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

Based on the given feature "n_r_ecg_p_01" and the task of determining whether a patient has chronic heart failure or not, we can analyze the relationship between the feature and the target class.

In this case, the feature "n_r_ecg_p_01" represents the presence of premature atrial contractions on an electrocardiogram (ECG) at the time of admission to the hospital. The possible values for this feature are "no" and "yes", indicating whether or not the patient had premature atrial contractions.

To determine if the patient has chronic heart failure, we need additional information or features related to chronic heart failure. Without such information, it is not possible to directly infer the presence of chronic heart failure from the feature "n_r_ecg_p_01" alone.

Based on the given feature and task, the possible values for the feature "n_r_ecg_p_01" are either "no" or "yes". Since the target variable is the presence of chronic heart failure, the feature values of "no" and "yes" do not provide direct information about chronic heart failure. Therefore, it is not possible to conclusively determine whether or not the patient has chronic heart failure based solely on the feature "n_r_ecg_p_01".