Based on the given task and feature, we need to analyze the relationship between the use of calcium channel blockers (ANT_CA_S_n) and chronic heart failure in patients. To do this, we can look at the distribution of ANT_CA_S_n values for each target class: "yes" (chronic heart failure) and "no" (no chronic heart failure).

By analyzing the data, we can create a dictionary as follows:

```json
{
    "no": ["yes"],
    "yes": ["yes", "no"]
}
```

Explanation:
- For the target class "no" (no chronic heart failure), the only possible value of ANT_CA_S_n is "yes". This means that if the patient has no chronic heart failure, they could still be using calcium channel blockers.
- For the target class "yes" (chronic heart failure), there are two possible values of ANT_CA_S_n: "yes" and "no". This suggests that patients with chronic heart failure may or may not be using calcium channel blockers.

Please note that this analysis assumes that only the feature ANT_CA_S_n is being considered and does not take into account any other features or factors that may influence the relationship between the use of calcium channel blockers and chronic heart failure.