Dexmedetomidine and Adenosine: Therapeutic Use for SVT

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

The purpose of this study is to evaluate the efficacy and safety of dexmedetomidine in the acute termination of Supraventricular Tachycardia (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.

Stepwise incremental approach of adenosine starting at 0.2 mg/kg (max 6 mg) followed by 0.3 mg/kg (max 12 mg) if initial dose was unsuccessful

Evaluation of the number of participants with sinus pause > 2.5 sec, after dexmedetomidine vs. adenosine induced SVT termination

Number of participants with tachyarrhythmias, including Ventricular (Ventricular Tachycardia & Fibrillation)and supraventricular (Atrial Flutter & Fibrillation) after dexmedetomidine vs. adenosine administration

Number of Participants With Hypotension by Non-invasive Cuff in First 10 Minutes After Medication Administration

Blood pressure changes after dexmedetomidine vs. adenosine. Blood pressure measured by non-invasive cuff prior to medication administration, and then at 1 min, 3 min, 5 min after medication administration. Number of participants with a significant drop in blood pressure (mmHg) compared to baseline would be counted for hypotension.

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

Chrysostomou C, Beerman L, Shiderly D, Berry D, Morell VO, Munoz R. Dexmedetomidine: a novel drug for the treatment of atrial and junctional tachyarrhythmias during the perioperative period for congenital cardiac surgery: a preliminary study. Anesth Analg. 2008 Nov;107(5):1514-22. doi: 10.1213/ane.0b013e318186499c.

Chrysostomou C, Sanchez-de-Toledo J, Wearden P, Jooste EH, Lichtenstein SE, Callahan PM, Suresh T, O'Malley E, Shiderly D, Haney J, Yoshida M, Orr R, Munoz R, Morell VO. Perioperative use of dexmedetomidine is associated with decreased incidence of ventricular and supraventricular tachyarrhythmias after congenital cardiac operations. Ann Thorac Surg. 2011 Sep;92(3):964-72; discussion 972. doi: 10.1016/j.athoracsur.2011.04.099.