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Biomedical subjects

H C Lue

Publications and source records attributed to H C Lue.

At least 55 records · Page 3Linked to original sources
PubMed1994

Usefulness of magnetic resonance imaging in the assessment of venoatrial connections, atrial morphology, bronchial situs, and other anomalies in right atrial isomerism.

Multiple complex venous and intracardiac anomalies are frequently seen in patients with right atrial isomerism, and complete anatomic information may not always be obtained from combined echocardiography and angiography. Twenty patients with right atrial isomerism were prospectively studied with use of magnetic resonance imaging (MRI); satisfactory imaging was obtained in 18 patients, aged 6 days to 12 years (median 3 months). All patients had undergone echocardiography, cardiac catheterization, and angiocardiography. The purpose of this study was to assess the usefulness of MRI in the evaluation of venoatrial connections, atrial morphology, bronchial situs, and additional anomalies. Bilateral superior venae cavae were documented in 12 patients and anomalous hepatic venous drainage in 11. The pulmonary venous system was imaged in all 18 patients, of whom 12 had total anomalous pulmonary venous connection: 9 supracardiac, 2 infracardiac, and 1 mixed type. Some obstruction to pulmonary venous return was present in 9 of the 12 patients, and the site of obstruction was demonstrated by MRI in 6. Bilateral morphologic right atrial appendages were imaged in 7 patients. Bilateral morphologic right bronchi were identified in 17 patients, asplenia was confirmed in 17 of 18 patients by the absence of splenic tissue on imaging, and hiatal hernia was imaged in 4. Compared with angiography and echocardiography, MRI more clearly defined the pulmonary venous connections in 10 patients with pulmonary venous obstruction. Anomalous hepatic venous connections were better defined by MRI in 2. Therefore, MRI provided valuable supplementary information on the cardiovascular and visceral anomalies in these patients.

Abnormalities, Multiple↗
PubMed1994

Prognostic significance of left ventricular diastolic indexes in beta-thalassemia major.

OBJECTIVE: To define the prognostic significance of left ventricular diastolic function in patients with beta-thalassemia major by noninvasive M-mode echocardiography and Doppler measurements. DESIGN: Cohort analytic study. SETTING: A university hospital in Taipei, Taiwan. PATIENTS: Forty-five patients (age range, 4 to 25 years) with transfusion-dependent beta-thalassemia major followed up for 5 years. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: M-mode and Doppler echocardiography were used to determine the left systolic time interval; ejection fraction; left atrium emptying index; isovolumetric relaxation period; diastolic total period; the duration, slope, and height of the early diastolic flow-velocity peak; and the ratio between the heights of early and atrial diastolic flow-velocity peaks. All patients had normal systolic ventricular function initially, but impaired diastolic function developed, especially in the older age group who had more evidence of iron loading. In nine of those with abnormal diastolic total period (n = 10) and duration of the early diastolic flow-velocity peak (n = 12) values, regardless of age, congestive heart failure developed during the period of follow-up. Of these nine, four died within 2 years after the advent of heart failure and five remained compensated after anticongestive treatment and use of deferoxamine mesylate. The presence of an abnormal diastolic total period and duration of the early diastolic flow-velocity peak values correlated well with the prognosis. CONCLUSIONS: Left ventricular diastolic filling variables by echocardiography are important predictors of the outcome of patients with transfusion-dependent beta-thalassemia major and could provide useful measures in determining the effects of medication during long-term follow-up.

Adolescent↗
PubMed1994

Age-related quinidine effects on ionic currents of rabbit cardiac myocytes.

Age-related cardiac actions of quinidine have been shown in prolongation of action potential duration, but not in the tonic and use-dependent block of the maximal velocity of action potential upstroke. To elucidate the underlying ionic mechanisms, currents through the Na, Ca and K channels were examined by using a whole-cell voltage clamp technique on isolated neonatal (< 5 day) and adult (> 3 months) rabbit cardiac myocytes under various concentrations (0.5, 1.5 and 4.5 microM) of quinidine. In neonatal and adult myocytes, quinidine caused a comparable degree of dose-dependent effects on Na currents including decrease in peak Na currents, left-shift of steady-state availability curve and slowing of the recovery from inactivation. However, the inwardly rectifier K current and the transient outward current were suppressed to a greater extent in the neonatal myocytes than in the adult (P = 0.0002 and 0.02, respectively). On the contrary, the magnitude of decrease in peak Ca currents after quinidine treatment was much smaller in the neonatal myocytes than in the adult (P = 0.01). These findings indicate that age-related ionic channel-block by quinidine is complex; and shows major differences in the Ca and K currents of cardiac myocytes. Accordingly, a differential therapeutic potential of quinidine may exist in hearts of different ages.

