Study: Long Term Monitoring Effective Detecting Atrial Fib
A recent study published in the New England Journal of Medicine reveals that the use of a 30-day cardiac event monitorwas superior at detecting atrial fibrillation compared to a 24-hour Holter monitoring study.
It is estimated that 25% of ischemic strokes are “cryptogenic”, where the cause of the stroke is not identified. One of the evolving theories for treatment and/or mangagement is early detection of asymptomatic Atrial fibrillation (A Fib). Atrial Fibrillation is an abnormal cardiac rhythm that can be intermittent and often not felt by the patient (asymptomatic) leading many experts to be the cause of these cryptogenic strokes. However, secondary prevention with anticoagulation (in post-stroke patients) is typically not indicated unless there is documentation of atrial fibrillation. Thus, various modalities to improve the detection of atrial fibrillation are currently under investigation.
The multi-center trial randomized post-ischemic cryptogenic stroke patients (with no history of atrial fibrillation, within 6 months of the event) to either cardiac monitoring with a 30-day event-triggered loop recorder versus an additional 24-hour Holter monitor study. The primary endpoint being the detection of atrial fibrillation lasting for more than 30 seconds within a 90-day period was proven to be superior with the event monitor.
Holter Monitors are generally only worn for a period of 24-48 hours. Event monitors are worn for an extended monitoring period of up to 30 days. The study showed the importance of extending the duration of cardiac monitoring in order to increase the detection of atrial fibrillation in post-stroke patients. Future studies will likely focus on comparing the detection of atrial fibrillation using current and newer outpatient devices as well as determining a feasible yet optimal duration for improving detection.
The study randomized 572 post-ischemic cryptogenic stroke patients within 6 months to either a 30-day loop cardiac event monitor or a second 24-hour Holter monitor (control) for detection of atrial fibrillation. The primary endpoint of detecting atrial fibrillation within 90-days of randomization occurred in 16.1% and 3.2% (p<0.001) in loop recorder and Holter monitoring groups, respectively. The higher rates of detecting atrial fibrillation also changed management as more patients in the intervention group received anti-coagulation (18.6% vs. 11.1%, intervention vs. control, p=0.01) or were switched from anti-platelet therapy to anti-coagulation (13.6% vs. 4.7%, intervention vs. control, p<0.001).