The relationship between daily atrial tachyarrhythmia burden from implantable device diagnostics and stroke risk: the TRENDS study.
BACKGROUND
It is unknown if brief episodes of device-detected atrial fibrillation (AF) increase thromboembolic event (TE) risk.


RESULTS
TRENDS was a prospective, observational study enrolling patients with > or = 1 stroke risk factor (heart failure, hypertension, age > or = 65 years, diabetes, or prior TE) receiving pacemakers or defibrillators that monitor atrial tachycardia (AT)/AF burden (defined as the longest total AT/AF duration on any given day during the prior 30-day period). This time-varying exposure was updated daily during follow-up and related to TE risk. Annualized TE rates were determined according to AT/AF burden subsets: zero, low (<5.5 hours [median duration of subsets with nonzero burden]), and high (> or = 5.5 hours). A multivariate Cox model provided hazard ratios including terms for stroke risk factors and time-varying AT/AF burden and antithrombotic therapy. Patients (n=2486) had at least 30 days of device data for analysis. During a mean follow-up of 1.4 years, annualized TE risk (including transient ischemic attacks) was 1.1% for zero, 1.1% for low, and 2.4% for high burden subsets of 30-day windows. Compared with zero burden, adjusted hazard ratios (95% CIs) in the low and high burden subsets were 0.98 (0.34 to 2.82, P=0.97) and 2.20 (0.96 to 5.05, P=0.06), respectively.


CONCLUSIONS
The TE rate was low compared with patients with traditional AF with similar risk profiles. The data suggest that TE risk is a quantitative function of AT/AF burden. AT/AF burden > or = 5.5 hours on any of 30 prior days appeared to double TE risk. Additional studies are needed to more precisely investigate the relationship between stroke risk and AT/AF burden.
Glotzer
Taya V
TV
Hackensack University Medical Center, Hackensack, NJ, USA. TayaVG@aol.com
Daoud
Emile G
EG
Wyse
D George
DG
Singer
Daniel E
DE
Ezekowitz
Michael D
MD
Hilker
Christopher
C
Miller
Clayton
C
Qi
Dongfeng
D
Ziegler
Paul D
PD
D000368:Aged; D000704:Analysis of Variance; D001281:Atrial Fibrillation / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D016009:Chi-Square Distribution; D017147:Defibrillators, Implantable; D005260:Female; D006801:Humans; D020766:Intracranial Embolism / Q000453:epidemiology / Q000209:etiology; D002546:Ischemic Attack, Transient / Q000453:epidemiology / Q000209:etiology; D008297:Male; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology / Q000209:etiology*; D015912:Thrombolytic Therapy