Hypertrophic cardiomyopathy is a condition in which the heart muscle is unusually thick. This can affect the amount of blood pumped to the body and cause heart rhythm problems.
Key points
In hypertrophic cardiomyopathy, the muscle in the heart is unusually thick, affecting its ability to pump blood to the body.
This condition is usually genetic and passed through families.
Doctors may recommend an implantable cardioverter defibrillator (ICD) to treat this condition when the heart thickness reaches a certain size.
Introduction
Normal left heart function1) Oxygenated blood is pumped into the left atrium from the lungs. The atrium contracts (pumps), pushing blood into the left ventricle. 2) The ventricles contract. 3) This contraction pumps the oxygenated blood out of the left ventricle and into the aorta. The aorta delivers oxygenated blood to the rest of the body. Deoxygenated blood is pumped into the pulmonary artery, to be taken to the lungs.Hypertrophic cardiomyopathy1) In hypertrophic cardiomyopathy, the muscle in the heart is unusually thick. This can reduce the size of the left ventricle or make the walls of the ventricle stiffer. 2) The left ventricle is unable to fill with as much blood as it normally would. 3) The thick heart muscle can block the blood from leaving the heart. 4) This may result in higher pressure in the left atrium and less blood flow to the rest of the body.
For patients with hypertrophic cardiomyopathy (HCM), the muscle in the heart, usually in
the ventricles, is unusually thick. This is known as hypertrophy. The thicker muscle can reduce the size of the left ventricle or make the walls of the ventricle stiffer, which affects the ability of the heart to fill and pump blood effectively to the body and/or the lungs. The altered arrangement of muscle fibres from the thickened muscle can cause abnormal heart rhythms (arrhythmias), which are potentially fatal. HCM can develop at any age.
HCM is less common in babies and children and more often diagnosed during adolescence. It occurs in 1 in every 500 people.
More information
What is cardiomyopathy
Cardiomyopathy is a disorder affecting the heart muscle. The heart may have a normal structure but there are problems in the way it develops or functions. Cardiomyopathy usually results in the heart being unable to pump properly, also known as
heart failure.
Cardiomyopathy can be caused by a number of factors, including infections, conditions affecting the body’s metabolism and genetics.
There are several different types of cardiomyopathy. The four main types of cardiomyopathy are:
Some people with HCM may not experience any symptoms for a long time.
Causes, risk factors and prevalence
What causes HCM in babies and children?
HCM can occur spontaneously; however in most cases, the cause is genetic, meaning it is passed along through families. For this reason, it is usually recommended that anyone who is a first-degree relative (parent, sibling or child) of someone with HCM have a cardiac evaluation, even if they do not have any health concerns or heart-related symptoms.
Treatment
Treatment of HCM
Implantable cardiac defibrillators (ICD) are recommended when the heart thickness reaches a certain size, even if your child does not have abnormal heart rhythms (arrhythmias). ICDs may reduce the risk of significant arrhythmias in certain types of HCM patients.
Many children will be on beta blocker medicine, a type of medicine that is used to slow the heart rate and ease the workload of the heart. On rare occasions, this condition may require a heart transplant.
Complications
Complications of HCM in children
Scar tissue in hypertrophic cardiomyopathyIn some cases, fibrous (scar) tissue can replace the healthy heart muscle. This can result in abnormal heart rhythms (arrhythmias).
HCM has been associated with sudden cardiac events in children and adolescents, often due to either the blockage of blood getting out of the heart or an
abnormally fast heart rhythm (arrhythmia). HCM is one of the most common causes of sudden death in young athletes.
Arrhythmias have been seen in up to 30-40% of patients with HCM. Ongoing research shows this may be related to the healthy, normal heart muscle (myocardium) being replaced by abnormal or scar tissue called myocardial fibrosis.
Infants with HCM may also have an underlying metabolic condition that may involve muscle groups or organs other than the heart.
