Cardiac channelopathies are abnormalities in heart cell proteins that control electrical activity of the heart and thus can cause heart rhythm disturbances.
(See also Overview of Abnormal Heart Rhythms.)
A channelopathy is a defect in one or more of the microscopic channels in the walls of heart cells through which electrolytes such as sodium, potassium, and calcium enter and leave the cells. It is this flow of electrolytes that is responsible for the normal electrical activity of the heart. There are several different types of channels, and a defect in one of them can interfere with the heart's ability to maintain a steady rhythm. The heart may suddenly go too fast or too slow or even stop completely (cardiac arrest).
Channelopathies are usually caused by a disorder in which there is a mutation in one of the genes that determine the make up of heart cell channels. However, some people develop a channelopathy as a complication of certain autoimmune or inflammatory disorders, such as systemic lupus erythematosus or Sjogren syndrome.
Most people who have cardiac channelopathies have no other heart disease, such as a heart attack or a heart valve disorder.
The most common channelopathies cause
Other, more rare cardiac channelopathies include the following:
Short QT syndrome
Early repolarization syndrome
Catecholaminergic polymorphic ventricular tachycardia (CPVT)
Brugada syndrome
Isolated progressive cardiac conduction disease
The electrical defects in the channelopathies sometimes cause ventricular tachycardia, a dangerously rapid heart rhythm, or ventricular fibrillation, in which the heart does not beat at all. Channelopathies are more common than doctors previously thought and may be the cause of about 10% of sudden cardiac deaths.
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Symptoms of Cardiac Channelopathies
Some people never have any symptoms, but many people have fainting because of ventricular tachycardia. Those who have ventricular fibrillation have sudden cardiac arrest.
Symptoms may be triggered by fever, exercise, or some medications, including some medications used to treat abnormal heart rhythms and some antidepressants.
Diagnosis of Cardiac Channelopathies
Electrocardiography
Doctors consider a channelopathy when people or their family members have a history of fainting or cardiac arrest without an obvious cause (such as a known heart problem), especially if the cardiac arrest occurred at a young age.
If doctors suspect a channelopathy, they do electrocardiography (ECG), continuous ambulatory heart monitoring, and usually cardiac stress testing. Genetic testing is sometimes done. If a channelopathy is confirmed, people should have regular follow up with ECG and ambulatory heart monitoring to look for asymptomatic heart rhythm disturbances.
Because channelopathies are usually a genetic disorder, family members of people with a channelopathy are at risk. Close family members should be evaluated by a doctor, including with ECG and ambulatory heart monitoring.
Treatment of Cardiac Channelopathies
Implantable cardioverter-defibrillator
Usually, an implantable cardioverter-defibrillator (ICD), a small device that can detect a dangerously abnormal heart rhythm and deliver a shock to correct it, is used. This procedure is similar to implantation of an artificial pacemaker. Doctors often advise people to avoid things that are known to trigger an abnormal heart rhythm in persons with their specific channelopathy.
More Information
The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.
American Heart Association: Arrhythmia: Information to help people understand their risks of arrhythmias as well as information on diagnosis and treatment
