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

Based on the feature description, the feature np_08 represents the presence or absence of Complete LBBB (Left Bundle Branch Block) in the patient's medical history. 

To determine whether the patient shows chronic heart failure, we need to analyze the relationship between np_08 and chronic heart failure. 

Since the feature np_08 is categorical and has two possible values: "no" and "yes", we can examine the distribution of these values in the data for both the "no" and "yes" classes of chronic heart failure.

From the given information, we don't have any additional details about other values that np_08 could take or their relation to chronic heart failure. Therefore, we can only confirm that if np_08 is "no", then chronic heart failure is also "no", and if np_08 is "yes", then chronic heart failure is also "yes".