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Your heart is a powerful pump that sends blood to every part of your body. In hypertrophic cardiomyopathy (HCM), the muscle of the left ventricle (the heart’s lower left chamber) becomes thicker and stiffer than normal. This makes it harder for the heart to relax and pump blood the way it should.
Apical HCM is a type of HCM that affects the apex, or bottom tip, of the left ventricle.
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 known as classic HCM. This type of HCM is diagnosed when the interventricular septum (the wall that separates the heart’s two ventricles) thickens.
Apical HCM is diagnosed when the apex of the left ventricle becomes thicker than normal. The apex is the very bottom tip of the heart, on the left side. You can think of it as the pointed end of a cone.
Apical HCM accounts for about 3 percent of all cases of HCM in the United States. It’s more common in certain ethnic groups, especially among people of Japanese descent. In Japan, around 15 percent of all people with HCM have apical HCM.
Apical HCM also happens in around 25 percent of HCM cases in Asian populations and up to 10 percent of cases in non-Asian populations, according to a study published in the Journal of the American Heart Association. Researchers also note that the condition is more common in men than in women. The average age at diagnosis is around 41 years old.
There are three main types of apical HCM:
Family history is a known risk factor for HCM, meaning that family members who have it are likely to pass it on. First-degree relatives (children of biological parents) have a 50 percent chance of inheriting the genetic risk for classic 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 higher cases of atrial fibrillation (AFib). This condition happens when the atria (top chambers of the heart) beat rapidly and irregularly, which increases the chance of blood clots. Apical HCM is also linked to a higher risk of stroke — both from apical aneurysms and from AFib. Despite these risks, overall survival tends to be higher than with some other forms of HCM.
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:
In some cases, stroke, heart attack, or congestive heart failure is the first clear sign of apical HCM that leads to a diagnosis.
Apical HCM is diagnosed using a few imaging techniques that help your cardiologist take a closer look at your heart. Your doctor might also use electrocardiography to measure your heart rhythm. No one test is used to diagnose apical HCM — instead, doctors use findings from several tests to make a final diagnosis.
Echocardiogram tests use ultrasound waves to create live images of the heart. These sound waves bounce off the heart’s structures and tissues. A hand-held wand, called a transducer, reads the waves and turns them into images.
Cardiologists may use one of two types of echocardiograms to look at your heart: a transthoracic echocardiogram (TTE) or a transesophageal echocardiogram (TEE). A TTE takes pictures using a transducer placed over your chest. Sometimes, the ribs or lungs can make the images hard to see. When this happens, a TEE may be used. This test uses an ultrasound probe placed gently into the esophagus to get clearer images.
Cardiologists use echocardiography to look for heart abnormalities, including thickening of the ventricular wall at the apex. Doctors don’t rely on just one number to diagnose apical HCM. Many use about 15 millimeters as a guide or compare the tip of the heart with the back wall. Even if the measurement is a little lower, the heart may still have apical HCM if the tip clearly looks thicker and has the usual shape.
A specific type of echocardiogram, called Doppler echocardiography, measures how fast blood moves through the heart. It can also show if there is a pressure buildup (a “gradient”) inside the left ventricle. This helps doctors check for a blockage in the pathway of the heart or, sometimes, in the middle of the ventricle. Apical HCM often has no blockage, but Doppler still helps guide care.
Cardiac MRI is another imaging technique for taking highly detailed pictures of your heart. MRIs use strong magnets and radio waves to generate images of your heart’s muscles, valves, and chambers.
Cardiac MRIs have an advantage over echocardiograms in that they can show the entire left ventricle and apex. This helps your cardiologist look for left ventricle 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 receive a contrast agent injected into your blood via an IV line. This helps your heart stand out more in the images. Gadolinium is a common contrast agent. It can also help cardiologists look for fibrosis (scar tissue) in the heart. In people with apical HCM, fibrosis can cause arrhythmias (irregular heartbeat) and may increase the risk of heart failure.
During an electrocardiogram (ECG), small patches with electrodes are placed on your skin to measure your heart’s electrical activity. Specifically, ECGs measure your heart’s rate and rhythm to look for any abnormalities that point to a heart condition.
ECGs read your heart rhythm through electrical signals as different parts of the heart contract (squeeze) and relax. This creates a pattern, called a tracing, on the electrocardiogram that lets your cardiologist know how well your heart is working.
One important part of the ECG is the T wave. The T wave shows the heart’s ventricles repolarizing, or resetting, to prepare for the next beat. One study found that more than 90 percent of people with apical HCM have abnormal T waves.
If you notice any symptoms of apical HCM, talk to your doctor or cardiologist. They may 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 cardiology team will work with you to develop a treatment plan. Many treatments for apical HCM are also used for classic HCM. These include beta-blockers and calcium channel blockers. If you have AFib or an apical aneurysm, your doctor may use blood thinners to help prevent clots.
Most people with apical HCM aren’t candidates for surgical or alcohol septal ablation because the septum usually isn’t involved in the disease. Your cardiologist will be able to explain the best options to manage your condition.
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Good article. Thank you
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