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Biomedical subjects

A A Graham

Publications and source records attributed to A A Graham.

6 recordsLinked to original sources
PubMed1998

Signal-averaged electrocardiography.

Signal-averaged electrocardiography (SAECG) is a technique involving computerized analysis of segments of a standard surface electrocardiogram. It is used for detecting small electrical impulses, termed ventricular late potentials, that follow the QRS segment. They are embedded in the electrocardiogram but ordinarily obscured by skeletal muscle activity and other extraneous sources of "noise" encountered in recording a standard electrocardiogram. Ventricular late potentials in patients with cardiac abnormalities, especially coronary artery disease or following an acute myocardial infarction, are associated with an increased risk of ventricular tachyarrhythmias and sudden cardiac death. Proponents of SAECG claim that it can obviate the need for invasive techniques commonly used to identify high-risk patients for interventions that treat or prevent ventricular tachyarrhythmia and sudden death. No randomized clinical trials evaluating SAECG have been completed; data from an ongoing National Institutes of Health-sponsored clinical trial are expected to be available in 3-4 years. The current data on SAECG show relatively consistent high negative predictive values, poor positive predictive values, and variable sensitivity and specificity when the technique is used on patients with cardiomyopathy or following a myocardial infarction. The available evidence also indicates that combining SAECG with other tests of cardiac function is superior to using any single test for risk. The utility of SAECG alone as an indicator of risk remains to be proven. SAECG combined with other standard tests of risk has been demonstrated to have clinical utility in patients following an acute myocardial infarction. Other patient populations have not been conclusively shown to benefit from its use.

Arrhythmias, Cardiac↗
PubMed1998

US Food and Drug Administration: adverse event reporting.

This article reviews adverse event reports associated with anesthesia devices submitted to the US Food and Drug Administration during the period of August 15, 1896 to August 15, 1998. Cardiovascular, general surgical, and plastic surgical devices are the most frequently reported devices. Deaths are most frequently associated with cardiovascular, general hospital, and gastrourological devices. The most frequently reported failures associated with ventilators are failures of audio or visual alarm systems.

Adverse Drug Reaction Reporting Systems↗
PubMed1996

Plethysmography: safety, effectiveness, and clinical utility in diagnosing vascular disease.

Plethysmography, a semiquantitative method of measuring segmental blood flow and velocity in the carotid and peripheral vascular systems, is safe, easy to perform, and inexpensive. Impedance, strain guage, air, and photoelectric plethysmographic methods are assessed in this publication for their relative safety, efficacy, and clinical utility in diagnosing vascular disease. Clinical evidence has demonstrated, for example, that oculoplethysmography is not a reliable screening test for carotid artery disease, particularly in bilateral disease and nonocclusive unilateral disease. Oculoplethysmography is thus no longer recommended for the diagnosis of carotid artery disease. Impedance, strain guage, and photoplethysmography methods can be used for the initial evaluation of acute and chronic venous insufficiency, although there is great variability in the reliability of these tests to predict venous disease in the presence of nonobstructive thrombi and comorbid conditions. Strain guage and photoelectric plethysmography can be safely used for the evaluation of peripheral arterial disease. But surgical candidates for arterial reconstruction and some venous disorders may require additional imaging such as duplex ultrasound, venography, or arteriography for anatomic information that is not elucidated by plethysmography. The plethysmographic techniques reviewed in this assessment, evaluating the ability to predict the presence of flow reduction in the carotid and peripheral circulations, are based on the technical performance of the tests as compared with a reference method. Establishing evidence-based conclusions proved difficult in light of biases such as nonrandomization, unstated patient selection criteria, poor followup of patients, and lack of blindness in some studies.

Humans↗
PubMed1989

Acrivastine in two doses compared with placebo in a multicentre, parallel group study for the treatment of seasonal allergic rhinitis.

In a placebo controlled, randomised, multicentre study the efficacy and safety of multiple doses of acrivastine, a derivative of the antihistamine tripolidine (Actidil) were evaluated in patients exhibiting symptoms of seasonal allergic rhinitis. Over the 10 day treatment period, 103 patients received, twice daily, either 4 mg and 8 mg of acrivastine or a placebo. Three patients withdrew from the study due to poor symptom control and two due to adverse experiences. The reporting of adverse experiences was evenly distributed between the treatment and placebo periods. Acrivastine did not affect the haematological, biochemical or urinalysis screens. Both 4 mg and 8 mg acrivastine alleviated the symptoms of seasonal allergic rhinitis with significant improvements in the symptom scores for sneezing, running nose and the calculated overall score. In addition, 8 mg acrivastine reduced the symptom scores for watery eyes and itchy throat. Acrivastine was both well tolerated and effective in the treatment of seasonal allergic rhinitis.

Adolescent↗