Everything to Know About Cardiac Muscle Tissue

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Cardiac muscle is found in the walls of the heart. It helps the heart perform its function of pumping blood throughout the body. Cardiac muscle tissue is located in the middle of three layers of the heart, called the myocardium. Problems in the myocardium can cause heart failure and arrhythmias or contribute to sudden cardiac death.

This article discusses the role of muscle tissue in the heart and ways to keep your heart's muscle tissue healthy.

Man holding chest, cardiac muscle tissue of heart

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Heart Tissue Layers

The heart has three layers of tissue:

  • Epicardium: The outermost layer of tissue
  • Myocardium: The middle layer of tissue, made of muscle
  • Endocardium: The tissue lining the inside of the heart and valves

The pericardium is the sac in which the heart sits.

Cardiac Muscle Tissue Function

The heart can be thought of as a pump. It is responsible for pumping blood throughout the body to provide oxygen and nutrients.

The heart's muscle is stimulated by the electrical system of the heart. Specialized pacemaker cells create an electrical signal that causes contraction, or shortening, of the muscle fibers. This muscle contraction is what causes the heart to squeeze and pump out blood.

At a cellular level, heart muscle tissue is made up of bundles or fibers of interconnected muscle cells, called cardiomyocytes. These cells are packed with units called sarcomeres that are made of proteins called actin and myosin. When stimulated, these two proteins slide against each other to result in contraction of the heart.

Types of Muscle Tissue

The body has three types of muscle tissue. All of them share the ability to contract and have important functions. The tissue types are:

  • Skeletal muscle tissue provides the function of body movement. It is under voluntary control.
  • Smooth muscle is found in the digestive tract and in the arteries. It is not under voluntary control.
  • Cardiac muscle is only found in the heart. It is responsible for pumping blood out of the heart.

Conditions That Affect Cardiac Muscle Tissue

Heart muscle problems have many causes.

Cardiomyopathy, or heart muscle weakness, is a general term for problems with the heart muscle. It can be caused by:

  • Genetic mutations
  • Lack of blood flow
  • Autoimmune or inflammatory conditions
  • Vitamin deficiency
  • Damage from toxins

Sometimes the cause is not determined, which is known as idiopathic cardiomyopathy.

Other conditions can affect cardiac muscle tissue. These can cause varying problems, from thickening of the heart muscle to heart failure, arrhythmias, and sudden cardiac death.

Most common causes:

High Blood Pressure and the Heart

Blood pressure is the force that the heart must pump against to eject blood. When blood pressure is high, the heart must work harder. Just like any other muscle, the heart muscle thickens in response to this increased work. This thickened (hypertrophied) heart muscle can lead to problems with heart filling and heart failure. High blood pressure is one of the more common causes of heart failure.

Other possible issues that could affect heart muscle include:

When to See a Healthcare Provider

If you are concerned about cardiomyopathy, you should see a healthcare provider for evaluation. Seek medical attention for symptoms like shortness of breath, exercise intolerance, leg swelling, and fatigue, which are signs of heart failure. Even if you don't have any symptoms, if heart failure runs in your family, you should discuss this with your healthcare provider to determine whether screening or genetic testing is needed.

How to Keep Cardiac Muscle Tissue Healthy

While not all types of cardiomyopathy can be prevented, there are things you can do to help keep your heart muscle as healthy as possible.

Living a healthy lifestyle can help keep the heart's muscle tissue healthy by preventing coronary artery disease, high blood pressure, and diabetes. This includes eating a healthy diet, getting regular physical exercise, maintaining a healthy weight, and avoiding tobacco use.

In addition to living a healthy lifestyle, the following can be done to prevent cardiomyopathy:

  • Controlling blood pressure
  • Controlling cholesterol levels
  • Treating coronary artery disease
  • Avoiding toxins such as drugs and excess alcohol
  • Controlling blood sugar (recent guidelines recommend sodium-glucose cotransporter-2 (SGLT2) inhibitors for those with diabetes and elevated risk of heart disease)

For those diagnosed with cardiomyopathy, several medications have been proven to prevent or reverse the abnormal remodeling that occurs due to heart disease. These include:

  • Certain beta-blockers
  • ACE (angiotensin-converting enzyme) inhibitors
  • Angiotensin receptor blocker/neprilysin inhibitor
  • Aldosterone antagonists
  • SGLT2 inhibitors

Cardiologists (doctors who specialize in heart disease) can prescribe and adjust these medications and provide an individualized treatment plan.


Cardiac muscle tissue is found in the middle of three layers of heart tissue. It enables the heart to pump blood and provide nutrients and oxygen throughout the body. Several things can cause problems with the heart muscle, including ischemic heart disease, heart attack, high blood pressure, and valvular heart disease.

The best ways to prevent cardiomyopathy are to live a healthy lifestyle, control blood pressure, cholesterol, and diabetes, and avoid substances that are known to be toxic to the heart. Those with cardiomyopathy can benefit from effective medications.

A Word From Verywell

The heart is arguably the most important muscle in the body. Keeping cardiac tissue healthy helps the heart function properly and decreases the risk of complications. Knowing your risk and controlling modifiable risk factors such as blood pressure, cholesterol, blood sugar, and smoking are important ways to lower your risk and protect your heart muscle.

Frequently Asked Questions

  • What are the characteristics of cardiac muscle tissue?

    Cardiac muscle tissue is a type of muscle tissue found only in the heart. It appears striated (striped) under a microscope due to the presence of sarcomere units that are responsible for its ability to contract. Heart muscle contracts in response to signals from specialized pacemaker cells located in the heart.

  • Where is cardiac muscle tissue located?

    Cardiac muscle tissue is located in the middle of three layers of the heart, called the myocardium. It is the thickest of the three layers. On its outer surface, the myocardium is surrounded by a thin, protective layer called the pericardium. On its inner surface, it is lined by the endocardium.

  • What is the heart made up of?

    The heart is made up of three layers of tissue. The epicardium is the outer, fibrous layer that lines and protects the heart. The myocardium is the thick muscular layer of tissue. The endocardium lines the inner surface of the heart. The heart also has four valves (aortic, mitral, tricuspid, and pulmonic).

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. American Heart Association. What is heart failure.

  3. Vikhorev PG, Vikhoreva NN. Cardiomyopathies and related changes in contractility of human heart muscleInternational Journal of Molecular Sciences. 2018; 19(8):2234. doi:10.3390/ijms19082234

  4. MedlinePlus. Types of muscle tissue.

  5. Brieler J, Breeden MA, Tucker J. Cardiomyopathy: an overviewAFP. 2017;96(10):640-646.

  6. Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA guideline for the management of heart failure: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2022;145:e895–e1032. doi:10.1161/CIR.0000000000001063

  7. American Heart Association. How to help prevent heart disease at any age.

By Angela Ryan Lee, MD
Angela Ryan Lee, MD, is board-certified in cardiovascular diseases and internal medicine. She is a fellow of the American College of Cardiology and holds board certifications from the American Society of Nuclear Cardiology and the National Board of Echocardiography. She completed undergraduate studies at the University of Virginia with a B.S. in Biology, medical school at Jefferson Medical College, and internal medicine residency and cardiovascular diseases fellowship at the George Washington University Hospital. Her professional interests include preventive cardiology, medical journalism, and health policy.