What is Hypertrophic Cardiomyopathy?

With Hypertrophic cardiomyopathy the heart muscle is thickened (hypertrophied) with no obvious cause. It is a disorder of the heart muscles. The heart muscle cells appear disorganized and irregular resulting in thickening of the heart muscle walls. The thickening typically occurs in the left ventricle and ventricular septum (the muscular wall that separates the right and left ventricles. It is largely genetic or inherited from a family member who has the same condition.

Left ventricular hypertrophy (LVH) or thickening of the heart muscle walls in the left ventricle because of elevated blood pressure, athlete’s heart, aortic stenosis, coarctation of the aorta or any left-sided obstruction is NOT the same as hypertrophic cardiomyopathy.

Effects and Symptoms

Thickening of the heart muscle in the left ventricle can make the left ventricle stiff and can make it hard for the heart to flow through the heart, and difficult for the heart to fully relax. This can lead to backup of blood in the left atrium and congestion in the lungs, causing fatigue and shortness of breath in severe forms. Thickening in certain areas can also cause obstruction in blood flow to the aorta and the rest of the body. This kind of obstruction, when severe, can cause symptoms during exercise. Children can feel dizzy or light-headed, experience chest pain, palpitations or fainting.

The irregular heart muscle cells can interfere with the normal electrical conduction in the heart leading to abnormal heart rhythms called ventricular tachycardia. It is important for anyone with HCM to be followed by a cardiologist with experience in caring for individuals with HCM.

Diagnosis

Children and adolescents are diagnosed with Hypertrophic Cardiology when they are referred to a cardiologist for symptoms of congestive heart failure, such as fast breathing and a fast heart rate or abnormal heart sounds.  A person may be asked to see a cardiologist if they have a parent or a sibling who was diagnosed with cardiomyopathy. 

Tests that help with diagnosis are: 

• A chest xray can show an enlarged heart. 
• An ECG or Holter monitor will check the heart rhythm.
• An echocardiogram can show the areas and degree of thickness of the ventricular walls, the presence of obstruction at rest and the presence of any associated heart defects. 
• Exercise stress tests and stress echocardiograms can demonstrate the presence of obstruction and/or capture any ECG changes during exercise.
• A cardiac MRI and/or cardiac catheterization can aid management choices and is helpful for monitoring purposes.

Genetic testing is recommended for all children and adolescents who are clinically diagnosed with HCM and all first degree relatives of confirmed cases.

Management and Treatment

Management of HCM can be challenging with different causes and degrees of obstruction, abnormal heart rhythms and symptoms. Patients with HCM and their families are treated by a team of experts that work together to provide the advice that is tailored to individual needs. Medications can be prescribed to help with symptoms of obstruction and advice on exercise and activity will also be provided.

In severe cases of obstruction, a surgical procedure called a septal myectomy can be performed to remove part of the heart muscle that causes the obstruction. An implantable cardioverter-defibrillator (ICD) is recommended to prevent sudden cardiac death in cardiac arrest survivors and patients who are at high risk for cardiac arrest. However, undergoing surgery or ICD implantation is associated with risks and complications. Cases are managed on an individual basis. Careful assessment and family discussion are needed in the evaluation for these procedures.

Because of the risk of sudden cardiac arrest, it is recommended that family members of people with HCM take CPR courses so they are able to respond if their loved one should have an episode at home. Ideally, sports events and exercise are supervised with AED (Automated External Defibrillator) and CPR-trained companions present in case of a cardiac arrest.

Adult and Adolescent Management

Lifelong follow up with a cardiologist is needed for clinical evaluation and regular imaging tests.

There is a possibility of an individual with HCM to genetically pass on this condition to his/her children. 

Women of child-bearing years are advised to consult with their cardiologist when they have plans of getting pregnant. Normal changes that occur during pregnancy can cause a worsening of obstruction HCM. Women who have symptoms before pregnancy and have moderate-severe obstruction are advised against pregnancy due to the increased risk of complications for them and their baby.