Based on prior knowledge, the feature n_r_ecg_p_06 represents the presence or absence of a persistent form of atrial fibrillation on an electrocardiogram (ECG) at the time of admission to the hospital. To analyze its relationship with the occurrence of chronic heart failure as the target, we can examine the distribution of n_r_ecg_p_06 values for each target class.

Here's the dictionary generated based on the analysis:

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

Explanation:
- For the target class "no" (indicating no chronic heart failure), the feature value "no" is possible.
- For the target class "yes" (indicating chronic heart failure), the feature value "yes" is possible.

Since this is a categorical feature, we only consider the distinct values observed in the data. In this case, there are only two possible values: "no" and "yes".