Based on my prior knowledge, premature ventricular contractions (PVCs) are abnormal heartbeats that begin in the ventricles, the lower chambers of the heart. PVCs can be caused by various factors such as heart disease, high blood pressure, certain medications, or stimulants like caffeine or nicotine.

To analyze the relationship between the feature nr_02 (Premature ventricular contractions in the anamnesis) and the task of determining if the patient has chronic heart failure, we can consider the following:

1. If nr_02 value is 'no', it suggests that the patient did not have premature ventricular contractions in their medical history. This could indicate a lower likelihood of chronic heart failure.
2. If nr_02 value is 'yes', it implies that the patient had premature ventricular contractions in their medical history. This may suggest a higher likelihood of chronic heart failure.

Given the categorical nature of the feature, we can create a dictionary with the following format:

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

In this case, the feature nr_02 only has two possible values: 'no' and 'yes'. The values are presented as strings in lists for each target class.