Dexmedetomidine Versus Adenosine: Electrophysiologic Effects and Therapeutic Use for Terminating Supraventricular Tachycardia

In 2006 the investigator found that dexmedetomidine, an alpha-2 adrenergic agonist with
primarily sedative properties, possesses additional anti-arrhythmic properties. So far the
investigator has found that dexmedetomidine has the ability to prevent or terminate
arrhythmias like atrial ectopic tachycardia (85% success) and junctional ectopic tachycardia
(75% success). The most dramatic effect however was observed in the acute termination of
reentrant SVT with a success rate of > 96%. More importantly we found that dexmedetomidine
terminates SVT without causing any sinus pause or asystole (frequently seen with adenosine)
and thus avoiding the feeling of "impending doom". In this study adenosine is being compared
head to head with dexmedetomidine in a cross over study, for both safety and efficacy when
given for the termination of SVT in the electrophysiology (EP) lab. Additional EP parameters
will be measured to elucidate the exact site of dexmedetomidine's mechanism of action.

Inclusion Criteria:

- Patients between the age of 5 - 30 years old, who are scheduled for cardiac
electrophysiology study for evaluation of reentrant SVT

Exclusion Criteria:

- Severe Heart Failure

- Presence of of any other antiarrhythmic medication within 24 hours of enrollment

- Third degree heart block

- Sick Sinus Syndrome