The aortic root dilation in the Tetralogy of Fallot (TOF) is a long-term clinical problem because a severely dilated aorta can lead to aortic regurgitation, dissection or rupture, which could be fatal and necessitate surgical intervention. However, the details of the mechanism of aortic root dilation are not unclear. We showed that aortic stiffness is increased in repaired TOF patients and may mirror the histological abnormality of elastic fiber disruption and matrix expansion. This aortic stiffness is closely related to the aortic dilation, indicating that aortic stiffness may become the predictive indicator for prognosis of aortic dilation. Furthermore, the aortic volume overload is a very important determinant of aortic diameter in TOF patients before corrective surgery. In addition, a chromosomal abnormality and TGF-βsignaling pathway, a major contributor to the aortic dilation in Marfan syndrome, also affect this mechanism. In this way, the aortic dilation in TOF patients is suggested to be a multifactorial disorder. In this review, we tried to clarify the mechanism of aortic dilation in TOF patients, focusing on our recent research findings. Studies linking histopathology, mechanical properties, molecular/cellular physiology, and clinical manifestation of aortic dilation lead to appropriate treatment intervention and improvement in the long-term prognosis for TOF patients.

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Procedural sedation and analgesia in children require a systematic approach to establish patient safety. Failure to rescue the patient and the absence of system issues have been key components in sedation disasters in the past. Points of interest include informed consent, pre-sedation history taking, and physical examinations especially focused on the airway, proper fasting prior to elective procedures, appropriate monitoring and emergency equipment, backup emergency services, independent personnel responsible only to monitor and assist the patient during the procedure, documentation, and appropriate monitoring and staffing during recovery. Issues are essentially the same in children with heart disease and are described here.

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Echocardiographic imaging and Doppler systems generate ultrasound signals that follow the laws of physics. Appropriate utilization of these instruments and interpretation of the data generated require an understanding of the fundamental principles of ultrasound physics and how they relate to the images produced and the spectral and color Doppler information. This understanding is considered an important requirement for clinical competence in all modalities of echocardiography.An essential component of the diagnostic accuracy of echocardiography is the skill and experience of the individual responsible for image and data acquisition.Technical skills includes appropriate knowledge of ultrasound instrument settings such as transducer frequency, use of depth, gain, time-gain-compensation, dynamic range, filtering, velocity scale manipulations, and display of received signals.Echocardiography is a powerful diagnostic tool that provides immediate access for the evaluation of cardiac and vascular structures and assessment of heart function. Intrinsic to a competent echocardiographic examination is a thorough understanding of the anatomy and physiology of the heart and great vessels. Two-dimensional imaging can accurately quantify cardiac chamber sizes, wall thickness, ventricular function, valvular anatomy, and great vessel size. Pulsed, continuous-wave, and color-flow Doppler echocardiography, especially when combined with two-dimensional imaging, can be used to quantify blood flow velocities and calculate blood flow; assess intracardiac pressures and hemodynamics; and detect and quantify stenosis, regurgitation, and other abnormal flow states.A segmental approach is the important and useful way to diagnose congenital heart disease.I will describe the fundamental knowledge of ultrasound, basic views, and segmental approach for congenital heart disease in this paper.

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Physical exercise is one of the important components of daily life in children and adults in terms of mental and physical health, even preventing cardiovascular diseases. However, because inappropriate physical exercise may be harmful and even create the risk of cardiac events in these patients, it is very important for pediatric and adult cardiologists to evaluate and stratify the exercise-associated risks of expected and/or unexpected events. In this respect, exercise testing can give us useful information not only on management but also on the pathophysiology and severity of cardiovascular diseases. Therefore, exercise testing, especially that with expired gas analysis, i.e., cardiopulmonary exercise testing (CPX), is expected to play an important role in the fields of clinical and research settings for pediatric and adult cardiovascular patients. However, performing an exercise test requires specialized knowledge and skills so that the appropriate stress tests can be done safely because exercise itself may be a risk factor for some patients, especially children. In this review, I show the global picture of exercise stress testing, including tips and pitfalls for practicing CPX, and referent normal values with CPX-derived variables.

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The Implantable Cardioverter Defibrillator （ICD） performs the functions of both a defibrillator and a pacemaker. Recent progress in ICD technology has been so remarkable that the device’s indications have had to be expanded to include implantation in children. It is therefore necessary to think about problems specific to pediatric implantation, such as growth, long-term follow-up, and complications related to children’s high activity levels and small bodies. ICD indication and the optimal implantation method must be determined through examination on a case-by-case basis.Cardiac Resynchronization Therapy （CRT） has been noted as a new non-drug therapy for refractory congestive heart failure, and some case reports on congenital heart disease in children have indicated that CRT was effective.

