People with atrial fibrillation detected through screening may have a threefold higher risk for heart failure (HF) than those without the condition, according to a post hoc analysis of the STROKESTOP and STROKESTOP II trials.

Researchers also found that the risk for HF among those who screened positive for atrial fibrillation (AF) was comparable to that of people with clinically diagnosed AF.

“These findings suggest that screening-detected AF is not a benign condition. This underlines the importance of echocardiographic assessment and early prevention strategies in this group,” said Gina Sado, cardiology resident and PhD student at Department of Medicine, Karolinska University Hospital, Karolinska Institutet, in Stockholm, Sweden.

Sado, who presented the findings at the European Heart Rhythm Association (EHRA) 2026, also told Medscape Medical News that the findings were, to some extent, unexpected.

“Screening-detected AF is often asymptomatic and typically associated with a lower AF burden compared with clinically detected AF. Given that, one might expect a lower risk of adverse outcomes. However, our findings suggest that this may not be the case for heart failure,” Sado said.

Sado won a Young Investigators Award for this research at the EHRA meeting.

Methodology

To determine the incidence and timing of HF in a group of people screened for AF, Sado and colleagues assessed participants without prior HF who were offered ECG screening for AF.

There were 6824 participants and 12,898 control individuals without previous HF in STROKESTOP, as well as 6601 participants and 12,905 control individuals without previous HF included in STROKESTOP II.

Both trials screened 75- or 76-year-old participants because this group offers the best balance between risk, benefit, and feasibility, according to Sado. This is a group where AF is common, stroke risk is high, and anticoagulation is already indicated based on age alone.

“That makes screening both clinically meaningful and cost-effective,” Sado said.

Key Findings

After a median follow-up of 6.9 years, 23% of the 252 participants with screening-detected AF in STROKESTOP developed HF, corresponding to an incidence rate of 3.76 per 100 person-years (95% CI, 2.85-4.87) compared with 1.08 (95% CI, 0.98-1.18) among those without AF and an adjusted hazard ratio (HR) of 3.19 (95% CI, 2.42-4.21).

Among the 556 participants with clinically diagnosed AF, the incidence rate for HF during follow-up was 4.43 per 100 person-years (95% CI, 3.74-5.22) and the adjusted HR was 2.86 (95% CI, 2.34-3.50) compared with participants without AF.

STROKESTOP II had a shorter median follow-up of 5.1 years. At that time, 20% of the 152 participants with screening-detected AF developed HF, corresponding to an incidence rate of 4.19 per 100 person-years (95% CI, 2.84-5.94) vs 0.93 (95% CI, 0.83-1.04) for those without AF and an adjusted HR of 4.73 (95% CI, 3.26-6.85).

Cautious Interpretation

“These results should be interpreted with some caution,” Sado said, noting that as with any observational study, residual confounding cannot be excluded. AF progression, echocardiographic characteristics, and lifestyle may have influenced the results, for example. There is also a potential for classification bias related to how the groups were defined.

In addition, this substudy only included 75- to 76-year-olds, so the findings are not fully generalizable, Sado said. “Therefore, we can’t assume the same results would apply to younger or older age groups.”

Dan Atar, MD, a professor of cardiology at the University of Oslo in Oslo, Norway, praised the design and execution of both STROKESTOP trials but noted their impact was not high.

“Both were disappointing in terms of convincing the cardiovascular community that screening for atrial fibrillation is a meaningful and effective way to decrease morbidity [ie, embolic stroke-rates] or even mortality in elderly people,” Atar told Medscape Medical News.

The current analysis provides insight that, at least for a subset of the studied populations, the detection of AF by screening has an impact on the incidence of HF, said Atar, who is also chair of the European Heart Academy and editor-in-chief of the journal Cardiology.

“This finding is of importance as the study shows that the mentioned incidence of HF in newly screen-detected AF patients is in the same range as in patients with previously-known AF,” Atar said. “This is a finding that has not been known from earlier screening studies.”

Atar shared a caveat about the findings: “the very low numbers.” He pointed out that combined the STROKESTOP studies assessed about 13,400 participants and an additional 25,800 control individuals.

“In contrast to these figures, the screening-detected AF patients that had HF events were numerically 57 and 31…after an observation period of 6.9 and 5.1 years, respectively.”

“Given the very rare occurrence of incident HF in this screened population, these data will not change the perception of the cardiovascular community that screening of elderly people for AFib is not a recommendable utility as of the current knowledge base,” Atar predicted.

Looking Ahead

“I believe that AF progression and AF burden may partly explain the comparable incidence rates and hazard ratios observed in screening-detected AF,” Sado said.

Sado is currently conducting a subanalysis focusing on AF burden in these patients, and examining its association with different outcomes, including HF and its subtypes, stroke, dementia, and mortality.

This study was independently supported. Sado and Atar reported having no relevant financial relationships.

Damian McNamara is a freelance contributor to Medscape Medical News. He worked full-time for Medscape and WebMD from 2018 to 2024. Damian has a BA in chemistry and an MA in science, health and environmental reporting/journalism.