In the past two decades, adopting molecular biological approaches helped to deepen our knowledge of molecular mechanisms underlying heterotaxy. However, many critical questions remain unanswered. Previous studies revealed that there are four key steps to establish left–right asymmetry in our bodies. First, the unidirectional leftward flow of extra-embryonic fluid in the node cavity, “Nodal Flow”, breaks the symmetry. Monocilia that localizes at the apical site of the node epithelial cells generate this Nodal Flow, which is translated into the asymmetric expression of the TGFβ superfamily, Nodal, at the node. Second, this asymmetric information of the node is transferred laterally to lateral plate mesoderm. Third, this transferred information induces a robust left-side specific expression of Nodal, followed by the unilateral activation of bicoid-type homeodomain transcription factor, Pitx2, in the left lateral plate mesoderm. Finally, Pitx2 governs left-side specific morphogenesis. Any of the anomalous events in this sequential cascade is, theoretically, a potent cause of heterotaxy and cardiac isomerism. Unfortunately, our knowledge in clinical genetics is still incomplete to integrate the knowledge that originates from model animals. The focus of this review is on an overview of the vital steps involved in generation of left–right asymmetry in mice, with potential application in human pediatric cardiology.

The surgical outcome of the Fontan operation has improved with refinements of the surgical technique and advances in perioperative management. As a large number of patients survive to adult after the surgery, the factors responsible for deterioration of patient quality of life have become important concerns. To maintain a sufficient Fontan circulation, catheterization or surgical re-intervention must be considered at the appropriate time together with meticulous follow-up and medical treatment.

With recent improvements in computer technology, prominent progress has occurred in cardiovascular imaging. Blood flow imaging visualizes complicated blood flow inside the cardiovascular lumen via 3D color video, in addition to providing traditional geometrical information such as heart chamber size and vessel diameter. Because blood flow imaging provides detailed information about diseased flow, elucidates the pathophysiology of cardiovascular disease, and visualizes mechanical stress on the ventricular chamber or vessel intima, it has been identified as a novel tool for predictive medicine for heart valve disease, cardiomyopathy, coronary arterial disease, and aortic disease. Congenital heart disease has a complicated anatomy and physiology; thus, blood flow imaging has been expected to have clinical applicability for congenital heart disease for decades. Even with the sophistication of perioperative patient management in congenital heart disease, blood flow imaging plays an essential role in predicting long-term outcomes in patients with congenital heart disease.

In this review, we explained the details of blood flow imaging, including 4D flow MRI, several types of novel echocardiography blood flow visualization software, and computational simulations. Echocardiography and MRI flow imaging are based on flow measurements, which carry limitations concerning spatial and temporal resolution. Conversely, computer simulation enables “virtual surgery” with sufficient resolution, but visualized flow is dependent on the calculation assumption. We also discussed effective clinical applications of these methods in patients with congenital heart disease, especially considering long-term outcomes, by reviewing the literature and introducing several complicated cases.

Arrhythmias are common complications in adults with congenital heart disease that might cause sudden cardiac death. Arrhythmias vary according to factors such as underlying heart disease and the methods of surgical repair, and they increase in prevalence with age. Therapeutic strategies differ with the complexity of underlying heart disease and hemodynamic status. Pacemaker implantation is indicated for patients with symptomatic bradyarrhythmias caused by either sinus node dysfunction or atrioventricular block. In patients with atrial flutter and fibrillation, anticoagulation therapy is important for preventing cardiogenic embolism. Various antiarrhythmic agents are used, and catheter ablation may be effective. In ventricular tachycardia, both pharmacologic and non-pharmacologic therapies are needed. Implantable cardioverter defibrillators represent the primary modality for preventing sudden cardiac death, and antiarrhythmic agents and catheter ablation are indicated as adjunctive therapies.

Background: The impact of device closure using an Amplatzer Septal Occluder (ASO) on atrial function in patients with atrial septal defect (ASD) remains unknown. This study aimed to clarify the short- and mid-term changes of left atrial (LA) and right atrial (RA) function after ASO implantation.

Methods: Forty-five patients with secundum-type ASD (30 treated by ASO and 15 treated by surgical closure [SC]) and 15 normal children (NC) as controls were investigated. The maximum (Max) and minimum (Min) areas of both atria were measured from the apical four-chamber view via transthoracic echocardiography, and atrial distensibility (Dis) was calculated as (Max−Min)/Min. The ASO group was further divided into two groups based on the ratio of device length to total atrial septal length (D/L) as follows: L-ASO (＞0.85) and S-ASO (＜0.85).

Results: LA Dis was significantly reduced in the ASO (1.10±0.22) and SC groups (1.0±0.44) compared to that in the NC group (1.51±0.25) (p＜0.001), and the rate of reduction was related to D/L in the ASO group. RA Dis was also lower in the ASO (0.87±0.27) and SC groups (0.59±0.24) than in the NC group (1.38±0.37), but the difference was not related to D/L. Max for both atria was similar between the ASO and NC groups whereas Min was elevated for both atria in the ASO group.

Conclusion: Dis declined with D/L in both atria in the ASO and SC groups, and longer follow-up of atrial functions is needed to clarify the potential risk of atrial arrhythmia or dysfunction.

We present the case of a 29-year-old man who was born with an interrupted aortic arch type A and a ventricular septal defect. At 5 days after birth, he underwent the Blalock–Park aortoplasty through a left thoracotomy. However, when he was one year old, stenosis was noted at the anastomotic site, and the Dacron patch aortoplasty was performed to enlarge the site. Approximately 20 years after the Dacron patch aortoplasty, a thoracic aortic aneurysm was detected at the patch enlargement site which reached a maximum diameter of 45 mm. Although this was the third recurrent left thoracotomy, we successfully performed aneurysmectomy and graft replacement of the thoracic aorta using femorofemoral bypass.