Heart Block

What Is Heart Block?

Heart block is a condition in which the heart beats too slowly or unsteadily due to a problem with heartbeat signal moving from the upper to lower parts of the heart. Treatment is usually only needed when the condition causes symptoms.

Heart Block Symptoms

Heart block symptoms may include:

• Dizziness
• Chest pain
• Tiredness
• Shortness of breath
• Fainting or feeling like you're about to faint

Symptoms can range from mild to severe depending on the type of heart block and its effect on you.

Types of Heart Block

There are three main types of heart block:

• First-degree: does not typically need treatment.
• Second-degree: sometimes needs treatment.
• Third-degree (complete): often needs treatment, usually a pacemaker.

What Causes Heart Block?

Causes of heart block include:

• Heart attack (myocardial infarction).
• Coronary artery disease.
• Heart muscle disease (cardiomyopathy).
• Heart valve disorders.
• Congenital heart conditions (present at birth).
• Heart damage caused by open heart surgery.
• Scarring in your heart conduction system due to an unknown cause.
• Side effects from certain medications, including beta blockers, digitalis and calcium channel blockers.
• Obstructive sleep apnea.
• Overactive thyroid.
• Lyme disease and other infections.
• Autoimmune diseases.
• Genetic anomalies.
• Exposure to toxins.

Heart Block Diagnosis

To diagnose heart block, your healthcare provider will perform a physical examination, review your personal and family medical history, and ask you questions about your health and lifestyle.

The main test used to diagnose heart block is an electrocardiogram (ECG), which records your heart’s electrical activity on a graph. An ECG can detect slow, fast or otherwise abnormal heart rhythms. In addition, your healthcare provider may ask you to wear a portable ECG for one or two days to monitor your heart.

Other tests that may be used to confirm diagnosis of heart block include:

• Echocardiogram or magnetic resonance imaging (MRI) scan: These imaging tests take pictures of the heart and the nearby blood vessels. In addition to showing the structure of the heart and its valves, these tests can reveal areas of poor blood flow in the heart.
• Exercise stress test: In this test, you walk on a treadmill or pedal a stationary bike while your heart activity is monitored. The test shows how your heart reacts to exercise. Sometimes an echocardiogram is given as part of the test.

Heart Block Treatment

Treatment is determined by the type of heart block you have. First-degree heart block doesn’t usually need treatment.

With second-degree heart block, you may need a pacemaker if symptoms are present or if the heart block is classified as a Mobitz Type II, a subtype of the condition that causes an irregular, slow heartbeat. Implanted beneath the skin near the collarbone through a minor surgery, a pacemaker releases electrical impulses to stimulate the heart when needed to keep it beating regularly. Two wires connect the device to the right side of the heart.

People with third-degree heart block usually need a pacemaker.