Bis-diamine, a potent teratogen, induces conotruncal diseases and thymic hypoplasia in rats similar to chromosome 22q11 deletion syndrome in humans. The precise mechanism underlying cardiac teratogenic effects of bis-diamine remains unknown. On the 10th day of gestation, 200 mg bis-diamine was administered to 40 pregnant rats. The fetuses were delivered by Cesarean section after the cervical dislocation of rats on the 21st day of gestation and were immediately frozen in acetone cooled to −76°C using dry ice. Each frozen thorax of the fetus was transversely cut, and the section surface was serially photographed with a stereoscopic microscope (Wild M400 Photomacroscope) at every 500 µm. The following cardiac diseases were recorded in 330 fetuses: Tetralogy of Fallot (16％), Tetralogy of Fallot with absent pulmonary valve (14％), Tetralogy of Fallot with pulmonary valvular and infundibular atresia (38％), truncus arteriosus (10％), ventricular septal defects (3％), interrupted aortic arch type B (2％), and atrioventricular septal defects (2％). Fetuses with the Tetralogy of Fallot and absent pulmonary valve showed pulmonary arteries aneurysmally dilated at the right and left pulmonary hila, obstructing the adjacent bronchus. Fetuses with atrioventricular canal defects showed thick nodular atrioventricular valve leaflets and signs of congestive heart failure, including the enlargement of all cardiac chambers and increased pericardial effusion. In addition, vascular diseases (right aortic arch, aberrant subclavian artery, and vascular ring) complicated the cardiac diseases. Thymus hypoplasia occurred in all fetuses (100％), while some fetuses developed diaphragmatic hernia (10％). No aortopulmonary collateral artery was noticed. These cross-sectional morphologies represent fetal echocardiographic diagnoses indicating congenital heart diseases associated with chromosome 22q11.2 deletion syndrome in rat model.

Background: Wolff–Parkinson–White syndrome with ventricular preexcitation may cause cardiac dysfunction and dilated cardiomyopathy even in the absence of recurrent and incessant tachycardia.

Purpose: This study aimed to determine the effect of ventricular preexcitation on cardiac function in pediatric patients with manifest accessory pathway.

Methods: We analyzed the clinical data of 20 patients who underwent electrophysiological examination and radiofrequency catheter ablation (RFA) for paroxysmal supraventricular tachycardia associated with accessory pathway [male : female, 8 : 12; age, 12 (0.8～16) years]. We divided the patients into two groups: patients with ventricular preexcitation (manifest group, n＝12) and those without ventricular preexcitation (concealed group, n＝8).

Results: LVEF before RFA was within the normal range in all patients but was significantly lower in the manifest group than in the concealed group [manifest group vs. concealed group, 66.0％ (47.7％–74.5％) vs. 78.1％ (70.1％–83.0％); p＝0.001]. LVEF increased after RFA in the manifest group [prior-RFA vs. post-RFA, 66.0％ (42.7％–74.5％) vs. 74.4％ (52.7％–80.7％); p＝0.003]. No change was observed in the LVEF after RFA in the concealed group. Cardiac dysfunction was detected in two patients, with the LVEF of 53.1％ and 42.7％, respectively. Both patients were in the manifest group, and the accessory pathway was located at the right posterolateral and right anterolateral, respectively. The LVEF after RFA in these patients improved to 75.7％ and 52.7％, respectively.

Conclusions: The LVEF was lower in patients with manifest accessory pathway than in patients with concealed accessory pathway, and the LVEF was shown to increase by the disappearance of preexcitation of the manifest accessory pathway.

FBN1 mutations causing severe and early-onset Marfan syndrome (MFS) cluster in exons 24–32. Here, we report the case of a male patient with early-onset MFS who was born with arachnodactyly, annuloaortic ectasia (AAE), and aortic regurgitation (AR). At 4 years of age, he presented with progressive AAE and severe AR and was referred to our hospital. He immediately underwent David procedure. The DNA sequencing of FBN1 identified a previously reported de novo mutation in the splicing donor site of intron 29 [IVS29＋1G＞A], and transcript analyses revealed that this mutation had mediated an in-frame skipping of exon 29. Currently, the pathogenic mechanisms underlying MFS are classified as dominant-negative effect or haploinsufficiency of FBN1. However, splicing mutations can be associated with both mechanisms and require qualitative and quantitative analyses of the gene products. The severe aortic phenotype in our case appeared to be affected by the “location” (FBN1 exon 29) and the “type” of mutation (splicing mutation).