Evelyn felt fine that morning. At 68, she was active, healthy, and just returned from her daily walk when her heart began to flutter. It wasn’t painful, just an odd sensation, like a fish flopping in her chest. It lasted around 10 minutes and then stopped. Although she thought it was strange, she soon dismissed it. A week later, she woke up unable to move her right side. A stroke had stolen her speech, her independence, and nearly her life. It took ER doctors to find what was hiding in plain sight: atrial fibrillation. Her heart’s atria had been quivering chaotically, allowing blood to pool and clot. One of these clots had broken free and traveled to her brain, causing a stroke.

But this could’ve been easier to detect, easier to prevent. If anyone detected her irregular heartbeat earlier, a simple blood thinner medication could have prevented everything. She could still be leading a normal life.

Unfortunately, a version of Evelyn’s story repeats itself around 160,000 times annually in the U.S. One in five strokes is caused by atrial fibrillation (AF); in other words, simply an irregular heartbeat. These strokes are often the most severe and deadly, yet they often go undetected until it’s too late. What’s shocking is that we already have the tools to detect atrial fibrillation before fatality. But why aren’t we using them?

The scope of the problem

In 2024, the European Society of Cardiology issued updated guidelines that recommended routine heart rhythm assessment for all individuals aged 65+ during any health care contact. They had realized the importance of considering AF, especially as its prevalence increases greatly with age. The data suggests that AF affects more than 10 percent of people over the age of 75. If left undetected and untreated, it increases stroke risk by five.

Additionally, between 1999 and 2020, the CDC found that approximately 490,000 deaths in the United States involved both stroke and AF. Studies show that stroke patients with AF have higher mortality rates (9.9 percent compared to 6.1 percent in those without the condition) and require 20 percent longer hospital stays at significantly higher cost.

What’s particularly concerning is that AF-related strokes are largely preventable. Once diagnosed, anticoagulation therapy can reduce stroke risk by more than 60 percent. And it isn’t even difficult to detect: A simple pulse check or brief ECG can detect the irregular rhythm. The technology exists. And the anticoagulation treatment works. So why aren’t we screening?

Systemic failures

The answer lies in a mixture of systemic failures. Primary care physicians, already squeezed for time in 15-minute appointments, lack the bandwidth and financial incentive for routine pulse checks. But the deeper issue is economical: Preventive care that isn’t reimbursed simply doesn’t happen.

Medicare, which covers depression screening, cardiovascular disease screening, and dozens of other preventive services, omits AF screening from its list of reimbursable preventive care. Without payment, there’s no systematic implementation as it becomes “optional” to patients.

Additionally, screening programs significantly increase detection rates. In screening programs targeting adults 65 and older, detection rates range from 3.6 percent in those aged 65 to 74 to 7.5 percent in those 75 or older. In the U.S., where more than 56 million people are 65+, a 3 percent to 4 percent detection rate through systematic screening would identify more than two million Americans with previously unknown AF. These are people who could start life-saving anticoagulation before their first stroke, saving their lives.

The smartwatch solution

Even more surprising is that there is another solution which is already on millions of wrists. Smartwatch technology has advanced to the point where consumer devices can detect AF. Recent studies show the Apple Watch achieves 95 percent sensitivity and specificity for AF detection. In large-scale trials, when smartwatch users received irregular pulse notifications, 34 percent were confirmed to have AF on subsequent ECG monitoring, and 84 percent of notifications proved concordant with actual AF. This could easily be implemented into the lives of the elderly.

Additionally, smartwatch-based monitoring provides continuous, passive surveillance. AF is often inconsistent, coming and going unpredictably. Continuous monitoring dramatically increases the likelihood of detection.

As a result, the path forward is clear. Medicare must add AF screening to its preventive services for beneficiaries aged 65 and older. This should include three components:

• Reimbursement for pulse checks and rhythm assessment during annual wellness visits.
• Coverage for smartwatch-enabled monitoring programs with medical oversight.
• Payment for confirmatory ECGs when AF is detected.

The cost would be modest compared to the savings from prevented strokes, and it would provide the immeasurable benefit of prevented disability and death.

Addressing the critics

Critics raise several concerns about universal AF screening. False positives could trigger anxiety and unnecessary follow-up testing. Smartwatch alerts might overwhelm already-strained cardiology practices with worried patients. And there’s the philosophical question: Should we medicalize aging by continuously monitoring healthy seniors?

However, modern smartwatch algorithms have been refined through millions of data points. Even accounting for false positives, the number needed to screen to prevent one stroke is favorable compared to other preventive measures. AF screening doesn’t require treatment of every detected case but rather decision-making between patients and physicians. What screening prevents is the worst outcome: Discovering AF only after it has caused irreversible harm.

The precedent for this kind of preventive screening is well-established. We screen for cancer, osteoporosis, and depression. AF is no different. The evidence supports screening. Technology enables it. The only thing missing is the policy infrastructure and payment mechanism to make it happen.

Every day we delay is another day of preventable strokes. For the hundreds of thousands of Americans currently walking around with undiagnosed AF, time is running out. Their hearts are sending warning signals. We just need to start listening.

Medicare should act now to require and reimburse annual AF screening for all Americans 65 and older. This isn’t a radical proposal; it’s just an overdue alignment of policy with science. AF screening works, and we should be doing it. Maybe then, people like Evelyn could be living the full lives they deserve.

Radhesh K. Gupta is a health policy advocate.