title: Adenosine for wide-complex tachycardia: efficacy and safety.
abstract: OBJECTIVE
  : To determine whether adenosine is useful and safe as a diagnostic and therapeutic agent for patients with undifferentiated wide QRS complex tachycardia. The etiology of sustained monomorphic wide QRS complex tachycardia is often uncertain acutely.
  
  
  METHODS
  : A retrospective observational study.
  
  
  METHODS
  : Treatment associated with emergency visits at nine urban hospitals.
  
  
  METHODS
  : Consecutive patients treated with adenosine for regular wide QRS complex tachycardia between 1991 and 2006.
  
  
  METHODS
  : Treatment with adenosine infusion.
  
  
  RESULTS
  : Measured outcomes included rhythm response to adenosine, if any, and all adverse effects. A positive response was defined as an observed change in rhythm including temporary atrioventricular conduction block or tachycardia termination. A primary adverse event was defined as emergent electrical or medical therapy instituted in response to an adverse adenosine effect. A rhythm diagnosis was made in each case. The characteristics of adenosine administration as a test for a supraventricular as opposed to ventricular tachycardia were determined, and the adverse event rates were calculated. A total of 197 patients were included: 104 (90%) of 116 (95% confidence interval, 83%-95%) and two (2%) of 81 (95% confidence interval, 0.3%-9%) supraventricular tachycardia and ventricular tachycardia patients demonstrated a response to adenosine, respectively. The odds of supraventricular tachycardia increased by a factor of 36 (95% confidence interval, 9-143) after a positive response to adenosine. The odds of ventricular tachycardia increased by a factor of 9 (95% confidence interval, 6-16) when there was no response to adenosine. The rate of primary adverse events for patients with supraventricular tachycardia and ventricular tachycardia was 0 (0%) of 116 (95% confidence interval, 0%-3%) and 0 (0%) of 81 (95% confidence interval, 0%-4%), respectively.
  
  
  CONCLUSIONS
  : Adenosine is useful and safe as a diagnostic and therapeutic agent for patients with regular wide QRS complex tachycardia.
authors.affiliation: Department of Emergency Medicine (KAM), Massachusetts General Hospital, Boston, MA, USA. kmarill@partners.org
authors.forename: Keith A
authors.initials: KA
authors.lastname: Marill
authors.forename: Sigrid
authors.initials: S
authors.lastname: Wolfram
authors.forename: Ian S
authors.initials: IS
authors.lastname: Desouza
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Nishijima
authors.forename: Darren
authors.initials: D
authors.lastname: Kay
authors.forename: Gary S
authors.initials: GS
authors.lastname: Setnik
authors.forename: Thomas O
authors.initials: TO
authors.lastname: Stair
authors.forename: Patrick T
authors.initials: PT
authors.lastname: Ellinor
mesh_terms: D000241:Adenosine / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013610:Tachycardia / Q000175:diagnosis* / Q000188:drug therapy*
chemical_list: D000889:Anti-Arrhythmia Agents; D000241:Adenosine