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Biomedical subjects

C W Chiang

Publications and source records attributed to C W Chiang.

At least 91 records · Page 5Linked to original sources
PubMed1990

Apical hypertrophic cardiomyopathy: clinical, echocardiographic and angiographic features in 3 Chinese patients.

We present 3 cases of apical hypertrophic cardiomyopathy. The presenting symptoms were dyspnea on exertion in 2 of 3 patients, typical anginal pain in 1 patient, atypical chest pain in 1 patient, and fatigue in 1 patient. One patient was asymptomatic with an abnormal electrocardiogram. Sustained apical impulse was noted in all patients, Grade 1/6 systolic murmur was audible in 2 patients. Electrocardiogram showed T wave inversion in the left precordial leads in all patients with amplitudes of 1.4, 0.8 and 2.0 mV, respectively. Isolated apical hypertrophy was noted in all patients. Two-dimensional echocardiogram and the left ventriculogram revealed a "spade-shaped" configuration of the left ventricular cavity at endo-diastole in only one patient. Left ventricular end diastolic pressures were elevated and coronary angiograms were normal in all 3 cases. We conclude that this disease entity should be considered in patients whose electrocardiogram shows a large inverted T wave in the left precordial leads, either accompanied by symptoms such as dyspnea on exertion or chest pain, or even when asymptomatic. Echocardiogram is the most useful screening tool in the diagnosis of apical hypertrophic cardiomyopathy.

Adult↗
PubMed1989

Echocardiographic findings of mobile atrial hepatocellular carcinoma. Report of five cases.

Hepatoma with cardiac metastasis is difficult to diagnose antemortem. Herein we describe five cases of hepatoma with intracardiac metastasis detected with two-dimensional echocardiography (2DE). The clinical presentations include cardiac murmur, syncope, and chest pain. The 2DE demonstrated a right atrial (RA) mass in each case and the presence of tumor echoes in the inferior vena cava connecting with the RA mass in four. In three cases the cardiac tumor was removed, whereas the other two patients agreed only to liver biopsy, which confirmed the diagnosis. This paper emphasizes the practical utility of 2DE for early detection of intracardiac hepatoma and also describes the clinicopathologic correlation of such a disease entity.

Adult↗
PubMed1989

Doppler echocardiographic findings in healthy Chinese adults.

To establish a norm for cardiac velocities in healthy Chinese adults, we examined 30 normal subjects (15 men and 15 women) with pulsed- and continuous-wave Doppler, and color flow mapping. The subjects ranged in age from 18 to 60 years (mean 37 years). We found that the early (E) and late (A) diastolic peak velocities for the mitral valve were 87 +/- 16 cm/sec and 61 +/- 15 cm/sec, respectively. The E/A ratio was 1.5 +/- 0.4. The E and A peak velocities for the tricuspid valve were 57 +/- 10 cm/sec and 40 +/- 7 cm/sec, respectively. The peak velocities for the left ventricular outflow tract, the ascending aorta, the proximal descending aorta and the main pulmonary artery were 77 +/- 19, 106 +/- 20, 96 +/- 24 and 74 +/- 17 cm/sec, respectively. None of the velocities exceeded 154 cm/sec. There were no significant differences between men and women. However, older subjects (greater than or equal to 40 years) had a higher mitral A velocity (69 +/- 13 cm/sec vs 57 +/- 17 cm/sec, p less than 0.05) and a lower E/A ratio (1.3 +/- 0.4 vs 1.6 +/- 0.3, p less than 0.05) than did subjects under 40 years of age. Mild tricuspid regurgitation was detected in 8 of the 30 subjects (27%), mitral regurgitation in 3 of the subjects (10%) and pulmonic regurgitation in one of the subjects (3%). There was no aortic regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Immediate prognostic significance of complete atrioventricular block in acute myocardial infarction.

To discern the relative prognostic role of complete atrioventricular block (CAVB) in patients with acute myocardial infarction (AMI), 908 consecutive patients with AMI were studied over a 7-year period. Of the 559 patients with anterior wall AMI, 13 (2.3%) demonstrated CAVB, of whom 10 (76.9%) died in the hospital (vs 10.4% in those without CAVB) (p less than 0.001). In 349 patients with inferior wall AMI, 30 (8.6%) developed CAVB, of whom 6 (20%) died (vs 6.3% in those without CAVB) (p less than 0.01). In anterior wall AMI, all 5 patients with narrow QRS complexes (vs 8/11 with wide QRS complexes) (p = NS) died; in inferior wall AMI, 4/25 with narrow QRS complexes (vs 2/5 with wide QRS complexes) (p = NS) died. The mortality rate of patients with an escape frequency of less than or equal to 50/min did not differ significantly from that of patients with greater than 50/min regardless of the site of infarction or whether a pacemaker was used. In anterior wall AMI, the mortality rate of paced patients was 70% (7/10) compared to 100% (3/3) of non-paced patients (p = NS). In inferior wall AMI, the mortality rate of paced (5/25) and non-paced (1/5) patients was both 20%. Thus, none of the clinical parameters such as escape rhythm, the width of escape QRS complexes and pacemaker therapy discriminated the survivors from the deaths. In anterior wall AMI, episodes of cardiac standstill or bradycardia were of short duration, and pacemaker therapy was only one of the therapies applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Doppler and two-dimensional echocardiographic features of sinus of Valsalva aneurysm.

