Analyzing the specific magnitude of exercise-induced ST-segment depression increases diagnostic information content by 41% compared to the standard categorical 1-mm criterion.
Does the application of information theory to electrocardiographic stress testing quantify its diagnostic value relative to coronary angiography?
Applying information theory to ECG stress testing reveals that analyzing specific magnitudes of ST depression significantly increases diagnostic information compared to a single categorical criterion, and its value heavily depends on disease prevalence.
The inherent imperfection of clinical diagnostic tests introduces uncertainty into their interpretation. The magnitude of diagnostic uncertainty after any test may be quantified by information theory. THe information content of the electrocardiographic ST-segment response to exercise, relative to the diagnosis of angiographic coronary artery disease, was determined using literature-based pooled estimates of the true- and false-positive rates for various magnitudes of ST depression from less than 0.5 mm to greater than or equal to 2.5 mm. This analysis allows three conclusions of clinical relevance. First, the diagnostic information content of exercise-induced ST-segment depression, interpreted by the standard 1.0-mm criterion, averages only 15% of that of coronary angiography. Second, there is a 41% increase in information content when the specific magnitude of ST-segment depression is analyzed, as opposed to the single, categorical 1-mm criterion. Third, the information obtained from ECG stress testing is markedly influenced by the prevalence of disease in the population tested, being low in the asymptomatic and typical angina groups and substantially greater in groups with nonanginal chest pain and atypical angina. The quantitation of information has broad relevance to selection and use of diagnostic tests, because one can analyze objectively the value of different interpretation criteria, compare one test with another and evaluate the cost-effectiveness of both a single test and potential testing combination.
Diamond et al. (Wed,) conducted a other in Coronary artery disease. Electrocardiographic stress test (ST-segment response to exercise) vs. Standard 1.0-mm criterion vs specific magnitude of ST depression was evaluated on Diagnostic information content relative to angiographic coronary artery disease. Analyzing the specific magnitude of exercise-induced ST-segment depression increases diagnostic information content by 41% compared to the standard categorical 1-mm criterion.