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Biomedical subjects

I S Chiu

Publications and source records attributed to I S Chiu.

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

One-stage repair of aortopulmonary septal defect and interrupted aortic arch.

Surgical repair of an aortopulmonary septal defect, interrupted aortic arch and the duct that coexists in this setting usually includes closure of the aortopulmonary septal defect, reconstruction of the arch, and interruption of the duct. A 20-month-old girl underwent a successful one-stage repair of such anomalies in which an intraarterial baffle was used. A Gore-Tex baffle was used both to close the aortopulmonary septal defect and to conduct the ascending aortic blood flow through the duct into the descending aorta. We recommend use of this intraarterial baffle as an alternative to the repair of an aortopulmonary septal defect and an interrupted aortic arch with a widely patent duct.

Aorta, Thoracic↗
PubMed1994

Angiographic classification of ventricular septal defects in tetralogy of Fallot.

The ventricular septal defect (VSD) in Fallot's tetralogy (TF) was classified into four types: perimembranous (PM), muscular outlet (MO), doubly committed subarterial (DS), and DS with perimembranous extension. From July 1990 to June 1992, we used angiocardiography to define preoperatively the types of VSD in 30 cases of TF, and correlated them with the operative findings. The angiographic images used to identify the types of VSDs were anteroposterior (AP) plus cranial tilting 20-30 degrees, right anterior oblique 30 degrees plus cranial tilting 30 degrees (elongated RAO view) and true lateral view of right ventricular (RV) angiography. DS type and MO type had a shadow of muscle bar postero-inferiorly in the AP and elongated RAO views, while perimembranous type and MO superiorly in the lateral view. DS with perimembranous extension type was devoid of both shadows. The results revealed 73% accuracy rate of prediction by angiocardiography. Most of the incorrectly predicted cases were attributed to a tiny inferior muscle bar in MO type and was mistaken as pm type VSD. We conclude that routine RV angiography before correction of tetralogy of Fallot to identify the types of VSDs is feasible. This information facilitates planning of surgical strategy.

Angiocardiography↗
PubMed1994

Unusual coronary artery pattern in a criss-cross heart.

In a case of criss-cross heart with atrioventricular and ventriculoarterial concordance, the right coronary artery and left anterior descending arose from the right hand sinus; the left circumflex originated from the left hand sinus. This pattern existed because of a persistent circle of Vieussens across the right ventricular outflow tract which located superiorly and leftward in such a criss-cross heart.

Child, Preschool↗
PubMed1994

Atrial natriuretic peptide is produced less in the intercaval sinus than in the pectinated right atrium.

To explain the lower atrial natriuretic peptide concentrations after total cavopulmonary connection than after the Fontan procedure, a prospective study was carried out in seven rats to count the specific granules of atrial natriuretic peptide by electronmicroscope. After fasting from water for 12 days, the quantity of specific granules in the right atrial appendage (pectinated part), intercaval sinus (smooth part), and superior vena cava were counted. The number of specific granules present in the pectinated part of right atrium was 97 +/- 19 in 20 cells, while in the intercaval sinus it was 23 +/- 19 (mean +/- SD). The difference was significant statistically (p < 0.0001). No granule was present in the superior vena cava. We conclude that the granularity of atrial natriuretic peptide is less in the intercaval sinus than the pectinated part of the right atrium.

Animals↗
PubMed1994

Subaortic blind mitral pouch in a double-inlet right ventricle.

A full-term baby girl was diagnosed at birth using echocardiography to have a single ventricle with common atrioventricular valve and subaortic ridge. On the 22nd day after birth she was admitted to hospital for intensive care after sudden onset of cyanosis. Three days later she died after repeated attacks of bradycardia. At necropsy the heart was examined by sequential segmental approach. Situs solitus with double-inlet right ventricle and ventriculoarterial discordance was revealed. The left atrial floor was separated from the ventricle by a small hole leading to a translucent blind pouch, which bulged toward the subaortic outflow tract with its hypoplastic tensor apparatus connected to the subaortic infundibulum. The aortic valve was normal. The pulmonary trunk with a competent bicuspid valve arose from the left-sided rudimentary left ventricle. The pulmonary blood flow was limited by a slit-like interventricular communication. Obstruction of the pulmonary venous return due to the natural closing of the patent foramen ovale and the mitral atresia led to her premature death.

Female↗
PubMed1994

[Anesthetic management of tetralogy of Fallot with absent pulmonary valve--a case report].

Tetralogy of Fallot is characterized by a VSD, overriding of the aorta, right ventricular hypertrophy, and pulmonary stenosis. Absence of the pulmonary valve occurs in 2.6-6% of patients with tetralogy of Fallot. Operative procedures to relieve respiratory symptoms have been described with an mortality of 35-100%. Respiratory compromise may be severe in these infants secondary to bronchial compression by the aneurysmally dilated pulmonary arteries and present a different hemodynamic profile than those with classic tetralogy of Fallot. An understanding of the anatomic and physiologic principles and their anesthetic implications will lead to improved management of these extremely ill infants. We reported the anesthetic considerations and management of a case of tetralogy of Fallot with absent pulmonary valve of an infant who experienced severe respiratory distress on the supine position.

