolated partial AVSD had no clear association with aneuploidies. There were additional cardiac anomalies in 96 (50.5%) and extracardiac anomalies in 134 (70.5%) of the cohort. There were no differences between partial and complete AVSD in rate of additional cardiac and extracardiac anomalies. AVSD was part of a heterotaxy in 47 (24.7%) of cases, and heterotaxy was associated with complete AVSD in the majority of cases (43/47, 91.4%, p = 0.003). Fetal partial AVSDs are associated with trisomy 18. Fetal complete AVSDs, even isolated, are associated with trisomy 21. There were no differences in association of other aneuploidies, additional cardiac findings, or extracardiac anomalies between prenatally diagnosed complete AVSDs and partial AVSDs.

Efficacy of atrioventricular valve regurgitation in the first trimester for the diagnosis of atrioventricular septal defect.

PURPOSE: To investigate the efficacy of atrioventricular valve regurgitation (AVVR) for predicting atrioventricular septal defect (AVSD) in the first trimester. METHODS: We performed a prospective observational study, screening for complicated congenital heart diseases and AVVR in fetuses at 11 to 13+6 weeks of gestation by advanced dynamic flow in four-chamber view and three-vessel-trachea view. RESULTS: 43 549 fetuses at 11 to 13+6 weeks of gestation were screened by echocardiography, of which 37 cases were diagnosed with AVSD, including complete AVSD (31 cases), intermediate AVSD (3 cases) and partial AVSD (1 cases), undiagnosed intermediate AVSD (2 cases), and misdiagnosed case (2 cases). AVVR was observed in 34 cases (34/37) in the first trimester, 59. 46% (22/37) nuchal translucency greater than 95th percentile, 29. 73% (11/37) absence of nasal bone, 32. 43% (12/37) ductus venosus A wave inversion, and 40. 54% (15/37) had tricuspid regurgitation. The sensitivity of common AVVR in predicting AVSD is better than other ultrasonic indexes. CONCLUSIONS: AVVR can be used as an ultrasonic indicator to predict AVSD in the first trimester, which is beneficial to detect AVSD.

Use of Interactive Visualization and 3D Printing in the Repair of Complex Congenital Heart Disease Presenting in Adult Life.

We report a case of a 25-year-old male with a heterotaxy-like constellation of congenital heart defects consisting of complete atrioventricular septal defect, transposition of the great arteries, subpulmonary stenosis, L-looped ventricles, hypoplastic right ventricle, and a distant aorta arising from the right ventricle. This case demonstrates how 3D printing and interactive 3D visualization may facilitate a unique surgical repair.

Association of tetralogy of Fallot and complete atrioventricular canal: a single-centre 40-year experience.

OBJECTIVES: Outcome data in tetralogy of Fallot (ToF) and complete atrioventricular canal (CAVC) are limited. We report our experience for over 40 years in this patient population. METHODS: Single-centre, retrospective analysis of patients who underwent surgical repair with the diagnosis of ToF-CAVC from 1979 to 2022, divided into 2 different periods and compared. RESULTS: A total of 116 patients were included: 1979-2007 (n = 61) and 2008-2021 (n = 55). Balanced CAVC (80%) and Rastelli type C CAVC (81%) were most common. Patients in the later era were younger (4 vs 14 months, P < 0.001), fewer had trisomy 21 (60% vs 80%, P = 0.019) and fewer had prior palliative prior procedures (31% vs 43%, P < 0.001). In the earlier era, single-patch technique was more common (62% vs 16%, P < 0.001), and in recent era, double-patch technique was more common (84% vs 33%, P < 0.001). In the earlier era, right ventricular outflow tract was most commonly reconstructed with transannular patch (51%), while in more recent era, valve-sparing repairs were more common (69%) (P < 0.001). In-hospital mortality was 4.3%. The median follow-up was 217 and 74 months for the first and second eras. Survival for earlier and later eras at 2-, 5- and 10-year follow-up was (85.1%, 81.5%, 79.6% vs 94.2%, 94.2%, 94.2% respectively, log-rank test P = 0.03). CONCLUSIONS: The surgical approach to ToF-CAVC has evolved over time. More recently, patients tended to receive primary repair at younger ages and had fewer palliative procedures. Improved surgical techniques allowing for earlier and complete repair have shown a decrease in mortality, more valve-sparing procedures without an increase in total reoperations. Presented at the 37th EACTS Annual Meeting, Vienna, Austria.

