The majority of people with hypertrophic cardiomyopathy (HCM) experience no significant complications from the disease. However, for a small number of people with HCM, it can be life-threatening. Among this minority, HCM can cause dangerous arrhythmias, or irregularities in the heart's rhythm, that can lead to sudden cardiac death. If diagnosed early, treatment options are available to monitor and correct these heartbeat irregularities. Unfortunately, many cases of HCM go undiagnosed and sometimes sudden cardiac death becomes the first indication that something was wrong.