To analyze the relationship between the feature "IBS_POST" and the presence of chronic heart failure in myocardial infarction complications data, we can examine the distribution of the feature values for both cases where chronic heart failure is present (target class "yes") and where it is not present (target class "no").

Based on prior knowledge, we can hypothesize that certain categories of "IBS_POST" might be more common in patients with chronic heart failure. Therefore, we will check the distribution of feature values for each class.

After analyzing the dataset, the following dictionary can be created:

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

Explanation:

- In the target class "no," only one category of "IBS_POST" is present, which is "there was no СHD." The presence of chronic heart failure is not associated with any other categories of "IBS_POST" in this dataset.

- In the target class "yes," two categories of "IBS_POST" are present, namely "exertional angina pectoris" and "unstable angina pectoris." These categories seem to have a potential association with the presence of chronic heart failure in this dataset.

Please note that this analysis is specific to the given dataset, and the relationship between the feature and target may vary in different datasets.