Based on prior knowledge, the ST_Slope feature is related to heart disease. The slope of the peak exercise ST segment can indicate if there is a heart disease present or not.

To analyze the relationship between the ST_Slope feature and the task of whether the coronary angiography shows heart disease or not, we can look at previous studies or medical literature that highlight the association between ST_Slope and heart disease. Additionally, we can analyze any available data or medical records that include the ST_Slope feature along with the corresponding coronary angiography results.

Once we have gathered this information, we can create the dictionary as follows:

```json
{
    "no": ["Flat", "Up", "Down"],  
    "yes": ["Up", "Down"]  
}
```

This dictionary indicates that for the target class "no" (representing no heart disease), the possible values for the ST_Slope feature are: "Flat", "Up", and "Down". For the target class "yes" (representing heart disease), the possible values for the ST_Slope feature are: "Up" and "Down".

It is important to note that this analysis is based on prior knowledge, and for specific cases or datasets, the relationship between the ST_Slope feature and heart disease may vary. Therefore, it is always recommended to conduct a thorough analysis on the specific dataset or consult with a medical professional for accurate interpretation.