roids makes you bigger therefore heart needs to work harder therefore grows bigger to respond to the extra demand.. nothing very dangerous here, just normal physiologyu..
Whats bad is the effect on lipid levels which increase chances of cardiac event if unchecked.. but this is an issue mostly with only some bbers using massive doses of oral aas, rec stuff, etc. Otherwise there would be much more bbers (cutler, coleman, levrone, ray, etc etc) who would have dropped dead long ago. Sure they may live to 75 instead of 80 but who cares.