Based on my prior knowledge, persistent form of atrial fibrillation on ECG at the time of admission to the hospital (feature n_r_ecg_p_06) can potentially have a relationship with chronic heart failure.

To analyze the relationship between the feature and the task, we need to examine the values of n_r_ecg_p_06 for patients with and without chronic heart failure.

Let's categorize the patients based on their feature values and determine the relationship:

For patients without chronic heart failure (target class no), possible values of n_r_ecg_p_06 can be:
- no

For patients with chronic heart failure (target class yes), possible values of n_r_ecg_p_06 can be:
- no
- yes

Based on this analysis, we can create the following dictionary:

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

This dictionary represents the possible values of n_r_ecg_p_06 for each target class.