Based on prior knowledge, a persistent form of atrial fibrillation on an electrocardiogram (ECG) at the time of admission to the hospital can be an important indicator for chronic heart failure. Atrial fibrillation is a common arrhythmia in patients with heart failure, and its presence can suggest the presence of chronic heart failure.

To analyze the relationship between the feature n_r_ecg_p_06 and the task of determining if the patient has chronic heart failure, we can examine the distribution of n_r_ecg_p_06 values for each target class.

Let's create the dictionary:

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

Since this feature is a categorical variable and its possible values are "no" and "yes", we include all values in the dictionary for both target classes.