Based on my prior knowledge, there may be a relationship between the feature "n_p_ecg_p_12" (Complete RBBB on ECG at the time of admission to the hospital) and the occurrence of chronic heart failure.

To analyze the relationship, we can look at the values within the feature for the two target classes: "no" (indicating no chronic heart failure) and "yes" (indicating chronic heart failure).

Here is the visualization of the relationship:

| Feature Value | Target Class |
| ------------- | ------------ |
| no            | no           |
| yes           | yes          |

Based on this analysis, we can create the dictionary:

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

Since the feature value "n_p_ecg_p_12" only takes two distinct values ("no" and "yes") and both values directly map to their respective target classes, we only include the single value for each target class in the dictionary.