Medically reviewed by Dr Nabila Laskar, Consultant Cardiologist (GMC 7040901). Hypertrophic cardiomyopathy is an inherited condition in which the heart muscle becomes abnormally thickened. It is the most common inherited heart condition and an important cause of sudden cardiac death in young athletes.
Genetic changes affecting the heart muscle proteins cause the left ventricle to thicken, making it stiff and, in some people, obstructing blood flow out of the heart. It affects roughly 1 in 500 people and is inherited in an autosomal dominant pattern.
Many people have none. Others experience breathlessness on exertion, chest tightness, palpitations, light-headedness or fainting — particularly during or immediately after exercise, which is a red flag requiring urgent assessment. See /conditions/syncope-fainting.
An ECG and echocardiogram are the core tests, with cardiac MRI and genetic testing where indicated. Because HCM is inherited, first-degree relatives should be offered screening — see /cardiac-screening-athletes for pre-participation assessment.
Management is individualised and includes cardiologist-prescribed medication to improve filling and reduce obstruction, activity advice, formal assessment of sudden cardiac death risk, and consideration of an implantable defibrillator or septal reduction therapy in selected patients.
Many people with HCM can exercise at moderate intensity, but competitive and high-intensity training requires individual risk assessment by a cardiologist. Never make this decision without specialist advice.
Most cases are genetic and autosomal dominant, meaning each first-degree relative has a 50% chance of carrying the same variant. A minority arise from new mutations with no family history.
With modern diagnosis, risk stratification and treatment, most people with HCM have a normal or near-normal life expectancy. The key is identifying the minority at higher risk of dangerous rhythms and protecting them appropriately.
Yes. First-degree relatives are usually offered ECG and echocardiogram screening, with the starting age and interval guided by a cardiologist and, where available, the family's genetic result.