Howards' condition has nothing to do Curry's most likely.
Irregular heartbeats are rather common if you look at the population as whole
Howard got a viral infection. That most likely means he has something called viral pericarditis (inflammation of the lining of the heart) or worse viral cardiomyopathy (where the heart enlarges). Really completely different from Curry's condition which is a problem of electrical wiring/pacemaker of the heart.
Steroids can rarely cause enlargement of the heart leading heart failure but I don't believe do anything with irregular heart beats. Other drugs definitely can so if they're using a new designer drug who know. Seriously doubt though that any of these heart issues are due to any steroid use.