Based on prior knowledge, premature atrial contractions can be a potential risk factor for developing chronic heart failure. Therefore, it is likely that the presence of premature atrial contractions in the anamnesis (nr_01 feature) may indicate chronic heart failure in the patient.

To analyze the relationship between the nr_01 feature and the presence of chronic heart failure (target variable), we can look at the distribution of nr_01 values for each class (yes and no) of the target variable.

Here is the dictionary that summarizes the relationship between feature nr_01 and the presence of chronic heart failure:

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

In this case, the presence of premature atrial contractions in the anamnesis only has two possible values for the yes class (yes) and the no class (no). Both classes have a clear and distinct value that indicates the presence or absence of premature atrial contractions.

Please note that since there are only two possible values for the nr_01 feature, we do not include a list for the "no" class as it only contains the value "no".