Tricuspid mechanical valve replacement for severe tricuspid stenosis in a child who underwent surgical correction of complete atrioventricular septal defect, a rare long-term complications.

BACKGROUND: Complete atrioventricular septal defect is a complicated congenital heart malformations, and surgical correction is the best treatment, the severe tricuspid stenosis is a rare long-term complication after the surgery. CASE PRESENTATION: We report a case with the complication of severe tricuspid stenosis 7 years after the surgical correction of complete atrioventricular septal defect in a child. Then the patient underwent tricuspid mechanical valve replacement, Glenn, atrial septostomy, and circumconstriction of the right pulmonary artery. CONCLUSIONS: The patient recovered successfully with good short-term.

Canonical Wnt signaling directs the generation of functional human PSC-derived atrioventricular canal cardiomyocytes in bioprinted cardiac tissues.

The creation of a functional 3D bioprinted human heart remains challenging, largely due to the lack of some crucial cardiac cell types, including the atrioventricular canal (AVC) cardiomyocytes, which are essential to slow down the electrical impulse between the atrium and ventricle. By utilizing single-cell RNA sequencing analysis and a 3D bioprinting technology, we discover that stage-specific activation of canonical Wnt signaling creates functional AVC cardiomyocytes derived from human pluripotent stem cells. These cardiomyocytes display morphological characteristics and express molecular markers of AVC cardiomyocytes, including transcription factors TBX2 and MSX2. When bioprinted in prefabricated cardiac tissues, these cardiomyocytes successfully delay the electrical impulse, demonstrating their capability of functioning as the AVC cardiomyocytes in vitro. Thus, these findings not only identify canonical Wnt signaling as a key regulator of the AVC cardiomyocyte differentiation in vitro, but, more importantly, provide a critical cellular source for the biofabrication of a functional human heart.

Interaction between clinicians and artificial intelligence to detect fetal atrioventricular septal defects on ultrasound: how can we optimize collaborative performance?

OBJECTIVES: Artificial intelligence (AI) has shown promise in improving the performance of fetal ultrasound screening in detecting congenital heart disease (CHD). The effect of giving AI advice to human operators has not been studied in this context. Giving additional information about AI model workings, such as confidence scores for AI predictions, may be a way of further improving performance. Our aims were to investigate whether AI advice improved overall diagnostic accuracy (using a single CHD lesion as an exemplar), and to determine what, if any, additional information given to clinicians optimized the overall performance of the clinician-AI team. METHODS: An AI model was trained to classify a single fetal CHD lesion (atrioventricular septal defect (AVSD)), using a retrospective cohort of 121 130 cardiac four-chamber images extracted from 173 ultrasound scan videos (98 with normal hearts, 75 with AVSD); a ResNet50 model architecture was used. Temperature scaling of model prediction probability was performed on a validation set, and gradient-weighted class activation maps (grad-CAMs) produced. Ten clinicians (two consultant fetal cardiologists, three trainees in pediatric cardiology and five fetal cardiac sonographers) were recruited from a center of fetal cardiology to participate. Each participant was shown 2000 fetal four-chamber images in a random order (1000 normal and 1000 AVSD). The dataset comprised 500 images, each shown in four conditions: (1) image alone without AI output; (2) image with binary AI classification; (3) image with AI model confidence; and (4) image with grad-CAM image overlays. The clinicians were asked to classify each image as normal or AVSD. RESULTS: A total of 20 000 image classifications were recorded from 10 clinicians. The AI model alone achieved an accuracy of 0.798 (95% CI, 0.760-0.832), a sensitivity of 0.868 (95% CI, 0.834-0.902) and a specificity of 0.728 (95% CI, 0.702-0.754), and the clinicians without AI achieved an accuracy of 0.844 (95% CI, 0.834-0.854), a sensitivity of 0.827 (95% CI, 0.795-0.858) and a specificity of 0.861 (95% CI, 0.828-0.895). Showing a binary (normal or AVSD) AI model output resulted in significant improvement in accuracy to 0.865 (P < 0.001). This effect was seen in both experienced and less-experienced participants. Giving incorrect AI advice resulted in a significant deterioration in overall accuracy, from 0.761 to 0.693 (P < 0.001), which was driven by an increase in both Type-I and Type-II errors by the clinicians. This effect was worsened by showing model confidence (accuracy, 0.649; P < 0.001) or grad-CAM (accuracy, 0.644; P < 0.001). CONCLUSIONS: AI has the potential to improve performance when used in collaboration with clinicians, even if the model performance does not reach expert level. Giving additional information about model workings such as model confidence and class activation map image overlays did not improve overall performance, and actually worsened performance for images for which the AI model was incorrect. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Nonsense-mediated mRNA decay affects hyperactive root formation in oculo-facio-cardio-dental syndrome via up-frameshift protein 1.

