Lexiscan / Lexiscan / Persantine / Adenosine nuclear stress test
Stress testing is used usually to determine if there is a problem with blood supply to an area of the heart (coronary artery blockage).
This test is more involved and gives more information (location, extent of blockages) than the EKG-only based standard treadmill exercise stress test. It is also more sensitive and specific (fewer false results) than the EKG-only based test.
As there is actually no physical stress to the heart with this test, it allows us to test higher risk people.
People with certain baseline EKG changes or implanted devices (pacemakers/defibrillators) may require this test over an exercise format.
Since there is no physical stress with this test, patients with physical limitations may undergo testing in this fashion.
Occasionally, this test is ordered for other reasons (such as in a work-up of arrhythmias).
Variable, usually a total of 2-3 hours. Most of the test time is spent imaging the heart with cameras and allowing time for the injected materials to distribute in the body.
An intravenous catheter will be placed, and you will be administered a very small dose of a nuclear agent (the amount of radiation is very safe). This will then distribute throughout the body, and a set of "rest" heart images will be taken with a special camera.
During imaging, you will be laying down on a table. The camera spins around your chest; however your head will not be in a confined area (for those that are claustrophobic). Imaging lasts approximately 20 minutes.
A second "distribution" time will then take place where you may be seated in the waiting area for 45 minutes.
The "non-exercise" portion will then begin. You will be connected to a special EKG machine and then a medication will be infused. At the time of peak effect of the medication, a second injection of the nuclear agent is given, and a second "stress" set of images is taken following another "distribution" time period.
If you are or may be pregnant, you must tell the technician.
Although you will not be required to exercise, a slow walk is sometimes performed (if you are able). We suggest you wear comfortable clothes. Any comfortable shoe may be acceptable.
You may have a light meal before the test; however caffeinated drinks (coffee, tea or caffeinated soda) must be avoided (preferably for a period of 36-48 hours before the test).
Yes, unless specifically advised not to do so by your doctor. If you are on any specific asthma medications, please bring in the prescription bottle or inhaler with you.