Action Potentials↗
PubMed1994

Levoatriocardinal vein in mitral atresia mimicking obstructive total anomalous pulmonary venous connection.

This report briefly describes two cases of levoatriocardinal vein, in the setting of mitral atresia and a restrictive interatrial shunt, with clinical as well as echocardiographic features mimicking obstructive total anomalous pulmonary venous connection. One patient died of pulmonary hypertensive crisis, and the other survived the palliative procedures including the atrioseptectomy and pulmonary artery banding. The echocardiography, cine-angiocardiography, and magnetic resonance image for such an anomalous channel are presented. It is tempting to speculate that the thrombocytopenia and indirect hyperbilirubinemia be associated with the destructive consumption of thrombocytes and red blood cells in the serpentine levoatriocardinal vein.

Cineangiography↗
PubMed1994

Infracardiac total anomalous pulmonary venous connection in tetralogy of Fallot with decreased pulmonary flow and masked pulmonary venous obstruction: report of one case.

We describe an 8-month-old male infant, who received a rerouting procedure for infracardiac total anomalous pulmonary venous connection and a 4-mm Gore-Tex central shunt for tetralogy of Fallot with pulmonary atresia. The masking effect of the pulmonary outflow in tetralogy of Fallot on the pulmonary venous obstruction in infracardiac total anomalous pulmonary venous connection is discussed. Preoperative recognition of this rare association is warranted, as palliative surgery alone may be disastrous. In addition, juxtaductal pulmonary artery coarctation in tetralogy of Fallot with pulmonary atresia may play a role in camouflaging the pulmonary venous obstruction in this case. Unmasking pulmonary venous obstruction by oral prostaglandin and augmenting pulmonary blood flow by a Gore-Tex shunt, pari passu, did harm this patient.

Arteriovenous Shunt, Surgical↗
PubMed1994

Characterization of aneurysmal transformation in perimembranous ventricular septal defects: an adhered anterior leaflet of tricuspid valve predisposes to the development of left ventricular-to-right atrial shunt.

BACKGROUND: The most common type of left ventricular-to-right atrial shunts are those associated with perimembranous ventricular septal defect when the defects diminish in size via aneurysmal transformation. This study is to characterize the echocardiographic features and to determine the possible mechanisms. METHODS AND RESULTS: From January 1986 to December 1992, of 930 consecutive patients with isolated perimembranous ventricular septal defect, 692 showed evidence of aneurysmal transformation. Excluding those with subaortic ridge, echocardiographic analysis was based on 664 of them. Of these, 94 patients had left ventricular-to-right atrial shunts, 115 had their defects spontaneously closed and in 455 only interventricular shunt persisted. Four types of echocardiographic findings featured in the aneurysmal transformation process: type A, both the anterior and septal leaflets of tricuspid valve contributed to the process; type B was similar to type A, but the arc-like structure from the anterior leaflet is much less evident; in type C, only the septal leaflet, and in type D, other adjacent tissues, contribute to the aneurysmal transformation. Type A morphology was closely associated with the development of left ventricular-to-right atrial shunt while types C and D were most commonly seen in those spontaneously closed defects and those with only interventricular shunt. The vegetations of infective endocarditis were located at the atrial side of the tricuspid valve in patients with left ventricular-to-right atrial shunts, while they were in the right ventricle in those with only interventricular shunt. CONCLUSION: The morphology of the aneurysmal transformation in perimembranous ventricular septal defect can be characterized by echocardiograms. Although the septal leaflet of the tricuspid valve is usually involved in this process, it is the incorporation of the anterior leaflet that predisposes to the development of left ventricular-to-right atrial shunts.

Cardiac Catheterization↗
PubMed1994

Implications of mitral valve prolapse in children with rheumatic mitral regurgitation.

