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

Based on the feature description, the feature `ritm_ecg_p_08` represents the ECG rhythm at the time of admission to the hospital. The possible categories are 'no' and 'yes', where 'no' indicates sinus rhythm with a heart rate below 60 and 'yes' indicates a different rhythm.

To determine if the myocardial infarction complications data of the patient shows chronic heart failure, we can analyze the relationship between the feature and target. 

If the patient has chronic heart failure, it is less likely to have a heart rate below 60. Therefore, if the target class is 'yes' (indicating chronic heart failure), we can expect the feature value to be 'no'. On the other hand, if the target class is 'no' (indicating no chronic heart failure), we can expect the feature value to be 'yes'.

Hence, the possible values for the feature 'ritm_ecg_p_08' for the target class 'no' are ['yes'], and for the target class 'yes' are ['no'].