Genetic testing in cardiac conditions involves analysing a blood or saliva sample to look for inherited variants in genes associated with heart conditions that can cause arrhythmias, cardiomyopathy, or sudden cardiac death. It is an important part of investigating the cause of cardiac arrest, particularly in younger patients or those without obvious structural heart disease.
When it is offered
Genetic testing is typically offered when a cardiac condition with a known or suspected genetic basis is identified or suspected, including:
- Hypertrophic cardiomyopathy (HCM)
- Dilated cardiomyopathy (DCM)
- Arrhythmogenic right ventricular cardiomyopathy (ARVC)
- Long QT syndrome
- Short QT syndrome
- Brugada syndrome
- Catecholaminergic polymorphic ventricular tachycardia (CPVT)
- Idiopathic ventricular fibrillation (unexplained VF in a structurally normal heart)
What a positive result means
Finding a pathogenic variant confirms the genetic basis of a condition and can guide clinical management. Crucially, it also opens the door to cascade screening: testing first-degree relatives (parents, siblings, and children) who may carry the same variant and be at risk, even if they have no symptoms yet.
What a negative result means
A negative result does not always rule out a genetic condition. Genetic testing is not comprehensive, and some variants are not yet recognised as disease-causing. Clinical assessment and monitoring of relatives should continue even when testing is negative, if the clinical suspicion remains.
Where testing takes place
Genetic testing for cardiac conditions is coordinated through specialist inherited cardiac condition (ICC) clinics, which are available at major cardiac centres across the UK. Referral is usually made by the cardiologist. Clinical genetics teams manage the testing process and provide pre- and post-test counselling.
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