```json
{
	"no": ["no"],
	"yes": ["yes"]
}
```
Based on the given feature description and task, the only value of the feature n_p_ecg_p_12 that is provided is either "no" or "yes". Therefore, for the target class "no", the only possible value of n_p_ecg_p_12 is "no", and for the target class "yes", the only possible value of n_p_ecg_p_12 is "yes".