PubMed Health⌕ Search

Biomedical subjects

F Y Lau

Publications and source records attributed to F Y Lau.

At least 55 records · Page 3Linked to original sources
PubMed1977

Clinical experience with the Smeloff-Cutter aortic valve prosthesis: an 8-year follow-up study.

A total of 46 patients who survived aortic valve replacement with the present model Smeloff-Cutter prosthesis between 1968 and 1973 were followed up postoperatively. All patients received oral anticoagulant therapy. The average age at implantation was 44 +/- 13 (mean +/- standard deviation) years; 36 patients were male and 10 were female. The valve damage was caused by rheumatic disease in 19 (41 percent), infective endocarditis in 14 (30 percent), congenital heart disease in 7 (15 percent) and other factors in 6 (13 percent). Late death occurred in eight patients (17 percent). All available patients were followed up until December 1976. During the 8 years of follow-up study, seven patients, including four heroin addicts, had postoperative endocarditis (15 percent); five of the seven had cerebral involvement, possibly from septic emboli. Four patients were reoperated on; three had active endocarditis and one had a high transvalve pressure gradient. The mean follow-up time was 4.9 years per patient. Of the 38 living patients, 33 have functional improvement and are still being followed up. Only one patient had a bland embolism to a systemic artery. No ball variance or other types of material failure have been detected. Although the chronic aspects of valve disease remain after prosthetic valve replacement, the Smeloff-Cutter aortic prosthesis deserves strong consideration when selecting a rigid prosthesis for aortic valve replacement.

Adult↗
PubMed1977

The role of serial echocardiography in the evaluation and differential diagnosis of pericardial disease.

Echocardiography is an established method for the diagnosis of pericardial effusion. Echographic findings in fibroadhesive disease have also been described. The interpretation of a changing serial echogram during the clinical course of pericardial disease has not been established. Sixteen patients with echographic evidence of pericardial effusion were followed with serial echographic studies. In seven, surgical or autopsy correlation was obtained. Because of the serial changes noted we undertook a study in dogs to clarify the problem of variability in intensity of sound reflected from the pericardial space. Three open-chested dogs were studied with rapid sequence surface echograms as blood introduced into the pericardial space was converted from the unclotted to the clotted state. In all three dogs blood clooting increased the intensity or sound reflected from the pericardial space. Our study of two patients with fibroadhesive pericardial disease documents serial changes in echoes from the pericardium and pericardial space accompanying the clinical evolution of the disease process, and suggests a method for avoiding the commonly encountered difficulty in proper identification of the pericardial and epicardial echoes. Our preliminary studies suggest that serial echograms should play an important role in the management of patients with pericardial effusion; further surgical/pathological correlations are required.

Adult↗
PubMed1977

Distortions in infant electrocardiograms caused by inadequate high-frequency response.

Frank lead ECG's from infants were studied for frequency content by introducing low-pass filters of 50, 75, 100, and 150 150 Hz bandwidths before obtaining computer measurements. Results indicated that a minimum bandwidth of 100 Hz is required to avoid amplitude error of 10 per cent or greater. This bandwidth requierement is essentially the same as that required for adult ECG's despite the fact that infant QRS durations are usually about half those of adults. Although the average infant ECG spectrum is likely to contain higher frequencies than the average adult ECG spectrum, duration values for Q, R, and S waves overlap in these populations to such an extent that bandwidth requirements are practically identical.

Electrocardiography↗
PubMed1977

Computer analysis of changes in frank vectorcardiograms of 666 normal infants in the first 72 hours of life.

Frank vectorcardiograms (VCGs) were collected on magnetic tape for 666 normal newborn infants at 1, 6, 12, 24, 36, 48, 60, and 72 hours after birth and analyzed by computers. The final total included 1,337 VCGs for white babies and 413 for blacks. No previous report has been made for the normal neonate with such a large sample, and no previous substantiation exists of possible age or sex differences at this early age. This study establishes a statistically significant change in vectorcardiographic patterns over the first three days, specifically in the measurements P duration, QRS duration, maximal spatial QRS amplitude, S in lead x, and T in lead z, as well as for several time-normalized QRS vectors. (P less than or equal to .005.) Racial differences were significant for T waves in lead z. This study supports the use of vectorcardiographic standards sensitive to the age of the newborn as well as to race.

Age Factors↗
PubMed1976

Diagnostic features of right ventricular myxoma.

The clinical diagnostic features of right ventricular myxoma are described in a recent patient and related to the 15 cases previously reported. The presence of a pulmonic systolic ejection murmur with a delayed (120 to 140 msec.) and accentuated pulmonic second sound, or calcification in the region of the right ventricular outflow tract should suggest this lesion. Cardiac catheterization with angiocardiography in diagnostic. Ga scanning may assist in the diagnosis and followup after surgical removal of the myxoma. Early surgical removal will avoid the possibility of sudden death.

Adult↗
PubMed1976

The effect of ACTH and cortisol on aldosterone and cortisol clearance and distribution in plasma and whole blood.

The mechanisms of increased aldosterone and cortisol metabolic clearance rates (MCR) following ACTH or cortisol administration were studied in 13 subjects undergoing cardiac catheterization and in 9 healthy controls. In control subjects, the MCR (plasma) of both steroids increased by 29% (aldosterone: from 936 +/- 57 to 1204 +/- 55 l/day/m2, cortisol: from 205 +/- 12 to 264 +/- 17 l/day/m2 +/- SE) after ACTH (12 units/h) for 1 to 4 h, and by 20 and 32%, respectively, after cortisol (12 mg/h) for 1 to 2 h. In contrast, aldosterone MCR (whole blood) did not change with ACTH or cortisol administration (from 1276 +/- 57 to 1330 +/- 59 l/day/m2), indicating that the plasma MCR increase results from a redistribution of aldosterone from plasma to red cells. Aldosterone splanchnic extraction was 92 +/- 1% (n = 12) with normal morning cortisol levels, and extraction was unchanged after ACTH administration. For cortisol, however, the splanchnic extraction increased from 8 +/- 0.8% to 17.8 +/- 5.0%, and the MCR (whole blood) likewise increased by 15 to 31% (from 295 +/- 23 to 357 +/- 30 l/day/m2), after ACTH or cortisol administration. In vivo and in vitro measurements (at 37 C) of tracer aldosterone concentration in plasma and in red cells showed an increase in distribution to red cells with increasing cortisol concentrations. The results suggest that a fraction of aldosterone is bound in plasma and displaced by cortisol into red cells. There is an increased aldosterone plasma MCR, but unaltered whole blood MCR, since the liver extracts aldosterone almost completely from both plasma and red cells. The increase in cortisol MCR (plasma) results from both an increased splanchnic extraction as plasma binding sites approach saturation and a redistribution into red cells.

Adrenocorticotropic Hormone↗
PubMed1970

Stereostethoscope.

Explore the source record for details and available documents.

Auscultation↗