Pulmonary Valve Morphology in Patients with Bicuspid Aortic Valves.

The aortic and pulmonary valve share a common developmental origin from the embryonic arterial trunk. Bicuspid aortic valve is the most common congenital anomaly and can occur isolated as well as in association with other congenital heart disease (CHD). Data on pulmonary valve morphology in these cases are scarce. In this study, we aimed to determine pulmonary valve morphology in hearts with BAV associated with CHD. In 83 post-mortem heart specimens with BAV and associated CHD, pulmonary valve morphology was studied and related to BAV morphology. In 14/83 (17%) hearts, the pulmonary valve was affected, bicuspid in 8/83 (10%), dome-shaped in 3/83 (4%) and atretic in 3/83 (4%). In specimens with a bicuspid pulmonary valve, 5/8 (63%) had a strictly bicuspid aortic valve (without raphe), 2/3 hearts (67%) with dome-shaped pulmonary valves and 2/3 hearts (67%) with atretic pulmonary valves had BAV without raphe. Six out of eight (75%) specimens with a bicuspid pulmonary valve had a perimembranous ventricular septal defect (VSD). 4/8 (50%) specimens with a bicuspid pulmonary valve were associated with chromosomal abnormalities: 3 (38%) had trisomy 18 and 1 (13%) had trisomy 13. In BAV with associated CHD, abnormal pulmonary valve morphology was observed in 17% of the hearts. The majority of hearts with abnormal pulmonary valve morphology had a Type B bicuspid aortic valve (without raphe). Bilateral semilunar valvular disease is associated with Type B BAVs and in many cases related to chromosomal abnormalities. As this study was performed in post-mortem specimens with high frequency of associated CHD, caution is warranted with application of these results to the general BAV population.

Imaging the first trimester heart: ultrasound correlation with morphology.

First trimester sonography is a widely used technique to examine the foetus early in pregnancy. The desire to recognise complex anatomy already in early developmental stages stresses the need for a thorough knowledge of basic developmental processes as well as recognition of cardiac compartments based on their morphology. In this paper, we describe the possibilities and limitations of sonographic assessment of the foetal heart between 10 and 14 weeks of gestation and correlate this to morphology. Examples of the most commonly detected congenital anomalies are atrioventricular septal defects, transposition of the great arteries, and hypoplastic left heart, which are shown in this paper.

Bicuspid aortic valve morphology and associated cardiovascular abnormalities in fetal Turner syndrome: a pathomorphological study.

INTRODUCTION: Bicuspid aortic valve (BAV) is common in Turner syndrome (TS). In adult TS, 82-95% of BAVs have fusion of the right and left coronary leaflets. Data in fetal stages are scarce. The purpose of this study was to gain insight into aortic valve morphology and associated cardiovascular abnormalities in a fetal TS cohort with adverse outcome early in development. MATERIAL AND METHODS: We studied post-mortem heart specimens of 36 TS fetuses and 1 TS newborn. RESULTS: BAV was present in 28 (76%) hearts. BAVs showed fusion of the right and left coronary leaflet (type 1 BAV) in 61%, and fusion of the right coronary and non-coronary leaflet (type 2 BAV) in 39%. There were no significant differences in occurrence of additional cardiovascular abnormalities between type 1 and type 2 BAV. However, all type 2 BAV hearts showed ascending aorta hypoplasia and tubular hypoplasia of the B segment, as opposed to only 55 and 64% of type 1 BAV hearts, respectively. DISCUSSION: The proportion of type 2 BAV seems higher in TS fetuses than in adults. Fetal type 2 BAV hearts all had severe aortic pathology, possibly contributing to a worse prognosis of type 2 than type 1 BAV in TS.

The arterial and cardiac epicardium in development, disease and repair.

