Based on my prior knowledge, the feature "STENOK_AN" refers to exertional angina pectoris in the patient's medical history. The feature has several categories representing different time frames when the angina pectoris occurred, ranging from "never" to "more than 5 years ago".

To analyze the relationship between this feature and the presence of chronic heart failure, we would need access to data that includes both the feature values and the target variable indicating whether the patient has chronic heart failure or not. Without the data, it is difficult to analyze the relationship between the feature and the task accurately.

However, based on general medical knowledge, it is possible to make some assumptions about the relationship between exertional angina pectoris and chronic heart failure. In patients with chronic heart failure, exertional angina pectoris may be more likely to occur due to the reduced blood flow to the heart muscle. Therefore, it is possible that patients with a history of exertional angina pectoris, especially if it has occurred more recently, could be more prone to chronic heart failure.

To create the dictionary based on these assumptions, I will include possible values of the feature "STENOK_AN" for each target class:

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

Please note that these assumptions are based on general medical knowledge and may not accurately reflect the specific relationship between the feature and the target variable in the given dataset. To obtain a more accurate analysis, it is necessary to have access to the actual data.