While high cholesterol, high blood pressure, diabetes and smoking are well known heart disease risks, not everyone who has a heart attack has them. In fact, previous research has shown that 14% to 27% of heart attack patients have none of these risk factors. Now, a new study finds that these patients had one thing in common: they all tended to have high levels of coronary calcium. Results of the study show that scans that detect this kind of plaque buildup should be considered as part of their standard care, even in the absence of the four standard modifiable risk...