OBJECTIVES: This study was conducted to determine the longterm prognosis of children with mitral valve prolapse associated with isolated rheumatic mitral regurgitation. BACKGROUND: Rheumatic fever may result in mitral valve prolapse, which sometimes leads to severe mitral regurgitation requiring surgical intervention during the active stage of rheumatic fever. However, the influence of mitral valve prolapse on the prognosis of patients with rheumatic mitral regurgitation remains largely unknown. METHODS: From 1971 to 1991, 181 children who fulfilled the revised Jones criteria of rheumatic fever were identified from a rheumatic fever prevention program. Of the 181 patients, isolated mitral regurgitation was diagnosed in 123 at age 4 to 12 years. The diagnosis of mitral valve prolapse was based on echocardiographic findings. Actuarial event-free curves for persistent murmur, cardiac improvement and surgical intervention were drawn according to the Kaplan-Meier nonparametric estimation. RESULTS: Evidence of mitral valve prolapse was shown in 37 (30%) of the 123 patients. Patients with mitral valve prolapse were more likely to have a larger cardiac size than those without mitral valve prolapse during the active stage of rheumatic fever. Although the cardiac status of patients with mitral valve prolapse may improve under adequate secondary prophylaxis, an actuarial analysis indicated that patients with mitral valve prolapse had a greater likelihood of murmur persistence and surgical intervention. This trend toward murmur persistence was observed even when patients with heart failure during the active stage of rheumatic fever were excluded from analysis. CONCLUSIONS: The presence of mitral valve prolapse in children with isolated rheumatic mitral regurgitation may predict a less favorable outcome.

Child↗
PubMed1994

Posttransfusion hepatitis C virus infection in children.

Hepatitis C virus (HCV) infection was investigated retrospectively and prospectively in children who had open heart surgery. The retrospective study included 196 patients who had open heart surgery 2 to 6 years before enrollment and were regularly followed. Antibody to HCV was detected in eight cases, and seven of these eight patients had viremia caused by HCV infection. The other patient's anti-HCV titer gradually decreased and HCV ribonucleic acid was absent throughout the course. Four of these eight had persistent viral replication without clinical evidence of hepatitis; the other three had viremia and chronic hepatitis. The HCV infection rate in the retrospective study group was about 4%. The HCV was of genotype 2 in five cases and of genotype 3 in two cases. The clinical outcome was not related to sex, age, amount of transfusion, or HCV genotype. For the prospective study, we enrolled 94 patients. Of the 56 enrolled after the initiation of anti-HCV screening in the blood bank, none was infected by HCV. Of the 94 patients, 38 were enrolled before screening; 4 had abnormal liver function 1 to 3 months after operation, and 2 were infected with HCV. One patient had an acute but resolving course; the other had persistent anti-HCV and HCV viremia, although the liver function test results returned to the normal range. The HCV in both cases belonged to genotype 2. We conclude that in Taiwan the seroconversion rate of HCV in children who underwent open heart surgery was 4% to 5%. Anti-HCV screening in donor blood significantly decreased the incidence of posttransfusion hepatitis C.

Acute Disease↗
PubMed1994

Long-term outcome of patients with rheumatic fever receiving benzathine penicillin G prophylaxis every three weeks versus every four weeks.

OBJECTIVE: To compare the efficacy of injections of 1.2 million units of benzathine penicillin G given every 3 weeks versus every 4 weeks for secondary prevention of rheumatic fever, based on the long-term outcome of patients receiving such prophylaxis. METHODS: A total of 249 consecutive patients with rheumatic fever, randomly assigned to either a 3-week or a 4-week regimen, were examined every 3 to 6 months, and followed for 794 and 775 patient-years, respectively. RESULTS: Compliance with each regimen was comparable: 83 (66.9%) of 124 patients in the 3-week group versus 92 (73.6%) of 125 patients in the 4-week group stayed in the program (p > 0.05). Streptococcal infections occurred less frequently in those receiving the 3-week regimen: 7.5 versus 12.6 per 100 patient-years (p < 0.01). Prophylaxis failed in 2 patients receiving the 3-week regimen and in 10 receiving the 4-week regimen (0.25 and 1.29 per 100 patient-years respectively; p = 0.015). Serum penicillin levels were adequate (> or = 0.02 micrograms/ml) in 100 (56%) of 179 samples obtained 21 days after penicillin injection in the 3-week regimen, and in 51 (33%) of 155 samples obtained 28 days after injection in the 4-week regimen (p < 0.01). Of 71 patients with mitral regurgitation in the 3-week regimen, 47 (66%) no longer had the murmur; of 87 patients in the 4-week regimen, 40 (46%) no longer had the murmur (p < 0.05). CONCLUSIONS: This 12-year controlled study indicates that the outcome of patients with rheumatic fever is better with a 3-week than with a 4-week penicillin prophylaxis regimen. Greater emphasis and more widespread use of the 3-week regimen should be recommended.