Doppler, contrast, and two-dimensional echocardiograms of 12 aneurysms of the sinus of Valsalva in 10 consecutive patients were analyzed in order to highlight the diagnostic features. The diagnosis were confirmed by surgical and/or catheterization findings. The aneurysms had ruptured in 7 of 12 (58%). Two-dimensional echocardiography prior to the contrast studies was able to delineate the aneurysms in 7 of 12 (58%). The contrast studies outlined two additional aneurysms. The right aneurysms directed anteriorly and caudally. The noncoronary aneurysms formed an extraneous lumen at the posterior part of the aortic root, mimicking aortic dissection. Doppler examinations showed systolic and diastolic turbulence in five of six (83%) of the right aneurysms rupturing into the right ventricular outflow tract. Color Doppler echocardiography showed a left ventricular diastolic turbulence emanating from the aneurysm in a case with a noncoronary aneurysm rupturing into the left ventricle. It is concluded that the principal Doppler, contrast, and two-dimensional echocardiographic features usually allow a rapid correct diagnosis of sinus of Valsalva aneurysm.

Adult↗
PubMed1988

Early diagnosis of acute myocardial infarction by myoglobin latex agglutination test.

Early elevation of the serum myoglobin level in acute myocardial infarction (AMI) has been noted for years. In this study, 39 patients admitted to the Coronary Care Unit with acute chest pain within 72 hours (mean 12 +/- 15 hours) or electrocardiographic changes suspected of acute myocardial infarction had a serum myoglobin latex agglutination test to evaluate its diagnostic accuracy in acute myocardial infarction. Of these 39 patients, 24 had documented acute myocardial infarction as their final diagnosis. By the time of admission, 18 of the 24 cases with infarction had positive myoglobin tests (sensitivity 75%). Of those 15 cases without myocardial infarction, 13 had negative myoglobin tests (specificity 87%). If only those 17 cases admitted within 5 hours of the onset of chest pain were analyzed, the serum myoglobin test became positive in 8 of 10 cases with documented AMI but the 2 cases with negative results turned positive 2 hours later (sensitivity 80% to 100%). Due to the fact that myoglobin tests were negative in all other 7 cases without infarction, the specificity was 7/7 (100%). In contrast, the creatine phosphokinase isoenzyme study was positive only in 3 of these 10 patients with documented AMI in the first blood sample taken during admission. In conclusion, the serum myoglobin latex agglutination test is a quick and reliable method that helps in the early diagnosis of acute myocardial infarction.

Adult↗
PubMed1987

Diagnostic accuracy of two-dimensional echocardiography for detection of left atrial thrombus in patients with mitral stenosis.

Two-dimensional echocardiograms of 56 patients with mitral stenosis, who subsequently underwent operation, were analyzed to evaluate the accuracy for the detection of left atrial thrombi. From left parasternal, apical, and subcostal cardiac windows, multiple planes (including standard planes and their derived scanning planes) were assessed for the presence or absence of mass echoes in the left atrium. The results showed 63% sensitivity, 95% specificity, 87% positive predictive value, 84% negative predictive value, and 83% overall diagnostic accuracy. Most of the false-negative cases had their thrombi confined to the left atrial appendage. We conclude that in patients with mitral stenosis, two-dimensional echocardiography is promising for the diagnosis of left atrial thrombi, particularly when they locate or extend to the main left atrial cavity (not confined to atrial appendage).

Adult↗
PubMed1986

Moving right atrial mass associated with hepatoma. Two cases detected by echocardiography.

Hepatoma with right atrial (RA) metastasis is rare, and to our knowledge, the echocardiographic description of a RA mass associated with hepatoma has never been described. Herein we report two cases of hepatoma, whose two-dimensional echocardiograms demonstrated a RA mass protruding into right ventricle during diastole, mimicking RA myxoma. However, in contrast to RA myxoma, these RA masses could be traced to the inferior venae cavae, which were dilated and filled with tumor echoes. Since prompt diagnosis and removal of these RA masses might prevent sudden cardiac death, we advocate performing echocardiographic examination in patients with hepatoma, who have cardiac symptoms or signs.

Carcinoma, Hepatocellular↗
PubMed1986

Importance of adequate gas-mixing in contrast echocardiography.

