Hypertrophic cardiomyopathy (HCM) is a heart condition in which the heart muscle in the left ventricle (LV) — the lower left chamber of the heart — becomes thickened and stiff. This makes it difficult for the heart to pump blood properly. Apical HCM is a specific type of HCM that affects the apex (bottom point) of the LV.

What Is Apical Hypertrophic Cardiomyopathy?

HCM is an umbrella term for conditions that cause hypertrophy (thickening) of the left ventricle wall. The most common type of HCM is asymmetric septal (also called classic HCM), which is diagnosed when the interventricular septum (wall that separates the two ventricles of the heart) becomes thickened. Apical HCM is diagnosed when the apex of the LV becomes thickened.

Apical HCM represents about 3 percent of all cases of HCM in the United States. Researchers have found that apical HCM is more common among certain ethnic groups: It’s most common in Japan, according to the Journal of Community Hospital Internal Medicine Perspectives, affecting around 15 percent of all people there who are living with HCM. It also occurs in around 25 percent of HCM cases in Asians and up to 10 percent of cases in non-Asians, according to the Journal of the American Heart Association. The journal notes that the condition affects men more often than women. The average age at diagnosis is around 46 years old.

There are three types of apical HCM:

• Pure apical HCM is diagnosed when there is thickening only in the apex.
• Mixed apical HCM has thickening in both the apex and the septum. Even though thickening occurs in both areas, there’s usually more seen in the apex.
• Relative apical HCM is diagnosed when a person doesn’t meet all of the criteria for proper diagnosis but has some features. Researchers believe that relative apical HCM is an early form of the disease.

Classic HCM has a strong genetic component, meaning that family members who have it are likely to pass it on. First-degree relatives (parents to their children) have a 50 percent chance of passing on HCM. However, studies show that apical HCM is less likely to be passed on in families. Only 13 percent to 25 percent of apical HCM cases are caused by known gene mutations, according to the Journal of the American Heart Association.

Compared to classic HCM, apical HCM is associated with more cases of atrial fibrillation (AFib). This condition occurs when the atria (top chambers of the heart) beat rapidly and irregularly, which increases the chance of blood clots. Apical HCM is also associated with more strokes — both from apical aneurysms and from AFib.

Symptoms of Apical Hypertrophic Cardiomyopathy

The symptoms of apical HCM often overlap with those of other heart conditions, which can make diagnosis difficult. Many people with the condition aren’t diagnosed until a few years after their symptoms begin.

Common signs and symptoms of apical HCM include:

• Angina (chest pain)
• Dyspnea (trouble breathing)
• AFib
• Syncope (passing out or fainting)
• Heart palpitations (fluttering or pounding heartbeat)
• Difficulty exercising or performing strenuous activities

In some cases, stroke, heart attack, or congestive heart failure are the first noticeable signs of apical HCM that lead to a diagnosis.

How Is Apical Hypertrophic Cardiomyopathy Diagnosed?

Apical HCM is diagnosed using a few different imaging techniques that help your cardiologist take a closer look at your heart. They may also use electrocardiography to measure your heart’s rhythm. There is no one test used to diagnose apical HCM — instead, doctors use findings from all three tests to make a final diagnosis.

Echocardiogram

Echocardiogram tests use ultrasound waves to create live images of the heart. The sound waves bounce off of the heart’s structures and tissues and are read by a hand-held wand, called a transducer, that turns them into images.

Cardiologists may choose to use either a transthoracic echocardiogram (TTE) or a transesophageal echocardiogram (TEE) to look at your heart. TTE takes pictures using a transducer placed over your chest. In some cases, your ribs or lungs may block the ability to get clear images. When this happens, you may have a TEE, which uses an endoscope, which is a long thin tube with a transducer attached to the end that’s inserted down your throat.

Cardiologists use echocardiography to look for abnormalities in your heart, including thickening of the ventricular wall at the apex. Apical HCM is diagnosed when the thickness of the LV wall is greater than 15 millimeters.

A specific type of echocardiography, known as Doppler echocardiography, can also be used to measure the blood flow through the heart. For people with HCM, cardiologists use the Doppler technique to check the difference in pressure between the bottom of the heart and the top with blood, where blood flows through the aortic valve into the body. This can let them know if you’re at risk for other complications. These include irregular heartbeats in the ventricles and thromboembolism — blockage of blood vessels with blood clots.

Cardiac MRI

Cardiac magnetic resonance imaging (MRI) is another imaging technique used to take highly detailed pictures of your heart. MRIs use strong magnets and radio waves to generate images of the muscles, valves, and chambers in your heart. Cardiac MRIs have an advantage over echocardiograms in that they can show the entire LV and apex, helping your cardiologist look for LV thickening. One study found that echocardiograms missed 40 percent of apical HCM cases that were later diagnosed with cardiac MRIs.

Before a cardiac MRI, you may have a contrast agent injected into your blood via IV line. This helps your heart stand out in images. Gadolinium is a common contrast agent used, and it can help cardiologists look for fibrosis (scar tissue) in the heart. In people with apical HCM, fibrosis can cause arrhythmias (irregular heartbeat) and may lead to the development of heart failure.

Electrocardiogram

During an electrocardiogram (ECG), patches containing electrodes are stuck to your skin to measure your heart’s electrical activity. Specifically, ECGs measure your heart’s rate and rhythm to find any abnormalities that point to a heart condition.

ECGs read your heart’s rhythm through electrical signals as the different parts of the heart contract (squeeze) and relax. This creates a distinct pattern, or tracing, on the electrocardiogram that lets your cardiologist know how well your heart is functioning.

One function read during an ECG is a T wave. A T wave shows the heart’s ventricles repolarizing — that is, preparing to beat again after a contraction. One study found that more than 90 percent of people with apical HCM have abnormal T waves.

Talk to Your Doctor About Apical Hypertrophic Cardiomyopathy

If you notice any symptoms of apical HCM, talk to your doctor or cardiologist. They’ll likely run some imaging tests and perform an ECG to look for any abnormalities and rule out other heart conditions.

Once you receive a diagnosis, your doctor will work with you to develop a treatment plan. Many treatments for apical HCM are also used for classic HCM, including beta-blockers and calcium channel blockers. If you have AFib, your doctor may also prescribe blood thinners to help prevent blood clots.

In some cases, people with apical HCM undergo surgery to remove some thickened muscle from the heart. This is known as a myectomy, and studies show that it can improve symptoms in people with apical HCM. An alcohol ablation may also be performed to help reduce thickening in the LV. During this procedure, a long thin tube known as a catheter is inserted into a blood vessel in the groin, which travels up to an artery that supplies the heart with oxygen. Alcohol is injected through the catheter, which ultimately kills some of the thickened heart tissue and replaces it with scar tissue to thin it out. Generally, this procedure is limited to people with a mixed form of HCM.

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