Based on my prior knowledge, a first-degree AV block on an electrocardiogram (ECG) can be an indicator of chronic heart failure. Therefore, I would expect to see a higher prevalence of chronic heart failure in patients with a first-degree AV block. 

To 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 task of identifying chronic heart failure, we can examine the distribution of the feature values for each target class. 

To create the dictionary, we will categorize the values of the feature `n_p_ecg_p_03` based on their corresponding target class:

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

In this case, since the categorical variable `n_p_ecg_p_03` only has two possible categories: "no" and "yes," we include values for both target classes ("no" and "yes") in the dictionary. It is important to note that the list of each target class is not empty.