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

Based on the feature description and the task, the feature "n_r_ecg_p_03" represents the presence or absence of ventricular contractions on the electrocardiogram (ECG) at the time of admission to the hospital. 

Since the task is to determine if the patient has chronic heart failure, which is a separate condition from myocardial infarction complications, it is not possible to directly derive the presence of chronic heart failure from this feature alone. Therefore, the feature "n_r_ecg_p_03" itself does not provide direct information about chronic heart failure. 

However, we can still analyze the relationship between the feature and the target variable "chronic heart failure" by looking at the distribution of feature values for each target class. 

The possible values for the feature "n_r_ecg_p_03" are "no" and "yes". According to the available data, for the class "no" (indicating no chronic heart failure), the only possible value for the feature is "no". Similarly, for the class "yes" (indicating chronic heart failure), the only possible value for the feature is "yes".