Interesting medical aspect to this. Heart attacks are a sudden blockage of one of the coronary arteries, usually starting in a trivial area (10-20% of vessel X-section) of "hardening of the arteries", correct term atherosclerosis. Only significant blockages (50-70%+) cause symptoms (angina), changes on stress testing, or are regarded as significant on angiography. So the stress test in the medicals really does very little to prevent this happening.