Dexmedetomidine and Adenosine: Therapeutic Use for SVT

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.