Based on the given feature description and task, we need to analyze the relationship between the feature "IBS_POST" and the presence of chronic heart failure.

To conduct this analysis, we will look at the values of the "IBS_POST" feature for each target class (yes and no) and determine if there are any patterns or differences that can help us predict the presence of chronic heart failure.

Here is the dictionary with the details:

```json
{
	"no": ["there was no СHD"],  
	"yes": ["exertional angina pectoris", "unstable angina pectoris"]
}
```

Explanation:

- For the target class "no" (no chronic heart failure), the only value of the "IBS_POST" feature is "there was no СHD". This suggests that patients who do not have chronic heart failure typically do not have any history of CHD.
- For the target class "yes" (chronic heart failure present), the values of the "IBS_POST" feature are "exertional angina pectoris" and "unstable angina pectoris". This indicates that patients with chronic heart failure may have a history of angina pectoris, either exertional or unstable.

Note: The dictionary only includes the values that are observed for each target class. If there are other values of "IBS_POST" that are not mentioned, it means they were not observed in the given dataset for the corresponding target class.