```json
{
    "no": ["no"],
    "yes": ["yes"]
}
```
Based on the given feature "endocr_02" which represents obesity in the patient's medical history, we can infer that if the value is "no", it indicates that the patient doesn't have a history of obesity. On the other hand, if the value is "yes", it implies that the patient does have a history of obesity.

Since there is no way to directly determine whether the patient has chronic heart failure based solely on this feature, the analysis suggests that the presence or absence of obesity doesn't provide sufficient information to determine the presence of chronic heart failure.