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Biomedical subjects

C I Noh

Publications and source records attributed to C I Noh.

At least 19 recordsLinked to original sources
PubMed2001

Modified Lecompte procedure for the anomalies of ventriculoarterial connection.

BACKGROUND: The Lecompte procedure for correcting transposition of the great arteries has an advantage because it obviates the need for an extracardiac conduit for the reconstruction of the pulmonary outflow tract. In this study, we evaluated the effectiveness and the application of the Lecompte procedure based on our experiences. METHODS: A retrospective review was conducted of the records of 45 patients who underwent the Lecompte procedure during the past 11 years to achieve direct right ventricle to pulmonary artery continuity. Mean age at operation was 2.4+/-1.7 years (range 3.5 months to 6.9 years). The diagnoses involved anomalies of the ventriculoarterial connection with ventricular septal defect and pulmonary outflow tract obstruction, such as transposition of the great arteries, double-outlet right ventricle, and double-outlet left ventricle. RESULTS: Early mortality was 4.4% (2 of 45 patients) and late mortality was 4.7% (2 of 43). The mean follow-up was 4.9+/-3.1 years. Fourteen patients (34.1% of survivors, n = 41) had pulmonary stenosis (pressure gradient above 30 mm Hg), the main reason for which was a calcified monocusp valve (n = 10, 71.4%). Eight of 45 patients (17.8%) underwent reoperation: 2 for residual ventricular septal defect, 1 for recurrent septic vegetation, and 5 for pulmonary stenosis. The cumulative survival rates were 91.1%+/-4.2% at 10 years. The actuarial probabilities of freedom from reoperation for pulmonary stenosis were 93.8%+/-4.3% and 71.4%+/-11.8% at 5 and 10 years, respectively. CONCLUSIONS: Our review suggests that the Lecompte procedure is an effective treatment modality for anomalies of the ventriculoarterial connection with ventricular septal defect and pulmonary outflow tract obstruction. Repair in early age is possible with acceptable morbidity and mortality, but recurrent right ventricular outflow tract obstruction caused by degeneration of the monocusp valve is a problem that needs resolution.

Actuarial Analysis↗
PubMed2001

Sustained ventricular tachycardia in children after repair of congenital heart disease.

To investigate an association between surface electrocardiographic (ECG) parameters and sustained ventricular tachycardia (VT) in children after repair of congenital heart disease (CHD), data were obtained and analyzed in three groups (group I, 7 postoperative patients with episode of sustained VT (4 tetralogy of Fallot (TOF), 2 double outlet right ventricle (DORV), 1 truncus arteriosus); group II, 14 children with postoperative TOF not associated with VT; group III, 14 normal children). Mean age at the onset of sustained VT was 129+/-77 months (range 60-232); mean age at corrective surgery, 44+/-33 months (range 10-102); mean follow-up period after surgery, 84+/-74 months (range 20-185); the duration from repair to the onset of sustained VT, range 1-185 months. Compared to group II and III, group I showed longer QRS duration (group I, 137+/-10 msec; group II, 114+/-22 msec; group III, 65+/-12 msec) and shorter corrected J to Tmax interval (group I, 209+/-24 msec; group II, 272+/-44 msec; group III, 249+/-18 msec). QT and corrected QT, J to Tmax interval, and their dispersions in group I and II are significantly different from those of group III. In conclusion, QRS duration and corrected J to Tmax interval could be helpful to predict ventricular tachycardia in postoperative CHD.

Adolescent↗
PubMed1999

Molecular genetic analysis of the DiGeorge syndrome among Korean patients with congenital heart disease.

