Q. Can you explain Bayesian Theorem?

Bayesian Theorem:

The predictive value of a test is related to the incidence of disease in the population. A history of typical angina in persons older than 30 is associated with at least an intermediate probability of CAD. Most accurate results are in patients with intermediate probability of CAD. A 50 years old man or 60 years old woman with a typical or probable angina has a 50 per cent probability of CAD. In low pre-test false positivity is higher. In high pre-test false negativity is higher.

Diagnostic uses: Sensitivity is 68 per cent and specificity is 77 per cent. In case of single vessel disease the sensitivity is 25 to 71 per cent and it is frequently associated with LAD followed by RCA and circumflex. In case of multivessel CAD the sensitivity is 81 per cent and the specificity is 66 per cent. In case of left main or TVD the sensitivity is 86 per cent and specificity is 53 per cent. Mostly lead V4 to V6 are specific for changes.