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

Based on the given feature description, the feature "n_r_ecg_p_03" represents the presence or absence of ventricular contractions on the electrocardiogram (ECG) at the time of admission to the hospital. The feature is a categorical variable with two possible categories: "no" and "yes".

To determine whether the patient's myocardial infarction complications data show chronic heart failure, we can analyze the relationship between the feature "n_r_ecg_p_03" and the target variable. 

From the available information, it is not possible to predict whether the presence or absence of ventricular contractions on the ECG is indicative of chronic heart failure. Therefore, we do not have evidence to suggest any specific relationship between the feature and the target. 

Since the feature only has two possible categories, the dictionary provides the possible values of the feature "n_r_ecg_p_03" for each target class. In this case, both the "no" and "yes" categories are included in the dictionary.