Based on the feature description provided, we can analyze the relationship between the feature "GEPAR_S_n" (Use of а anticoagulants in the ICU) and the task of determining whether the myocardial infarction complications data of this patient show chronic heart failure.

To analyze the relationship, we can examine the values of the "GEPAR_S_n" feature for patients who have chronic heart failure (target class "yes") and patients who do not have chronic heart failure (target class "no").

Here's the dictionary representing the relationship:

```json
{
    "no": ["yes", "no"],
    "yes": ["yes", "no"]
}
```

Based on the available information, patients with both chronic heart failure and without chronic heart failure can have values of "yes" or "no" for the feature "GEPAR_S_n". Therefore, both target classes have a range of possible values for the feature.

Note: If there are additional specific values for "GEPAR_S_n" that are relevant to the task but not mentioned in the given information, they can be included in the respective lists for the target classes.