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Biomedical subjects

K Peterson

Publications and source records attributed to K Peterson.

At least 109 records · Page 6Linked to original sources
PubMed1979

Assessment of early ventricular systole by first pass radionuclide angiography: useful method for detection of left ventricular dysfunction at rest in patients with coronary artery disease.

To identify abnormal left ventricular function without exercise stress in patients with coronary artery disease first-pass radionuclide angiograms were analyzed in 32 normal subjects (Group I); 31 patients with coronary disease and normal contrast ventriculograms (Group II); and 17 patients with coronary disease and depressed left ventricular function (Group III). Total ejection fraction (EF) was computed with standard angiographic methods and from each time-activity curve. During the first third of systole, ejection fraction was determined manually by averaging three to five beats and the value compared with that obtained with contrast ventriculography: (Formula: see text). Both total radionuclide ejection fraction (r = 0.95) and first-third ejection fraction (r = 0.91) correlated well with angiography. Intraobserver and interobserver variation was small, averaging 0.02 +/- 0.02 (range 0 to 0.05). The radionuclide first-third ejection fraction was 0.25 or greater in normal subjects and less than 0.25 in 29 of 31 patients (94 percent) in Group II and in all patients in Group III. It is concluded that the first-third ejection fraction obtained with first pass angiography identifies subtle abnormalities of left ventricular function at rest in more than 90 percent of patients with coronary disease that may not be recognized by total ejection fraction alone.

Adult↗
PubMed1979

Left ventricular volumes by gated equilibrium radionuclide angiography: a new method.

To compare radionuclide end-diastolic (EDV) and end-systolic (ESV) volumes with angiographic volume, we studied 52 patients with equilibrium radionuclide angiography using 99mTc-human serum albumin within 48 hours of contrast angiography. Each RR interval was divided into 20--28 equally timed frames and a time-activity curve generated. End-diastolic counts were taken at the early peak of the curve and end-systolic counts at its nadir. Counts were divided by the total number of processed heart beats and normalized for: 1) dose per body surface area; 2) plasma volume; and 3) counts/ml of plasma. A cardiac phantom was developed and serial volumes were studied using a normalization factor. Radionuclide values were expressed as dimensionless units and compared with either biplane angiographic volumes (in the patient studies) or known phantom volumes. Good correlations were obtained with methods 1 and 2 in 35 patients (r greater than 0.84), but the best correlation was obtained in 17 patients when normalization for counts/ml of plasma was used (r = 0.98; y = 0.255 x -0.121). The standard error of the estimate (SEE) was +/- 11.5 ml for EDV and +/- 7.3 ml for ESV. The phantom study also showed an excellent correlation (r = 0.99), with a SEE of +/- 6.5 ml. We conclude that a radionuclide method independent of geometric assumptions can be used to estimate left ventricular volume in man.

Adult↗
PubMed1978

Active valvulitis associated with chronic rheumatic valvular disease and active myocarditis.

From ten patients aged 15 to 40 years with chronic rheumatic valvular disease and histologically proved Aschoff bodies of active rheumatic myocarditis, the valves were evaluated for incidence, distribution and degree of severity of active inflammation. Prior to death, there had been clinical evidence of active rheumatic fever. In each case, active rheumatic valvulitis was present in at least one valve. Of the individual valves studied, 83% were involved by active inflammation of the leaflets or the anulus or both. The aortic valves was involved in 100% of cases, the mitral valve in 86%, the tricuspid valve in 78% and the pulmonary valve in 70%. The mitral and aortic valves were most frequently involved, but the mitral and tricuspid valves were most severely involved when affected. In every case, active rheumatic lesions of the left atrial appendage were present, but these tended to be less widely distributed than the myocardial Aschoff bodies. The high incidence of active valvulitis supports the concept that chronic fibrosing rheumatic valvular disease results from recurrent active inflammation. Such inflammation may occur without clinical suspicion of active rheumatic fever.

Adult↗
PubMed1978

Evaluation of the in vivo function of the Hancock porcine xenograft in the aortic position.

