Based on the feature description, it is unclear how exactly the feature "IBS_POST" relates to the task of determining chronic heart failure. To analyze the relationship further, we can examine the possible values of the "IBS_POST" feature and see if there is any indication of chronic heart failure based on these values.

Since the feature "IBS_POST" represents the presence and type of angina pectoris (chest pain), it might be indirectly related to chronic heart failure. Angina pectoris is a symptom of coronary heart disease (CHD), which is a risk factor for heart failure.

To create the dictionary, we need to identify the possible values of the "IBS_POST" feature for each target class (yes: chronic heart failure present, no: chronic heart failure not present). However, the task requires specifying the "IBS_POST" values for each class in a list format, even if certain values are hard to predict.

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

In this case, since we don't have further information about the relationship between "IBS_POST" and chronic heart failure, we include the values that are provided and do not exclude any possibilities. It is important to note that without additional context or data, the accuracy of the prediction based solely on this feature may vary.