Adenosine challenge
Why do I need an adenosine challenge?
Your doctor recommends an adenosine challenge because they suspect you have an accessory pathway. This is an extra electrical connection between the heart's top chambers (atria) and bottom chambers (ventricles).
Accessory pathways are congenital, meaning they are present from birth. The adenosine challenge is a widely used test that uses a drug called adenosine to reveal the characteristic ECG (heart tracing) changes associated with an accessory pathway. This test confirms whether or not an accessory pathway is present.
It's crucial to identify an accessory pathway as it can lead to potentially life-threatening heart rhythm disturbances (arrhythmias), for which curative treatments exist.
What is an adenosine challenge?
Adenosine is a naturally occurring substance found in small quantities in all cells. Doctors routinely use it to diagnose and treat abnormal heart rhythms. In this test, adenosine temporarily blocks the normal electrical signal between the heart's top and bottom chambers to reveal any accessory pathways. During the test, you may feel dizzy, breathless, and discomfort in your chest, but these symptoms should only last for a few seconds.
Pregnancy
If you are pregnant or suspect you might be, please call the Cardiac Catheter Lab on 020 8321 2618. We will need to perform a pregnancy test when you arrive for the procedure.
Eating and drinking
Avoid all caffeine products—like tea, coffee, cola, chocolate—for 24 hours before your test.
Coming in to hospital
Please arrive promptly at the time stated in your letter. Upon your arrival, a nurse will conduct a few tests to prepare you for your adenosine challenge.
A doctor will also meet with you to explain the procedure in detail and ask you to sign a consent form. This is to ensure you understand the procedure and its associated risks. Don't hesitate to ask any questions or express any concerns you may have. It's important to inform your nurse or doctor if you have any allergies or have had adverse reactions to drugs or other tests in the past.
We strive to avoid delays, but sometimes they are unavoidable. As the hospital's only catheter suite, emergencies can result in delays to your case. We will do our best to keep you updated and are always willing to discuss any concerns you may have.
During the procedure
During the test, your doctor will administer adenosine through a cannula in a vein in your arm and continuously record your ECG. It's common to experience a metallic taste in your mouth during the administration of the adenosine. Adenosine can cause your heart to go into a slow rhythm, which may temporarily cause dizziness, visual disturbances, such as double vision, breathlessness, or chest discomfort.
These side effects only last for a few seconds and resolve quickly once the infusion is completed. The entire test typically takes less than a minute.
After the procedure
After the test, we will take you back to the day ward, where you can eat and drink when you feel ready.
Your doctor will explain the results of your test once it's completed. Since adenosine is a very short-acting drug and its effects last only a few seconds, you should be able to go home an hour after the test.
When can I resume my normal activities?
You can resume your normal daily activities (walking, bathing, showering etc) and return to work upon discharge from hospital.
Risks of the procedure
The adenosine challenge is safe and complications associated with this procedure are very rare. However, if you are asthmatic, please tell your doctor as adenosine may trigger an asthma attack. Rarely, adenosine administration can cause heart rhythm disorders.
Feel free to ask your doctor about any of these complications. Remember, the benefits of a procedure always outweigh the potential risks.
Contact details
Cardiac Catheter Lab: 020 8321 2618 (Mon–Fri, 8am to 6pm)
Syon 1 Ward: 020 8321 5130