Anesthesia↗
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

Left ventricular pseudoaneurysm diagnosed by magnetic resonance imaging in a nine-year-old boy.

An asymptomatic 9-year-old boy was found to have a cardiac murmur in a heart disease survey. Two-dimensional echocardiogram identified a large left ventricular pseudoaneurysm. Color flow imaging showed a transtunnel "to-and-fro" mosaic pattern between the pseudoaneurysm and left ventricle. ECG-gated magnetic resonance imaging demonstrated the exact size and related location of the left ventricular pseudoaneurysm and its ostium. Without cardiac catheterization or angiography, he was successfully operated on by closure of the communicating tunnel.

Child↗
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↗
PubMed1993

Right pulmonary artery arising from ascending aorta: report of a successfully treated case.

A nine-day-old neonate presented with signs of congestive heart failure during the first week of life. The echocardiogram showed an early bifurcating great vessel originating from the left ventricle. In addition, there was another vessel originating from the right ventricle directly connected to the descending aorta without early branching into the bilateral pulmonary arteries. A muscular ventricular septal defect (VSD) was also found. Cardiac catheterization and angiography showed that: 1) the anomalous origin of the right pulmonary artery arose from the ascending aorta; 2) a large patent ductus arteriosus (PDA) connected the main pulmonary artery and the descending aorta; and 3) a muscular VSD existed. Magnetic resonance imaging also demonstrated the above findings. Reimplantation of the anomalous right pulmonary artery to the main pulmonary artery and ligation of the PDA were done. To the best of our knowledge, this very unusual case is the first such neonatal case with successful surgical repair in Taiwan.

Aorta↗
PubMed1992

Surgical implications of juxtaposed atrial appendages and the associated anomalies.

Juxtaposition of the atrial appendages (JAA) is an uncommon anomaly of the heart that is frequently associated with other cardiac abnormalities, such as transposition of the great arteries and tricuspid atresia. We encountered 7 patients with JAA from July 1984 to July 1989 at National Taiwan University Hospital. The JAA was right-sided in 1 patient and left-sided in 6. The patients' ages ranged from 10 months to 12 years. The cardiac anomalies in the patient with right JAA were double-outlet right ventricle and ventricular septal defect, which was repaired with a patch. Of the 6 patients with left JAA, 5 had transposition of the great arteries, and in 3 of them obstructive tricuspid lesions (tricuspid stenosis in 1, tricuspid atresia in 2) were noted. Three patients with left JAA and normal tricuspid valve underwent total correction (one Senning operation and two Rastelli operations). The other 3 patients with tricuspid obstruction underwent total cavopulmonary connection (2) and Fontan operation (1). We concluded that, first, left JAA was more frequently seen and associated with more morbid anatomy than right JAA. Second, if left JAA is discovered in planning biventricular repair for transposition of the great arteries, the tricuspid valve should be inspected carefully to rule out tricuspid obstruction.

Child↗
PubMed1992

Total cavopulmonary connection for surgical treatment of complex congenital heart disease.

Diversion of vena caval flow directly into the pulmonary circulation--total cavopulmonary connection--has been tried at our hospital for two years as an alternative to the modified Fontan procedure for surgical treatment of complex congenital heart disease other than tricuspid atresia in 26 cases with six operative mortalities. The causes of death were low cardiac output in four, uncontrollable paroxysmal supraventricular tachycardia in one and airway obstruction in one. Except for one late death which occurred three months after surgery due to sepsis, the 19 patients who survived the operation were followed up for four to 27 months (mean 15 months). All of them improved clinically (NYHA Class 1). Graded bicycle exercise tests were performed in five of them at three to 12 months after surgery, and their exercise tolerance was comparable to that of patients with an atriopulmonary connection. In conclusion, total cavopulmonary connection is an acceptable alternative to the modified Fontan operation for surgical treatment of complex congenital heart disease, although longer follow-up is necessary.

Adolescent↗
PubMed1992

Cardiovascular effects of endothelin in chronic hypoxic rats.

This study was undertaken to investigate the effects of endothelin (ET) on cardiovascular function in chronic hypoxic rats (HA) and sea level controls (SL). Catheters were placed in femoral and pulmonary arteries for measurements of mean systemic arterial pressure (Psa) and mean pulmonary arterial pressure (Ppa). The cardiac output was measured by thermodilution method. It is very interesting to find that intravenous injection of ET (0.2 and 1 nmol/kg) caused a decrease in pulmonary arterial pressure (from 44 +/- 2.6 to 36 +/- 1.9 mmHg, p < 0.05) which sustained for about 10 min while the systemic arterial pressure rise (1 nmol/kg) or no significant change (0.2 nmol/kg) in the HA rats. The depressor action of ET is mainly resulted from the drop of cardiac output in HA rats, since the pulmonary vascular resistance resisted to the action of ET in those chronic hypoxic rats could be due to a simple loss of reaction to ET or the release of vascular dilators which balance the ET vasoconstrictive action. This report also found indomethacin and saralasin did not involve the action of ET on pulmonary arterial depression.

Animals↗