The DiGeorge syndrome (DGS) is a developmental defect of the third and fourth pharyngeal pouches, which is associated with congenital heart defects, hypoparathyroidism, cell-mediated immunodeficiency, velo-pharyngeal insufficiency and craniofacial dysmorphism. The aetiological factor in a great majority of DGS cases is monosomy for the chromosomal region 22q11. To analyze DGS at the molecular level, a new molecular probe (DGCR680) encompassing the ADU balanced translocation breakpoint was prepared. When 13 Korean patients with DGS-type congenital heart disease were analyzed with this probe, 9 turned out to have a deletion at this locus, and all of them except one exhibited a typical facial dysmorphism associated DGS. Though only 9 independent patients were detected to have a deletion at the locus using the commercial probe N25 (D22S75), which maps at about 160 kb from the ADU breakpoint to the telomeric end, results from fluorescence in situ hybridization revealed a deletion in all cases tested at this locus. Two patients who had a deletion at the locus D22S75 but not at DGCR680 did not exhibit any DGS-type facial abnormalities. This result implies that the 680 bp probe covering the ADU translocation breakpoint might be a candidate for a molecular marker that can distinguish a specific phenotype, such as facial features associated with the DiGeorge syndrome. This study also suggested that systematic approaches with several small DNA probes along the DGCR could help to dissect the complex phenotypes associated with the DiGeorge syndrome, such as cardiac defects, abnormal faces, thymic hypoplasia, cleft palate, and hypocalcemia, etc.

Adolescent↗
PubMed1999

Non-linear cardiac dynamics and morning dip: an unsound circadian rhythm.

The frequency of sudden cardiac death increases in the morning. The relationship between decreased complexity of heart rate dynamics and sudden cardiac death has been documented. An understanding of circadian variation in the complexity of cardiac dynamics may be important to predict and prevent sudden cardiac death. Dynamic 24-h electrocardiographic recordings were obtained from 30 healthy ambulant subjects aged 41-50 years, and the digitized data were partitioned into sections of 30 min duration. For each section, four indexes obtained from separate algorithms of non-linear dynamics of the RR interval--modified correlation dimension, Lyapunov exponent, approximate entropy, and fractal dimension--were calculated. Normalized low-(0.04-0.15 hertz) and high-frequency (> 0.15 hertz) components were also calculated. All four indexes of non-linear dynamics showed a remarkably similar circadian rhythm: a prominent morning dip preceded by a steep decline during the late night, a recovery during the evening and a peak around midnight. In the morning, the low-frequency component rose rapidly with concomitant reduction in the high-frequency component. The complexity of cardiac dynamics decreases significantly in the morning, and this may contribute to the ominously increased rate of cardiac death in the morning hours.

Adult↗
PubMed1999

Atypical pulmonary artery sling with diffuse-type pulmonary arteriovenous fistula.

The case of a cyanotic infant with a rare combination of atypical pulmonary artery sling, imperforate anus, absence of the left kidney, interruption of the inferior vena cava, left side hemihypertrophy and diffuse-type pulmonary arteriovenous fistula is described. The clinical features were confusing, because of compounding abnormalities involving the respiratory tract and pulmonary circulation. The diagnostic approach to the etiology of cyanosis is discussed and the embryonic origin of pulmonary artery sling is reviewed.

Arteriovenous Fistula↗
PubMed1999

Pulmonary hypertension in a child with juvenile-type autosomal recessive polycystic kidney disease.

An 11 year-old girl, whose condition was diagnosed as juvenile-type autosomal recessive polycystic kidney disease (ARPKD) at five years of age, presented with chest pain and dyspnea that had developed suddenly two months previously. Two-dimensional echocardiography, Doppler study and cardiac catheterization confirmed pulmonary hypertension. The underlying mechanism of the diagnosis was not defined. Two and a half months after the onset of symptoms, the patient died of pulmonary hypertensive crisis. Careful regular checks of cardiopulmonary status using two-dimensional echocardiography and Doppler should be considered for the early detection of pulmonary hypertension even in an asymptomatic patient with juvenile-type ARPKD.

Biopsy↗
PubMed1998

Percutaneous transluminal coronary angioplasty in a child with Kawasaki disease.

