The A in ARVC stands for arythmia ie abnormal heart rythmns which would have an effect on your life. If you have never had an arrythmia you might be advised to consult a cardiologist again to review your notes and check the diagnosis. However although you will need to discuss this with the CAA for a definitive reply, I am not optimistic you will be allowed a Class 1. The condition has a risk of sudden decapacitation which is the number one concern of the CAA even though many people with the condition live an otherwise normal life. I am sorry not to be optimistic but you are right to get this sorted before paying for training.
As we always say, please come back and tell us the outcome. I would be delighted to be proved wrong.