```json
{
    "no": ["no"],
    "yes": ["yes"]
}
```
Based on the given feature "np_05" which represents the presence of LBBB (anterior branch) in the medical history, we can assume that if the feature value is "yes", it indicates that the patient has a history of LBBB, and if the feature value is "no", it indicates no history of LBBB. 

To determine if there is a relationship between this feature and the occurrence of chronic heart failure, we need to analyze the myocardial infarction complications data. It is not explicitly mentioned how the data indicates chronic heart failure, so we cannot definitively conclude the relationship between this feature and the target variable without further information.