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

Based on the feature description, the n_r_ecg_p_04 feature has two categories: "yes" and "no". 
To determine if the myocardial infarction complications data of this patient show chronic heart failure, we need to check if the value of n_r_ecg_p_04 is "yes". 

Therefore, the dictionary includes the possible values of n_r_ecg_p_04 for both target classes "yes" and "no". In this case, the possible values for "no" are ["no"] and the possible values for "yes" are ["yes"].