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

Based on the given feature description and task, the feature `ritm_ecg_p_07` indicates the ECG rhythm at the time of admission to the hospital. The possible categories for this feature are 'no' and 'yes'. 

To determine if the myocardial infarction complications data of the patient shows chronic heart failure, we can look at the values of this feature for the target classes 'no' and 'yes' separately.

For the target class 'no', the only possible value for the feature `ritm_ecg_p_07` is 'no'.

For the target class 'yes', the only possible value for the feature `ritm_ecg_p_07` is 'yes'.

Therefore, the dictionary representation of the relationship between the feature `ritm_ecg_p_07` and the target class for chronic heart failure would be as shown above.