Based on my prior knowledge, the relationship between the feature L_BLOOD (White blood cell count) and the task of determining whether or not the patient shows chronic heart failure can be analyzed as follows:

Analysis:
- High white blood cell count (leukocytosis) is often associated with inflammation, infection, or an immune response in the body.
- In the context of myocardial infarction complications, chronic heart failure can occur due to ongoing inflammation or structural damage to the heart.

Based on this analysis, we can assume that higher values of L_BLOOD may indicate a higher likelihood of chronic heart failure.

Here is the dictionary with specific L_BLOOD values for each target class:

```json
{
    "no": [4.5, 4.6, 4.7, 4.8, 4.9],
    "yes": [5.4, 5.5, 5.6, 5.7, 5.8]
}
```
Note: These are example values and may not reflect the actual relationship between L_BLOOD and chronic heart failure in the dataset. Please use appropriate statistical analysis techniques to confirm the relationship.