Based on my prior knowledge, premature ventricular contractions (PVCs) in the anamnesis can be a potential risk factor for chronic heart failure. Therefore, it is worth analyzing the relationship between the feature "nr_02" (Premature ventricular contractions in the anamnesis) and the task of determining whether the patient shows chronic heart failure.

Here is a dictionary detailing the possible values of feature "nr_02" for each target class:

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

In this case, the dictionary shows that the feature "nr_02" only has "no" and "yes" as possible values, indicating the presence or absence of premature ventricular contractions in the anamnesis. The target class "no" corresponds to patients without chronic heart failure, while the target class "yes" represents patients with chronic heart failure.

Note: If there are any additional possible values for feature "nr_02" that are hard to predict or not mentioned in the data, they are not included in the dictionary. However, it is important to ensure that the lists for each target class are not empty.