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

Based on the feature description and task, the feature 'n_r_ecg_p_02' represents the presence or absence of frequent premature atrial contractions on the electrocardiogram (ECG) at the time of admission to the hospital. 

Since the question is specifically asking about the presence of chronic heart failure, it is reasonable to assume that the feature 'n_r_ecg_p_02' may have a direct relationship with chronic heart failure complications. However, without further information about the dataset and other features, it is difficult to determine the exact relationship and provide more specific details.

In the dictionary, the key "no" represents the target class where chronic heart failure complications are absent, and the key "yes" represents the target class where chronic heart failure complications are present. The values for each key contain the possible values of the feature 'n_r_ecg_p_02' for the respective target class. In this case, the possible values are ["no"] for the "no" class and ["yes"] for the "yes" class.