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

Based on the feature description, the possible values of feature `n_r_ecg_p_08` are "no" and "yes". 

Since the task is to determine if the patient shows chronic heart failure, we need to analyze how the feature relates to this target. Unfortunately, without further information or prior knowledge, it is difficult to predict the relationship between the feature `n_r_ecg_p_08` and the presence of chronic heart failure. Therefore, we include all possible values of `n_r_ecg_p_08` for both the "no" and "yes" target classes in the dictionary.