Based on my prior knowledge, the presence of a first-degree AV block on an ECG at the time of admission to the hospital can be an indicator of chronic heart failure in patients with myocardial infarction complications. However, it is important to note that this is a categorical variable and the association between the feature and the task may vary depending on other factors.

To analyze the relationship between the feature "n_p_ecg_p_03" and the task of determining if the patient has chronic heart failure, we can examine the distribution of the feature values across the target classes.

Here is the analysis of the relationship between the feature and the task:

For patients without chronic heart failure:
- The possible values of feature "n_p_ecg_p_03" for the target class "no" are: ['no']

For patients with chronic heart failure:
- The possible values of feature "n_p_ecg_p_03" for the target class "yes" are: ['no', 'yes']

Based on this analysis, we can create a dictionary with the following format:

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

Please note that the possible values of feature "n_p_ecg_p_03" for the target class "yes" include both "no" and "yes" categories. This suggests that the presence of a first-degree AV block on an ECG does not definitively indicate the presence or absence of chronic heart failure.