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Biomedical subjects

P K Chun

Publications and source records attributed to P K Chun.

At least 19 recordsLinked to original sources
PubMed1989

Asymptomatic left main coronary artery disease and silent myocardial ischemia.

Gathering data on the prognosis, detection, and natural history of asymptomatic left main coronary artery disease with silent myocardial ischemia is difficult. Epidemiologic studies of unexpected death and postmortem studies on silent myocardial infarction suggest this entity to be common. We reviewed 89 consecutive patients with left main coronary artery disease (LMD), defined as 50% or greater reduction of luminal diameter. Of this group, 10 patients (11%) were asymptomatic (ALMD) and 79 patients (88%) were symptomatic (SLMD). All 10 ALMD patients were men, with a mean age of 53 years (range 40 to 65). Treadmill tests (TMT) were performed for: ECG abnormalities six; pre-jogging evaluation two; risk factor evaluation two. The TMT within 9 minutes showed 2 mm or greater ST depression in seven (70%) and 1 to 2 mm in three (30%). Similar TMT results were obtained in the SLMD group, although two patients had negative responses. The degree of stenosis of the left main coronary artery and the frequency of three-vessel disease were similar in both groups. The ejection fraction (EF) and contractile pattern of the left ventricle (LV) were normal in all 10 ALMD patients, but the left ventricular end-diastolic pressure (LVEDP) was abnormal in three (70%). In the SLMD group, 51 (64%) had an abnormal ejection fraction, 50 (65%) had wall motion abnormalities, and 25 (32%) had an abnormal LVEDP.

Adult↗
PubMed1985

Genetic relationships among Neisseria species assessed by comparative enzyme electrophoresis.

The electrophoretic mobilities of 12 enzymes from 19 Neisseria species (including 6 strains of N. perflava), Gemella haemolysans, Escherichia coli and Branhamella catarrhalis were characterized by polyacrylamide slab gel electrophoresis. All strains and species tested exhibited qualitatively different zymogram patterns. Species and strain relationships were quantified by pairwise comparisons of all 12 enzyme systems to obtain similarity indices; these data were subjected to numerical clustering methods to obtain groups and a phenogram. The electrophoretic classification compared favourably with those obtained by other criteria. In addition, the quantitative clustering data indicated that N. ovis and N. caviae are sufficiently different from the other Neisseria species to warrant their separation into a distinct group. These two species also lacked the characteristic NADPH-diaphorase zymogram pattern found in all the other Neisseria species. Intra-species similarity indices were generally greater than the inter-species index values. However, certain species such as N. meningitidis and N. gonorrhoeae had similarity index values in the range of inter-strain index values.

Dihydrolipoamide Dehydrogenase↗
PubMed1985

Cardiac sarcomas presenting as metastatic disease.

We describe two patients with primary sarcoma of the heart in whom metastatic lesions were the first evidence of disease. One patient had a fibrosarcoma of the tricuspid valve with only pulmonary metastases. The second had a pleomorphic sarcoma of the mitral valve with renal and bony metastases. The possibility of a primary cardiac tumor should be considered in patients with occult metastatic sarcoma.

Adolescent↗
PubMed1984

Acute takeoffs of the coronary arteries along the aortic wall and congenital coronary ostial valve-like ridges: association with sudden death.

Congenital coronary artery anomalies have been associated with sudden death. Twenty-two patients who were victims of sudden death (mean age 46) and who had no significant anatomic cause of death were examined at autopsy and compared with 19 patients who died of known causes (control group). The hearts of these 41 patients were examined for abnormalities of acute angle takeoff of the coronary artery and presence of ostial valve-like ridges. Of the 22 patients who died suddenly, 13 (59%) had acute angle takeoff of the coronary artery and 9 (41%) had ostial valve-like ridges. Of the 19 control subjects, 4 (21%) had acute angle takeoff and only 2 (11%) had an ostial valve-like ridge. The difference was statistically significant (p = 0.015 and 0.031, respectively). It is suggested that aortic root dilation may compress coronary arteries with acute angle takeoff and that ostial valve-like ridges may act as occlusion valves. Thus, either may cause acute obstruction of the proximal coronary artery and lead to sudden death. A very lethal combination for sudden death would be the presence of severe coronary artery disease, an acute angle takeoff and an ostial valve-like ridge.

Adult↗
PubMed1984

Length of left main coronary artery. Lack of correlation to coronary artery dominance and bicuspid aortic valve: an autopsy study of 54 cases.