The importance of the epicardium covering the heart and the intrapericardial part of the great arteries has reached a new summit. It has evolved as a major cellular component with impact both in development, disease and more recently also repair potential. The role of the epicardium in development, its differentiation from a proepicardial organ at the venous pole (vPEO) and the differentiation capacities of the vPEO initiating cardiac epicardium (cEP) into epicardium derived cells (EPDCs) have been extensively described in recent reviews on growth and transcription factor pathways. In short, the epicardium is the source of the interstitial, the annulus fibrosus and the adventitial fibroblasts, and differentiates into the coronary arterial smooth muscle cells. Furthermore, EPDCs induce growth of the compact myocardium and differentiation of the Purkinje fibers. This review includes an arterial pole located PEO (aPEO) that provides the epicardium covering the intrapericardial great vessels. In avian and mouse models disturbance of epicardial outgrowth and maturation leads to a broad spectrum of cardiac anomalies with main focus on non-compaction of the myocardium, deficient annulus fibrosis, valve malformations and coronary artery abnormalities. The discovery that in disease both arterial and cardiac epicardium can again differentiate into EPDCs and thus reactivate its embryonic program and potential has highly broadened the scope of research interest. This reactivation is seen after myocardial infarction and also in aneurysm formation of the ascending aorta. Use of EPDCs for cell therapy show their positive function in paracrine mediated repair processes which can be additive when combined with the cardiac progenitor stem cells that probably share the same embryonic origin with EPDCs. Research into the many cell-autonomous and cell-cell-based capacities of the adult epicardium will open up new realistic therapeutic avenues.

Morphogenesis of outflow tract rotation during cardiac development: the pulmonary push concept.

BACKGROUND: Understanding of cardiac outflow tract (OFT) remodeling is essential to explain repositioning of the aorta and pulmonary orifice. In wild type embryos (E9.5-14.5), second heart field contribution (SHF) to the OFT was studied using expression patterns of Islet 1, Nkx2.5, MLC-2a, WT-1, and 3D-reconstructions. Abnormal remodeling was studied in VEGF120/120 embryos. RESULTS: In wild type, Islet 1 and Nkx2.5 positive myocardial precursors formed an asymmetric elongated column almost exclusively at the pulmonary side of the OFT up to the pulmonary orifice. In VEGF120/120 embryos, the Nkx2.5-positive mesenchymal population was disorganized with a short extension along the pulmonary OFT. CONCLUSIONS: We postulate that normally the pulmonary trunk and orifice are pushed in a higher and more frontal position relative to the aortic orifice by asymmetric addition of SHF-myocardium. Deficient or disorganized right ventricular OFT expansion might explain cardiac malformations with abnormal position of the great arteries, such as double outlet right ventricle.

Cardiac Fibrosis and Innervation State in Uncorrected and Corrected Transposition of the Great Arteries: A Postmortem Histological Analysis and Systematic Review.

In the transposition of the great arteries (TGA), alterations in hemodynamics and oxygen saturation could result in fibrotic remodeling, but histological studies are scarce. We aimed to investigate fibrosis and innervation state in the full spectrum of TGA and correlate findings to clinical literature. Twenty-two human postmortem TGA hearts, including TGA without surgical correction (n = 8), after Mustard/Senning (n = 6), and arterial switch operation (ASO, n = 8), were studied. In newborn uncorrected TGA specimens (1 day-1.5 months), significantly more interstitial fibrosis (8.6% ± 3.0) was observed compared to control hearts (5.4% ± 0.8, p = 0.016). After the Mustard/Senning procedure, the amount of interstitial fibrosis was significantly higher (19.8% ± 5.1, p = 0.002), remarkably more in the subpulmonary left ventricle (LV) than in the systemic right ventricle (RV). In TGA-ASO, an increased amount of fibrosis was found in one adult specimen. The amount of innervation was diminished from 3 days after ASO (0.034% ± 0.017) compared to uncorrected TGA (0.082% ± 0.026, p = 0.036). In conclusion, in these selected postmortem TGA specimens, diffuse interstitial fibrosis was already present in newborn hearts, suggesting that altered oxygen saturations may already impact myocardial structure in the fetal phase. TGA-Mustard/Senning specimens showed diffuse myocardial fibrosis in the systemic RV and, remarkably, in the LV. Post-ASO, decreased uptake of nerve staining was observed, implicating (partial) myocardial denervation after ASO.

Anatomical perspective on radiofrequency ablation of AV nodal reentry tachycardia after Mustard correction for transposition of the great arteries.