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Background: Ectopic Atrial Tachycardia (EAT) in pediatric patients without structural heart disease is not frequent with an incidence of 10% to 15% of pediatric patients referred for catheter ablation, and its clinical manifestation is diverse. The aim of this study is to clarify the clinical manifestation and appropriate management in these patients.
Methods: A retrospective review identified 22 children with EAT without structural heart disease at the Chiba Cardiovascular Center from April 1998 to March 2013. Patients were classified into three groups according to the duration of EAT; those were Group A (EAT eventually ceases spontaneously by 6 years old), Group B1 (EAT is persistent with permanent or incessant tachycardia), and Group B2 (EAT is persistent with paroxysmal tachycardia), and we compared clinical features among these groups. Patients with a genetic abnormality were excluded.
Results: Age at diagnosis was significantly younger in Group A than Group B1 and B2 (p = 0.002) (Group A; median 0.3 years: range 0-1.8 years, Group B1; median 10.4 years: range 0.9-15.4 years, Group B2; median 10.4 years: range 4.4-13.5 years). Both Group A and Group B2 showed a favorable response to drug therapy. Group B1 was more refractory to drug therapy than the others. All 15 children with persistent tachycardia received radiofrequency catheter ablation (RFCA) with a success rate of 93% (14/15).
Conclusion: EAT is expected to generate spontaneous resolution; therefore, antiarrhythmic drug therapy should be the first choice in patients with non-structured heart disease and early onset EAT, especially for a fetus, neonate, and infant. The indication is to show different clinical manifestations according to type of tachycardia in cases with persistent EAT. In cases with sustained or recurrent EAT, in those tachycardia-induced cardiomyopathy (TIC) could develop, meticulous follow-up and management including RFCA is necessary.

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We experienced a neonate with aortic-left ventricular tunnel （ALVT） who underwent a radical operation in the neonatal period. A 7-day-old male newborn had exhibited aortico-left ventricular blood flow reflux during the fetal period. He was diagnosed with ALVT immediately after birth, and heart failure symptoms subsequently appeared. A surgical operation was performed during the neonatal period. The aortic end of the ALVT was located in the right-noncoronary commissure and the measured diameter was approximately 5 mm. Direct closure of the ALVT was performed without limiting the movement of the aortic valves. The postoperative course of the patient was uneventful so far.

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In the present case, extremely high blood pressure was identified in a school-based screening in a 13-year-old girl. Based on the detection of differences in blood pressure between the upper and lower limb, and abdominal bruit, an abnormality of the thoracoabdominal aorta was suspected. Contrast-enhanced computed tomography showed hypoplasia throughout the abdominal aorta, and the left and right renal arteries, as well as atrophy of the right kidney. In addition, stenosis was observed in part of the abdominal aorta distal to the renal artery bifurcation. Catheterization showed a pressure differential of 40 mmHg at this site, and this was thought to be the cause of the difference in blood pressure between the upper and lower limbs. Plasma renin activity was markedly increased after captopril administration. Based on these findings, mid-aortic syndrome and renovascular hypertension were diagnosed. In addition, captopril renography showed marked functional impairment of the right kidney. Oral antihypertensive drugs were initiated but were not effective. Catheter intervention and surgical treatment were considered difficult based on the morphology of the renal vessels, and a nephrectomy of the non-functioning kidney was performed. We also increased the dose of oral medications. With systolic blood pressure at 150−160 mmHg as of the time of writing, extremely high blood pressure improved a little. Careful follow-up is considered necessary in the future. Moreover, patients with secondary hypertension commonly have no subjective symptoms despite marked hypertension, and blood pressure tests are extremely important to enable early intervention.

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Neonatal Marfan syndrome (nMFS) is a rare disease with extremely poor prognosis due to severe cardiopulmonary failure that may be present at birth or develop during early infancy. In Japan, only 12 cases of nMFS have been reported to date. Here we report a female nMFS patient who received propranolol from 1 month of age, losartan from 2 months of age, and mitral valve replacement at 5 years of age. On the second day after birth, she was presented to a local hospital with poor sucking and vomiting. She also had arachnodactyly and a senile appearance. Echocardiograms demonstrated dilatation of the aortic root, mitral valve prolapse, and mitral regurgitation. She was referred to our hospital at 26 days of age after diagnosis of nMFS. Sequence analysis of the fibrillin-1 gene identified a mutation in exon 24 (Gly1013Arg). During follow-up, mitral regurgitation worsened progressively despite administration of diuretics, propranolol, losartan, and enalapril, and mitral valve replacement with a St. Jude Medical valve (25 mm) was performed successfully at 5 years of age. Histopathological evaluation revealed myxomatous thickening of the mitral valve. Ectopia lentis and progression of scoliosis were also observed during follow-up. At the time of this report, she was 7 years old and has had an uneventful postoperative course. Thus, losartan showed a potential role in the treatment of nMFS in the present case； however, more case studies are necessary to establish its efficacy.

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