OBJECTIVES: Oculo-facio-cardio-dental (OFCD) syndrome is a rare X-linked genetic disorder caused by mutations in the BCL6 co-repressor (BCOR) and is mainly characterized by radiculomegaly (elongated dental roots). All BCOR mutations reported to date have been associated with premature termination codons, indicating that nonsense-mediated mRNA decay (NMD) might play a vital role in the pathogenesis of OFCD syndrome. However, the molecular mechanisms underlying NMD remain unclear. In this study, we investigated the involvement of up-frameshift protein 1 (UPF1), which plays a central role in NMD, in the hyperactive root formation caused by BCOR mutations. METHODS: Periodontal ligament cells, isolated from a Japanese woman with a c.3668delC frameshift mutation in BCOR, and primary human periodontal ligament fibroblasts (HPdLFs) were used for an RNA immunoprecipitation assay to confirm the binding of UPF1 to mutated BCOR. Additionally, the effects of UPF1 on the BCOR transcription levels and corresponding gene expression were determined by performing relative quantitative real-time polymerase chain reactions. RESULTS: RNA immunoprecipitation revealed that UPF1 binds to exon 9 of mutated BCOR. Additionally, UPF1 knockdown via siRNA upregulated the transcription of BCOR, whereas overexpression of wild-type and mutated BCOR with the same frameshift mutation in HPdLFs altered bone morphogenetic protein 2 (BMP2) expression. CONCLUSIONS: Our findings indicate that BCOR mutations regulate the transcription of BCOR via UPF1, which may in turn regulate the expression of BMP2. NMD, caused by a c.3668delC mutation, potentially leads to an OFCD syndrome phenotype, including elongated dental roots.

Improvement of myocardial contractility with leadless endocardial single-lead atrial sensing ventricular pacing in patients with prolonged PQ interval.

Aim: Micra AV represents a leadless endocardial pacing system able to detect atrial contractions providing atrioventricular synchrony. A reduction of myocardial contractility may be detected in case of first-degree atrioventricular block (AVB). Materials & methods: In six patients with first-degree AVB (PQ interval ≥220 msec) was evaluated the left ventricle global longitudinal strain (LV GLS) by speckle tracking (ST) echocardiography during single-lead atrial sensing ventricular pacing (VDD) stimulation as compared with spontaneous rhythm (SR), 24-48 h after Micra AV implantation. Results: A statistically significant difference between the two modalities was observed (LV GLS during SR: -14.7% [interquartile range (IQR) 5.5], LV GLS during VDD pacing: -16.1% [IQR 5.2]; p value = 0.041). Conclusion: Our preliminary results suggest an improvement of myocardial contractility with VDD pacing as compared with SR.

What is this article about? The Micra AV is an electronic device placed in the heart chambers capable to supply the electrical activity of the heart. A reduction of cardiac contractility may be observed in patients with electrical disorders of the heart. What were the results? In six patients affected by electrical cardiac disorders, we observed an improvement of cardiac contractility using Micra AV as compared with the spontaneous electrical activity of the heart. What do the results of the study mean? The results of this study suggest that in patients carrying this electronic device should be preferred a specific modality of activation of the device as compared with the spontaneous electrical activity of the heart in order to improve the contractility of the cardiac walls.

Oculo-facio-cardio-dental (OFCD) syndrome: a case report.

