```json
{
	"no": ["no"],
	"yes": ["yes"]
}
```
Since the feature "n_r_ecg_p_02" indicates the presence or absence of frequent premature atrial contractions on an ECG at the time of admission to the hospital, the possible values for this feature are "yes" and "no". Given the task of determining if the patient shows chronic heart failure, the only relevant value for this feature is "yes", indicating the presence of frequent premature atrial contractions. Therefore, the possible values for the feature "n_r_ecg_p_02" in the target class "yes" are ["yes"], and there are no possible values for the feature in the target class "no".