After analyzing the relationship between the feature "nr_11" (Observing of arrhythmia in the anamnesis) and the task of determining if the patient shows chronic heart failure, we can generate the dictionary as follows:

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

Since the feature is categorical and has two possible categories - "no" and "yes", we can see that if the patient has a history of observing arrhythmia in the anamnesis (nr_11 = "yes"), it indicates that the patient shows chronic heart failure. On the other hand, if the patient has no history of arrhythmia (nr_11 = "no"), it indicates that the patient does not show chronic heart failure.

Please note that the list of each target class is not empty, as required.