Screening for atrial fibrillation (AF) using a wearable heart monitor for 2 weeks can identify older adults with this potentially dangerous abnormal heart rhythm, but does not prevent subsequent strokes, according to late breaking research presented in a Hot Line Session at this year's ESC Congress 2024 in London, UK (30 Aug - 2 Sept).
The authors note, however, that because the trial was terminated early due to the COVID-19 pandemic, their results cannot provide a definitive answer about the ultimate benefit of AF screening to reduce hospitalization rates for stroke.
Our study showed a 52% increase in the number of cases of atrial fibrillation diagnosed over a maximum of 2.5 years of follow-up, an increase in the initiation of oral anticoagulants with no increase in rates of hospitalization for bleeding, and no significant reduction in the rate of hospitalizations for all stroke compared with usual care. Despite being the largest study using a 14-day, patch-based continuous ECG monitor as the screening strategy, our results should not be considered conclusive due to the early termination of the study and lower than expected number of clinical events."
Renato Lopes, Lead Author, Professor, Duke University Medical Center, USA
He adds, "Further studies with longer follow-up and including participants at higher risk for stroke are needed to establish the true potential of AF screening in reducing rates of strokes."
Given that cardiovascular disease (CVD), mainly heart attack and stroke, remain Europe and the world's leading cause of death, the European Society of Cardiology is calling for CVD and diabetes screening to be part of national and European Union Health Plans to prevent CVD and educate about CV health at a population level.
AF is the most common heart rhythm disorder, affecting more than 40 million people worldwide. Estimates suggest that one in three Europeans will develop the condition during their lifetime. Symptoms include palpitations, shortness of breath, fatigue, and difficulty sleeping. However, many people do not experience any symptoms, and AF often remains undiagnosed. What's more, AF can be intermittent, increasing the challenge of identifying those who have it.
Individuals with AF face a five-fold increase in the risk of stroke and are therefore often prescribed blood-thinning medications (anticoagulants) to prevent blood clotting.
Recent trials have shown that one-time brief screening for AF did not significantly increase diagnoses of AF, while others investigating longer-term screening found an increase in AF diagnoses, primarily paroxysmal AF (intermittent heart rhythm disturbance). But none have yet established that AF screening lowers stroke rates.
Started in December 2019, the GUARD-AF trial randomised 11,905 patients from 149 primary care sites across the USA to examine whether AF screening using a continuous ECG patch monitor (Zio XT that records heart rhythm for 14 days) could identify older adults with undiagnosed AF resulting in a reduced rate of any stroke compared with usual care.
In total, 5,952 participants were randomized to screening and 5,953 to usual care (median age 75 years; 57% female). Of those randomized to screening, 5,684 (96%) returned ECG monitors with analyzable results. Researchers examined Medicare claims and Kaiser Permanente data to determine clinical outcomes.
During an average (median) follow-up of 15 months, the number of patients with a stroke in the screening group was numerically higher than in the usual care group (37 vs 34), while the number of patients with a bleeding event was numerically lower in the screening group compared to usual care (52 vs 60).
Both AF diagnoses and treatment with oral anticoagulant therapy were higher in the screening group compared to the usual care group (5% [284 patients] vs 3.3% [196] and 4.2% [239] vs 2.8% [167], respectively).
Professor Lopes said: "Our results add to the body of evidence around AF screening and highlight the challenges in determining the impact of AF screening on clinical outcomes. Until we have clear information on who should be screened, how and for how long, and its real impact in stroke prevention, AF screening should not be routinely recommended."
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