A study was done to evaluate the sensitis ity and specificity. of an electrocardiography (ECG) test for detecting left ventricular hypertrophy (LV11), a binary measure of cardiovascular disease. The authors reported the following results from their sample of 2042 men. (Levy et al. 1)etenninants of sensitivity and specificity of electrocardiographic criteria for ventricular hypertrophy. Circulation. 1990; 81: 815-820.) a) What is the sensitivity of the ECG test for detecting LVII in men'

b) What is the specificity of the ECG test for detecting LVII in men?

c) (el pt) Assuming these 2042 men were randomly sampled from the population of males, what is the negative predictive value of the test for men?

d) In the study. the authors also evaluated whether the sensitivity and specificity of the test varied by factors such as age and body mass index (BMI. a measure of obesity). The authors reported that among 509 men with BMI in the highest quarterly, the sensitivity was 10%. the specificity was 98%, and the prevalence of LVII was 20%. What is the positive predictive value of the test for men with BMI in the highest quartile?

e) Above, I simplified the author's table and results. There are actually various methods to determine LVH. For example, echocardiography and magnetic resonance imaging are commonly used. In this study, the authors used echocardiography to determine LVH status and reported the sensitivity and specificity of electrocardiography to detect "echocardiographic LLHV''. Why is it useful that the authors use the term "echocardiographic LVH" instead of just LVH?

Test positive Test negative LVH = Yes 26 34 LVH-No 264 1718