Based on prior knowledge, we can analyze the relationship between the feature "n_p_ecg_p_07" (LBBB - anterior branch on ECG at the time of admission to the hospital) and the task of determining whether the patient shows chronic heart failure.
LBBB is a specific ECG abnormality that relates to the electrical conduction in the heart's ventricles. It indicates a delay or blockage in the electrical signals. Chronic heart failure is a condition where the heart's ability to pump blood efficiently is reduced.

Possible scenario:

If the patient has LBBB (n_p_ecg_p_07 = 'yes'), it may suggest a pre-existing conduction abnormality. In this case, LBBB could be associated with chronic heart failure, as it is a common finding in patients with underlying heart disease.

If the patient does not have LBBB (n_p_ecg_p_07 = 'no'), the absence of this ECG abnormality does not necessarily exclude the presence of chronic heart failure. Other diagnostic tests and clinical indicators should be considered.

Let's create the dictionary:

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

Since the feature "n_p_ecg_p_07" can only take two categorical values ('no' or 'yes'), we include both of these values as possible indicators in the dictionary.