Based on the given feature description and task, we need to analyze whether the use of anticoagulants in the ICU (GEPAR_S_n) is related to the presence of chronic heart failure.

To perform this analysis, we can examine the distribution of GEPAR_S_n values for each target class (yes or no) in the myocardial infarction complications dataset.

Here is the dictionary with the analysis results:

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

Explanation:
- For the target class "no" (indicating no chronic heart failure), the only observed value of GEPAR_S_n is "yes". This suggests that when a patient does not have chronic heart failure, they have used anticoagulants in the ICU.
- For the target class "yes" (indicating the presence of chronic heart failure), both "yes" and "no" values of GEPAR_S_n are observed. This implies that some patients with chronic heart failure have used anticoagulants in the ICU, while others have not.

Based on the available information, these are the possible values of GEPAR_S_n for each target class. Remember that this analysis is based on the given data and is subject to change if more information becomes available.