Major Risk factors for heart attack: Age, sex (males at higher risk), family history (probably most important), hypertension, diabetes, smoking and dyslipidemia. Let us assume Anthony did nothing else but steroids; forget the GH, insulin, diuretics, etc. First of all, if he had any heart disease and continued steroids he was being foolish. The reason is the steroids are pro-atherogenic and screw people's cholesterol panel up nicely. He would have an increase in triglycerides and LDL (bad cholesterol). His good cholesterol would go down (HDL). This is undeniable fact. Look up anabolic steroids and their side effects. Moreover, assuming that he was taking non-pharmaceutical grade anabolics (probably vet grade from overseas) that were not prescribed by his family physician, there is a strong possibility that whatever the steroids injection medium may have some pro-inflammatory properties. For you googlers, look up C reactive protein and cardiovascular risk. It is has been proposed that a pro-inflammatory state by itself is a risk for cardiovascular events.
Now, if Anthony used insulin, GH and diuretics there is a very strong possibility that this combination could have put him over the edge. I would surmise he had dyslipidemia, high blood pressure and possibly diabetes (if he abused GH). Together, with his sex and age (near fifty), he was probably a walking time bomb. What is scary is that he is not an isolated incident. I would surmise that less than 10 percent of national level bodybuilders who routinely abuse this stuff get followed by a physician. I can gurantee one thing, a lot of these "Supermen" look like a 75 year old man inside. BB is a scary endeavor if you test the bounds, and don't do it simply for health.