What is heart block?

Heart block is a condition that affects the electrical signals that control your heartbeat. These signals help the upper and lower chambers of the heart work together to pump blood through the body. When the signals move too slowly or become blocked, the heart may beat too slowly or irregularly.

There are several types of heart block. Some are mild and may not cause symptoms, while more serious forms can affect blood flow and require prompt treatment.

Heart block may happen because of age-related changes in the heart’s electrical system or from damage to the heart. Other possible causes and risk factors include:

• Coronary artery disease or previous heart attack
• Cardiomyopathy
• Lyme disease
• Autoimmune or inflammatory conditions
• Congenital heart conditions present at birth
• Electrolyte imbalances such as high potassium
• Certain medications that slow the heart rate
• Heart surgery
• Severe hypothyroidism

Severe heart block can become life-threatening if the heart cannot maintain a steady rhythm.

Symptoms

Heart block can develop gradually or appear suddenly. Some people do not notice symptoms at first, especially with milder forms.

Common symptoms may include:

• Dizziness or lightheadedness
• Fainting
• Fatigue or weakness
• Shortness of breath
• Chest discomfort
• Slow or irregular heartbeat
• Feeling like the heart skips beats

How is it diagnosed?

Your healthcare provider will ask about your symptoms, medical history, medications, and family history of heart disease. A physical exam can help identify signs of an abnormal heart rhythm.

Testing often includes an electrocardiogram (ECG), which records the heart’s electrical activity. Some people may also need a portable monitor worn at home to track heart rhythms over time. In certain cases, additional testing such as an electrophysiology study may be recommended to evaluate how electrical signals move through the heart.

How is it treated?

Treatment depends on the type and severity of heart block. Mild cases without symptoms may only need regular monitoring.

When treatment is needed, care may include:

• Adjusting medications that affect heart rhythm
• Treating related medical conditions
• Monitoring the heart with follow-up testing
• Implanting a pacemaker to help maintain a healthy heartbeat

A pacemaker is commonly used for more advanced heart block. This small device helps regulate the heart’s rhythm and can improve symptoms such as fatigue, dizziness, and fainting.

Many people are able to return to normal daily activities with proper treatment and ongoing care.