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

Based on the feature description, it seems that the "ritm_ecg_p_07" feature represents the ECG rhythm at the time of admission to the hospital. The possible categories for this feature are "no" and "yes", indicating whether the ECG rhythm is sinus with a heart rate above 90 or not.

To determine if the patient has chronic heart failure (CHF) as indicated by the myocardial infarction (MI) complications data, we can analyze the relationship between "ritm_ecg_p_07" and CHF. 

Since there is no information provided about the relationship between "ritm_ecg_p_07" and CHF, we can assume that the presence of CHF is independent of the ECG rhythm at admission. Therefore, all possible values of "ritm_ecg_p_07" can be considered for both target classes ("no" and "yes") of chronic heart failure.