Relevance of electrical remodeling in human atrial fibrillation: results of the Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial mechanisms of atrial fibrillation study.
BACKGROUND
In animal models of atrial fibrillation (AF), changes in atrial electrophysiological properties are associated with the development of AF. Their relevance to human AF is unclear.


RESULTS
The Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial enrolled 2580 patients receiving a dual-chamber pacemaker, who were older than the age of 65 and had a history of hypertension, but no history of AF. Serial noninvasive electrophysiological testing was performed over 2 years in a subgroup of 485 patients. There were no differences in the clinical characteristics between patients with and those without device-detected atrial tachyarrhythmias during the first year. Patients with atrial tachyarrhythmias had longer paced (153±29 versus 145±28 ms; P=0.046) and sensed (128±46 versus 118±25 ms; P=0.06) P-wave durations and were more likely to have AF induced during electrophysiological testing (23.5% versus 13.6%; P=0.03). They had similar corrected sinus node recovery times at 90 bpm (388±554 versus 376 ± 466 ms; P=0.86), atrial effective refractory periods at 90 bpm (250±32 versus 248±36 ms; P=0.70), and rate-adaptive shortening of the atrial effective refractory periods (14±13 versus 12±14 ms; P=0.11). There were no significant differences in the change in electrophysiological properties over 2 years between patients with and those without atrial tachyarrhythmias.


CONCLUSIONS
Prolonged P-wave duration, but not differences in atrial effective refractory periods, was associated with the development of atrial tachyarrhythmias in pacemaker patients.
Population Health Research Institute, McMaster University, Hamilton, Canada. jeff.healey@phri.ca
Jeff S
JS
Healey
Carsten W
CW
Israel
Stuart J
SJ
Connolly
Stefan H
SH
Hohnloser
Girish M
GM
Nair
Syamkumar
S
Divakaramenon
Alessandro
A
Capucci
Isabelle C
IC
Van Gelder
Chu-Pak
CP
Lau
Michael R
MR
Gold
Mark
M
Carlson
Ellison
E
Themeles
Carlos A
CA
Morillo
D000200:Action Potentials; D000368:Aged; D000369:Aged, 80 and over; D058070:Asymptomatic Diseases; D001281:Atrial Fibrillation / Q000209:etiology* / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects*; D022062:Electrophysiologic Techniques, Cardiac; D004867:Equipment Design; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial / Q000009:adverse effects*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012032:Refractory Period, Electrophysiological; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000209:etiology* / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome