Analysis of Adenosine on Sinus and Atrioventricular Nodal Conduction in the Pediatric Transplanted Heart
Status:
Completed
Trial end date:
2017-07-01
Target enrollment:
Participant gender:
Summary
Heart transplants save the lives of nearly 500 children in heart failure per year. Columbia
is one of the largest pediatric heart transplant centers in the world, averaging 25
transplants per year, and providing ongoing care to nearly 250 children with transplanted
hearts. After transplant, children are at increased risk to develop sudden onset of
abnormally fast heart rates. This research project will study adenosine, a medication that is
routinely used to slow fast heart rates in non-transplanted children (i.e. normal hearts),
and its effects on the transplanted heart. Adenosine is often not used in patients with
transplanted hearts because, based on prior limited research in adult patients, the standard
adult dose may have a longer medication effect, producing a slower heart rate for an
undesirable period of time. However, the current alternatives to adenosine treatment are
either inappropriate for the pediatric age range, or have increased risk of unwanted side
effects. This research project will answer two questions: is adenosine safe to give a child
who has had a heart transplant, and will it be effective in treating the fast heart rate?
All pediatric heart transplant patients undergo regular heart testing, known as a cardiac
catheterization, one or more times per year. Three days before testing, participants will be
asked to stop a regular medication, dipyridamole, because it slows the breakdown of adenosine
in the body, and may increase its effects. (Of note, all patients that are on dipyridamole
are also on aspirin, which gives a second line of heart protection, and will not be stopped.)
After regular cardiac catheterization, all patients will already have intravenous (IV) access
to give medication. Also, this setting allows the opportunity to have a back-up pacing
catheter in the heart, ensuring that there will not be a longer than desired effect from the
medication. Adenosine will be given per a low-dose protocol until either the medication
effect is seen or the maximum dose is reached. There will be no difference in procedure
recovery period time, and patients will resume regular home medications after finishing the
test. As Columbia is one of largest pediatric heart transplant centers in the world, studying
the effects of adenosine at low doses will benefit the investigators population greatly,
either to find a new recommended medication dose, or to provide evidence that this medication
is truly inadvisable for the investigators patients.
The initial study was completed with all 80 patients enrolled and tested. Subsequent testing
is now ongoing on patients in whom dipyridamole was stopped prior to their initial testing
with a repeat study without discontinuing the dipyridamole. We anticipate re-testing about 30
of the 80 patients.