A case of radiofrequency catheter ablation of atrioventricular (AV) nodal reentry tachycardia, in a patient with transposition of the great arteries after venous rerouting according to Mustard, is described. An electroanatomical map of the His and AV nodal region was created from inside the systemic venous atrium. Retrograde mapping of the pulmonary venous atrium was performed and the arterial catheter retracted to a position in close proximity to the venous catheter inside the intraatrial baffle. This position was chosen to deliver radiofrequency current.

Aberrant lymphatic development in euploid fetuses with increased nuchal translucency including Noonan syndrome.

OBJECTIVE: Increased nuchal translucency in the human fetus is associated with aneuploidy, structural malformations and several syndromes such as Noonan syndrome. In 60­70% of the Noonan syndrome cases, a gene mutation can be demonstrated. Previous research showed that aneuploid fetuses with increased nuchal translucency (NT) demonstrate an aberrant lymphatic endothelial differentiation. METHOD: Fetuses with increased NT and normal karyotype (n = 7) were compared with euploid controls having normal NT (n = 5). A Noonan syndrome gene mutation was found in three out of seven fetuses with increased NT. Endothelial differentiation was evaluated by immunohistochemistry using lymphatic markers (PROX-1, Podoplanin, LYVE-1) and blood vessel markers vascular endothelial growth factor-A (VEGF-A), Neuropilin-1 (NP-1), Sonic hedgehog, von Willebrand factor, and the smooth muscle cell marker, smooth muscle actin. RESULTS: Nuchal edema and enlarged jugular lymphatic sacs (JLSs) were observed in fetuses with increased NT, together with abnormal lymphatic endothelial differentiation i.e. the presence of blood vessel characteristics, including high levels of VEGF-A and NP-1 expression. The enlarged JLSs contained erythrocytes and were surrounded by smooth muscle cells. CONCLUSION: This study shows an aberrant lymphatic endothelial differentiation in fetuses with increased NT and a normal karyotype (including Noonan syndrome fetuses), as was previously reported before in aneuploid fetuses.

Deficient Myocardial Organization and Pathological Fibrosis in Fetal Aortic Stenosis-Association of Prenatal Ultrasound with Postmortem Histology.

In fetal aortic stenosis (AS), it remains challenging to predict left ventricular development over the course of pregnancy. Myocardial organization, differentiation and fibrosis could be potential biomarkers relevant for biventricular outcome. We present four cases of fetal AS with varying degrees of severity and associate myocardial deformation on fetal ultrasound with postmortem histopathological characteristics. During routine fetal echocardiography, speckle tracking recordings of the cardiac four-chamber view were performed to assess myocardial strain as parameter for myocardial deformation. After pregnancy termination, postmortem cardiac specimens were examined using immunohistochemical labeling (IHC) of key markers for myocardial organization, differentiation and fibrosis and compared to normal fetal hearts. Two cases with critical AS presented extremely decreased left ventricular (LV) strain on fetal ultrasound. IHC showed overt endocardial fibro-elastosis, which correlated with pathological fibrosis patterns in the myocardium and extremely disturbed cardiomyocyte organization. The LV in severe AS showed mildly reduced myocardial strain and less severe disorganization of the cardiomyocytes. In conclusion, the degree of reduction in myocardial deformation corresponded with high extent to the amount of pathological fibrosis patterns and cardiomyocyte disorganization. Myocardial deformation on fetal ultrasound seems to hold promise as a potential biomarker for left ventricular structural damage in AS.

Altered jugular vein and ductus venosus flow velocities in fetuses with increased nuchal translucency and distended jugular lymphatic sacs.

OBJECTIVE: We sought to assess blood flow in relation to jugular lymphatic distension in fetuses with increased and normal nuchal translucency (NT). STUDY DESIGN: In all, 72 fetuses with normal NT and 71 fetuses with NT >95th percentile were evaluated. NT size, jugular lymphatic sacs (JLS), jugular vein and ductus venosus pulsatility index for veins (PIV), and intracardiac velocities were measured. RESULTS: JLS were visualized in 22/72 fetuses with normal and in 55/71 fetuses with increased NT. Jugular vein and ductus venosus PIV was higher in fetuses with increased NT compared to normal NT (P < .01). Visibility of JLS was associated with a higher ductus venous PIV (P < .05), but not with a higher jugular vein PIV. Larger NT and larger JLS volumes were associated with higher jugular vein and ductus venosus PIV (P < .05). CONCLUSION: This study shows a relation among increased NT, jugular lymphatic distension, and altered blood flow in jugular vein and ductus venosus.

