Based on my prior knowledge, I can analyze the relationship between the feature "n_p_ecg_p_03" (First-degree AV block on ECG at the time of admission to the hospital) and the presence of chronic heart failure in the patient.

To perform this analysis, we would typically compare the distribution of the "n_p_ecg_p_03" feature for patients who have chronic heart failure (target class "yes") and patients who do not have chronic heart failure (target class "no").

In this case, we would create a dictionary with the following format:

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

Since the feature "n_p_ecg_p_03" is a categorical variable with only two possible values ("no" and "yes"), we can directly include these values in the dictionary. However, since the feature description does not provide any information about which value is more likely to be associated with chronic heart failure, we cannot make any specific conclusions about the relationship between the feature and the target.