Were you having symptoms of Tachy before hand also? Or A fib? Reason I ask is the irregular beat increase chances of clot and thus blockage also. Reason being, the irregular heart beat induces irregular movement of blood, thus creating hemolysis (blood cell damage) due to turbulent flow (this is also how aneurysms are started in weak vessels). Hemolysis releases prothrombin (a clotting chemical) which produces thrombin, which converts into fibrinogen and then fibrin, forming a fibrin clot. This is kind of how the clotting cascade works.
Tachy, A fib, high BP, RBC / platelet count (which is increased on gear), all can contribute to inducing the clotting cascade which all starts with blood cell damage. Now...you add stenotic (narrowed) arteries into the equation from atherosclerosis (fat build up on vascular walls from bad cholesterol - also can be caused by gear- or genetics o r bad eating) then you have a perfect equation for a heart attack. The stenotic vessels mean that the clot doesn't have to be near as large as it would otherwise to create a blockage.
Only reason I know this stuff is I sell medical implants / prosthetics for open heart surgeries. I am in surgery watching CABG (coronary artery bypass graft) and valve reconstruction / replacement surgeries 3-4 times per week. Most patients that I see are obese, smokers, old, or steroid users or a mixture of the above. However, some just have bad genetics and are none of the above. I will say that the smokers have the worst anatomical integrity as far as the health of their arterial vessels that are being grafted to the heart to re-route a blocked artery. DON"T SMOKE...especially if you use gear!