Abnormal ductus venosus flow in first-trimester fetuses with increased nuchal translucency: relationship with the type of cardiac defect?

OBJECTIVE: The purpose of this study was to evaluate ductus venosus flow velocities and a possible relationship with the type of cardiac defect in fetuses with increased nuchal translucency (NT). METHODS: Seventy-two fetuses with normal NT and 137 fetuses with increased NT (>95th percentile) were evaluated. The ductus venosus pulsatility index for veins (PIV), late diastolic velocity (velocity during atrial contraction [a-V]), and intracardiac velocities were evaluated. In cases of pregnancy termination, a postmortem examination was performed. Cardiac defects were grouped into septal defects, left and right inflow obstruction, left and right outflow obstruction, and other defects. Data were evaluated by multilevel analysis. RESULTS: A cardiac defect was found in 45 fetuses with increased NT. Fetuses with increased NT showed a higher ductus venosus PIV and a lower a-V compared to fetuses with normal NT (P < .05). Within the group of fetuses with increased NT, a higher PIV and a lower a-V were found in cases with a cardiac defect compared to cases with a normal heart (P < .001). No differences in PIV and a-V were found between the types of cardiac defects. Intracardiac velocities showed no differences between fetuses with normal and increased NT, irrespective of the presence of a cardiac defect. CONCLUSIONS: Ductus venosus flow velocities in fetuses with increased NT are not related to a certain type of cardiac defect. This indicates that the altered ductus venosus flow velocities found in fetuses with increased NT cannot be explained by cardiac failure due to a specific altered cardiac anatomy.

The Development of the Ascending Aortic Wall in Tricuspid and Bicuspid Aortic Valve: A Process from Maturation to Degeneration.

BACKGROUND: Patients with a bicuspid aortic valve (BAV) have an increased risk for aortic dilation and dissection. In this study, we provide a histological stratification of the developing aorta in the tricuspid aortic valve (TAV) and the BAV populations as a reference for future studies on aortopathy and related syndromes. METHODS: Non-dilated TAV and BAV ascending aortic wall samples were collected, including 60 TAV (embryonic-70 years) and 32 BAV specimens (fetal-72 years, categorized in eight age groups. RESULTS: In TAV, intimal development starts in the neonatal phase. After birth, the thickness of the medial layer increases significantly by increase of elastic lamellae up to and including the "young child" phase stabilizing afterwards. The BAV shows already prenatal intimal thickening becoming significantly thinner after birth subsequently stabilizing. In BAV, increase in elastic lamellae is seen between the young child and the adolescent phases, stabilizing afterwards. CONCLUSIONS: Vascular development in TAV is described in three phases: maturation, stabilization, and degeneration. For BAV, the development can be described in two phases: maturation (already prenatally) and degeneration. After birth, the development of the aorta is characterized by degeneration, leading to weakening of the ascending aortic wall and increasing the risk of aortopathy.

Pulmonary ductal coarctation and left pulmonary artery interruption; pathology and role of neural crest and second heart field during development.

