ECG was performed on a total of 700 subjects with complaints of acute chest pain. Of these, 520 patients had myocardial infarction. Calculate the positive predictive value of ECG is:rnrn rnrnrnrnMYOCARDIAL INFARCTIONrnrn rn rn rnrnrnrnECGrnrnrnPRESENTrnrnrnABSENTrnrnrnTOTALrnrnrnrnrnPOSITIVErnrnrn416rnrnrn9rnrnrn425rnrnrnrnrnNEGATIVErnrnrn104rnrnrn171rnrnrn275rnrnrnrnrnTOTALrnrnrn520rnrnrn180rnrnrn700rnrnrnrnrnrn

**Core Concept**
The positive predictive value (PPV) of a diagnostic test is the proportion of individuals who test positive for a disease and actually have the disease. In this context, the PPV of an ECG for diagnosing myocardial infarction is being calculated.

**Why the Correct Answer is Right**
To calculate the PPV, we need to identify the number of true positives (patients with myocardial infarction who test positive on ECG) and divide it by the total number of patients who test positive (true positives + false positives). Here, the true positives are the patients with myocardial infarction who have a positive ECG (416), and the total number of patients who test positive is the sum of true positives and false positives (416 + 9).

PPV = True Positives / (True Positives + False Positives)
PPV = 416 / (416 + 9)
PPV = 416 / 425

**Why Each Wrong Option is Incorrect**
**Option A:** This option cannot be determined without calculating the PPV.
**Option B:** This option is incorrect because it does not consider the denominator correctly.
**Option C:** This option is incorrect because it does not take into account the number of false positives.
**Option D:** This option is incorrect because it does not match the calculated PPV.

**Clinical Pearl / High-Yield Fact**
When interpreting diagnostic test results, it's essential to consider the PPV, which helps in understanding how likely a positive result is to indicate the presence of a disease. A high PPV suggests that the test is relatively accurate, while a low PPV may indicate that the test is less reliable.

**Correct Answer: A. 416/425**

✓ Correct Answer: D. 98%