BACKGROUND: Oculo-facio-cardio-dental (OFCD) syndrome is a rare condition that affects the eyes, face, heart, and teeth of patients. One notable dental characteristic of OFCD is radiculomegaly, or root gigantism, which highlights the role of dentists in detecting this syndrome. OFCD is an X-linked dominant syndrome that results from a variant in the BCOR gene. Our study presents the first documented case of OFCD in Vietnam and reports a novel BCOR gene variant observed in this case. CASE PRESENTATION: A 19-year-old Vietnamese female patient with an extremely long root with an abscess was clinically examined for the expression of OFCDs. The radiograph and the variant in BCOR gene were also evaluated. We identified abnormalities in the teeth, as well as ocular, facial, and cardiac features, with radiculomegaly of the canines being a specific symptom for OFCDs. The patient's genetic analysis revealed a pathogenic heterozygous deletion at intron 11 of the BCOR gene, representing a novel variant. CONCLUSION: Oculo-facio-cardio-dental syndrome (OFCD) is an extremely rare condition characterized by abnormalities in the eyes, face, heart, and teeth, often caused by variants in the BCOR gene. Radiculomegaly, or enlarged dental roots, is a key diagnostic feature of OFCD, and early detection is crucial for preventing future dental complications.

Outcomes of atrioventricular septal defects with and without down syndrome: analysis of the national inpatient database.

BACKGROUND: Controversial data exist about the impact of Down syndrome on outcomes after surgical repair of atrioventricular septal defect. AIMS: (A) assess trends and outcomes of atrioventricular septal defect with and without Down syndrome and (B) determine risk factors associated with adverse outcomes after atrioventricular septal defect repair. METHODS: We queried The National Inpatient Sample using International Classification of Disease codes for patients with atrioventricular septal defect < 1 year of age from 2000 to 2018. Patients' characteristics, co-morbidities, mortality, and healthcare utilisation were evaluated by comparing those with versus without Down syndrome. RESULTS: In total, 2,318,706 patients with CHD were examined; of them, 61,101 (2.6%) had atrioventricular septal defect. The incidence of hospitalisation in infants with atrioventricular septal defect ranged from 4.5 to 7.5% of all infants hospitalised with CHD per year. A total of 33,453 (54.7%) patients were associated with Down syndrome. Double outlet right ventricle, coarctation of the aorta, and tetralogy of Fallot were the most commonly associated with CHD in 6.9, 5.7, and 4.3% of patients, respectively. Overall atrioventricular septal defect mortality was 6.3%. Multivariate analysis revealed that prematurity, low birth weight, pulmonary hypertension, and heart block were associated with mortality. Down syndrome was associated with a higher incidence of pulmonary hypertension (4.3 versus 2.8%, p < 0.001), less arrhythmia (6.6 versus 11.2%, p < 0.001), shorter duration for mechanical ventilation, shorter hospital stay, and less perioperative mortality (2.4 versus 11.1%, p < 0.001). CONCLUSION: Trends in atrioventricular septal defect hospitalisation had been stable over time. Perioperative mortality in atrioventricular septal defect was associated with prematurity, low birth weight, pulmonary hypertension, heart block, acute kidney injury, and septicaemia. Down syndrome was present in more than half of atrioventricular septal defect patients and was associated with a higher incidence of pulmonary hypertension but less arrhythmia, lower mortality, shorter hospital stay, and less resource utilisation.

Cardiac magnetic resonance predictors for successful primary biventricular repair of unbalanced complete common atrioventricular canal.

BACKGROUND: Patients with unbalanced common atrioventricular canal can be difficult to manage. Surgical planning often depends on pre-operative echocardiographic measurements. We aimed to determine the added utility of cardiac MRI in predicting successful biventricular repair in common atrioventricular canal. METHODS: We conducted a retrospective cohort study of children with common atrioventricular canal who underwent MRI prior to repair. Associations between MRI and echocardiographic measures and surgical outcome were tested using logistic regression, and models were compared using area under the receiver operator characteristic curve. RESULTS: We included 28 patients (median age at MRI: 5.2 months). The optimal MRI model included the novel end-diastolic volume index (using the ratio of left ventricular end-diastolic volume to total end-diastolic volume) and the left ventricle-right ventricle angle in diastole (area under the curve 0.83, p = 0.041). End-diastolic volume index ≤ 0.18 and left ventricle-right ventricle angle in diastole ≤ 72° yield a sensitivity of 83% and specificity of 81% for successful biventricular repair. The optimal multimodality model included the end-diastolic volume index and the echocardiographic atrioventricular valve index with an area under the curve of 0.87 (p = 0.026). CONCLUSIONS: Cardiac MRI can successfully predict successful biventricular repair in patients with unbalanced common atrioventricular canal utilising the end-diastolic volume index alone or in combination with the MRI left ventricle-right ventricle angle in diastole or the echocardiographic atrioventricular valve index. A prospective cardiac MRI study is warranted to better define the multimodality characteristic predictive of successful biventricular surgery.