Geltman observed that the letter contained no information about the health of Clinton's heart, such as an electrocardiogram. Those are fairly standard tests, and as people age, it is important to establish a baseline, he said. Heart disease is the number one killer in the United States. But because she does not smoke, does not appear to be particularly overweight and has good cholesterol levels, Clinton does not appear to be at risk for a heart attack, he said.