Cardiomyopathy is a term used to describe heart muscle disease. There are several different types of cardiomyopathy:
Hypertrophic Cardiomyopathy (also called HCM, HOCM or ‘hocum’) is where the walls of the heart, particularly the pumping chamber on the left side (left ventricle) are thicker than normal. This is relatively common, and many people live a full normal life without any symptoms and do not require treatment. Sometimes affected people may experience chest discomfort or pain, especially during some form of activity, shortness of breath, palpitations or dizzy spells and blackouts. A very small proportion of affected people are at risk of dying suddenly. It often but not always runs in families, and can usually be diagnosed by having an ECG(electrocardiogram) and echo (ultrasound scan of the heart). Genetic tests can be useful but only in about 50% of families.
Dilated Cardiomyopathy (also known as DCM) is where the heart is larger than normal, but the walls are usually normal thickness or even slightly thinned. The pump function in the heart is usually less efficient than normal in DCM. This may result in ‘heart failure’, where people experience shortness of breath on exercise or when lying flat, or extreme fatigue. The most common cause is coronary disease or ‘hardening of the arteries’, especially after heart attack(s). Sometimes there is no coronary disease, and the condition may run in families, or may be though to have occurred as a result of a viral infection. It is diagnosed by doing an ECG and echo (ultrasound scan of the heart), although additional tests are often done to look for the cause.
Arrhythmogenic Right Ventricular Cardiomyopathy (also known as ARVC or ARVD) is thought to be a rare condition affecting the right side of the heart more than the left. It often runs in families. It may not cause any symptoms, or can cause palpitations, dizzy spells, blackouts, or in a small proportion of people it can cause heart failure or sudden death. It can be hard to diagnose in its milder form – tests used include ECG, echo, exercise test, heart rhythm monitoring and sometimes MRI scans of the heart.
Restrictive Cardiomyopathy (also known as RCM) is probably a variant of HCM (above), where the heart may only be slightly thicker than normal, but it becomes very stiff, and does not pump normally. This can result in shortness of breath, swelling of the abdomen or tummy due to fluid accumulation, or swelling of the ankles and legs. The diagnosis is usually made on echo (ultrasound of the heart), although additional tests such as MRI scan of the heart may be requested.