```json
{
    "no": ["no"],  
    "yes": ["yes"]
}
```
Since the feature "n_r_ecg_p_01" represents premature atrial contractions on ECG at the time of admission to the hospital, there are only two possible categories: "no" and "yes". In this case, if the patient does not have premature atrial contractions, the target class will be "no" for chronic heart failure. On the other hand, if the patient does have premature atrial contractions, the target class will be "yes" for chronic heart failure. There are no other categories for this feature, so the lists will only contain the respective category itself for each target class.