Hypertrophic cardiomyopathy (HCM) is a thickening of the lower main pumping chamber of the heart (the left ventricle). It can affect people of any age but is more likely as age increases. It is most often diagnosed in middle age and symptoms can vary widely. Following are some symptoms: . Chest pain • Shortness of breath • Fatigue • Fainting • Dizziness • Rapid or irregular heartbeat (palpitations) • Swelling in the ankles, feet, legs and abdomen