Yong Soo Yun

Pulmonary hypertension in preterm infants with bronchopulmonary dysplasia.

Background and Objectives With the increasing survival of preterm infants, pulmonary hypertension (PH) related to bronchopulmonary dysplasia (BPD) has become an important complication. The aim of this study was to investigate the characteristics and outcome of PH in preterm infants with BPD and to identify the risk factors for PH. Subjects and Methods We reviewed the records of 116 preterm infants with BPD cared for at a single tertiary center between 2004 and 2008. Results Twenty-nine (25%) infants had PH >2 months after birth. PH occurred initially at a median age of 65 days (range, 7-232 days). Severe BPD, a birth weight <800 g, long-term ventilator care and oxygen supplementation, a high ventilator setting, infection, and a patent ductus arteriosus (PDA) were related to PH based on univariate analysis (p<0.05). The infants who had longer oxygen supplementation were significantly more likely to have PH (odds ratio, 18.5; 95% confidence interval, 4.1-84.6; p<0.001). PH was improved in 76% of infants after a median of 85 days (range, 20-765 days). Four infants (14%) died. The death of 3 infants was attributed to PH. Conclusion BPD was frequently complicated by PH. Although PH resolved in the majority of infants, PH in preterm infants with BPD can be fatal. Regular screening for PH and adequate management are required.

Takayasu arteritis in Korean children: Clinical report of seventy cases

SummarySeventy cases of Takayasu arteritis in Korean children are reported. There were 57 females and 13 males (male-to-female ratio; 1:4.4). The youngest patient was a 3-year-old female. Family history was positive in one patient. The most common chief complaints on admission were dyspnea, headache, palpitation, and edema which were due to hypertension and congestive heart failure. Hypertension was seen in 65 out of 70 patients (92.8%). The abdominal aorta, thoracic aorta, and renal arteries were the most commonly involved sites in these children. Two patients had nephrotic syndrome. The frequency of positive tuberculin reaction was much higher in children with Takayasu arteritis compared with the general population, and the intensity of the reaction was also stronger. The majority of the patients required immediate medical treatment to control congestive heart failure due to hypertension at initial presentation. When ESR was elevated, corticosteroid was administered. Surgical treatment showed good results in six out of ten cases. Percutaneous intraluminal angioplasty was effective for lowering the blood pressure in six out of nine cases. In three cases, restenosis occurred and angioplasty was repeated in two cases.

Anomalous subaortic position of the brachiocephalic vein (innominate vein): an echocardiographic study.

In 24 (0.98%) of 2457 patients with congenital heart disease the brachiocephalic vein was in an anomalous position below the aortic arch. This is a much higher proportion of such cases than reported so far. This high frequency may arise from differences in the study population and the method of diagnosis. This venous anomaly was more common in patients with tetralogy of Fallot or ventricular septal defect with pulmonary atresia. Patients with the venous anomaly were more likely to have a right aortic arch. The anomalous course of the brachiocephalic vein from the neck to the junction of the superior vena cava was shown by cross sectional echocardiography. In doubtful cases, Doppler study usually clarified the anatomical arrangement.

Endothelial Dysfunction and Microvascular Complications in Type 1 Diabetes Mellitus

We examined whether alterations in vascular endothelial function and early structural changes in atherosclerosis are associated with microvascular complications in patients with type 1 diabetes mellitus (DM). Flow-mediated dilation (FMD) of the brachial artery and carotid intima-media thickness (IMT) measurement were performed in 70 young adults (aged 19 to 35 yr), 48 with type 1 DM, and 22 normal controls. Patients with diabetes had a lower peak FMD response (7.8+/-3.9 vs. 11.1+/-1.9%, p<0.001) and increased IMT (0.51+/-0.10 vs. 0.42+/-0.07 mm, p<0.001) compared with controls. Twenty (41.7%) of the patients had microvascular complications including neuropathy, nephropathy, or retinopathy. In these complicated diabetic patients, we found a lower FMD response (6.1+/-2.5 vs. 9.9+/-3.5%, p=0.001) compared with diabetics without microvascular complications. The presence of microvascular complications was also associated with older age and longer duration of the disease. However, no differences were observed in IMT, body size, blood pressure, HbA1c, C-reactive protein, low-density lipoprotein or high-density lipoprotein cholesterol levels between complicated and non-complicated patients. Endothelial dysfunction and early structural atherosclerotic changes are common manifestations in type 1 DM, and endothelial dysfunction is thought to be an early event in the atherosclerotic process and important in the pathogenesis of microvascular complications.

Epidemiologic picture of Kawasaki disease in Korea, 2000–2002

Background : The aim of this study was to investigate the incidence rate and epidemiologic patterns of Kawasaki disease in Korea for a 3 year period during 2000 to 2002.

Dexrazoxane for Preventing Anthracycline Cardiotoxicity in Children with Solid Tumors

This study attempted to assess the incidence and outcome of anthracycline cardiotoxicity and the role of dexrazoxane as a cardioprotectant in childhood solid tumors. The dexrazoxane group included 47 patients and the control group of historical cohort included 42. Dexrazoxane was given in the 10:1 ratio to doxorubicin. Fractional shortening and systolic and diastolic left ventricular diameters were used to assess the cardiac function. The median follow-ups were 54 months in the dexrazoxane group and 86 months in the control group. The mean cumulative doses of doxorubicin were 280.8±83.4 mg/m2 in the dexrazoxane group and 266.1±75.0 mg/m2 in the control group. The dexrazoxane group experienced significantly fewer cardiac events (27.7% vs. 52.4%) and less severe congestive heart failure (6.4% vs. 14.3%) than the control group. Thirteen cardiotoxicities including one cardiac death and 2 congestive heart failures occurred in the dexrazoxane group, and 22 cardiotoxicities including 2 cardiac deaths and 4 congestive heart failures, in the control group. Five year cardiac event free survival rates were 69.2% in the dexrazoxane group and 45.8% in the control group (P=0.04). Dexrazoxane reduces the incidence and severity of early and late anthracycline cardiotoxicity in childhood solid tumors.

