Based on prior knowledge, the use of lidocaine in the ICU (feature LID_S_n) may be an important predictor for chronic heart failure in patients with myocardial infarction complications. It is possible that patients who have received lidocaine in the ICU may be more likely to develop chronic heart failure.

To analyze the relationship between LID_S_n and chronic heart failure, we can examine the dataset and identify the values of LID_S_n for patients with and without chronic heart failure.

Considering the task "Does the patient show chronic heart failure?", we can create a dictionary with the possible values of feature LID_S_n for each target class:

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

In this case, both target classes have the same possible values for LID_S_n, which are "yes" and "no". This suggests that the use of lidocaine in the ICU (LID_S_n) does not provide a clear distinction between patients with chronic heart failure and those without.

Please note that the values "yes" and "no" in the dictionary represent the categories of the feature LID_S_n, not the actual occurrence or absence of chronic heart failure.