A successful attempt at percutaneous transluminanl coronary angioplasty (PTCA) to relieve stenosis of the mid-portion of the left anterior descending artery was achieved in a 6-year 9-month old boy who had multiple coronary aneurysms and stenosis due to Kawasaki disease. Despite the progression of coronary stenosis he had been well except for the perfusion defect of the anterior wall of myocardium on 99mTc-MIBI SPECT with dipyridamole infusion until PTCA was carried out after 4-year 4-months of the onset of illness. The area of stenosis was 70% before PTCA and 20% after PTCA. No restenosis at the site of PTCA was observed on follow-up angiography at 26 months after PTCA. This successful attempt may indicate that this procedure should be considered early in subclinical stenosis to prevent ischemic cardiac damage.

Angioplasty, Balloon, Coronary↗
PubMed1997

Head-up tilt test in complicated neurocardiogenic syncope in children.

To confirm the usefulness of head-up tilt test (HUT) in neurocardiogenic syncope (NCS) with complicating clinical features, retrospective analysis were done on 12 selected children. The age at onset was 12.7 +/- 1.9 (mean +/- SD) years. Associated clinical features were postoperative congenital heart disease (PO CHD) in 3, coexistent arrhythmia in 8 (persistent ventricular arrhythmia during exercise in 3, premature ventricular contractions in 2, ventricular couplets in 1, sinoatrial exit block in 1 and resting sinus bradycardia in 1) and ST segment depression during exercise in 1. Four of them had a history of exercise-related syncope. All 3 patients with PO CHD had arrhythmia (ventricular tachycardia in 1, sinus bradycardia in 1 and atrioventricular block in 1). HUT provoked NCS in 8 (2 during baseline tilt, 6 during isoproterenol infusion). In one each, ventricular tachycardia and loss of consciousness without hypotension and bradycardia were induced. Atenolol was tried in 5 with improvement of NCS in 4 and aggravation of dizziness in 1. During follow-up, 7 became asymptomatic (2 with atenolol) and 5 were stationary. In conclusion, HUT was valuable in diagnosing NCS even in children with complicating clinical features such as arrhythmias or PO CHD. HUT could be done as apart of initial diagnostic tests if the past history suggests NCS, regardless of associated clinical features. In some cases, the unexpected results of the test turned out useful in managing children with syncope or dizziness.

Adolescent↗
PubMed1995

Ventricular tachycardia and exercise related syncope in children with structurally normal hearts: emphasis on repolarisation abnormality.

OBJECTIVE: To emphasize the importance of ventricular tachycardia associated with repolarisation abnormality in syncope associated with exercise. DESIGN: Retrospective analysis of data on children presenting with syncope between 1985 and 1993. PATIENTS: 5 apparently normal children with recurrent exercise related syncope associated with electrocardiographically abnormal TU complexes. RESULTS: 3 children were diagnosed as having an intermediate form of the long QT syndrome and catecholamine sensitive ventricular tachycardia because the abnormal TU complexes were associated with polymorphic ventricular tachycardia that was not typical of torsades de pointes. Tachycardia was induced by exercise in all patients and by isoprenaline in the one patient who was tested. One patient also had sinus node dysfunction. One child had incessant salvos of polymorphic ventricular arrhythmias and intermittent abnormal TU complexes suggestive of repolarisation abnormalities. The other had typical congenital long QT syndrome. Treatment was effective in three patients; two patients took a beta blocker alone and one took a beta blocker and low doses of amiodarone. One patient died suddenly, death being associated with sinus node dysfunction. In one patient with incessant ventricular arrhythmias treatment with a beta blocker, amiodarone, or Ic drugs was ineffective and always associated with proarrhythmia or syncope. He was not given further treatment and was asymptomatic despite having mild cardiomegaly. CONCLUSIONS: Ventricular tachycardia associated with repolarisation abnormality was an important cause of exercise related syncope in apparently normal children. TU complex abnormalities can be identified by repeated electrocardiography. beta Blockers are effective in preventing recurrent episodes. The role of amiodarone in this type of ventricular tachycardia needs further evaluation.

Adrenergic beta-Antagonists↗
PubMed1992

Developmental cellular electrophysiologic effects of propafenone on the rabbit atrioventricular node.

