Based on my prior knowledge, exertional angina pectoris in the anamnesis could potentially be a contributing factor to the development of chronic heart failure in a patient with myocardial infarction complications. The presence of exertional angina pectoris in the anamnesis may indicate ongoing cardiovascular issues and could be suggestive of chronic heart failure.

Below is the dictionary that represents the relationships between the feature "STENOK_AN" and the task of determining chronic heart failure:

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

In this dictionary, the "no" class includes cases where the patient does not show chronic heart failure, and the corresponding values of the feature "STENOK_AN" are "never", "more than 5 years ago", and "4-5 years ago". The "yes" class includes cases where the patient shows chronic heart failure, and the corresponding values of the feature "STENOK_AN" are "during the last year", "one year ago", "two years ago", and "three years ago".

Note that the values of the feature "STENOK_AN" that are not included in the dictionary are considered hard to predict or do not have a strong relationship with chronic heart failure and hence are not included in the analysis.