Obstructive vs. Nonobstructive Hypertrophic Cardiomyopathy (HCM): What Your Diagnosis Means for Treatment and Lifestyle

If you or a loved one has recently been diagnosed with hypertrophic cardiomyopathy (HCM), you may have questions about what it means for your health and how to manage the condition. Understanding whether your HCM is obstructive or nonobstructive can offer some more specific answers.

“The distinction matters for symptoms, risk assessment, and treatment decisions,” says Kevin Shah, MD, a board-certified cardiologist and program director of heart failure outreach at MemorialCare Heart and Vascular Institute at Long Beach Medical Center in Long Beach, California.

Explore what features set obstructive and nonobstructive HCM apart, the symptoms they can cause, and what it all means for your treatment plan.

• Obstructive HCM Parts of the heart wall block or limit blood flow from the left ventricle to the aorta, the artery that carries freshly oxygenated blood to other parts of the body. Two-thirds of people with HCM have the obstructive type.
• Nonobstructive HCM The heart wall is thickened, but blood flow out of the heart isn’t blocked.

Knowing which type of HCM you have is important, since both need to be treated and managed differently. “Ideally, every patient with hypertrophic cardiomyopathy should be told whether it’s obstructive or nonobstructive,” says Karishma Patwa, MD, a board-certified cardiologist at Manhattan Cardiology in New York City.

If your cardiologist hasn’t told you, it’s worth asking. If they’re unsure — obstructions aren’t always detectable in tests when you’re at rest — they can conduct additional tests, such as an exercise stress test, to confirm whether you have an obstruction, says Dr. Patwa.

• Chest pain
• Dizziness
• Fatigue
• Heart palpitations
• Lightheadedness or fainting
• Shortness of breath

You may be more likely to have these symptoms if you have obstructive HCM, especially when you’re dehydrated or physically active, says Dr. Shah. “Nonobstructive HCM can still cause symptoms, but they may be more subtle or gradual,” he says.

There’s no cure for HCM, but treatment can help you feel your best and reduce your risk of complications.

“In obstructive HCM, treatment focuses on reducing the outflow obstruction and calming excessive contraction of the heart,” says Shah. “In nonobstructive HCM, treatment is more focused on managing stiffness, rhythm issues, and symptoms rather than relieving obstruction. The underlying goals overlap, but the strategies differ.”

• Septal Ablation This procedure involves injecting alcohol into the thickened part of the heart in an effort to shrink it, and placing a catheter in an artery to maintain blood supply to that area of the heart.
• Septal Myectomy This open-heart surgery involves removing a thickened part of the heart wall to improve blood flow out of the heart.

Each treatment option comes with benefits and risks, so consult your doctor to determine which one may be best for you.

You may need to adjust your lifestyle when you have HCM, particularly if you have the obstructive type.

“Anything that reduces your cardiac output — the volume of blood your heart can pump per minute — can worsen obstructive HCM,” says Patwa. To manage your symptoms and reduce your risk of complications, Patwa and Shah say you may need to:

• Avoid getting overheated
• Drink plenty of fluids to prevent dehydration
• Exercise caution if you take medications like diuretics or vasodilators (your healthcare provider will monitor you closely if they prescribe them)

Healthy habits matter, too. While they won’t necessarily improve HCM, eating a heart-healthy diet and getting regular exercise can help you feel your best overall and reduce your risk of other heart problems like heart disease, says Shah.

• Hypertrophic cardiomyopathy (HCM) is classified as either obstructive (when blood flow in the heart is partially blocked) or nonobstructive (when the heart is stiff but blood flow isn’t blocked).
• While both types share symptoms like chest pain, fatigue, and shortness of breath, obstructive HCM is more common, and symptoms are often more severe during physical activity or when you’re dehydrated.
• Treatment for obstructive HCM focuses on relieving the physical blockage through specialized medications or surgical procedures. Nonobstructive HCM treatment focuses primarily on managing heart stiffness and rhythm issues.
• Lifestyle management for both types involves staying hydrated, avoiding overheating, and engaging in doctor-approved, low-impact exercise to protect heart health and prevent complications.