Types of cardiomyopathy

A diagram summarizing the overall classification of cardiomyopathies (Source: Singh et al., 2012).
HCM - hypertrophic cardiomyopathy; DCM - dilated cardiomyopathy; ARVC - arrhythmogenic right ventricular cardiomyopathy; RCM - restrictive cardiomyopathy.

Dilated cardiomyopathy

In dilated cardiomyopathy, the muscle walls of the heart have become stretched and thin, so they can't contract (squeeze) properly to pump blood around the body.

How serious is it?

If you have dilated cardiomyopathy, you're at greater risk of heart failure, where the heart fails to pump enough blood around the body at the right pressure.

Heart failure typically causes shortness of breath, extreme tiredness, and ankle swelling. Learn more about the symptoms of heart failure.

There's also a risk of heart valve problems, an irregular heartbeat, and blood clots. You'll need to have regular appointments with your GP so the disease can be monitored.

Who's affected?

Dilated cardiomyopathy can affect both children and adults.

The heart muscle can become stretched if you have an unhealthy lifestyle or an underlying medical condition, or both. The following can all play a role in the disease:

  • uncontrolled high blood pressure
  • an unhealthy lifestyle such as a lack of vitamins and minerals in the diet, heavy drinking, and recreational drug use
  • a viral infection that causes inflammation of the heart muscle
  • a heart valve problem
  • a disease of the body tissues or vessels such as Wegener's granulomatosis, sarcoidosis, amyloidosis, lupus, polyarteritis nodosa, vasculitis or muscular dystrophy
  • inheriting a mutated (changed) gene that makes you more vulnerable to the disease
  • pregnancy cardiomyopathy can sometimes develop as a complication of pregnancy

But for many people, the cause is unknown.


Hypertrophic cardiomyopathy


In hypertrophic cardiomyopathy, the heart muscle cells have enlarged and the walls of the heart chambers thicken.

The chambers are reduced in size so they can't hold much blood, and the walls can't relax properly and may stiffen.

How serious is it?

Most people with hypertrophic cardiomyopathy will be able to live a full, normal life. Some people don't even have symptoms and don't need treatment.

But that doesn't mean the condition can't be serious. Hypertrophic cardiomyopathy is the most common cause of sudden unexpected death in childhood and in young athletes.

The main heart chambers can become stiff, leading to back pressure on the smaller collecting chambers. This can sometimes worsen the symptoms of heart failure and lead to abnormal heart rhythms (atrial fibrillation).

Blood flow from the heart may become reduced or restricted (known as obstructive hypertrophic cardiomyopathy).

Also, the mitral heart valve can become leaky, causing blood to leak backward. Most people inherit the disease from their parents.


Restrictive cardiomyopathy

Restrictive cardiomyopathy is rare and mostly affects older adults. The walls of the main heart chambers become stiffened and rigid and can't relax properly after contracting. This means the heart can't fill up properly with blood.

It results in reduced blood flow from the heart and can lead to symptoms of heart failure, such as breathlessness, tiredness and ankle swelling, as well as heart rhythm problems.

In many cases, the cause is unknown, although sometimes it can be inherited.


Arrhythmogenic right ventricular cardiomyopathy

In arrhythmogenic right ventricular cardiomyopathy (ARVC), the proteins that normally hold the heart muscle cells together are abnormal. Muscle cells can die and the dead muscle tissue is replaced with fatty and fibrous tissue.

The walls of the main heart chambers become thin and stretched, and can't pump blood around the body properly.

People with ARVC typically have heart rhythm problems. Reduced blood flow from the heart can also lead to symptoms of heart failure.

ARVC is an uncommon inherited condition caused by a mutation (change) in one or more genes. It can affect teenagers or young adults and has been the reason for some sudden unexplained deaths in young athletes.

There's increasing evidence that prolonged, strenuous exercise worsens the symptoms of ARVC. It's important that people with or at risk of ARVC have a careful discussion about this with their cardiologist.


Bhulan Kumar Singh, Krishna Kolappa Pillai, Kanchan Kohli and Syed Ehtaishamul Haque (2012). Classification and Definitions of Cardiomyopathies, Cardiomyopathies - From Basic Research to Clinical Management, Prof. Josef Veselka (Ed.), ISBN: 978-953-307-834-2, InTech, Available from http://www.intechopen.com/books/cardiomyopathies-from-basic-research-to-clinicalmanagement/classification-and-definitions-of-cardiomyopathies


Medically Reviewed by a doctor on 19 Apr 2018
Medical Author: Dr. med. Diana Hysi