Long QT syndrome (LQTS)is a cardiac disorder that may lead to ventricular arrythmias and
culminate in syncope and/or possible death.
Recently, researchers have developed a way of discovering patients with LQTS by using low
doses of epinephrine by a continuous, intravenous infusion in adults. Epinephrine, or
adrenaline, is produced by our bodies in times of stress. By producing adrenaline, your body
allows itself to adapt to its stressful environment and take appropriate actions (i.e. fight
or flight response). By simulating this response with very small amounts of epinephrine,
researchers have shown prolongation of the QT interval does not occur in normal healthy
adults. However, adults with confirmed LQTS Type 1 (LQTS-1) will prolong their QT interval
when given low dose epinephrine. Therefore, this test can act as a safe means of identifying
adults with LQTS-1 who do not have prolonged QT intervals on their resting EKGs.
However, LQTS is not just a disease of adults, it affects children as well. Currently the
standard of care is to obtain resting EKGs on our pediatric patients which can miss those
patients with concealed LQTS. Those patients, who are old enough, can undergo exercise
testing. Yet this leaves young children unable to run on a treadmill without a diagnostic
Hypothesis: The low-dose epinephrine infusion stress test does not cause prolongation of the
QT interval in an electrophysiologically normal healthy pediatric population.
This study will involve asking fifty children coming to the hospital for their standard of
care procedure to treat a separate cardiac condition to participate. Patients approached will
already have an intravenous line in place for their procedure. After consent and assent as
necessary are obtained, the patient be brought to a separate room for the low-dose
epinephrine infusion trial. The patient will lie down on a table, be hooked up to an EKG
machine and the infusion will start. The amount of epinephrine actually infused is based on
the weight of the patient but is substantially less than the dose received from an
epinephrine auto-injection for anaphylaxis. After about 40 minutes, the trial will be
completed and the patient may return to the waiting room for their original procedure. We
have performed this test on a number of pediatric patients suspected of having LQTS with
promising results and with little to no side effects. The patient will be awake for the
procedure and will be able to verbalize concerns or complaints. A pediatric
electrophysiologist and nurse will be present throughout the entire procedure.
The purpose of this study is to determine if children who are infused with low amounts of
epinephrine will also maintain their normal QT interval as it does with healthy adults. This
study would hope to prove that low-dose epinephrine infusion trials can serve as a way of
identifying children with LQTS so that they may be effectively treated and potentially have
their lives saved.
1. Patients ages 3-18 years
2. Patients undergoing device closure of an atrial septal defect in the cardiac
3. normal electrocardiogram without prolonged absolute or corrected QT interval(less than
1. Patients with a history of any other structural or acquired heart disease besides the
atrial septal defect.
2. Patient with a family history of sudden cardiac death, or personal history of syncope.
3. Patient on alpha or beta-blocking medications.