title: Inducibility of atrial fibrillation during electrophysiologic evaluation is associated with increased dispersion of atrial refractoriness.
abstract: The impact of atrial dispersion of refractoriness (Disp_A) in the inducibility and maintenance of atrial fibrillation (AF) has not been fully resolved.
  
  
  OBJECTIVE
  To study the Disp_A and the vulnerability (A_Vuln) for the induction of self-limited (<60 s) and sustained episodes of AF.
  
  
  RESULTS
  Forty-seven patients with paroxysmal AF (PAF): 29 patients without structural heart disease and 18 with hypertensive heart disease. Atrial effective refractory period (ERP) was assessed at five sites--right atrial appendage and low lateral right atrium, high interatrial septum, proximal and distal coronary sinus. We compared three groups: group A - AF not inducible (n=13); group B - AF inducible, self-limited (n=18); group C - AF inducible, sustained (n=16). Age, lone AF, hypertension, left atrial and left ventricular (LV) dimensions, LV systolic function, duration of AF history, atrial flutter/tachycardia, previous antiarrhythmics, and Disp_A were analysed with logistic regression to determine association with A_Vuln for AF inducibility. The ERP at different sites showed no differences among the groups. Group A had a lower Disp_A compared to group B (47+/-20 ms vs 82+/-65 ms; p=0.002), and when compared to group C (47+/-20 ms vs 80+/-55 ms; p=0.008). There was no significant difference in Disp_A between groups B and C. By means of multivariate regression analysis, the only predictor of A_Vuln was Disp_A (p=0.04).
  
  
  CONCLUSIONS
  In patients with PAF, increased Disp_A represents an electrophysiological marker of A_Vuln. Inducibility of both self-limited and sustained episodes of AF is associated with similar values of Disp_A. These findings suggest that the maintenance of AF is influenced by additional factors.
authors.affiliation: Cardiology Department, Santa Marta Hospital, Lisbon, Portugal.
authors.forename: Mario
authors.initials: M
authors.lastname: Oliveira
authors.forename: M Nogueira
authors.initials: MN
authors.lastname: da Silva
authors.forename: Ana T
authors.initials: AT
authors.lastname: Timoteo
authors.forename: Joana
authors.initials: J
authors.lastname: Feliciano
authors.forename: Lidia
authors.initials: L
authors.lastname: Sousa
authors.forename: Sofia
authors.initials: S
authors.lastname: Santos
authors.forename: Luis
authors.initials: L
authors.lastname: Silva-Carvalho
authors.forename: Rui
authors.initials: R
authors.lastname: Ferreira
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*; D054326:Coronary Sinus / Q000503:physiopathology; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006346:Heart Septum / Q000503:physiopathology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012032:Refractory Period, Electrophysiological / Q000502:physiology*; D012720:Severity of Illness Index; D055815:Young Adult