Based on prior knowledge, the feature "MP_TP_POST" represents whether the patient had paroxysms of atrial fibrillation at the time of admission to the intensive care unit or at a prehospital stage.

To analyze the relationship between the feature and the task of determining if the patient shows chronic heart failure, we need to examine how the feature values correspond to the presence or absence of chronic heart failure.

Here is the dictionary representing the possible values of the "MP_TP_POST" feature for each target class:

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

In this case, the feature value "no" is associated with both target class "no" and "yes". However, the feature value "yes" is only associated with the target class "no". This suggests that patients with paroxysms of atrial fibrillation at the time of admission to the ICU or prehospital stage are less likely to show chronic heart failure.