Analyzing the relationship between the feature 'AST_BLOOD' and the task of determining whether the patient shows chronic heart failure, prior knowledge suggests that AST (Aspartate Aminotransferase) is an enzyme primarily found in the liver and heart. Elevated levels of AST in the blood can indicate liver or heart damage.

To determine the appropriate ranges of values for AST_BLOOD, we can consider the normal range of AST levels in the blood, as well as the ranges that are typically associated with heart failure. 

Normal AST levels in the blood vary depending on the laboratory, but generally, levels below 40 IU/L (international units per liter) are considered normal for adults.

In the context of myocardial infarction complications and chronic heart failure, elevated AST levels may be observed. However, it is important to note that AST levels alone may not be sufficient to diagnose chronic heart failure, as there may be other factors and tests needed for a comprehensive diagnosis.

Based on this analysis, we can create the dictionary as follows:

```json
{
	"no": [20.5, 30.3, 25.7, 35.9, 28.1],
	"yes": [45.2, 50.6, 55.8, 48.9, 52.3]
}
```

In this dictionary, the "no" key represents the possible values of AST_BLOOD for patients without chronic heart failure, while the "yes" key represents the possible values of AST_BLOOD for patients with chronic heart failure. The values provided in the lists are just examples and should not be considered definitive or comprehensive.