Dear Dave:
From what you have told me, I can't tell you much. Yes, this can be from anxiety. Actually, if your heart rate was only at 19 beats per minute for a prolonged time, likely you had severe ischemic damage to multiple organs and would be having multiple problems of brain damage, kidney damage, and heart damage that would have landed you into the hospital for a prolonged period. So, I would expect that it was very transitory. I will bet that the EEG will be normal. From what your telling me, I would favor that you have an anxiety disorder.
Sincerely,
CCF Neuro MD