Developments in the treatment of inherited cardiac conditions

Inherited cardiac conditions such as heart muscle or rhythm problems may be well known within families or only discovered after a family member dies unexpectedly. These diseases affect people of all ages and ethnicities, says consultant cardiologist Dr Elijah Behr of Mayo Clinic Healthcare. Improvements in cardiac imaging and ECG technology and the development of genetic screening and genetic counselling are helping doctors and families work together to identify and manage the conditions.

“An inherited cardiac condition is a disease affecting the heart that is caused by genetic problems. These are misspellings of the genetic code, known as DNA, and are often called mutations,” Dr Behr says. “Mutations can be inherited from parents or, if it is a sporadic mutation, occur for the first time in a specific family member.”

Those who carry the mutation may be at risk from complications of heart disease, including heart rhythm problems, heart failure and strokes. Many people will not have symptoms, but some may experience palpitations, blackouts, breathlessness or chest pain. “If a family member has died suddenly and unexpectedly at a young age, it is possible that genetic heart disease is the cause. This means that other family members may be at risk,” Dr Behr continues. “Expert evaluation of cases of sudden death and family members is an important way to try to prevent further deaths.”

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Major types of heart conditions that may be genetic include:

— Cardiomyopathies: heart muscle diseases such as hypertrophic cardiomyopathy, heart muscle thickening that makes it harder for the heart to pump blood; dilated cardiomyopathy, where an enlarged left ventricle prevents effective pumping of blood; and arrhythmogenic cardiomyopathy, where replacement of the right and sometimes left ventricle by scar and fat tissue leads to heart rhythm problems.

— Channelopathies or arrhythmias: diseases of the heart’s electrical function that can cause fast, chaotic heartbeats, leading to blackouts and cardiac arrest. Those include long QT syndrome, Brugada syndrome, and early repolarisation syndrome; catecholaminergic polymorphic ventricular tachycardia (CPVT), which can cause a dangerously fast heart rhythm during exercise; and idiopathic ventricular fibrillation.

— Premature coronary artery disease usually caused by high cholesterol levels due to problems with how the body processes cholesterol, known as familial hypercholesterolemia.

— Unexpected sudden deaths, known as sudden arrhythmic death syndrome (SADS), which are often caused by genetic conditions, especially in young people.

Mayo Clinic Healthcare in London is now providing services to detect and treat inherited cardiac conditions, including advanced imaging and electrocardiography (ECG) and genetic testing. Patients will have an initial interview with a cardiac genetic nurse or counsellor followed by a focused evaluation by the cardiologist. Tests can be arranged for a day prior to the doctor’s assessment and at the patient’s convenience.

Genetic counselling is an important part of the care on offer. Genetic counsellors help families understand genetic testing and its implications. Sometimes family members come to the clinic together for testing and counselling.  “Sometimes there can be a taboo or anxiety around discussing inherited medical conditions within families,” Dr Behr says. “Genetic counsellors help break these barriers by having that conversation.”