Duration of device-detected subclinical atrial fibrillation and occurrence of stroke in ASSERT.
BACKGROUND
ASSERT demonstrated that subclinical atrial fibrillation (SCAF) is common in pacemaker patients without prior AF and is associated with increased risk of ischemic stroke or systemic embolism. SCAF episodes vary in duration and little is known about the incidence of different durations of SCAF, or their prognosis.


RESULTS
ASSERT followed 2580 patients receiving a pacemaker or ICD, aged >65 years with hypertension, without prior AF. The effect of SCAF duration on subsequent risk of ischemic stroke or embolism was evaluated with time-dependent covariate Cox models. Patients in whom the longest SCAF was ≤6 min were excluded from the analysis (n=125). Among 2455 patients during mean follow-up of 2.5 years, the longest single episode of SCAF lasted >6 min to 6 h in 462 patients (18.8%), >6-24 h in 169 (6.9%), and >24 h in 262 (10.7%). SCAF duration >24 h was associated with a significant increased risk of subsequent stroke or systemic embolism (adjusted hazard ratio [HR] 3.24, 95% confidence interval [CI] 1.51-6.95, P=0.003). The risk of ischemic stroke or systemic embolism in patients with SCAF between 6 min and 24 h was not significantly different from patients without SCAF.


CONCLUSIONS
SCAF >24 h is associated with an increased risk of ischemic stroke or systemic embolism.
Department of Cardiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands.
Isabelle C
IC
Van Gelder
Population Health Research Institute, McMaster University, 237 Barton Street East, Hamilton, ON L8L 2X2, Canada.
Jeff S
JS
Healey
Department of Cardiology, Maastricht University Medical Centre, Cardiovascular Research Institute Maastricht (CARIM), P. Debyelaan 25, 6202 AZ Maastricht, The Netherlands.
Harry J G M
HJGM
Crijns
Population Health Research Institute, McMaster University, 237 Barton Street East, Hamilton, ON L8L 2X2, Canada.
Jia
J
Wang
Department of Cardiology, J.W. Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
Stefan H
SH
Hohnloser
Division of Cardiology, Medical University of South Carolina, 114 Doughty Street, MSC 592, Charleston, SC 29425-5920, USA.
Michael R
MR
Gold
Clinica di Cardiologia, Università Politecnica delle Marche, Via Conca 71, Ancona 60126, Italy.
Alessandro
A
Capucci
Cardiology Division, Queen Mary Hospital, University of Hong Kong, 102 Pokfulam Road, Hong Kong SAR, China.
Chu-Pak
CP
Lau
Population Health Research Institute, McMaster University, 237 Barton Street East, Hamilton, ON L8L 2X2, Canada.
Carlos A
CA
Morillo
Department of Cardiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands.
Anne H
AH
Hobbelt
Department of Cardiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands.
Michiel
M
Rienstra
Population Health Research Institute, McMaster University, 237 Barton Street East, Hamilton, ON L8L 2X2, Canada.
Stuart J
SJ
Connolly
D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications* / Q000401:mortality / Q000628:therapy; D015992:Body Mass Index; D002545:Brain Ischemia / Q000209:etiology* / Q000401:mortality; D017147:Defibrillators, Implantable; D004617:Embolism / Q000209:etiology* / Q000401:mortality; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D053208:Kaplan-Meier Estimate; D008297:Male; D010138:Pacemaker, Artificial; D012307:Risk Factors; D020521:Stroke / Q000209:etiology* / Q000401:mortality; D016896:Treatment Outcome