His bundle electrography is a test that measures electrical activity in a part of the heart that carry the signals that control the time between heartbeats (contractions).

The bundle of His is a group of fibers that carry electrical impulses through the center of the heart. If these signals are blocked, you will have problems with your heartbeat.

The His bundle electrography is part of an electrophysiology (EP) study. You are given a mild sedative before the test. An intravenous catheter (IV line) is inserted into your arm, so that you can be given medicines during the test.

Electrocardiogram (ECG) leads are placed on your arms and legs. Your arm, neck, or groin while be cleaned and numbed with a local anesthetic. After the area is numb, the cardiologist makes a small cut in a vein and inserts a thin tube called a catheter inside.

The catheter is carefully moved through the vein up into the heart. An x-ray method called fluoroscopy helps guide the doctor to the right place. During the test, your heartbeat is watched for any arrhythmias. The catheter has a sensor on the end, which is used to measure the electrical activity of the bundle of His.

You will be told not to eat or drink anything for 6 to 8 hours before the test. The test will be done in a hospital. Some patients may need to check into the hospital the night before the test. Otherwise, you check in the morning of the test.

Your health care provider will explain the procedure and its risks. You must sign a consent form before the test starts.

About half an hour before the procedure, you will be given a mild sedative to help you relax. You will wear a hospital gown. The procedure may last from 1 to several hours.

You are awake during the test. You may feel some discomfort when the IV is placed into your arm, and some pressure at the site when the catheter is inserted.

This test may be done to:

• Determine if you need a pacemaker or other treatment
• Diagnose arrhythmias
• Find the specific location where electrical signals through the heart are blocked

The time between electrical signals from the bundle of His are evenly spaced.

A pacemaker will be needed if the test results are abnormal.

Abnormal results may mean you have or had:

• Chronic conduction system disease
• Carotid sinus pressure
• Recent heart attack
• Atrial disease

Risks of the procedure include:

• Arrhythmias
• Cardiac tamponade
• Embolism from blood clots at the tip of the catheter
• Heart attack
• Hemorrhage
• Infection
• Injury to the vein or artery
• Low blood pressure
• Stroke

Miller JM. Diagnosis of Cardiac Arrhythmias. In: Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 8th ed. St. Louis, Mo; WB Saunders; 2007: chap. 32.

Rakel RE. Textbook of Family Practice. 6th ed. Philadelphia, Pa: WB Saunders; 2005:733.