Based on my prior knowledge, the presence of LBBB (anterior branch) on an ECG at the time of admission to the hospital can be an indicator of chronic heart failure. Therefore, it is likely that the n_p_ecg_p_07 feature showing "yes" would indicate the presence of chronic heart failure, while "no" would indicate the absence.

Based on this analysis, here is the dictionary with the possible values of the n_p_ecg_p_07 feature for each target class:

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

In this case, both the "no" and "yes" categories are included in the dictionary, as it seems that the values are either "yes" or "no".