Three main types of cardiomyopathy are recognised:

Dilated cardiomyopathy (DCM): The left ventricle of the heart becomes enlarged and its ability to pump enough blood diminishes. The common measure of heart function called as Left Ventricular Ejection Fraction (EF) reduces in such cases.

Hypertrophic cardiomyopathy (HCM): Abnormal thickening of the heart muscles particularly affecting the left ventricle – the heart’s main pumping chamber, that is not related to hypertension or valve disease. Most affected patients have a family history of the disease, and some genetic mutations are common in them. It can develop at any age, but the condition tends to be more severe if it becomes apparent during childhood.

Restrictive cardiomyopathy (RCM): The least common type and can arise when the heart muscle becomes stiff and less elastic causing difficulty in relaxation and filling with blood between heartbeats. It is often seen in elderly people.

The other less common varieties of cardiomyopathies are :

Arrhythmogenic Right Ventricular Dysplasia (ARVD)

Peripartum Cardiomyopathy (Occurs in relation to pregnancy)

Chemotherapy induced cardiomyopathy

Unclassified cardiomyopathy: Other types of cardiomyopathy fall into this category.

Symptoms:

In the early stages there may be no symptoms and cardiomyopathies are sometimes detected on routine testing. But as the condition advances, the following may be seen:

• Breathlessness on exertion or later at rest
• Fatigue
• Swelling of the feet, ankles and legs
• Loss of appetite and bloating of the abdomen
• Cough while lying down
• Palpitations of the heart
• Chest discomfort or pressure
• Dizziness, light-headedness, and fainting.

Causes:

Cause of cardiomyopathy is often unknown. Genetic abnormalities, heart muscle damage from a previous heart attack, chronic irregular or rapid heart rate, high blood pressure, diabetes, heart valve issues, chronic alcoholism, obesity, thyroid disorders, amyloidosis (disorder that causes abnormal proteins accumulation) and rarely towards the end of pregnancy.

Diagnosis and treatment:

The following tests may be performed to confirm the disease:

• Electrocardiogram
• Chest X-ray
• Echocardiogram
• Cardiac Magnetic Resonance Imaging (cMRI)
• Cardiac catheterization and/or Coronary angiography. A cardiac biopsy may be performed in rare cases. 
• Blood tests to check the iron levels, liver, thyroid and kidney functions.
• Genetic screening may also be conducted occasionally.

Treatment:

Medications to alleviate symptoms, delay the progression of heart failure and to  improve the heart functioning are prescribed. Management of high blood pressure, diabetes and obesity is advised.

In some cases of DCM, devices such as Biventricular pacemakers, Implantable Defibrillators (ICD), Ventricular Assist Devices (VADs) etc are suggested. Patients who are severely ill are considered for cardiac transplantation.

In Hypertrophic cardiomyopathy medicines to improve symptoms are initially advised. The risk of mortality including sudden cardiac death is assessed using family history, echocardiography, heart rhythms monitors and genetic testing. Implantable cardioverter-defibrillator (ICD) and interventions such as Alcohol Septal ablation, Septal myectomy, Mitral valve replacement and Dual Chamber pacemakers are other treatment options in select cases.

Restrictive Cardiomyopathies are mainly treated symptomatically.