Comparison of adenosine effects on atrioventricular node reentry and atrioventricular reciprocating tachycardias.
BACKGROUND
Adenosine is an established first line therapy for the treatment of narrow complex tachycardias. The two most common etiologies of paroxysmal supraventricular tachycardia (SVT) are atrioventricular node reentry tachycardia (AVNRT) and atrioventricular reciprocating tachycardia (AVRT).


OBJECTIVE
We postulated that adenosine might have different effects on the termination of AVNRT vs. AVRT, and that these differences might assist in the noninvasive differentiation between these diagnoses.


METHODS
Fifty-nine patients referred for the diagnosis and treatment of SVT were included in the study. All patients had SVT induced during electrophysiology testing, and each patient received adenosine during SVT. The adenosine dose, time to tachycardia termination, and site of tachycardia termination were recorded. Seventeen patients required isoproterenol administration to initiate SVT. This subset of patients was compared with those not requiring isoproterenol.


RESULTS
There was no statistically significant difference in the adenosine dose or time to tachycardia termination when comparing patients with AVNRT with those with AVRT. All patients with AVNRT had termination of tachycardia in the antegrade direction with final activation in the atria. Patients requiring isoproterenol for tachycardia initiation experienced tachycardia termination significantly faster than those not requiring isoproterenol, although there was no difference in the dose of adenosine required for termination.


CONCLUSIONS
These data demonstrate that patients with dual AV node physiology and AVNRT do not have altered sensitivity to adenosine compared with patients with AVRT and normal AV nodes. Further investigation will be required to determine the clinical utility of the significantly shorter time to tachycardia termination for patients receiving isoproterenol.
Donahue
J K
JK
Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Orias
D
D
Berger
R D
RD
Tomaselli
G F
GF
Lawrence
J H
JH
Calkins
H
H
D000241:Adenosine / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D003627:Data Interpretation, Statistical; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007545:Isoproterenol / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D013566:Sympathomimetics / Q000008:administration & dosage; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis / Q000188:drug therapy*; D013617:Tachycardia, Supraventricular / Q000139:chemically induced / Q000175:diagnosis / Q000188:drug therapy*; D013997:Time Factors
D000889:Anti-Arrhythmia Agents; D013566:Sympathomimetics; D000241:Adenosine; D007545:Isoproterenol