OBJECTIVES: In congenital heart malformations with pulmonary stenosis to atresia an abnormal lateral ductus arteriosus to left pulmonary artery connection can lead to a localised narrowing (pulmonary ductal coarctation) or even interruption We investigated embryonic remodelling and pathogenesis of this area. MATERIAL AND METHODS: Normal development was studied in WntCre reporter mice (E10.0-12.5) for neural crest cells and Nkx2.5 immunostaining for second heart field cells. Data were compared to stage matched human embryos and a VEGF120/120 mutant mouse strain developing pulmonary atresia. RESULTS: Normal mouse and human embryos showed that the mid-pharyngeal endothelial plexus, connected side-ways to the 6th pharyngeal arch artery. The ventral segment formed the proximal pulmonary artery. The dorsal segment (future DA) was solely surrounded by neural crest cells. The ventral segment had a dual outer lining with neural crest and second heart field cells, while the distal pulmonary artery was covered by none of these cells. The asymmetric contribution of second heart field to the future pulmonary trunk on the left side of the aortic sac (so-called pulmonary push) was evident. The ventral segment became incorporated into the pulmonary trunk leading to a separate connection of the left and right pulmonary arteries. The VEGF120/120 embryos showed a stunted pulmonary push and a variety of vascular anomalies. SUMMARY: Side-way connection of the DA to the left pulmonary artery is a congenital anomaly. The primary problem is a stunted development of the pulmonary push leading to pulmonary stenosis/atresia and a subsequent lack of proper incorporation of the ventral segment into the aortic sac. Clinically, the aberrant smooth muscle tissue of the ductus arteriosus should be addressed to prohibit development of severe pulmonary ductal coarctation or even interruption of the left pulmonary artery.

Tetralogy of fallot and alterations in vascular endothelial growth factor-A signaling and notch signaling in mouse embryos solely expressing the VEGF120 isoform.

The importance of vascular endothelial growth factor-A (VEGF) and subsequent Notch signaling in cardiac outflow tract development is generally recognized. Although genetic heterogeneity and mutations of these genes in both humans and mouse models relate to a high susceptibility to develop outflow tract malformations such as tetralogy of Fallot and peripheral pulmonary stenosis, no etiology has been proposed so far. Using immunohistochemistry, in situ hybridization, and quantitative RT-PCR on embryonic hearts, we have shown spatiotemporal increase and abnormal patterning of Vegf/VEGF/(phosphorylated) VEGFR-2, (cleaved) Notch1, and Jagged2 in the outflow tract of Vegf120/120 mouse embryos. This coincides with hyperplasia of specifically the outflow tract cushions and a high degree of subpulmonary myocardial apoptosis that, in later stages, manifest as pulmonary stenosis and ventricular septal defects. We postulate that increase of VEGF and Notch signaling during right ventricular outflow tract development can lead to abnormal development of both cushion and myocardial structures. Defective right ventricular outflow tract development as presented provides new insight in the etiology of tetralogy of Fallot.

Abnormal Shh and FOXC2 expression correlates with aberrant lymphatic development in human fetuses with increased nuchal translucency.

OBJECTIVE: Previous research in fetuses with increased nuchal translucency (NT) showed abnormal lymphatic endothelial differentiation characteristics, including increased vascular endothelial growth factor (VEGF)-A expression, and aberrant smooth muscle cells (SMCs) surrounding enlarged jugular lymphatic sacs (JLS). We hypothesized that abnormal Sonic hedgehog (Shh) expression would result in altered VEGF-A signaling in the lymphatic endothelial cells of the JLS and that aberrant acquisition of SMCs could be caused by downregulation of forkhead transcription factor FOXC2 and upregulation of platelet-derived growth factor (PDGF)-B in the lymphatic endothelial cells of the JLS. METHODS: Five trisomy 21 fetuses and four controls were investigated using immunohistochemistry for Shh, VEGF-A, FOXC2 and PDGF-B expression in the lymphatic endothelial cells of the JLS. RESULTS: An increased Shh, VEGF-A and PDGF-B expression, and decreased FOXC2 expression were shown in the lymphatic endothelial cells of the JLS of the trisomic fetuses. CONCLUSIONS: Increased Shh and VEGF-A expression is correlated with an aberrant lymphatic endothelial differentiation in trisomy 21 fetuses. The SMCs surrounding the JLS can possibly be explained by an increase of PDGF-B-induced SMC recruitment and/or differentiation. This underscores earlier findings that indicate the loss of lymphatic identity in trisomy 21 fetuses and a shift towards a blood vessel wall phenotype.

Coronary anatomy in Turner syndrome versus patients with isolated bicuspid aortic valves.

