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

Based on the given feature "n_p_ecg_p_10" and the task of determining whether the patient has chronic heart failure or not, it can be observed that the feature has two categories: "no" and "yes". 

In this case, the presence of "LBBB on ECG at the time of admission to hospital" (n_p_ecg_p_10) indicates a positive diagnosis of chronic heart failure. So, if the value of "n_p_ecg_p_10" is "yes", it is likely that the patient has chronic heart failure. On the other hand, if the value is "no", it is unlikely that the patient has chronic heart failure.

Hence, the possible values for the feature "n_p_ecg_p_10" for the target class "no" are ["no"], and for the target class "yes" are ["yes"].