```json
{
	"no": ["no"],
	"yes": ["yes"]
}
```
Since the feature GEPAR_S_n represents the use of anticoagulants in the ICU, and the task is to predict chronic heart failure, there is a direct relationship between the feature and the target variable. If the GEPAR_S_n value is "no", it indicates that there is no use of anticoagulants in the ICU, which does not show chronic heart failure (target class "no"). If the GEPAR_S_n value is "yes", it indicates the use of anticoagulants in the ICU, which may indicate chronic heart failure (target class "yes").

Therefore, the possible values of GEPAR_S_n for the target class "no" are ["no"], and the possible values for the target class "yes" are ["yes"].