Based on prior knowledge, frequent premature ventricular contractions on ECG at the time of admission to the hospital may indicate a higher likelihood of chronic heart failure. Therefore, it is likely that the feature "n_r_ecg_p_04" has a positive relationship with the task of determining whether the patient shows chronic heart failure.

Based on this analysis, the relationship between the feature "n_r_ecg_p_04" and the task of determining chronic heart failure can be summarized in the following dictionary:

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

This indicates that patients who do not show chronic heart failure ("no" class) have "no" frequent premature ventricular contractions on ECG at the time of admission to the hospital. On the other hand, patients who show chronic heart failure ("yes" class) have "yes" frequent premature ventricular contractions on ECG at the time of admission to the hospital.

Note: As per the task requirements, the dictionary only includes the possible values of the feature for each target class and does not include any hard-to-predict values.