Based on prior knowledge, exertional angina pectoris in the anamnesis (STENOK_AN) is a common symptom and potential complication of chronic heart failure. Therefore, it is likely that the presence of exertional angina pectoris in the anamnesis may indicate the existence of chronic heart failure. 

To analyze the relationship between the feature and the task, we can examine the myocardial infarction complications data of patients who have chronic heart failure and those who don't. By determining the values of STENOK_AN for each target class, we can observe any patterns or differences.

Possible values of feature STENOK_AN for target class "no" (no chronic heart failure): ['never', 'during the last year', 'more than 5 years ago', '4-5 years ago', 'one year ago', 'two years ago', 'three years ago']

Possible values of feature STENOK_AN for target class "yes" (chronic heart failure): ['never', 'during the last year', 'more than 5 years ago', '4-5 years ago', 'one year ago', 'two years ago', 'three years ago']

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

Based on the analysis, there is no evident distinction in the possible values of STENOK_AN for patients with chronic heart failure and those without. Thus, it is difficult to predict chronic heart failure based solely on the values of STENOK_AN.