Microbubble formation has been accepted as the mechanism producing contrast echoes. Comparisons of the contrast effects of various agents have been studied extensively, but the importance of gas-mixing has been less appreciated. To test the hypothesis that good gas-mixing, by facilitating microbubble formation, would enhance contrast effect, this study compared the contrast echocardiograms of ten adult patients before and after mixing carbon dioxide with various contrast agents. Contrast agents tested included a 5 percent glucose in water, vitamin B complex, vitamin C, and Cardiogreen solutions. First, we recorded echocardiograms by injecting each diluted contrast solution alone, then repeated the examinations using 10 ml of each diluted solution with 1 ml of carbon dioxide (CO2), mixed by means of a four-way stopcock. Satisfactory or excellent results were obtained in seven of ten, ten of ten, ten of ten, and ten of ten tests, respectively, after thorough gas-mixing, vs one of ten, seven of ten, eight of ten, and six of ten, respectively, before gas-mixing. We conclude that the addition of sufficient amounts of gas, followed by thorough mixing, is of great importance in contrast echocardiography. Consistently good results can be achieved with vitamin C, vitamin B or Cardiogreen solutions by this simple and safe method.

Adolescent↗
PubMed1985

Early postoperative echocardiographic studies of atrial septal defects.

Fifteen consecutive adult patients with uncomplicated atrial septal defects (ASD) underwent echocardiographic examinations both before and 3-8 days (mean 7 days) after surgery to study the early postoperative changes in cardiac dimensions and interventricular septal motion. Echocardiographic analyses included patterns of interventricular septal motion, right and left ventricular dimensions at end-diastole (RVDd & LVDd), aortic root dimension at end-diastole (ARDd) and left atrial dimension at end-systole (LADs). The results showed that the septal motion was abnormal in 87% (13/15) before and 40% (6/15) after operation. RVDd decreased from 36 +/- 7 mm to 27 +/- 7 mm (p less than 0.01) while LVDd increased from 33 +/- 6 mm to 39 +/- 4 mm (p less than 0.01). There were no significant changes in LADs and ARDd after surgery. These observations suggest that in patients with ASD the ventricular dimensions and patterns of interventricular septal motion are changed significantly shortly after surgical repair.

Adolescent↗
PubMed1984

Marijuana effect and delta-9-tetrahydrocannabinol plasma level.

delta-9-Tetrahydrocannabinol (THC) kinetics and dynamics of self-reported psychologic "high" effect are analyzed in six subjects who smoked marijuana cigarettes of three different potencies. Correlation of the pharmacologic response to smoking a marijuana cigarette with plasma THC levels was done with compartmental models and phase plots. It was concluded that the effect compartment for psychologic high is directly coupled to the central (plasma) compartment. It was observed that effect is directly proportional to mean THC levels from approximately 1 to 4 hr after the start of smoking a marijuana cigarette.

Cannabis↗
PubMed1984

Dose-dependent kinetics of probenecid in rhesus monkeys--infusion studies.

14 infusion studies to steady state with probenecid were carried out in 2 monkeys. Plasma clearance decreased with increasing rate of infusion. The urinary excretion data showed a decrease in the fraction of the dose excreted as probenecid conjugate, an increase in the total N-depropyl metabolites, and no change in the 2-hydroxy metabolites with increasing probenecid dose. Pooled Michaelis-Menten constants for probenecid metabolism were estimated from a plot of the linearized Michaelis-Menten equation using infusion rates of probenecid versus the plasma clearances of the drug.

Animals↗
PubMed1984

Cardiac dimensions and motion shortly after mitral valve surgery.

We studied 71 adult patients echocardiographically both before and 2-16 days (mean 8 days) after mitral valve surgery to systematically evaluate the early postoperative changes in cardiac dimensions and motion. The patients were divided into 4 groups: group I with predominant mitral stenosis (MS) (26 patients), group II with predominant mitral insufficiency (MI) (12 patients), group III with MS + MI (16 patients) and group IV with combined mitral and aortic valvular disease (17 patients). After operation the left atrial dimension at endsystole decreased (mean +/- standard deviation, 56 +/- 12 mm vs 46 +/- 11 mm, p less than 0.001), but did not completely normalize in the majority of patients. The left ventricular dimension at enddiastole decreased in group II from 67 +/- 12 mm to 54 +/- 5 mm (p less than 0.01) and in group IV from 59 +/- 13 mm to 54 +/- 13 mm (p less than 0.01), but increased in group I from 43 +/- 8 mm to 46 +/- 9 mm (p less than 0.05). Mitral EF slope increased from 15 +/- 11 mm/sec to 52 +/- 20 mm/sec (p less than 0.001) after commissurotomy, and decreased from 136 +/- 61 mm/sec to 66 +/- 30 mm/sec (p less than 0.05) after annuloplasty. However, the postoperative means were subnormal in these subgroups. Paradoxical or hypokinetic septal motion occurred in 5/71 (7%) before and 50/71 (70%) after operation. We conclude that: 1) partial normalization of cardiac dimensions and subnormal mitral EF slopes shortly after mitral valve surgery suggest a residual pressure gradient across the mitral valve as well as partial irreversibility of the heart after longstanding mechanical overloading, and 2) postoperative abnormal septal motion, which may be caused by pericardiotomy, can occur after any type of open heart surgery.

Adolescent↗