Based on prior knowledge, the relationship between the feature "GB" (Presence of an essential hypertension) and the task of determining if the patient has chronic heart failure may not be very strong. Essential hypertension is a common condition characterized by high blood pressure without any specific underlying cause. It is important to note that hypertension can contribute to the development of chronic heart failure, but the presence of essential hypertension alone is not enough to confirm the presence of chronic heart failure.

Considering this, we can create a dictionary to summarize the relationship between the feature "GB" and the task of identifying chronic heart failure:

```json
{
	"no": ["there is no essential hypertension"], 
	"yes": ["Stage 2", "Stage 3", "Stage 1"]
}
```

In this case, patients with chronic heart failure can have different stages of essential hypertension (Stage 2, Stage 3, Stage 1). However, it's important to note that the absence of essential hypertension (there is no essential hypertension) does not automatically indicate the absence of chronic heart failure.