Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the leading cause of heart-related sudden death in people under the age of 40. According to the HCM Association website, publications from the 2000’s indicate that HCM is the most common of all genetic heart conditions affecting over 1 in 500 people in the general population. Based on these data we may estimate that between 700K and 725K people in the United States have HCM. Symptoms may be mild, and many times are dismissed as attributable to other conditions. An ECG (electrocardiogram) can identify this condition 90% of the time. Once detected, either through an ECG or a physical exam, an echocardiogram can confirm HCM.

Hypertrophic cardiomyopathy is a thickening of the heart muscle walls, making it more difficult to pump blood effectively.  While many people can have this condition but never experience symptoms and never even know they have it, for some, it is severely life-threatening. In HCM,  the cells which make up the heart are not aligned normally; this abnormality is called “myocardial disarray”. This disarray is usually not present in 100% of the heart muscle but affects it in patches.

It is theorized this patchy “disarray” is what interferes with the electrical impulses of the heart, causing abnormal heart rhythms (arrhythmia), which may lead to sudden cardiac arrest during times of physical exertion. This occurs most publicly among young male athletes, with basketball and soccer players leading the list. There are countless news stories about seemingly healthy individuals suddenly collapsing on the court or field. Around 14% of the time, autopsies reveal hypertrophic cardiomyopathy is the culprit – a condition which could have been identified with a routine ECG. In some cases, athletes are able to be revived through CPR and early defibrillation with an automated external defibrillator (AED), making the case not only for CPR training of anyone in a sports leadership position (athletic trainers, coaches, umpires, referees), but better access to AEDs, and more thorough prescreening procedures to identify those athletes at risk as well.

Hypertrophic cardiomyopathy does not have to be a death sentence. Knowing you have the condition is the best defense against an unexpected event. Most people with the condition live normal, active lives. It definitely does not mean you should not exercise at all. In fact, not exercising is detrimental to your overall health and may lead to obesity and other health concerns which could impact your heart such as high cholesterol and high blood pressure. However, high-impact and competitive sports are not recommended.

Treatments for HCM vary depending on the severity of the condition in individual patients. One of the most effective treatments for identified high-risk HCM patients is an implantable defibrillator which will administer a shock any time it senses the heart has gone into a shockable rhythm, ventricular fibrillation or ventricular tachycardia. Medications prescribed for HCM are designed to treat symptoms of the condition, rather than the condition itself for which there is no cure. Beta-blockers and calcium channel blockers help the heart contract and relax and may be prescribed to relieve pain in the chest and shortness of breath during exercise. Blood thinners are sometimes prescribed to reduce the risk of blood clots (if there is an arrhythmia present due to atrial fibrillation).   

Occasionally, circumstances or other conditions prevent patients from taking medications or receiving an implantable defibrillator.  In these instances, surgery may be an option. When blood flow out of the heart is severely blocked, symptoms can become severe. An operation called surgical myectomy may be done where a portion of the thickened heart muscle wall is removed to allow better blood flow. In other cases, patients may be given an injection of alcohol into the arteries which feed the thickened part of the heart (alcohol septal ablation). The bulging wall shrinks, allowing for better blood flow. People who have this procedure often show much improvement.

Since hypertrophic cardiomyopathy is genetic, it is recommended people with an immediate family (parents, siblings, children) history of sudden cardiac death be evaluated by their physician if they have exhibited any of the following symptoms (from the Cleveland Clinic website):

• Chest pain or pressure that usually occurs with exercise or physical activity, but also may occur with rest or after meals.
• Shortness of breath and fatigue, especially with exertion. These symptoms are more common in adults with hypertrophic cardiomyopathy and are most likely caused by a backup of pressure in the left atrium and lungs.
• Syncope (fainting or passing out) may affect HCM patients. Syncope with HCM may be caused by irregular heart rhythms, abnormal responses of the blood vessels during exercise, or no cause may be found.
• Palpitations (fluttering in the chest) due to abnormal heart rhythms (arrhythmias) such as atrial fibrillation or ventricular tachycardia. Atrial fibrillation occurs in about 25 percent of those with HCM and increases the risk for blood clots and heart failure.

There may be no cure for HCM, but understanding the implications of living with this condition are critical to survival for those who have it.