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G L Knatterud

Publications and source records attributed to G L Knatterud.

77 records · Page 5Linked to original sources
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The Psychophysiological Investigations of Myocardial Ischemia (PIMI) study: objective, methods, and variability of measures.

OBJECTIVE: This study evaluated physiological, neuroendocrine, and psychological status and functioning of patients with coronary artery disease in order to clarify their role in the expression of symptoms during myocardial ischemia (MI), and to establish repeatability of responses to mental stress. Design and methods of the study are presented. METHODS: One hundred ninety-six coronary artery disease patients were examined during physical and mental stress tests in four hospitals. Eligibility criteria included narrowing of at least 50% in the diameter of at least one major coronary artery or verified history of myocardial infarction, and evidence of ischemia on an exercise treadmill test. Psychological, biochemical, and autonomic function data were obtained before, during, and after exposure to mental and exercise stressors during 2 or 3 half-days of testing. Ventricular function was assessed by radionuclide ventriculography, and daily ischemia by ambulatory electrocardiography. Sixty patients returned for a short-term mental stress repeatability study. Twenty-nine individuals presumed to be free of coronary disease were also examined to establish reference values for cardiac responses to mental stress. RESULTS: Study participants were 41 to 80 years of age; 83 (42%) had a history of MI, 6 (3%) of congestive heart failure, and 163 (83%) of chest pain; 170 (87%) were men; and 90 (46%) had ischemia accompanied by angina during exercise treadmill testing. Ischemia during ambulatory monitoring was found in 35 of 90 (39%) patients with and 48 of 106 (45%) patients without angina during exercise-provoked ischemia. Intraobserver variability of ejection fraction changes during bicycle exercise and two mental stress tests (Speech and Stroop) was good (kappa = 1.0, .90, and .76, respectively; percent agreement = 100, 97.5, and 93.8%, respectively). Variability of assessed wall motion abnormalities during bicycle exercise was better (kappa, agreement = 85%) than during Speech or Stroop kappa and .57, percent agreement = 70% and 82.5%, respectively). CONCLUSIONS: Study design, quality control data, and baseline characteristics of patients enrolled for a clinical study of symptomatic and asymptomatic myocardial ischemia are described. Lower repeatability of reading wall motion abnormalities during mental stress than during exercise may be due to smaller effects on wall motion and lack of an indicator for peak mental stress.

Adult↗
PubMedDate not supplied

Reproducibility of mental stress-induced myocardial ischemia in the Psychophysiological Investigations of Myocardial Ischemia (PIMI).

OBJECTIVE: Many patients with coronary artery disease (CAD) develop myocardial ischemia in response to mental stress. This has been documented both in the natural environment and in the laboratory. However, the reproducibility of laboratory mental stress-induced ischemia has not been investigated. METHOD: Sixty patients with documented CAD and a positive exercise stress test discontinued cardiac medications and underwent two standardized mental stress tests (a timed Stroop Color-Word test and a public speaking task) in a nuclear cardiology laboratory (Visit 1), and repeated this procedure between 2 and 8 weeks later (Visit 2). Measurements of cardiovascular function and neurohormonal responses were obtained throughout testing, and mood state was assessed before and after testing. RESULTS: Sixty-eight percent of the 56 patients with detailed radionuclide data from both visits had consistent responses (ie, ischemia either present during both sessions or absent during both) to the Stroop task (kappa = .29, p = .03), 61% had consistent responses to the speech task (kappa = .20, p = .12), and 60% had consistent responses when ischemia was considered present if it occurred during either the Stroop test, the speech task, or both, and absent if it did not occur during either task (kappa = .22, p = .07). Hemodynamic and neuroendocrine responses to the tests were moderately reproducible. CONCLUSIONS: We conclude that two popular laboratory tests for mental stress-induced myocardial ischemia are modestly reproducible. The relatively low reproducibility is probably influenced by uncertainties in detecting relatively small changes in wall motion, habituation of the patient to repeated exposure to psychological stressors, and physiological differences in threshold for ischemia on different days of testing.

Adult↗
PubMedDate not supplied

Factors influencing clinical outcomes after revascularization in the asymptomatic cardiac ischemia pilot (ACIP). ACIP Study Group.

BACKGROUND AND AIM: The Asymptomatic Cardiac Ischemia Pilot is the first randomized trial where revascularization involved choice of either coronary bypass or angioplasty used in an early or a delayed symptom-driven approach. One-year outcomes were favorable (reduced recurrent ischemia and adverse outcomes) for an early revascularization strategy (within 4 weeks), compared with an early medical strategy when revascularization was delayed until symptom-driven. This ancillary study examined variables influencing outcomes after these 2 revascularization approaches (early vs. delayed until symptom-driven). METHODS: Participants were clinically stable coronary disease patients with stress-induced and daily life ischemia who underwent revascularization. Characteristics associated with clinical outcomes occurring within the year following revascularization were examined using Cox regression analysis. RESULTS: A total of 262 patients received revascularization; 170 in the early approach and 92 in the delayed symptom-driven approach. Thirty-three patients had adverse outcomes (death, nonfatal myocardial infarction, or repeat revascularization) during 1-year follow-up. The most important independent predictor of improved outcome during the follow-up year was attempted revascularization of > or = 66% of vessels with significant stenosis for the early (risk ratio [RR] 0.25, 95% confidence interval [CI] 0.09-0.67) and the delayed (RR 0.21, CI 0.08-0.58) approaches. Factors such as age, stress test results, and coronary angiographic findings did not predict clinical outcome. CONCLUSIONS: Our findings are important in the planning of a large trial with longer follow-up.

Adult↗
PubMedDate not supplied

The course of peripheral vascular disease in non-insulin-dependent diabetes.

The present report is an analysis of the course of peripheral vascular disease (PVD) in 619 patients with non-insulin-dependent diabetes (NIDDM) recruited within 1 yr of diagnosis and followed quarterly for up to 14 yr (X = 10.5 yr). At 13 yr duration, the actuarially determined cumulative risks for intermittent claudication (IC), nonpalpable dorsalis pedis pulse (NPUL), and arterial calcification (CALC) were, respectively, 37.9%, 34.5%, and 60.9% for men and 24.3%, 37.6%, and 32.2% for women. Major amputations (AMP) occurred in only 1.3% of the patients, equivalent to approximately one case per 1000 patients per year. The corresponding incidences of IC, NPUL, and CALC were, respectively, 29, 27, and 47 per 1000 men and 19, 27, and 25 per 1000 women per year. CALC and NPUL were strongly related to mortality. Baseline risk factors with probability levels that suggest a relationship to PVD were, in women, age versus CALC (P less than 0.01), age versus NPUL (P less than 0.05), weight versus NPUL (P less than 0.05), systolic BP versus CALC (P less than 0.01), summed glucose tolerance test versus CALC (P less than 0.01), and triglyceride level versus CALC (P less than 0.05). In men, the only significant risk factors were diminished vibration perception, which was related to NPUL (P less than 0.05), and the serum triglyceride level, which was related to IC (P less than 0.05). In patients who are carefully followed prospectively, IC is far more common, but AMP is far less common than has been generally appreciated. Further studies are needed to clarify the roles of the diverse risk factors that are possibly related.

Amputation, Surgical↗