Based on prior knowledge, we can analyze the relationship between the feature nr_11 (Observing of arrhythmia in the anamnesis) and the task of determining if the patient has chronic heart failure.

Since there is no specific information about the feature's relationship with chronic heart failure, we can only make general assumptions. However, it is reasonable to assume that if a patient has a history of arrhythmia, there may be an increased likelihood of developing chronic heart failure.

To create the dictionary, we need to analyze how the values of nr_11 are associated with the target classes (yes or no) of chronic heart failure.

Here's the dictionary based on this analysis:

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

Since the feature is categorical, we include the possible values of nr_11 for each target class. In this case, "no" and "yes" are the only possible values for nr_11, and they correspond directly to the target classes "no" and "yes" for chronic heart failure, respectively.