How Is Heart Block Diagnosed?

Heart block may be diagnosed as part of a routine doctor's visit or during an emergency situation (third-degree heart block is an emergency).

Your doctor will diagnose heart block based on your family and medical histories, a physical exam, and results from tests.

Specialists Involved

Your primary care doctor may be involved in diagnosing heart block. However, if you have the condition, you may need to see a heart specialist. Heart specialists include:

• Cardiologists (doctors who treat adults with heart problems)
• Pediatric cardiologists (doctors who treat babies and youths with heart problems)
• Electrophysiologists (cardiologists or pediatric cardiologists who specialize in the heart's electrical system)

Family and Medical Histories

To find out your family and medical histories, your doctor may ask whether:

• You have any signs or symptoms of heart block
• You have any health problems, such as heart disease
• Any of your family members have been diagnosed with heart block or other health problems
• You're taking any medicines, including herbal remedies and prescription and over-the-counter medicines
• You smoke or use alcohol and drugs

Your doctor also may ask about other health habits, such as how much physical activity you do.

Physical Exam

During the physical exam, your doctor will listen to your heart's rhythm. He or she will listen carefully for abnormal rhythms or heart murmurs (extra or unusual sounds heard during heartbeats).

Your doctor also may:

• Check your pulse to find out how fast your heart is beating
• Check for swelling in your legs or feet, which could be a sign of an enlarged heart or heart failure
• Look for signs of other diseases that could be causing a problem with the heart's rate or rhythm (such as coronary artery disease)

Diagnostic Tests and Procedures

EKG (Electrocardiogram)

Doctors usually use a test called an EKG (electrocardiogram) to help diagnose heart block. This simple test detects and records the heart’s electrical activity. It shows how fast the heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through each part of the heart.

The data is recorded on a graph. Different types of heart block have different patterns on the graph. (For more information, see “Types of Heart Block.”)

A standard EKG test only records the heart’s activity for a few seconds.

Holter and Event Monitors

To diagnose first- or second-degree heart block, your doctor may have you wear a Holter or event monitor.

Holter and event monitors are similar to EKGs, but they're portable devices. You can wear a Holter or event monitor while you do your normal daily activities. This allows the device to record your heart's electrical activity for a longer time than an EKG.

Electrophysiology Study

For some cases of heart block, doctors may do electrophysiology studies (EPS). During an EPS, a thin, flexible wire is passed through a vein in your groin (upper thigh) or arm to your heart. The wire records your heart's electrical signals.

Other Tests

To diagnose heart block, your doctor may need to do tests to rule out other types of arrhythmias (irregular heartbeats). For more information, see "How Are Arrhythmias Diagnosed?"