OBJECTIVE: Variations in coronary anatomy, like absent left main stem and left dominant coronary system, have been described in patients with Turner syndrome (TS) and in patients with bicuspid aortic valves (BAV). It is unknown whether coronary variations in TS are related to BAV and to specific BAV subtypes. AIM: To compare coronary anatomy in patients with TS with/without BAV versus isolated BAV and to study BAV morphology subtypes in these groups. METHODS: Coronary anatomy and BAV morphology were studied in 86 patients with TS (20 TS-BAV, 66 TS-tricuspid aortic valve) and 86 patients with isolated BAV (37±13 years vs 42±15 years, respectively) by CT. RESULTS: There was no significant difference in coronary dominance between patients with TS with and without BAV (25% vs 21%, p=0.933). BAVs with fusion of right and left coronary leaflets (RL BAV) without raphe showed a high prevalence of left coronary dominance in both TS-BAV and isolated BAV (both 38%). Absent left main stem was more often seen in TS-BAV as compared with isolated BAV (10% vs 0%). All patients with TS-BAV with absent left main stem had RL BAV without raphe. CONCLUSION: The equal distribution of left dominance in RL BAV without raphe in TS-BAV and isolated BAV suggests that presence of left dominance is a feature of BAVs without raphe, independent of TS. Both TS and RL BAV without raphe seem independently associated with absent left main stems. Awareness of the higher incidence of particularly absent left main stems is important to avoid complications during hypothermic perfusion.

Catheter ablation of ventricular tachycardia after repair of congenital heart disease: electroanatomic identification of the critical right ventricular isthmus.

BACKGROUND: Catheter ablation of ventricular tachycardia (VT) after repair of congenital heart disease can be difficult because of nonmappable VTs and complex anatomy. Insights into the relation between anatomic isthmuses identified by delineating unexcitable tissue using substrate mapping techniques and critical reentry circuit isthmuses might facilitate ablation. METHODS AND RESULTS: Sinus rhythm voltage mapping of the right ventricle was performed in 11 patients with sustained VT after repair of congenital heart disease. Unexcitable tissue from patch material, valve annulus, or dense fibrosis, identified from bipolar voltage (<0.5 mV) and pacing threshold (>10 mA), was defined as an anatomic isthmus boundary bordering 4 isthmuses between (1) the tricuspid annulus and scar/patch in the anterior right ventricular outflow, (2) the pulmonary annulus and right ventricular free wall scar/patch, (3) the pulmonary annulus and septal scar/patch, and (4) the septal scar/patch and tricuspid annulus. The reentry circuit isthmuses of all induced 15 VTs (mean cycle length, 276+/-78 ms; 73% poorly tolerated), identified by activation, entrainment, and/or pace mapping, were located in an anatomic isthmus (11 of 15 VTs in anatomic isthmus 1). Transecting the anatomic isthmuses by ablation lesions abolished all VTs. During 30.4+/-29.3 months of follow-up, 91% of patients remained free of VT. CONCLUSIONS: Reentry circuit isthmuses in VT late after repair of congenital heart disease are located within anatomically defined isthmuses bordered by unexcitable tissue. The boundaries can be identified with 3-dimensional substrate mapping and connected by ablation lines during sinus rhythm. These findings should facilitate catheter and surgical ablation of stable and unstable VTs.

A new syndrome with noncompaction cardiomyopathy, bradycardia, pulmonary stenosis, atrial septal defect and heterotaxy with suggestive linkage to chromosome 6p.

We report a three-generation family with nine patients affected by a combination of cardiac abnormalities and left isomerism which, to our knowledge, has not been described before. The cardiac anomalies include non-compaction of the ventricular myocardium, bradycardia, pulmonary valve stenosis, and secundum atrial septal defect. The laterality sequence anomalies include left bronchial isomerism, azygous continuation of the inferior vena cava, polysplenia and intestinal malrotation, all compatible with left isomerism. This new syndrome is inherited in an autosomal dominant pattern. A genome-wide linkage analysis suggested linkage to chromosome 6p24.3-21.2 with a maximum LOD score of 2.7 at marker D6S276. The linkage interval is located between markers D6S470 (telomeric side) and D6S1610 (centromeric side), and overlaps with the linkage interval in another family with heterotaxy reported previously. Taken together, the genomic region could be reduced to 9.4 cM (12 Mb) containing several functional candidate genes for this complex heterotaxy phenotype.

