Heart Block | Symptoms, Risks, Tests & Treatments | MedStar Health

Discover the symptoms of this electrical problem of the heart and who may be at risk

Heart block, also known as atrioventricular (AV) block, is a partial or total blockage of the electrical signal that controls the heartbeat. This blockage prevents the signal from reaching the ventricles, the heart’s two lower chambers. Heart block is a form of bradycardia, a slower-than-normal heartbeat.

If you have heart block, you may need treatment to manage the condition. Our electrophysiology program provides advanced therapies for heart block and other complex heart conditions.

What are the symptoms of heart block?

You may not notice symptoms in mild cases. For more severe cases, heart block can cause the following symptoms:

  • Chest pain

  • Dizziness

  • Fainting

  • Fatigue

  • Trouble breathing

Get medical help right away if you notice these symptoms.

Who is at risk for heart block?

Heart block may be present at birth and is known as  congenital heart disease. However, most people develop heart block because of another heart condition or treatment, such as:


Diagnosing heart block is the first step to developing a treatment plan. Our specialists may recommend one or more diagnostic and imaging procedures.


An echocardiogram uses high-frequency sound waves to create images of your heart.

Electrocardiogram (ECG)

An electrocardiogram, also known as an ECG, measures the heart’s electrical activity.

Electrophysiology Testing

Electrophysiology testing is used to evaluate the cause and location of an abnormal heartbeat (known as an arrhythmia).

Event Monitors

An event monitor is a small device that records the heart’s electrical activity. It’s similar to an electrocardiogram, but where an electrocardiogram takes place over a few minutes, an event monitor measures heart rhythms over a much longer time.

Holter monitors

A Holter monitor is a small device that records the heart’s electrical activity. It’s similar to an electrocardiogram, but whereas an electrocardiogram records over a few minutes, a Holter monitor records over the course of a day or two.

Loop recorder

A loop recorder is a device that’s implanted underneath the skin of your chest to record your heart rhythm for up to three years.

Stress Tests

Stress tests are used to assess how your heart works during physical activity. There are several types of stress tests, including treadmill or bike stress tests, nuclear stress tests, stress echocardiograms, and chemically induced stress tests.

Tilt table test

Tilt table testing allows your doctor to determine the cause of explained fainting while monitoring changes in your blood pressure and heart rate while tilted at different angles.


A pacemaker is a device that helps control various types of heart rhythm disorders.

Additional information

Electrophysiology program

We are leaders in developing and using the latest procedures and technologies to treat heart rhythm disorders, and our cardiac electrophysiology laboratory is one of the most sophisticated in North America.

Ask MedStar Heart & Vascular Institute

Have general questions for our heart and vascular program? Email us at AskMHVI@medstar.net. If you have clinically-specific questions, please contact your physician’s office.