```json
{
    "no": ["no"],
    "yes": ["yes"]
}
```
Based on the feature description and task, it seems that the feature "n_r_ecg_p_02" represents the presence or absence of frequent premature atrial contractions on ECG at the time of admission to the hospital. The target variable is whether or not the patient has chronic heart failure.

In this case, the possible values for the feature "n_r_ecg_p_02" are categorical: "no" and "yes". The dictionary presents the possible values for each target class.

It is important to note that the dictionary only includes the exact values mentioned in the feature description. If there are additional values for the feature that are not specified, they are not included in the dictionary.