FAQ

Hypertrophic Cardiomyopathy (HCM) is the most common inherited heart muscle condition. In HCM, the walls of the heart — most often the left ventricle — become abnormally thickened (hypertrophied), which can obstruct blood flow, cause the heart to pump less efficiently, and create dangerous arrhythmias.

HCM affects approximately 1 in 500 people and is a leading cause of sudden cardiac death in young people, including young athletes. Many people with HCM have no symptoms at all; others experience breathlessness, chest pain, palpitations, or blackouts. In some cases, the first sign of HCM is a cardiac arrest.

HCM is caused by mutations in genes that encode the proteins of the heart muscle, most commonly MYH7 and MYBPC3. It is inherited in an autosomal dominant pattern, meaning each first-degree relative of someone with HCM has a 50% chance of carrying the same gene variant.

Treatment depends on symptoms and risk profile and may include medication (beta-blockers, calcium channel blockers), a procedure called septal reduction therapy (to reduce obstruction), and ICD implantation for those at high risk of sudden cardiac arrest.

Family screening — with ECG, echocardiogram, and genetic testing — is strongly recommended for all first-degree relatives.

While there are a number of possible causes, three are particularly common in the UK. The first is Hypertrophic Cardiomyopathy (HCM), a genetic heart muscle condition in which the walls of the heart’s left ventricle become abnormally thickened. This can obstruct blood flow from the heart, causing loss of consciousness and a dangerous arrhythmia leading to cardiac arrest. The second is Long QT Syndrome, an often-unrecognised inherited condition affecting the heart’s electrical system that can predispose young people to life-threatening arrhythmias. Episodes are most commonly triggered by physical exertion or emotional stress. The third is commotio cordis, an electrical disturbance triggered by a sharp blow to the chest at a critical moment in the heart’s cycle. It can occur in contact sports such as football, cricket, rugby, and martial arts, as well as any situation involving a forceful blow to the chest.