Presentation: Patient with a family history of cardiomyopathy
Cardiomyopathy is a general term for conditions of the heart muscle that make it harder for blood to be pumped around the body. Around 40%–60% of non-ischaemic cases are familial.
At a glance:
- Cardiomyopathies are a group of pathologies affecting cardiac structure and function. The most prevalent forms are dilated, hypertrophic and arrhythmogenic cardiomyopathies.
- Cardiomyopathies are heterogeneous conditions: Around 60%–70% of all cardiomyopathy cases are ischaemic. For non-ischaemic cardiomyopathies, around 40%–60% of cases are familial.
- There are a number of different genetic variants linked to cardiomyopathy. The age of onset and degree of penetrance vary significantly.
- Alert! Cardiomyopathy is a significant cause of sudden cardiac death, accounting for about 22%. A young patient with a family history and symptoms of heart failure or syncope should be investigated urgently.
Example clinical scenario
A 20-year-old man attends your clinic requesting advice about cardiac screening. His paternal aunt died suddenly at a young age and his father was recently diagnosed with hypertrophic cardiomyopathy following an echocardiogram.
Identifying those at risk of a genetic condition
- Cardiomyopathy is usually diagnosed following secondary care investigations. This involves the patient meeting specific diagnostic criteria based on an echocardiogram and an electrocardiogram (ECG).
- Familial cardiomyopathy is suspected when a patient meets the diagnostic criteria on investigation (echocardiogram and ECG with or without an MRI) but non-familial causes are absent. In these cases, the patient may be offered diagnostic genomic testing.
- A pathogenic genetic variant can be identified in 30%–50% of patients with familial cardiomyopathy. This proportion is increasing as more variants are discovered.
- As inheritance is often autosomal dominant, first-degree relatives are likely to have a 50% chance of carrying the same variant.
- In rare circumstances, there may be a different mode of inheritance or the cardiomyopathy may be part of a recognised condition, such as Fabry disease, amyloidosis or Noonan syndrome.
What should you do next?
- It is important to take a careful family history that includes any sudden deaths in the family.
- Patients should be offered referral to a clinical genetics service if they have an affected first-degree relative with an identified pathogenic variant.
- In cases in which no pathogenic variant has been identified but familial cardiomyopathy is suspected, first-degree relatives of affected patients should be referred to cardiology services for screening, including an ECG and an echocardiogram.
- Due to varying degrees of penetrance, signs of cardiomyopathy may be absent on initial screening but develop later in life. Because of this, screening is often offered on an ongoing basis.
- The consensus view of the European Society of Cardiology (see the resources list below) is that children should be referred to paediatric cardiology for clinical screening from around 10 years of age, or earlier if there is a family history of childhood-onset cardiomyopathy. The age from which predictive testing is offered is usually guided by the clinical genetics team.
- If you are discussing genomics concepts with your patients, you may find it helpful to use the visual communication aids for genomics conversations.
Resources
For clinicians
- European Society of Cardiology
- NHS England: National Genomic Test Directory
- Patient Info: Cardiomyopathies
For patients
- British Heart Foundation: Cardiomyopathy