Based on prior knowledge, we do not have direct information about the relationship between the feature "STENOK_AN" (Exertional angina pectoris in the anamnesis) and the target variable of chronic heart failure. Exertional angina pectoris is a symptom of reduced blood supply to the heart muscle, which can be caused by various conditions including chronic heart failure.

To analyze the relationship between the feature and the task, we can assume that patients who have experienced exertional angina pectoris in the anamnesis are more likely to have chronic heart failure. However, this assumption may not hold true in all cases since angina pectoris can also be caused by other factors.

Based on this analysis, we can create a dictionary with the possible values of the "STENOK_AN" feature for each target class:

```json
{
    "no": ["never", "during the last year", "more than 5 years ago", "4-5 years ago"],
    "yes": ["one year ago", "two years ago", "three years ago"]
}
```

Note that we have excluded the values that are hard to predict or are not mentioned in the feature description. It is important to note that this analysis is based on general assumptions and without specific domain knowledge or a dataset, it is difficult to provide a definitive conclusion on the relationship between the feature and the task.