Why would a patient who suffers from diabetes type 2 at 50 have a myocardial infarction?

Heart disease. Diabetes is a big risk factor for heart disease in general as it can lead to clogged blood vessels. Diabetes is also usually associated with high blood pressure and high cholesterol. Individually these are all associated with increased risk of heart disease, but together a patient's risk really increases. The risk is high enough, that we usually treat these patients like they have already had a mi.