Based on prior knowledge, the feature FIB_G_POST (Ventricular fibrillation at the time of admission to the intensive care unit) is a categorical variable with two categories: 'no' and 'yes'. 

To analyze the relationship between this feature and the target (chronic heart failure), we would need data on both the feature and the target variable. Without this data, it is not possible to directly determine if the myocardial infarction complications data of a patient indicates chronic heart failure.

However, if we assume that the feature FIB_G_POST is related to chronic heart failure, we can create a dictionary based on this assumption. Assuming 'no' category indicates no chronic heart failure and 'yes' category indicates chronic heart failure, the dictionary would look like this:

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

Please note that this dictionary assumes a direct relationship between the feature FIB_G_POST and chronic heart failure based on their respective categories. Without actual data, this relationship cannot be established conclusively.