Based on prior knowledge, a third-degree AV block in the anamnesis (medical history) is associated with chronic heart failure. Therefore, it is likely that the presence of a third-degree AV block in the anamnesis indicates the existence of chronic heart failure.

Here is the dictionary representing the relationship between the feature "np_04" and the target variable "chronic heart failure":

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

Explanation:
- For the target class "no" (indicating no chronic heart failure), the only possible value for feature "np_04" is "no".
- For the target class "yes" (indicating chronic heart failure), the only possible value for feature "np_04" is "yes".

Since the feature has only two possible values, and they directly map to the target classes, the only values included in the dictionary are "no" and "yes".