First Aid (and Read and Write) is a pre-req for Healing Arts, but not the other way around. The frustration you may run into (speaking from personal experience) with having only First Aid is that when someone is down, you cannot assess them in any way. All you can do is attempt First Aid and hope that it works.
ARB v1.1 said:
The recipient can make no response as to whether the First Aid is having an effect or whether it is successful. Healing Arts must be used to determine the success of failure of First Aid.
