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

Based on the feature description, the value of "n_p_ecg_p_11" can be either "no" or "yes". Therefore, for the target class "no" (patient does not show chronic heart failure), the possible value of "n_p_ecg_p_11" is only "no", and for the target class "yes" (patient shows chronic heart failure), the possible value of "n_p_ecg_p_11" is only "yes".