Based on prior knowledge, we can analyze the relationship between the feature "n_p_ecg_p_03" and the presence of chronic heart failure as follows:

First-degree AV block on ECG is a type of conduction abnormality characterized by a delay or blockage of the electrical impulses from the atria to the ventricles. It can be identified on an ECG (electrocardiogram) test.

To determine if there is a relationship between the feature and the presence of chronic heart failure, we can examine the medical literature or consult a cardiologist. However, without further information or data specific to the dataset we are analyzing, we can't make direct assumptions about the relationship.

To create the dictionary as requested, considering that we don't have enough information about the relationship, we could provide a generic dictionary with the possible values for the "n_p_ecg_p_03" feature for each target class:

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

In this case, the feature "n_p_ecg_p_03" has only two possible values which are "no" and "yes". We include both values in the dictionary for each target class, although it is not certain if these values can accurately predict chronic heart failure without more context.