Adolescent↗
PubMed1994

Probability of supraventricular tachycardia recurrence in pediatric patients.

Supraventricular tachycardia (SVT) in pediatric patients is usually associated with a better prognosis than that in adults. However, late recurrence of SVT has been recently described. A total of 90 patients who had their initial SVT episode before 15 years of age were retrospectively studied (2-228 follow-up months; median, 215 months). Concomitantly congestive heart failure was present in 14 (16%) patients, and a cerebrovascular accident occurred in 1 patient. Intravenous verapamil was most frequently used to convert the initial SVT episodes without adverse effects, even in those younger than 1 year of age (9 patients). Older children could also be converted spontaneously or by vagal maneuvers. Patients with SVT recurrence were associated with an older age at initial SVT episodes (p < 0.001). By Kaplan-Meier actuarial analysis, the chance of remaining SVT-free during the follow-up was much lower in patients with initial SVT after 5 years of age than in patients with initial attacks before the age of 1 and between the age of 1 and 5 (p = 0.02 and 0.04, respectively). Even though, about 40% of the patients whose initial attacks occurred during infancy had recurrences 5 years later. Only those who had the initial attacks during the prenatal period remained free from SVT recurrences. Patients with initial SVT episodes during infancy have a longer period without SVT attacks and a lower chance of recurrences; nonetheless, a substantial number of them had recurrence at later childhood except those with initial SVT attacks during the prenatal period.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1994

Comparison of conventional and simultaneous compression-ventilation cardiopulmonary resuscitation in piglets.

To determine the mechanism of cardiac output and hemodynamic changes during cardiopulmonary resuscitation (CPR), we performed 60 min of CPR using a mechanical resuscitator ("Thumper", MII, USA) in 20 piglets (13.7 +/- 1.2 kg) following cardiac arrest induced by intravenous injection of KCl. Conventional CPR (C-CPR), i.e., 60 external chest compressions (60 psi force, 3 cm deep, and 50% duration) and 12 ventilations (following every 5th compression, with peak airway pressure of 30 cmH2O) per minute, was performed in 10 piglets; and simultaneous compression and ventilation CPR (SCV-CPR), i.e., 60 external chest compressions of the same magnitude, simultaneously with 60 ventilations (with peak airway pressure of 60 cmH2O) per minute, was performed in the 10 other piglets. Cardiac output in C-CPR and SCV-CPR was maintained near 70% or more of baseline throughout the CPR. Systemic vascular resistance dropped to below 50% of baseline. Systolic, mean and diastolic arterial pressures were maintained above 70, 40, and around 20 mmHg, respectively, during the first 30 min of CPR. Central venous pressure rose after arrest and subsequent CPR to above 25 mmHg, and remained high in SCV-CPR, but declined thereafter in C-CPR. Aortic diastolic minus right atrial diastolic pressure was around 15 mmHg early in CPR and dropped to almost zero thereafter. Serial arterial blood gas analyses showed a significant deterioration after 20 min of SCV-CPR. All but one piglet in the SCV-CPR group died after 60 min of CPR. Postmortem examination revealed that pulmonary barotrauma was more extensive and severe in SCV-CPR than in C-CPR.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Implication of aneurysmal transformation in isolated perimembranous ventricular septal defect.

Defects on the membranous ventricular septum (perimembranous ventricular septal defect [VSD]) may spontaneously close or diminish in size by "aneurysmal transformation" (i.e., adherence of the tricuspid valve or adjacent tissue onto the VSD). It was recently shown that the appearance of aneurysmal transformation may be associated with subaortic ridges, as well as left ventricular (LV)-to-right atrial (RA) shunts. In all, 877 consecutive patients with isolated perimembranous VSD were retrospectively studied. Results of actuarial analysis showed that patients with a perimembranous VSD had a 98% probability of aneurysmal transformation by the age of 240 months. Of these patients, the expected probabilities of developing LV-RA shunt, spontaneous closure and subaortic ridge were 45, 35 and 6%, respectively. Patients with LV-RA shunts had higher probabilities of developing infective endocarditis (p = 0.002) and persistent left-to-right shunts (p < 0.001). The presence of a subaortic ridge may be accompanied by LV outflow tract obstruction (10 of 25 patients), infundibular pulmonary stenosis (n = 3), or aortic valve deformity or aortic regurgitation (n = 5), and none of those with a subaortic ridge closed spontaneously. It was confirmed that a substantial proportion of aneurysmal transformation of isolated perimembranous VSD is associated with LV-RA shunts and subaortic ridges.

