After analyzing the relationship between the feature "n_r_ecg_p_03" and the task of determining if the patient shows chronic heart failure, we can create a dictionary to summarize the possible values of the feature for each target class.

Based on prior knowledge, we may assume that patients with chronic heart failure may have different patterns of ventricular contractions on ECG compared to patients without chronic heart failure.
Let's create the dictionary:

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

In this case, the feature "n_r_ecg_p_03" has only two possible categories: "no" and "yes". For the target class "no", the possible values of the feature are only "no". For the target class "yes", the possible values of the feature are only "yes".

Please note that this analysis assumes a direct relationship between the feature and the target variable. Further analysis and data exploration may be required to confirm the relationship between this specific feature and chronic heart failure.