What Is Heart Block, and Does It Mean You Need a Pacemaker?

What happens in heart block?

Heart block happens when the electrical system of the heart slows down. Normally, the electrical signal that controls the heartbeat travels from the atria (upper chambers of the heart) to the ventricles (lower chambers of the heart) through a cluster of electrical cells called the AV node. 

In heart block, the electrical signal either slows or stops completely as it passes through the AV node. As a result, the heart beats more slowly and can even skip heartbeats, making it more difficult for the heart to effectively pump blood out to the lungs and the rest of the body.

Heart block can start out as mild, where the heart is still able to pump blood effectively around the body. As heart block becomes more severe, it can lead to life-threatening complications, such as:

• Arrhythmia: This is an irregular heart rhythm.

• Heart failure: This occurs when the heart does not pump effectively.

• Sudden cardiac death: This occurs when the heart suddenly stops beating.

Who gets heart block? 

Heart block can be caused by underlying heart problems and some medical conditions. Some people can be born with heart block. 

You are more likely to get heart block as you get older. You are also at higher risk for heart block if you have: 

• Underlying heart disease, such as coronary artery disease or heart valve disease

• Recently had a heart procedure or open heart surgery

• A genetic condition that causes heart block 

• A rheumatologic disease, such as lupus, sarcoidosis, or Lyme disease

• Electrolyte imbalances, such as high or low levels of potassium, or calcium

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Can medications cause heart block?

Yes. Some medications can slow down the electrical impulses of the heart; they can lead to, or worsen, heart block. These include:

• Digoxin: This is used for certain arrhythmias and heart failure.

• Beta blockers: These include metoprolol, atenolol, and sotalol.

• Calcium channel blockers: These include verapamil and diltiazem. 

If you develop heart block while you are taking these medications, your healthcare provider will likely lower the doses or stop them altogether.

Types of heart block

There are three types of heart block, depending on how slow the electrical signal is:

1. First-degree heart block: This occurs when the electrical signal is slow but no heartbeats are blocked.

2. Second-degree heart block: This occurs when some electrical signals are blocked between the atria and the ventricles, leading to skipped heartbeats. When second-degree heart block becomes worse, it can lead to third-degree heart block.

3. Third-degree heart block: This is also called complete heart block. It occurs when the electrical signal between the atria and the ventricles is completely blocked. This can result in serious symptoms, such as passing out and chest pain. 

What are the symptoms of heart block?

Many people who have heart block, particularly mild heart block, do not have any obvious symptoms. Signs or symptoms may include: 

• Dizziness

• Fainting

• Chest pain

• Shortness of breath

• Fatigue

• Palpitations, which are the feeling of being aware of your own heartbeat

Signs that you need emergency care for heart block

If you have been told you have heart block and you develop any of the following symptoms, you should seek immediate medical attention:

• Dizziness or passing out

• Chest pain 

• Shortness of breath

• Swollen legs and feet

Getting a diagnosis of heart block

Usually, heart block is diagnosed on an electrocardiogram, or EKG. An EKG is a test that records your heart’s electrical activity. It can determine if the electrical signals are moving properly through your heart. Based on the EKG, the symptoms you have experienced, and a physical examination, your healthcare provider can determine how severe the heart block is. 

Most people with heart block are referred for further evaluation to a cardiologist or an electrophysiologist (a physician who specializes in electrical activity in the heart).

Sometimes, a person may need additional testing to diagnose heart block, such as:

• Holter/Event Monitor: a device worn on the chest wall that monitors the heart rhythm for days or weeks

• Implantable loop recorder: a small device placed under the skin of the chest to monitor heart rhythm for longer periods of time, up to 3 years

• Electrophysiology study: a procedure using catheters in the heart to study the heart’s electrical system

Treatments for heart block

Mild heart block usually does not require treatment, although your healthcare provider may tell you to avoid certain medications that can cause slow conduction. When heart block is severe, most people will require a pacemaker.

Pacemaker implantation

If your healthcare worker thinks your heart block is dangerous and you are at risk for other health problems, they may recommend a pacemaker. A pacemaker is a small device that uses low-energy electrical pulses to control the heartbeat. 

A pacemaker is implanted during a short procedure that involves placing a small battery box under the skin, usually near the left collarbone, and attaching it to a wire that is fed through a blood vessel into the heart. After that, you’ll need regular pacemaker checks with a provider to make sure that the battery and wires are working properly.  

Do all people with heart block need a pacemaker?

No. Usually, only people with severe types of heart block need a pacemaker. Typically, these are people with second-degree heart block and third-degree (also known as complete) heart block.

Can you live a normal life with heart block?

Yes. If you have mild heart block, your physician will review your medications and lifestyle habits and may make recommendations to help prevent the heart block from getting worse. You will need to keep regular doctor’s appointments to monitor your heart block, and you will be able to live a normal, active life. 

If you need a pacemaker, you can still live a normal life, although you will need to get your pacemaker checked regularly, avoid contact sports, and, if you need an MRI, be sure to let technologists know that you have a pacemaker. 

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Written by:

Alice Perlowski, MD, MA, FACC

Dr. Alice Perlowski is a board-certified cardiologist and fellow of the American College of Cardiology. She has seen patients and supervised trainees in the academic and private sector, with focuses in interventional cardiology, vascular medicine, preventative cardiology, and women’s heart health.

Edited by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. An experienced and dedicated pulmonologist and hospitalist, she spent a decade practicing and teaching clinical medicine at academic hospitals throughout London before transitioning to a career in health education and health technology.

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