title: Electrophysiologic characteristics of atria in patients without heart disease.
abstract: BACKGROUND
  The significance of atrial fibrillation or tachycardia (AF) induction remains debatable. Some believe that the presence of heart disease (HD) increases the sensitivity and decreases the specificity of programmed atrial stimulation (PAS). There are few data in patients without HD. The purpose of the study was to evaluate the results of PAS in asymptomatic patients without HD and in those with documented spontaneous AF, but without HD, to know the diagnosis value of the technique.
  
  
  METHODS
  A total of 4,900 PAS were consecutively performed. The control group (I, N=67) was defined by the absence of preexcitation syndrome, dizziness/syncope, hypertension, history of tachycardia, or other documented HD together with a normal 2D echocardiogram and 24-hour Holter monitoring. They were compared to a group (II) of 54 patients with documented paroxysmal AF and without HD. PAS used one and two extrastimuli, delivered during sinus rhythm and two drive rates (600, 400 ms). Atrial-effective refractory periods (ARP), their adaptation to cycle length, and conduction times were noted. AF induction was defined as the induction of AF lasting more than 1 minute.
  
  
  RESULTS
  Group I patients (1.4% of 4,900) were younger than group II (51 +/- 17 vs 65 +/- 11 years, P < 0.001). A single extrastimulus never induced sustained AF in group I, but did so in 11 group II patients (20%); sustained AF was induced by two extrastimuli in 15 group I patients (22%) and in 31 group II patients (57%) (P < 0.001). There were no ARP and conduction time differences in group I patients with and without inducible AF, but there was a longer sinus cycle length in patients with inducible AF (977 +/- 164 vs 838 +/- 141 ms, P < 0.02). There were no electrophysiological differences in group II patients with and without inducible AF. No group I patient developed spontaneous AF (follow-up 4 +/- 2 years). The sensitivity of PAS with one extrastimulus was 20% and the specificity 100%; the sensitivity of PAS with two extrastimuli was 57% and the specificity 78%.
  
  
  CONCLUSIONS
  Sustained AF was not induced by one extrastimulus in control patients without symptoms, nor heart disease, but sustained AF was induced by two extrastimuli in 22% of these patients. The induction of a sustained AF by two extrastimuli should be interpreted cautiously, particularly in patients with a relative sinus bradycardia. However, the sensitivity of PAS with one extrastimulus was very low and two extrastimuli were required in patients with spontaneous AF to induce the tachycardia. Other electrophysiological parameters were not useful to differentiate patients with and without inducible AF.
authors.affiliation: Cardiology, CHU of Brabois, Vandoeuvre Les Nancy, France. b.brembilla-perrot@chu.nancy.fr
authors.forename: Béatrice
authors.initials: B
authors.lastname: Brembilla-Perrot
authors.forename: Daniel
authors.initials: D
authors.lastname: Beurrier
authors.forename: Pierre
authors.initials: P
authors.lastname: Houriez
authors.forename: Christine
authors.initials: C
authors.lastname: Suty-Selton
authors.forename: Marc
authors.initials: M
authors.lastname: Nippert
authors.forename: Olivier
authors.initials: O
authors.lastname: Claudon
authors.forename: Marius
authors.initials: M
authors.lastname: Andronache
authors.forename: Yves
authors.initials: Y
authors.lastname: Ernst
authors.forename: Emad
authors.initials: E
authors.lastname: Khaldi
authors.forename: Hadj
authors.initials: H
authors.lastname: Belhakem
authors.forename: Batric
authors.initials: B
authors.lastname: Popovic
authors.forename: Arnaud
authors.initials: A
authors.lastname: Terrier de la Chaise
authors.forename: Pierre
authors.initials: P
authors.lastname: Louis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*; D016275:Atrial Function; D004558:Electric Stimulation; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013610:Tachycardia / Q000175:diagnosis* / Q000503:physiopathology*