Inherited heart conditions are more common than most people realise. They often go undetected for years and can lead to serious harm when untreated — including heart attacks and cardiac arrest. But what are they, and why do they happen?
The genetic basis
Your body is built from trillions of cells, each carrying instructions encoded in your DNA called genes. There are tens of thousands of genes in every cell, determining a cell's shape, function, and even when it grows or dies. Genes come in matched pairs — one copy inherited from your mother, one from your father.
A small change in those instructions might make someone taller, or dislike the taste of coriander, or predispose them to a heart condition. When a heart condition results from genes inherited from a parent, we call it an inherited heart condition.
What causes them?
Genes hold the instructions for building proteins. A faulty instruction in a heart cell could cause it to beat irregularly or grow abnormally, depending on which protein is affected. Because genes come in pairs, a working copy can often compensate for a faulty one — which means it is entirely possible to carry a faulty gene, never experience symptoms yourself, and still pass it on. With most inherited heart conditions, each child of a carrier has a 50% chance of inheriting the variant.
The main types
Cardiomyopathies
Defects in the growth and function of the heart muscle:
- Hypertrophic cardiomyopathy — the muscle thickens, reducing how much blood the heart can hold
- Dilated cardiomyopathy — the chambers stretch and weaken, reducing pumping strength
- Arrhythmogenic right ventricular cardiomyopathy — muscle is replaced by fatty or fibrous tissue
Arrhythmias
Disruptions in the electrical system that coordinates the heartbeat:
- Long QT syndrome — the heart takes longer than normal to recharge between beats
- Brugada syndrome — affects sodium channels and can trigger dangerous rhythms
- Catecholaminergic polymorphic ventricular tachycardia — rapid rhythms triggered by exercise or stress
Inherited high cholesterol
- Familial hypercholesterolaemia — cholesterol is not cleared efficiently from the blood, accelerating artery narrowing from a young age. It affects roughly 1 in 250 people, and most remain undiagnosed.
Symptoms to watch for
Inherited heart conditions may cause no symptoms at all until a serious event occurs. When symptoms do appear they can be vague:
- Feeling lightheaded or dizzy, particularly during or just after exercise
- Unusual breathlessness or fatigue
- Palpitations — an awareness of the heart pounding, racing or skipping
- Fainting or blacking out, especially during exertion or emotional stress
- Chest pain on exertion
Fainting during exercise is a red flag that should always be assessed by a doctor.
How they are diagnosed
A family history of heart problems at a young age — particularly sudden unexplained death under 40 — should raise suspicion. Investigations may include an ECG, an echocardiogram, a cardiac MRI, exercise testing, an ambulatory heart monitor, and genetic testing.
If a family member is diagnosed
Inherited heart conditions run in families, so a specialist may recommend that close relatives are tested too. This process, called cascade testing, is offered through NHS inherited cardiac conditions clinics and helps identify family members who carry the same variant before problems develop.
Why get tested?
- Risks can be addressed early, before permanent damage occurs
- Lifestyle and dietary changes can be started to reduce coronary artery disease risk
- Monitoring and treatment can begin before dangerous symptoms appear
- Family members can learn whether they are also at risk
Where to get support
- The British Heart Foundation runs a Genetic Information Service helpline on 0300 456 8383 during working hours
- NHS specialist inherited cardiac conditions clinics take referrals from your GP
- Rightangled's DNA tests assess genetic markers linked to cardiovascular risk, with results reviewed by our clinical team, which includes GPhC-registered independent prescribers, and medical oversight from our doctor, Dr Abdullah
A consumer genetic test is a screening and awareness tool — it is not a substitute for specialist diagnostic testing in an NHS inherited cardiac conditions clinic. If you have a strong family history, ask your GP for a referral.
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Related reading: types of inherited heart condition.
This article is for general information and does not replace personalised medical advice.
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Basic Heart Health
Types of Inherited Heart Condition