His electrogram

Alternative names
His bundle electrography

Definition
His bundle electrography is a test that measures electrical activity in a part of the heart known as the bundle of His. The bundle of His is a group of fibers that carry an electrical impulse through the center of the heart to ensure the sequence of the heart’s contractions.

How the test is performed

His bundle electrography is part of an electrophysiology (EP) study. You are given a mild sedative prior to the test. An intravenous catheter (IV line) is started in your arm to allow for the administration of medication during the procedure.

Electrocardiogram (ECG) leads are placed on your extremities. A cardiologist inserts a catheter through a small incision in a vein in your arm, neck, or groin after cleansing the site and numbing it with a local anesthetic.

The catheter is then carefully threaded into the heart using an x-ray image technique called fluoroscopy to guide the insertion. Your heart is monitored by ECG for arrhythmias during catheter placement.

The catheter, which is equipped with an electrode, then measures the electrical activity of the bundle of His.

How to prepare for the test

Food and fluid are restricted 6 to 8 hours before the test. The procedure takes place in a hospital. Sometimes you enter the hospital the night before the test. Otherwise, you enter as an outpatient or inpatient the morning of the procedure. Your health care provider will explain the procedure and its risks.

His bundle electrography requires witnessed, signed consent prior to the procedure.

About half an hour before the procedure, you receive a mild sedative. The procedure may last from 1 to several hours. You must wear hospital clothing.

For infants and children:
The preparation you can provide for this test depends on your child’s age and experience. For specific information regarding how you can prepare your child, see the following topics:

     
  • Infant test/procedure preparation (birth to 1 year)  
  • Toddler test/procedure preparation (1 to 3 years)  
  • Preschooler test/procedure preparation (3 to 6 years)  
  • Schoolage test/procedure preparation (6 to 12 years)  
  • Adolescent test/procedure preparation (12 to 18 years)

How the test will feel

During the test, you are awake and able to follow instructions. An incision is made into a vein in your arm, neck, or groin for threading the catheter into the heart. Local anesthesia is given to insert the catheter, so the only sensation is one of pressure at the site.

Discomfort may arise from having to remain still for a prolonged period of time.

Why the test is performed

This test may be performed for the following reasons:

     
  • To find the specific location of a block in the electrical conduction through the heart  
  • To determine if there is a need for pacemaker placement or implementation of a medication regimen  
  • To diagnose dysrhythmias

Normal Values
Conduction intervals that are appropriately spaced.

What abnormal results mean

Abnormal results may indicate:

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

What the risks are

Risks of the procedure are cardiac arrhythmias, Cardiac tamponade, trauma to the vein or artery, low blood pressure, infection, embolism from blood clots at the tip of the catheter, hemorrhage, stroke, and heart attack.

Johns Hopkins patient information

Last revised: December 3, 2012
by Gevorg A. Poghosian, Ph.D.

Medical Encyclopedia

  A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | 0-9

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.