Obstructive hypertrophic cardiomyopathy (oHCM) is a condition in which the heart muscle becomes thicker than normal over time. This thickening can block or reduce blood flow out of the heart (often from the left ventricle, the main pumping chamber).

It’s common for people living with oHCM to not notice any symptoms at all. When symptoms do happen, they are often due to the heart working harder than usual to pump blood through the narrowed pathway.

What Causes Symptoms in oHCM?

The obstructive type of HCM causes the heart muscle to thicken in the septum (the wall between the two lower chambers of the heart, called the ventricles). This thickening can narrow or block the pathway that blood uses to leave the heart.

When this happens, oxygen-rich blood may not flow as easily from the heart to the rest of the body as it should. When your organs don’t get enough oxygen, the body tries to make up for it, and you may notice symptoms.

It’s common for people with oHCM to not notice any symptoms at all. When symptoms occur, it’s because the thickened heart muscle has to work harder to pump blood.

Many of the most noticeable symptoms of oHCM are linked to reduced blood flow and lower oxygen delivery throughout the body.

Another type of HCM, called nonobstructive HCM or nHCM, occurs when the heart muscle thickens in other areas of the heart that do not block blood flow leaving the heart.

5 Symptoms of Obstructive Hypertrophic Cardiomyopathy

Although oHCM doesn’t always cause symptoms, some people may experience them, especially during physical activity or as the condition progresses.

1. Shortness of Breath

The most common symptom of oHCM is shortness of breath, often during exercise. When your body’s tissues don’t get enough oxygen-rich blood from the heart, your body may signal your lungs to breathe faster to try to bring in more oxygen.

Shortness of breath with oHCM may be worse during physical activity and while lying down. With obstructive HCM, reduced blood flow out of the heart can increase pressure in the heart and lungs, leading to congestion (fluid buildup) in or around the lungs. This can make breathing harder.

2. Chest Pain

Chest pain can feel like pressure or squeezing in your chest. It can spread to your shoulders, arms, or back.

Chest pain happens when your heart muscle isn’t getting enough oxygen-rich blood. According to the American Heart Association, it’s important to have a healthcare professional evaluate any chest pain.

Chest pain can be a sign of a life-threatening heart problem. If you have new, severe, or ongoing chest pain, seek emergency medical care right away.

Chest pain can be a sign of a life-threatening heart problem. If you have new, severe, or ongoing chest pain, seek emergency medical care right away.

To identify the cause of your chest pain, your healthcare team will likely ask you about your family history and recommend some testing, such as:

• Electrocardiogram (ECG) — A test that records the heart’s electrical activity
• Echocardiogram — An ultrasound (sound wave test) of the heart
• Stress test — A test that measures how the heart works during physical activity
• Cardiac magnetic resonance (CMR) — A detailed MRI scan of the heart

Chest pain during exercise or physical activity with oHCM can happen because the heart needs more oxygen, but narrowed blood flow makes it harder to meet that demand.

3. Lightheadedness or Fainting

Feeling lightheaded and fainting can be signs of oHCM, especially during exertion. These symptoms may happen when the brain doesn’t get enough blood flow, sometimes due to reduced blood flow out of the heart.

Unexplained fainting can be related to a rare and life-threatening complication of oHCM, especially in younger people. Seek medical care right away if you faint without a clear reason.

4. Heart Palpitations

If your heartbeat feels or sounds unusual, this could be a sign of oHCM. A fast, pounding, fluttering, or irregular heartbeat is called a palpitation. Abnormal heart rhythms can be life-threatening.

People with oHCM may experience palpitations because the thickened heart muscle can disrupt the heart’s normal electrical signals (which control the heartbeat). It can also occur because oHCM may cause disorganization within the heart cells that disrupts the heartbeat.

Some rare but serious abnormal heart rhythms, such as ventricular tachycardia and ventricular fibrillation, can cause very fast or chaotic heartbeats. These irregular heart rhythms can be life-threatening and require emergency treatment.

5. Fatigue

Feeling very tired can be a sign of oHCM. When your muscles and organs don’t get enough oxygen-rich blood, you may feel tired and low on energy, even if you’ve had enough sleep.

Other Signs of HCM To Know

In addition to the five symptoms above, people living with oHCM may notice other signs that could point to a heart problem.

One example is a heart murmur, a “whooshing” or “swishing” sound that a healthcare provider may hear using a stethoscope. A murmur doesn’t always cause noticeable symptoms on its own, but it can be a clue that blood is not flowing normally through the heart.

Other symptoms of HCM may include swelling in the legs, ankles, hands, or feet (called edema, or fluid buildup) and enlarged neck veins, which can happen when pressure builds up in the blood vessels.

These symptoms can happen when the heart is under extra strain or when reduced blood flow begins to affect other parts of the body.

What Age Do oHCM Symptoms Occur?

Many people with oHCM never develop symptoms at all. For others, symptoms may begin during the teen years or early adulthood, but they can start at any age.

Symptoms don’t always stay the same over time. In some people, they may worsen gradually. In others, they can change more quickly. Some people may go long periods with few or no changes in symptoms.

Symptoms are often more noticeable when the heart is under extra stress. Common triggers can include:

• Engaging in physical activity
• Being dehydrated
• Eating a heavy meal

These situations can make it harder for the heart to maintain steady blood flow, which may make symptoms more noticeable.

When To Talk to Your Doctor

Seek urgent or emergency medical attention if you experience:

• Chest pain
• Unexplained fainting
• Severe shortness of breath
• A fast or irregular heartbeat that doesn’t stop
• Symptoms that come on suddenly or feel severe

If you notice these symptoms, it’s important to talk with a healthcare professional. Even mild symptoms can be worth mentioning, especially if they’re new or happening more often.

A healthcare professional can help determine whether oHCM or another heart condition is causing your symptoms. Getting symptoms checked early can help you understand what’s going on and may help lower the risk of serious complications.

Pay Attention to Your Symptoms

Obstructive hypertrophic cardiomyopathy can be hard to recognize because many people may not have symptoms at first. But when symptoms do happen, they often reflect the heart working harder to move blood through a narrowed pathway out of the heart.

Paying attention to new, changing, or worsening symptoms can help you know when to seek medical advice and when you may need urgent medical care.

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What symptoms, if any, did you have with oHCM? Let others know in the comments below.