Angina/Non-ST-Elevation Myocardial Infarction : ACC/AHA 2007 Guidelines for the Management of Patients With Unstable ISSN: 1524-4539 Copyright © 2007 American Heart Association. All rights reserved. Print ISSN: 0009-7322. Online 72514 Circulation is published by the American Heart Association. 7272 Greenville Avenue, Dallas, TX doi: 10.1161/CIRCULATIONAHA.107.18194

https://cdr.lib.unc.edu/downloads/vd66w2108

ACC/AHA 2007 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction. A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction)...

http://hwmaint.circ.ahajournals.org/cgi/reprint/110/9/e82.pdf

ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction

Knowledge of regional cerebral hemodynamics has widespread application for both physiological research and clinical assessment because of the well-established interrelation between physiological function, energy metabolism, and localized blood supply. A magnetic resonance technique was developed for quantitative imaging of cerebral hemodynamics, allowing for measurement of regional cerebral blood volume during resting and activated cognitive states. This technique was used to generate the first functional magnetic resonance maps of human task activation, by using a visual stimulus paradigm. During photic stimulation, localized increases in blood volume (32 +/- 10 percent, n = 7 subjects) were detected in the primary visual cortex. Center-of-mass coordinates and linear extents of brain activation within the plane of the calcarine fissure are reported.

https://science.sciencemag.org/content/sci/254/5032/716.full.pdf

Functional mapping of the human visual cortex by magnetic resonance imaging

Knowledge of regional hemodynamics has widespread application for both physiological research and clinical assessment. Here we review the use of MR contrast agents to measure tissue perfusion. Two primary mechanisms of image contrast are discussed: relaxivity and susceptibility effects. Relaxivity effects result from dipolar enhancement of T1 and T2 rates. Because tissue T1 rates are intrinsically smaller, the dominant effect is shortening of T1 relaxation times. The second mechanism of image contrast is the variation in tissue magnetic field produced by heterogeneous distribution of high magnetic susceptibility agents. Quantitation of tissue perfusion requires a detailed understanding of the relation between contrast agent concentration and associated MR signal changes. Studies to date show a linear relationship between contrast agent concentration and rate change in most organs. The exact nature of this relationship in the dynamic setting of rapid contrast agent passage through the microcirculatory bed is less well established. If this relationship is known, tracer kinetic modeling can be used to calculate regional blood flow and blood volume. Data are presented which indicate that this approach is feasible, and suggest the potential of contrast-enhanced NMR for high resolution in vivo mapping of both physiology and anatomy.

Perfusion imaging with NMR contrast agents

A system and method for providing computerized, knowledge-based medical diagnostic and treatment advice. The medical advice is provided to the general public over networks, such as a telephone network or a computer network. The invention also includes a stand-alone embodiment that may utilize occasional connectivity to a central computer by use of a network, such as the Internet. New authoring languages, interactive voice response and speech recognition are used to enable expert and general practitioner knowledge to be encoded for access by the public. “Meta” functions for time-density analysis of a number of factors regarding the number of medical complaints per unit of time are an integral part of the system. A re-enter feature monitors the user's changing condition over time. A symptom severity analysis helps to respond to the changing conditions. System sensitivity factors may be changed at a global level or other levels to adjust the system advice as necessary.

Computerized medical diagnostic and treatment advice system including network access

• Several theoretical formulations have recently been proposed to explain the shape of peripheral indicator dilution curves." One such mathematical approach utilizes convolution integrals,' '*• "*• °~ in which concentration of the indicator is handled as an unknown and unspecified function of time, C(t). The widespread use of this method, however, will be limited because the required mathematical manipulations, when applied to curves obtained in vivo, involve intricate and lengthy calculations. This type of analysis would be facilitated if the indicator concentration could be conveniently expressed as a specific functon of time.' If such a suitable function were available, it would also be possible to characterize more accurately normal and abnormal indicator dilution curves and perhaps to gain insight into some of the factors determining the shape of the curves. In addition, the availability of such a function would allow more efficient processing of experimental curves by high-speed computers. A number of theoretical and empirical mathematical expressions for C(t) have been suggested.' "•' These have found limited application and have not been subjected to extensive experimental verification using a large number of normal and abnormal curves. One expression for C(t), proposed by Evans in

https://www.ahajournals.org/doi/pdf/10.1161/01.RES.14.6.502

Indicator Transit Time Considered as a Gamma Variate

A method for estimating regional cerebral blood flow is described in which tracer amounts of 133 Xe are inhaled for 2 min and monitored extracranially over the next 45 to 60 min. A three-compartment model used to analyze the resulting clearance curves provided separate blood flows for "gray" and "white" matter, plus a decay constant for a slow third component, believed to arise from extracerebral tissue. The analysis included a correction for recirculation of all three components, based on radioisotope concentration of the expired air or arterial blood. Results from the analysis were compared with those obtained by the more traditional two-compartment approach, using data from 15 healthy young males. Whereas the three-compartment method yielded measurements comparable with those obtained by established techniques (average CBF = 54.7 ml/100 g/min), the two-compartment analysis gave consistently lower values (average CBF = 30.2). Comparison of results based on expired air and arterial sampling suggested that end-expiratory air is a reasonable substitute for arterial blood. Although the 133 Xe inhalation method is technically simpler and less traumatic than other methods, complex analytic treatment of the data is necessitated by the presence of appreciable recirculation and extracerebral contamination.

Determination of Regional Cerebral Blood Flow by Inhalation of 133-Xenon

One hundred sixty patients from a defined population with acute myocardial infarction were questioned about their activities before hospital arrival. Hospital arrival time was divided into prodromal period, patient decision time, lay consultation period, medical decision time and travel time. Forty-eight percent experienced prodromal chest pain before the acute onset of symptoms. The median hospital arrival time for all patients was 2 hours, 45 minutes. Hospital arrival time was significantly prolonged in patients experiencing an increase in the severity of angina pectoris, and in those with a physician decision time of more than 1 hour. Implications for intervention techniques are discussed.

Components of delay in the pre-hospital phase of acute myocardial infarction

A computer-based, self-administered, interactive questionnaire has been designed for interview and diagnosis of patients with functional headaches. Patients respond on a simple keyboard to a sequence of questions on a cathode-ray oscilloscope. The system selects pertinent questions depending on the patient's individual responses. The questionnaire included clinical symptoms, neurological manifestations, prior treatment, emotional factors, and personality problems. Upon completion, a computer-generated printed summary is presented for the clinical record. The system utilizes the acquired data to differentiate between common, classical, and cluster migraine, muscle contraction, and other types of headache. Computer diagnoses agreed with those of the physician in 36 of 50 patients. The automated interview saves physician's time, offers a data base for research, and provides a diagnostic aid for patients with functional headaches.

Computer-Assisted Interview of Patients With Functional Headache

Urinary excretion of norepinephrine and epinephrine was measured in 30 patients with myocardial infarction for five days after admission to a cardiac care unit. Patients with uncomplicated hospital courses or those with primary ventricular fibrillation or complete atrioventricular block showed a similar pattern, ie, high initial levels with a slope to normal range over the five-day period. Patients with multiple complications, particularly of a hemodynamic nature, showed lower initial levels and a different slope over the five-day period. Some instances of catechol elevation at time of psychological stress are presented.

Howard K. Thompson

Papers

Indicator Transit Time Considered as a Gamma Variate

Determination of Regional Cerebral Blood Flow by Inhalation of 133-Xenon

Components of delay in the pre-hospital phase of acute myocardial infarction

Computer-Assisted Interview of Patients With Functional Headache

Catecholamine Excretion in Myocardial Infarction