Transmembrane recordings and surface electrograms were used to evaluate the influence of propafenone on the cellular electrophysiology of isolated neonatal and adult rabbit atrioventricular node (AVN) preparations. An automatic interval of 863 +/- 82 ms (mean +/- SEM, n = 14) in neonates was found to be significantly shorter than the 1510- +/- 205-ms (n = 12) automatic interval observed in adults. Propafenone in a concentration of 5 x 10(-6) M significantly increased the automatic interval of neonatal pacemakers but not that of the adult preparations. These changes in automaticity produced by propafenone were not dependent on the adrenergic receptor-blocking action of the drug. The pacemaker escape time after overdrive pacing was also shorter in the neonate than in the adult. Propafenone prolonged the escape time of the neonatal tissues but not those of the adult. AVN refractory period, A-H interval, and antegrade Wenckebach rate were comparably increased in a concentration-dependent manner in both age groups. The maximum diastolic potential was decreased by propafenone in the neonatal atrionodal tissue but not in other regions of the AVN and not in any region of the adult AVN. Action-potential duration was increased in all regions of the AVN in both age groups. Action-potential amplitude and maximum upstroke velocity were decreased by propafenone in both age groups. Unlike other excitable tissues of the heart, the action-potential duration of AVN nodal cells increased with decreasing pacing intervals as the pacing interval approached the Wenckebach interval.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1991

Cellular electrophysiology of neonatal and adult rabbit atrioventricular node.

Adult and neonatal rabbit atrioventricular node (AVN) preparations were studied using transmembrane and surface electrogram recordings. Action potentials were categorized into four types, atrionodal (AN), nodal (N), "high" nodo-His (NH) (HNH), and "low" NH (LNH), according to their action potential characteristics and their location within the A-H interval. The electrophysiological parameters of the lower three regions were identical between the two age groups. Action potentials from the neonatal AN region were lower in amplitude and maximum diastolic potential than they were in the adult. The N cell action potential parameters did not differ between the two age groups, however, there did appear to be qualitative differences. AVN conduction times (A-H intervals) were the same in both age groups, as were the antegrade and retrograde refractory periods, and the Wenckebach intervals. Pacemaker activity was significantly greater in the neonates than in the adults and, in 11 of 13 neonatal preparations, originated in the AN region or higher. In 13 of 14 adult preparations, pacemaker activity resided within the AVN.

Action Potentials↗
PubMed1991

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.

Cardiovascular System↗
PubMed1990

Clinical and electrophysiological characteristics of ventricular tachycardia in children with normal hearts.

Characteristics of 18 patients with clinical ventricular tachycardia (VT) and normal hearts documented by physical examination, echocardiography, and angiocardiography were analyzed. There were 13 males and 5 females, aged 1 to 16 years (mean +/- SD, 9.7 +/- 4.8 years). Six patients had hemodynamic instability during VT and the other 12 patients were hemodynamically stable. Two patients (11%) presented with sustained VT and 16 (89%) with episodes of nonsustained VT at varying intervals (3 of 16 with repetitive monomorphic VT). Among 14 patients on whom exercise tests were performed, seven had exercise-induced VT. During electrophysiologic studies, VT was induced in 16 of 18 (89%) (in 13 patients with morphology identical to clinical VT). VT was induced by programmed stimulation (single, double, and burst stimulation of the right atrium or right ventricular apex during sinus rhythm or during pacind for eight beats) in 5 of 18 (28%) patients; with isoproterenol, VT was aggravated spontaneously in 6 of 15 (40%) patients; and during stimulation VT was induced in 8 of 15 (53%) patients. Among patients whose VT was not induced during programmed stimulation, VT was induced with the addition of isoproterenol in 11 of 12 (92%). All 14 patients in follow-up are in stable condition, seven patients with medication and seven without medication. Pediatric patients with normal hearts and clinically detected VT usually have VT induced by programmed stimulation, either with or without isoproterenol stimulation.

Adolescent↗
PubMed1990

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.

Aorta, Thoracic↗