We evaluated the vivo hemodynamic function of the stent-mounted glutaraldehyde-fixed porcine xenograft in 23 patients who had undergone aortic valve replacement from 2 days to 24 months prior to the study. Functional aortic valve orifice areas for the porcine xenograft ranged from 0.58 to 3.0 sq. cm., the average area being 1.36 sq. cm. Six patients had calculated prosthetic valve orifice areas less than 1.0 sq. cm. Valve orifice area did not correlate significantly with valve size or the time interval from surgery to postoperative study. Left ventricular stroke volume showed a significant, positive correlation with calculated xenograft orifice area. Systemic thromboembolism was not encountered. One patient required reoperation for xenograft stenosis caused by dense fibrin deposition on the aortic leaflets. We conclude that use of the stent-mounted glutaraldehyde-fixed porcine xenograft can be associated with significant functional stenosis which may be related to annulus size or inertial properties of the valve. These factors should be taken into consideration when considering use of the stent-mounted glutaraldehyde-fixed porcine xenograft in individual patients.

Adult↗
PubMed1976

Cardiac amyloidosis, contrictive pericarditis and restrictive cardiomyopathy.

Cardiac amyloidosis is not characterized by a single hemodynamic pattern. Some of the cases present the clinical findings of restrictive cardiomyopathy and in these differentiation from constrictive pericarditis remains difficult in spite of the introduction of techniques designed to assess myocardial contractility and ventricular diastolic compliance. The clinical features and the demonstration of left ventricular diastolic pressure greater than right remain the most useful means of distinguishing restrictive cardiomyopathy from constrictive pericarditis. In other cases of cardiac amyloidosis the diastolic pressure is elevated throughout diastole and ventricular ejectile ability is lost. These cases do not simulate constrictive pericarditis and should not be classified as restrictive cardiomyopathy.

Amyloidosis↗
PubMedDate not supplied

Effectiveness of coping strategies among critical care nurses.

Although research on job stress has focused on the extent or causes of stress in critical care, few studies have focused on the effects of stress reduction strategies by the critical care staff. The results of a study that examined the strategies critical care nurses used to manage job stress and the effectiveness of these techniques are described.

Adaptation, Psychological↗
PubMedDate not supplied

The Beaver Dam Health Outcomes Study: initial catalog of health-state quality factors.

The Beaver Dam Health Outcomes Study (BDHOS) is an ongoing longitudinal cohort study of health status and health-related quality of life for a random sample of adults (age range at interview was 45 to 89 years; mean = 64.1, SD = 10.8) in a community population. In a face-to-face interview lasting approximately an hour, each participant responds to several batteries of questions. Included are a history of chronic medical conditions, current medications, and past surgeries; the SF-36 (a general health-status questionnaire); the Quality of Well-being index; self-rated health status on a five-point scale from "excellent" to "poor"; and evaluation of current health using the method of time tradeoffs. The authors present results from 1,356 interviews on these four principal measures, reporting mean scores by sex, by age, and for persons reporting being affected by various medical conditions. They believe data from the BDHOS will provide researchers and policy makers a reference collection of vital statistics for health-related quality of life. Additionally, the data provide a way to compare results from studies that utilize different indices from among the four principal measures of the BDHOS.

Adult↗
PubMedDate not supplied

Overuse injuries in triathletes. A study of the 1986 Seafair Triathlon.

A questionnaire was mailed to 600 to 657 finishers in the Seafair Triathlon (July 20, 1986); 45% of those polled returned the questionnaire. Over the preceding year, 49% of the respondents suffered a training-related injury serious enough to cause them to stop training for at least 1 day, seek medical care, or take medicine, Seventy percent of the injuries were due solely or partly to running. The knee, shoulder, and ankle were most frequently affected. Female triathletes and those more than 40 years of age showed a similar injury incidence and distribution. Elite triathletes averaged more miles per week in each sport than the athletes as a whole and showed a higher incidence of injury (60%), although this was not a significant difference. Higher weekly swimming, cycling, and running mileages did not lead to a higher incidence of injury. The likelihood of injury was independent of age, sex, body mass index, mileage per week, or other training factors evaluated in the study.

Adult↗