At an early age, Breedlove had been diagnosed with hypertrophic cardiomyopathy (HCM). It is a condition in which the heart muscle becomes thick. Often, only one part of the heart is thicker than the other parts. The thickening can make it harder for blood to leave the heart, forcing the heart to work harder to pump blood. It also can make it harder for the heart to relax and fill with blood. 