Mitochondrial cardiomyopathy is characterized by an oxidative phosphorylation (OXPHOS) disorder due to genetic mutations in genes encoding the structure and function of myocardial mitochondria. Mutations in both mitochondrial and nuclear DNA can cause mitochondrial cardiomyopathy, and it is typically recognized as one of the generalized manifestations of neurological and metabolic disorders. Cardiomyopathy, however, can be the only phenotype of mitochondrial disease and is often misdiagnosed. Cardiac manifestations vary from asymptomatic to catastrophic heart failure or sudden death. Although recent evolution in genetic testing has allowed for the identification of the causative gene, tissue sampling to identify an OXPHOS disorder is still regarded as the gold standard for diagnosis.

Congenital heart disease is a multifactorial inheritance disorder that is induced by genetic and environmental factors during morphogenesis of the cardiovascular system in the embryos. Cardiac embryology plays an important role in reaching a definitive diagnosis, understanding the pathophysiology of disease, selecting the most appropriate medical/surgical treatment, and predicting complications and prognosis. Therefore, a thorough understanding of the process involved in cardiac embryology is essential for pediatric cardiologists and cardiac surgeons. In this review, cardiac embryology and cardiovascular morphogenesis are discussed to assist physicians in understanding the etiological mechanisms of congenital heart disease. The molecular and cellular mechanisms of congenital heart disease using genetically engineered mice are available in any expertized textbooks and journals. Thus, in this review, basic and comprehensive outlines of cardiac embryology and morphogenesis are presented using illustrations.

Stenting of the right ventricular outflow tract (RVOT) is an emerging alternative for the management of cyanotic tetralogy of Fallot (TOF) in the neonatal or early infancy stage. We describe our treatment of a TOF in the early infancy stage, using RVOT, in a patient for whom the TOF physiology was associated with major aortopulmonary collateral arteries (MAPCAs), all of which had a dual blood supply from the pulmonary arteries. The procedure was successful, with sufficient antegrade blood flow of the native pulmonary arteries achieved for occlusion of all MAPCAs. RVOT stenting provided an effective strategy for the management of cyanotic TOF, without the need for unifocalization, in the presence of MAPCAs with dual blood supply.

Incomplete Kawasaki disease (iKD) is widely accepted as a risk factor for developing coronary artery lesions, partly because of a delay in treatment initiation. However, its association with giant aneurysm (GA) formation has rarely been reported. Here we report a 3-year-old boy with iKD who developed multiple GAs at both the right and left coronary arteries. The boy was admitted to a previous hospital for fever lasting for seven days and conjunctival injection. First, he was treated with antibiotics, but his fever did not resolve. Echocardiography revealed remarkable dilatation of the bilateral coronary arteries. He was transferred to our hospital under the diagnosis of iKD on day 11 of illness. His symptoms improved immediately after the administration of intravenous immunoglobulin, but the diameter of his coronary aneurysms increased. Coronary angiography performed three months after onset revealed multiple GAs at both coronary arteries. An aneurysm at the right coronary artery occluded two years from onset. In case of prolonged fever of unknown origin, it is important to consider incomplete KD and carefully examine echocardiograms, even when there are few major KD symptoms present.

True aneurysms occur only rarely in the peripheral arteries of the upper extremity. As such, a treatment protocol deciding how and when to conduct surgical repair is still unestablished. In this paper, we report the case of a 21-month-old boy who presented with a painless, pulsatile swelling in the mid-arm on the right side; he was subsequently diagnosed with an idiopathic true brachial artery aneurysm. The size of the aneurysm rapidly increased over the course of 2 months and ultrasound examination delineated a thrombus inside the aneurysm. Therefore, the aneurysm was surgically resected and completely repaired by end-to-end anastomosis using cephalic vein grafting. Follow-up angiography showed excellent blood flow within the graft, and there was no stenosis. No neurological complications were observed during the 2 years follow-up period.