Based on the feature description, we can analyze the relationship between the feature "ZSN_A" and the target variable "chronic heart failure".

To do this, we need to examine the possible values of the feature for each target class and identify any patterns or trends.

Upon analysis, we can generate a dictionary with the relevant details:

```json
{
	"no": ["there is no chronic heart failure"], 
	"yes": ["I stage", "IIА stage", "IIB stage"]
}
```

In this case, the feature "ZSN_A" has the value "there is no chronic heart failure" exclusively for the target class "no". The values "I stage", "IIА stage", and "IIB stage" are present in the feature for the target class "yes".

Note that for the purpose of this analysis, we only included the values that are relevant to the target classes. Other values for "ZSN_A" were not included in the dictionary.

This dictionary provides a summary of the possible values of the feature "ZSN_A" for each target class of the task.