Age Factors↗
PubMed1993

Double-inlet ventricle in Chinese patients.

This study was performed to elucidate the anatomic features of double-inlet ventricle in the Chinese population. The echocardiograms of 60 Chinese patients diagnosed as having double-inlet ventricle were reviewed and analyzed. Both atria were connected to a dominant right ventricle in 36 patients (60%), to a dominant left ventricle in 17 (28%) and to an indeterminate ventricle in 7 (12%). Right atrial isomerism was present in 30 patients (83%) with double-inlet right ventricle, in 5 (29%) with double-inlet left ventricle, and in 6 (86%) with double-inlet indeterminate ventricle. Right atrial isomerism was more frequently associated with double-inlet right and indeterminate ventricles (p < 0.01; chi-square). Common atrioventricular valve was frequently present in both double-inlet right and indeterminate ventricles. Double-outlet main chamber was the predominant type of ventriculoarterial connection in double-inlet right and indeterminate ventricles. Total anomalous pulmonary venous connection was found exclusively in 9 patients with right atrial isomerism (5 with double inlet right and 4 with double-inlet indeterminate ventricles). In contrast to other reports, this series found double-inlet right ventricle to be the predominant type of double-inlet ventricle. This discrepancy may be due to a greater prevalence of right atrial isomerism that is usually associated with double-inlet right ventricle in Chinese patients.

Child↗
PubMed1993

Obstructed total anomalous pulmonary venous connection.

With the advent of echocardiography, total anomalous pulmonary venous connection (TAPVC) can be readily diagnosed without much difficulty. However, noninvasive detection of the presence of pulmonary venous obstruction in TAPVC remains a difficult issue. During a 5.5-year period, 42 patients were found to have TAPVC by catheterization, surgery, and/or autopsy: 17 had supracardiac drainage, 13 paracardiac drainage, nine infracardiac drainage, and three mixed drainage. Obstruction to pulmonary venous drainage was found in 24 patients (57%). Patients with right isomerism tended to have a higher incidence of pulmonary venous obstruction than those with the usual atrial arrangement (80% vs. 44%, p < 0.05). Color Doppler combined with cross-sectional echocardiography provided accurate delineation of drainage sites in 93% cases (39 of 42). Among the 39 cases with correct echocardiographic delineation of the drainage site, obstruction was detected by echocardiography in 22 cases with a sensitivity of 100% (22 of 22) and a specificity of 85% (17 of 20). Therefore, complete echocardiography, including cross-sectional images and color Doppler proved to be a reliable tool in the detection of drainage sites and pulmonary venous obstruction in TAPVC.

Cardiac Catheterization↗
PubMed1993

Association of hiatus hernia with asplenia syndrome.

During a 13-month period, 13 patients with asplenia syndrome were evaluated with MRI for cardiovascular and visceral anomalies. The MR images were reviewed for the presence of haitus hernia which was found in three patients. One of the remaining ten patients with no MRI evidence of hiatus hernia was diagnosed as having gastro-oesophageal reflux and hiatus hernia by an oesophagogram and 24-h pH monitoring. This patient had undergone fundoplication prior to MRI. Out of the 13 patients (31%) with asplenia syndrome, 4 had hiatus hernia. It appears that among patients with the asplenia syndrome, hiatus hernia is a frequent finding. Recurrent pneumonia or bronchiolitis in patients with asplenia syndrome requires evaluation for the presence of hiatus hernia and gastro-oesophageal reflux.

Adolescent↗
PubMed1993

Infundibular pulmonic stenosis with intact ventricular septum: a report of 15 surgically corrected patients.

Infundibular pulmonic stenosis with intact ventricular septum of primary origin is an uncommon condition. We report 15 such patients (nine males and six females, aged 7-36 years) who had undergone surgical correction for the anomaly during the period between 1975 and 1992. The occurrence of this clinical setting represents 0.19% (15/7826) of all cardiac operations and 0.46% (15/3222) of congenital heart diseases undergoing surgical correction during that period of time. The lesion was of discrete fibromuscular hypertrophy of the infundibulum in all 15 patients. The presenting symptoms of most patients were exertional dyspnea and syncope; however, five patients with severe obstruction were asymptomatic. The peak systolic pressure gradient across the infundibulum ranged from 71 to 230 mmHg. There was only one operative death; the remainder had remained well following the surgery over a mean follow-up period of 35 months. Surgical correction for infundibular pulmonic stenosis is rewarding in the absence of heart failure.

Adolescent↗