Previous coronary angiographic data have suggested that the left main length of the coronary artery correlated with dominance (origin of the posterior descending branch) and bicuspid aortic valves. In our autopsy study with direct measurements of left main lengths, 41 patients with tricuspid aortic valves and 13 with bicuspid aortic valves were examined for right, left, or codominance. There was no statistically significant difference in either coronary dominance or the length of left main coronary artery between the congenital bicuspid and tricuspid aortic valves. Age, sex, heart weight, extent of coronary artery disease, left ventricular wall thickness, and site of prior infarction did not correlate with left main length or dominance. Thus, short left main lengths do not correlate with coronary dominance or with aortic valves. Angiographic assessment of left main coronary artery length is subject to magnification, oblique projection, and catheter position errors.

Adult↗
PubMed1982

Clinical clue of severe aortic stenosis. Simultaneous palpation of the carotid and apical impulses.

In patients with severe aortic stenosis, simultaneous palpation of the carotid and apical impulses yields a palpable lag time between the two. Apexcardiograms and carotid pulse tracings were recorded in 66 control subjects and in 30 patients with aortic stenosis. Using QRS peak as reference, the peak appearance time of the carotid pulse tracings and apexcardiograms was measured, and the difference was calculated as palpable lag time; 21/30 patients had a palpable lag time, whereas nine did not; 22/30 patients with aortic stenosis had aortic valve areas of less than 1 sq cm. Twenty-one of these 22 patients had a palpable lag time. The sensitivity of a palpable lag time for aortic valve areas of less than 1 sq cm was 95%, specificity 100%, positive predictive value 100%, and negative predictive value 89%. The group means for measured lag times between controls (70 +/- 7 ms) and those patients with aortic stenosis (133 +/- 7 ms) showed a definite difference. The palpable lag time by linear regression analysis had an r of .68, third in rank to the aortic valve gradient and ECG for predicting aortic valve area. Multiple regression analysis found the palpable lag time, ECG, syncope, and shudder waves together able to predict the aortic valve area (r = .85).

Adolescent↗
PubMed1982

The cardiac fibrous skeletal ring model: simple, inexpensive method to illustrate normal and abnormal cardiac anatomy three dimensionally.

A novel, innovative, simple, and inexpensive graphic method is proposed to facilitate illustrating the variety of cardiovascular pathology. Six-ring plastic container holders, resected selectively, or circles carefully drawn to represent the cardiac fibrous skeleton, enable visualization of the cardiac pathology three-dimensionally without notations. Given 9 axioms, this systematic technique is easy to learn and teach, enabling a nonartistic neophyte to understand complex, cardiac anatomic perspectives and diagram specific cardiac anomalies.

Atrioventricular Node↗
PubMed1982

Myxomatous degeneration of mitral valve. M-mode and two dimensional echocardiographic findings.

This report presents a patient with an unusual clinical course associated with a mitral "mass" recorded by M-mode and cross-sectional echocardiography. The "mass" was confirmed at operation to be redundant myxomatous mitral valve leaflets. The problem of echocardiographic resolution in the setting of mitral valve prolapse and of the differential diagnosis of mitral mass is discussed in detail.

Diagnosis, Differential↗
PubMed1982

Coronary atherosclerosis in mitral stenosis.

Eighty-two patients with mitral stenosis underwent cardiac catheterization with coronary angiography. Twenty-one patients (26 percent) had coronary artery disease. Characteristics of the mitral valve area, cardiac output, pulmonary artery pressure, pulmonary vascular resistance, left ventricular end-diastolic pressure, left ventricular ejection fraction, and atypical chest pain did not correlate with findings of angina pectoris or of coronary artery disease; however, there was correlation with sex, age, and angina. Coronary artery disease occurred only after the age of 40 years and was more frequent in males with angina. Coronary artery disease could not be ruled out in patients with mitral stenosis, especially those over age 40, without coronary arteriography.

Aged↗
PubMed1982

Suture obliteration of the circumflex coronary artery in three patients undergoing mitral valve operation. Role of left dominant or codominant coronary artery.

Three patients, two undergoing mitral valve replacement and one a mitral valve annuloplasty with a Carpentier-Edwards ring, had suture obliteration of the circumflex coronary artery. Examination of the distance of the circumflex artery from the mitral anulus in 15 specimens showed a direct correlation to the type of coronary dominance. That is, left dominance (4.1 mm, range 3 to 6.5) or codominance (5.5 mm, range 4.5 to 7.5), where the posterior descending artery arises from the circumflex, was associated with greater proximity to the mitral anulus than right dominance (8.4 mm, range 6 to 11.5). Two of our patients had left dominance and one codominance, predisposing them to circumflex injury. Factors that identify patients at high risk for such injury are therefore left dominance and codominance. Surgeons forewarned with this information can now focus on the proximal third of the circumflex--the area most predisposed to injury.

Coronary Vessels↗