Decreased Left Ventricular Torsion and Untwisting in Children with Dilated Cardiomyopathy

The purpose of this study was to analyze left ventricular (LV) torsion and untwisting, and to evaluate the correlation between torsion and other components of LV contraction in children with dilated cardiomyopathy (DCM). Segmental and global rotation, rotational rate (Vrot) were measured at three levels of LV using the two-dimensional (2D) speckle tracking imaging (STI) method in 10 DCM patients (range 0.6-15 yr, median 6.5 yr, 3 females) and 17 age- and sex-matched normal controls. Global torsion was decreased in DCM (peak global torsion; 10.9±4.6° vs. 0.3±2.1°, p<0.001). Loss of LV torsion occurred mainly by the diminution of counterclockwise apical rotation and was augmented by somewhat less reduction in clockwise basal rotation. In DCM, the normal counterclockwise apical rotation was not observed, and the apical rotation about the central axis was clockwise or slightly counterclockwise (peak apical rotation; 5.9±4.1° vs. -0.9±3.1°, p<0.001). Systolic counterclockwise Vrot and early diastolic clockwise Vrot at the apical level were decreased or abolished. In DCM, decreased systolic torsion and loss of early diastolic recoil contribute to LV systolic and diastolic dysfunction. The STI method may facilitate the serial evaluation of the LV torsional behavior in clinical settings and give new biomechanical concepts for better management of patients with DCM.

Cardiac Dysfunction After Renal Transplantation; Incomplete Resolution in Pediatric Population

Background. Long-term data of cardiac function after renal transplantation (RT) are limited, especially in children. Thus, we evaluated the status of left ventricular hypertrophy and various indices of left ventricular (LV) function in pediatric RT patients. Methods. Blood pressure, serum biochemical profiles, electrocardiogram, and echocardiogram of 32 pediatric patients (mean age, 15.5±4.4 years) who underwent RT 5.1±2.5 years before and 29 body surface area-matched control subjects were studied. Results. Repolarization abnormalities shown on electrocardiogram of pre-RT patients improved significantly after RT (QTc dispersion 50.8±37.3 to 37.4±11.9 msec, P=0.009). Left ventricular hypertrophy with increased LV mass index of pre-RT patients regressed remarkably after RT (LV mass index 120.9±40.5 to 69.2±14.5 g/m2, P<0.001); still, LV mass was significantly higher in RT patients than the controls (54.0±9.6 g/m2, P<0.001). Compared with the controls, the RT patients showed diastolic dysfunction (lower E/A ratio and higher isovolumic relaxation time) and lower myocardial performance (higher LV Tei index and weaker strain pattern). Patients who had shorter duration of non-RT renal replacement therapy showed better LV function (lower LV Tei index and stronger strain pattern) in the long-term follow-up. Conclusions. Because cardiac dysfunction did not resolve after RT in pediatric population, regular evaluation for cardiovascular function after RT is required. Early RT may also be beneficial to global LV performance after RT.

Pediatric emergency room presentation of congenital heart disease.

Background and Objectives Only a few studies have specifically investigated the reasons for emergency room (ER) visits in patients with congenital heart disease (CHD). The aim of this study was to identify the major reasons for ER presentation among patients with CHD that were acutely and seriously ill at a tertiary medical center in Korea. Subjects and Methods All 368 admissions of patients with CHD via the ER from 2003 to 2008 were enrolled. We conducted a retrospective study with review of the medical records. Results Eighty two patients were newly diagnosed as having CHD. Their major presentations were: symptoms of heart failure (41.5%), murmur (31.7%), and cyanosis (18.3%). There were 286 visits that were cases with known CHD. Their major presentations were respiratory tract infection (24.1%, 2.7±4.1 years of age), dysrhythmia (16.4%, 16.7±9.5 years), symptoms of heart failure (14.3%, 7.6±9.4 years), aggravated cyanosis (5.6%, 0.8±1.4 years), protein-losing enteropathy (4.9%), hemoptysis (4.5%), drug side effects (4.1%), and infective endocarditis (3.0%). There were significant correlations between the age distributions and major modes of presentation. Surgical treatments were required within 1 month in 38%, and 2.7% of all patients died during hospitalization. The patient group with respiratory infections and CHD showed the highest mortality (5.8%). Atrial flutter was the most frequent arrhythmia (70.2%) and 70% of these patients were post-Fontan surgery condition. The causes of heart failure in the patients with previous surgical repair were: pulmonary hypertension, myocardial dysfunction, valve regurgitation, and uncorrected lesions. Conclusion Improved understanding of the common problems in the ER can help prepare clinicians to manage patients that present with CHD.

Study on Doppler waveforms from the fetal cardiovascular system.

In order to see whether Doppler parameters from the fetal cardiovascular system change with fetal growth and to compare Doppler values from the various sites, a total of 274 Doppler studies on 73 human fetuses were analyzed. With advancing gestation, the heart rate decreased, the diastolic filling period of both atrioventricular valves increased, and the systolic ejection time of both semilunar valves remained unchanged. Most of the Doppler parameters from the 4 cardiac valves, the aortic arch, the branch pulmonary artery, and the ductus arteriosus increased with increasing gestation. Doppler waveforms from the branch pulmonary artery, the ductus arteriosus, and the aortic arch each had a distinct shape. More study is needed to define the exact relationship between the gestation period and the Doppler parameters and to determine whether Doppler parameters will be useful in assessing fetal heart function.