Based on the given feature description, I will analyze the relationship between the feature "IBS_POST" and the task of determining whether the patient shows chronic heart failure.

Looking at the feature "IBS_POST", it represents the presence of coronary heart disease (CHD) in recent weeks, days before admission to the hospital. The feature has three categories: 'there was no СHD', 'exertional angina pectoris', and 'unstable angina pectoris'. It is unclear from the feature description alone how it directly relates to chronic heart failure.

To analyze the relationship between "IBS_POST" and the presence of chronic heart failure, it would be necessary to have additional information about the dataset, the target variable, and other features that might be relevant.

Without further information, it is not possible to determine the relationship between the feature and the task accurately. However, to create the requested dictionary, I will assume that the presence of CHD in recent weeks, days before admission to the hospital might be a risk factor for chronic heart failure.

Therefore, the dictionary would look like this:
```json
{
	"no": ["there was no СHD"],
	"yes": ["exertional angina pectoris", "unstable angina pectoris"]
}
```

Please note that this is an assumption based on limited information, and further analysis with more data and domain knowledge would be required to make accurate predictions or determine the actual relationship between "IBS_POST" and chronic heart failure.