ADENOSINE-INDUCED ATRIAL ARRHYTHMIA - A PROSPECTIVE ANALYSIS

Background: Adenosine is considered safe and effective for paroxysmal supraventricular tachycardia (PSVT), but anecdotal experience suggests that adenosine can precipitate atrial arrhythmias. Objectives: To det ermine the frequency and mechanisms of adenosine-induced atrial arrhyt hmias. Setting: Clinical electrophysiology laboratory at a university medical center.Design: Prospective observational study. Patients: 200 consecutive patients with PSVT undergoing an electrophysiology procedu re. Intervention: During PSVT, 12 mg of adenosine was administered cen trally through the femoral vein. Measurements: Frequency of adenosine- induced atrial fibrillation. Results: Paroxysmal supraventricular tach ycardia terminated after adenosine administration in 198 patients (99% [95% CI, 96% to 100%]). Adenosine led to atrial fibrillation (n = 22) or atrial fibrillation and atrial flutter (n = 2) in 24 patients (12% [CI, 7.5% to 16.5%]). An atrial premature complex occurred in all 24 patients who developed atrial fibrillation, atrial flutter, or both an d in 102 of the 176 patients (58%) who did not (P < 0.001). The mean ( +/-SD) time from the preceding atrial complex to the atrial premature complex was shorter when an atria[ arrhythmia occurred, and the mean r atio of this interval to the preceding atrial cycle length was also lo wer when atrial fibrillation developed (0.37 +/- 0.16 compared with 0. 49 +/- 0.16; P = 0.002). Conclusions: The incidence of atrial fibrilla tion induced by 12 mg of adenosine administered through the femoral ve in was 12%. Fibrillation seems to be associated with a ''long-short'' atrial sequence. If the mechanism of PSVT is unknown and the Wolff-Par kinson-White syndrome is possible, administration of adenosine should be limited to medical facilities that have emergency resuscitation equ ipment.