Published online before print August 4, 2009, doi: 10.1161/CIRCEP.109.849638
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Original Articles |
The Relationship Between Daily Atrial Tachyarrhythmia Burden From Implantable Device Diagnostics and Stroke Risk
The TRENDS Study
From the Hackensack University Medical Center (T.V.G.), Hackensack, NJ; The Ohio State University Medical Center (E.G.D.), Columbus Ohio; Libin Cardiovascular Institute of Alberta (D.G.W.), Calgary, Alberta, Canada; Massachusetts General Hospital (D.E.S.), Boston, Mass; Lankenau Institute for Medical Research (M.D.E.), Philadelphia, Pa; and Medtronic, Inc (C.H., C.M., D.Q., P.D.Z.), Minneapolis, Minn.
Correspondence to Taya V. Glotzer, MD, Electrophysiology Associates of Northern New Jersey, 20 Prospect Ave, Suite 701, Hackensack, NJ 07601. E-mail TayaVG{at}aol.com
Received January 20, 2009; accepted July 27, 2009.
Background— It is unknown if brief episodes of device-detected atrial fibrillation (AF) increase thromboembolic event (TE) risk.
Methods and Results— TRENDS was a prospective, observational study enrolling patients with 
1 stroke risk factor (heart failure, hypertension, age 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 (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 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.
Key Words: atrial fibrillation • tachyarrhythmias • stroke • risk factors • pacemakers
CLINICAL PERSPECTIVE
This study is registered at clinicaltrials.gov (NCT00279981).
Related Article
Circ Arrhythm Electrophysiol 2009 2: 471-473.