Thanks for using Healthcaremagic,
You have suffered Rheumatic arthritis
that is why ASO titre was high there are other findings and investigations are considered.
Penicillin is given to prevent recurrent infection of throat with streptococcus
It is not clear did you suffer on heart known as carditis.
if so you need to take penicillin every month till the age of 40 years or more.
It is given to prevent damage to valves of heart.
You should consult a cardiologist
and get a 2 D echocardiography
to see if any effect is there on heart.
Hope this information helps
Dr.Akhilesh Dubey M.D.