If an abnormal ECG as determined by S-T segment depression is regarded as the gold standard for the presence of heart disease and an AAI of < 1.0 is regarded as a possible test criterion for heart disease, then what is the sensitivity of the test? 

Cardiovascular Disease
The ankle-arm blood-pressure index (AAI) is defined as the ratio of ankle systolic blood pressure/arm systolic blood pressure and is used for the diagnosis of lower extremity arterial disease. A study was conducted to investigate whether the AAI can be used as a screening test for atherosclerotic diseases in general [20]. The subjects were 446 male workers in a copper smelter in Japan. Each subject had an AAI determination as well as an electrocardiogram (ECG). From the ECG, an S-T segment depression was defined as an S-T segment ‰¥ 0.1 mV below the baseline in at least 1 of 12 leads in a resting ECG. S-T segment depression is often used as one characterization of an abnormal ECG. The data in Table 3.22 were presented relating AAI to S-T segment depression.

Table 3.22: Association between ankle-arm blood pressure index (AAI) and S-T segment depression

Transcribed Image Text:

S-T segment depression AAI < 1.0 ΑAΙ Σ1.0 20 13 95 318