Coronary anatomy in children with bicuspid aortic valves and associated congenital heart disease.

OBJECTIVE: In patients with bicuspid aortic valve (BAV), coronary anatomy is variable. High take-off coronary arteries have been described, but data are scarce, especially when associated with complex congenital heart disease (CHD). The purpose of this study was to describe coronary patterns in these patients. METHODS: In 84 postmortem heart specimens with BAV and associated CHD, position and height of the coronary ostia were studied and related to BAV morphology. RESULTS: High take-off right (RCA) and left coronary arteries (LCA) were observed in 23% and 37% of hearts, respectively, most frequently in hearts with hypoplastic left ventricle (HLV) and outflow tract anomalies. In HLV, high take-off was observed in 18/40 (45%) more frequently of LCA (n=14) than RCA (n=6). In hearts with aortic hypoplasia, 8/13 (62%) had high take-off LCA and 6/13 (46%) high take-off RCA. High take-off was seen 19 times in 22 specimens with perimembranous ventricular septal defect (RCA 8, LCA 11). High take-off was associated with type 1A BAV (raphe between right and left coronary leaflets), more outspoken for the RCA. Separate ostia of left anterior descending coronary artery and left circumflex coronary artery were seen in four hearts (5%), not related to specific BAV morphology. CONCLUSION: High take-off coronary arteries, especially the LCA, occur more frequently in BAV with associated CHD than reported in normal hearts and isolated BAV. Outflow tract defects and HLV are associated with type 1A BAV and high take-off coronary arteries. Although it is unclear whether these findings in infants with detrimental outcome can be related to surviving adults, clinical awareness of variations in coronary anatomy is warranted.

Impact of surgery on presence and dimensions of anatomical isthmuses in tetralogy of Fallot.

OBJECTIVE: In tetralogy of Fallot (TOF), the dominant ventricular tachycardia substrates are slow-conducting anatomical isthmuses. Surgical correction has evolved, which might have influenced isthmus presence and dimensions. METHODS: One hundred and forty-two postmortem TOF specimens (84/58 corrected/uncorrected) were studied for isthmus presence. Isthmus 1 is located between the tricuspid annulus and right ventricular (RV) outflow tract (RVOT) patch/RV incision, isthmus 2 between RVOT patch/RV incision and pulmonary valve, isthmus 3 between pulmonary valve and ventricular septal defect (patch), isthmus 4 between ventricular septal defect (patch) and tricuspid annulus. Isthmus width and thickness were measured. RESULTS: Of 84 corrected postmortem TOF specimens (death: 6.6 years (4.0-11.5)), 83 demonstrated isthmus 1 (99%, width=25±10 mm, thickness=5±2 mm), 35 isthmus 2 (42%, width=10±9 mm, thickness=3±2 mm), 83 isthmus 3 (99%, width=10±6 mm, thickness=5±2 mm), and 5 isthmus 4 (6%, width=4±2 mm, thickness=2±1 mm). Transatrial-transpulmonary correction (n=49) as compared with transventricular correction (n=35) prevented isthmus 2 (0% vs 100%, P<0.001). Transatrial-transpulmonary correction at age <1 year (n=7) as compared with ≥1 year (n=42) required a smaller transannular RVOT patch (28±15 vs 45±14 mm, P<0.001). Mode and timing of correction did not influence presence and dimensions of isthmus 3. In corrected and uncorrected TOF specimens (death 1.8 years (0.5-6.6)), the range of isthmus 3 dimensions was broad (width: min=2 mm, max=32 mm; thickness: min=1, max 13 mm) across all ages. Isthmus 3 width and thickness were strongly correlated (r=0.65, P<0.001). CONCLUSIONS: In TOF, the current routine use of transatrial-transpulmonary correction prevents isthmus 2. Correction <1 year reduces transannular patch size, which may influence isthmus 1 width later in life. Mode and timing of correction did not change prevalence and dimensions of isthmus 3, in which dimensions varied widely in uncorrected and corrected TOF.