Study: Risk of Atrial Fibrillation Remains High After 3 Years, Including Those With Heart Failure

The risk of atrial fibrillation (AF) detection after stroke due to large-artery atherosclerotic disease (LAD) or small-vessel occlusive disease (SVD) was shown to last beyond 1 year for patients with insertable cardiac monitors (ICMs), with heart failure (HF) and left atrial enlargement (LAE) being significant risk factors, according to results from the STROKE AF study (NCT02700945).

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Results of the study, published in JAMA Neurology, showed that the detection with ICMs increased from 12.5% at 1 year to 21.7% at 3 years, compared to the 2.4% detection rates from the standard monitoring. Most AF cases in the ICM group were asymptomatic, with most patients having at least 1 episode that was longer than 1 hour, according to the results.

The STROKE AF study was conducted at 33 sites in the United States, enrolling 496 individuals from April 2016 to July 2019, with a follow up through July 2022, according to the study authors. For this part of the study, individuals with ischemic stroke were classified by Trial of Org 10172 in acute stroke treatment (TOAST) criteria to determine if the cause was by LAD or SVD. They were randomized to either receive an ICM or site-specific standard-of-care within 10 days of stroke.

Individuals included were also aged 60 years or older, or aged 50 to 59 with at least 1 stroke risk factor, including heart failure, hypertension, diabetes, ischemic stroke more than 90 days before index stroke, or other ischemic vascular disease, according to the study authors. The median age of individuals included in the study was 66 years, with 37.6% being women and a median CHA2DS2-VASc Score for Atrial Fibrillation Stroke Risk of 5.

Investigators noted that there was a median follow up of 29.4 months with 21 crossovers during the follow-up, including: 8 assigned to ICM after never receiving it, 5 assigned to ICM switched to the usual care more than 1 year after ICM insertion, and 8 assigned to the usual care that received an ICM in the follow-up.

The study authors noted that the AF detection levels increased in the ICM group throughout the study, with 2.6% at 1 month, 7.9% at 6 months, 12.5% at 1 year, and 18.5% at 2 years. The median time to AF detection was 9.3 months with ICM and 6.8 months for the control group. Investigators also found 20.5% of individuals in the ICM group had at least 1 day where 1 hour or more of AF burden was detected by year 3, according to the results.

Furthermore, the investigators found that at least 1 of the independent predictors, including body mass index, congestive HF, LAE, and QRS duration, resulted in greater than a 4-fold increase in AF detection by 3 years compared to individual who did not have any AF predictors. The study authors noted, “patients with [LAE], [HF], obesity, or prolonged QRS may constitute high-risk groups in which monitoring might be most cost-effective.”

They also said that AF is common for patients after stroke with noncardioembolic causes, and monitoring by physicians should take place after 1 year, as the patient’s risk increased for at least 3 years after stoke, according to the result of the study.

Reference

Bernstein RA, Kamel H, Granger CB, et al. Atrial Fibrillation In Patients With Stroke Attributed to Large- or Small-Vessel Disease: 3-Year Results From the STROKE AF Randomized Clinical Trial. JAMA Neurol. doi:10.1001/jamaneurol.2023.3931