Cardiomyopathy refers to progressive impairment of the structure and function of the muscular walls of the heart chambers.
There are 3 main types of cardiomyopathy:
Dilated cardiomyopathy, in which the ventricles (the two lower heart chambers) enlarge (dilate)
Hypertrophic cardiomyopathy, in which the walls of the ventricles thicken and become stiff
Restrictive cardiomyopathy, in which the walls of the ventricles become stiff but not necessarily thickened
Any dilated or hypertrophic cardiomyopathy (see Overview of Cardiomyopathy) can cause changes in the heart that can lead to different abnormal heart rhythms (arrhythmias), including excessively slow or fast rhythms and sudden death (cardiac arrest). Certain cardiomyopathies are particularly likely to cause arrhythmias. These are referred to as arrhythmogenic cardiomyopathies, and include
Arrhythmogenic right ventricular cardiomyopathy
Lamin A/C cardiomyopathy
Non-compaction cardiomyopathy
Cardiac sarcoidosis
Some of these disorders have genetic causes, which are typically inherited mutations.
The symptoms of the arrhythmogenic cardiomyopathies include symptoms of heart failure itself, along with those of a too slow or too rapid heart beat. Heart failure manifestations include shortness of breath during exertion, excessive fatigue, difficulty breathing while lying flat (orthopnea), and/or swelling of the legs and feet. Abnormal heart rhythms may cause palpitations, light-headedness, fainting, cardiac arrest, and sudden death.
Evaluation typically includes family history, electrocardiography (ECG), chest x-ray, echocardiography, and magnetic resonance imaging (MRI) of the heart. Sometimes, doctors need other tests, including exercise testing, ambulatory electrocardiographic monitoring, chest computed tomography (CT), electrophysiologic testing, coronary angiography, and/or biopsy of the heart. Genetic testing is usually done when a genetic cause is suspected.
Close relatives of people with an arrhythmogenic cardiomyopathy may be at risk and should be examined by a doctor to look for evidence of heart disease. Relatives may need certain tests as well.
Treatment depends on the cause of the cardiomyopathy and the specific rhythm disturbance, but treatment typically includes standard treatments for heart failure, antiarrhythmic medications, and sometimes an implantable cardioverter-defibrillator (ICD).
