The arrival of Smartwatches with heart health features It is beginning to have a real impact on how certain heart problems are detected, especially those that go unnoticed for years. Among these is atrial fibrillation, a very common arrhythmia that significantly increases the risk of stroke.
A series of recent studies, led by a clinical trial conducted in the University Medical Center Amsterdam (Amsterdam UMC) and published in the Journal of the American College of Cardiology, suggests that the Apple Watch could play a relevant role in screening for these arrhythmias in older people and those with high vascular risk, something especially interesting for health systems such as the Spanish and European ones.
A real-world trial with older, high-risk patients
The research conducted in the Netherlands was designed as a randomized clinical trial under real-life conditionsnot in a laboratory. The researchers selected 437 people aged 65 or older, with a high-risk profile for stroke, a situation quite similar to that found in many primary care and cardiology clinics in Spain and Europe.
The participants were divided into two groups in an even manner: 219 received an Apple Watch They were instructed to use it for about 12 hours a day, while another 218 continued with standard care, based on regular check-ups and medical visits when symptoms appeared or reviews were scheduled.
The follow-up period extended during six monthsDuring that time, the smartwatch group had almost continuous heart monitoring, while the control group relied on usual clinical practice, i.e., occasional electrocardiograms and additional tests only if there were suspicions.
It is important to note that this is a study with moderate sample size (437 people) and a median age of around 75 years. The authors acknowledge that a cohort with different characteristics could yield somewhat different figures, although they believe the main conclusions would be similar.
Four times more arrhythmias detected with Apple Watch
The results obtained after six months have attracted the attention of the medical community. In the group that used the Apple Watch, A cardiac arrhythmia was diagnosed in 21 patients, most of them atrial fibrillation. In the group that received standard care, however, only were identified 5 cases.
In practice, this means that doctors They detected arrhythmias about four times more often between those wearing the Apple Watch and those only attending routine checkups without a wearable device. This difference is statistically significant and supports the idea that continuous monitoring can uncover problems that would otherwise remain hidden.
Furthermore, in more than half of the cases in the group with Apple Watch, specifically around the 57% of diagnosed patientsNo prior symptoms had been reported. In other words, these were people who felt well and who, most likely, would not have mentioned any discomfort during the consultation because they didn't perceive anything unusual.
In the standard care group the situation was very different: the five patients in whom an arrhythmia was identified Yes, they presented clear symptomsIn practice, this means that only the most obvious cases were detected, while the silent ones most likely went undiagnosed.
Why does atrial fibrillation go so unnoticed?
The most common arrhythmia found in these studies was the atrial fibrillationArrhythmia is a rhythm disorder that causes a chaotic, shaky heartbeat in the upper chambers of the heart (the atria). Instead of contracting in a coordinated way, the atrial wall quivers, which can cause blood to pool.
As cardiologists explain, the inside of the atrium is not a smooth surface, but rather presents folds, recesses, and small pocketsIf these areas stop contracting effectively and only "vibrate," blood can pool and form clots. When a clot breaks off and travels through the bloodstream, it can block a cerebral artery and cause a stroke.
According to the American Heart Association and other European scientific societies, atrial fibrillation can multiply the risk of suffering a stroke by fiveThe problem is that approximately half of the cases are intermittent and, very often, produce no symptoms, or these are so mild that they go unnoticed or are mistaken for tiredness or stress.
When someone has a conventional electrocardiogram in the doctor's office, the doctor only has access to a “snapshot” of a few seconds of the heart rhythm. If a fibrillation episode doesn't coincide with that precise moment, the recording will appear normal and the problem will remain hidden. This is one of the major challenges in detecting arrhythmia.
Key advantage: continuous monitoring from the wrist
That's where the Apple Watch comes in. Since the arrival of the Apple Watch Series 4 in 2018The device incorporated two functions specifically designed for heart health: a photoplethysmography (PPG) system that measures heart rate continuously and a single-lead electrocardiogram (ECG) app capable of recording the rhythm when activated by the user.
Photoplethysmography allows the detection of variations in pulse that may suggest a irregular heartbeatThe integrated ECG provides a simple yet useful electrical tracing for identifying patterns consistent with atrial fibrillation. The watch can send irregular rhythm notifications and suggest that the user consult a healthcare professional.
Compared to other monitoring methods, such as traditional Holter monitors with adhesive electrodes and bulky monitors or short-term implantable devices, the smartwatch has the advantage that it is usually worn for many hours a day without major discomfort, and in comparisons such as Apple Watch vs. Fitbit It is often highlighted precisely because of its ease of use. This continued use increases the likelihood of "catching" sporadic incidents that would otherwise go unnoticed.
The authors of the study point out that devices capable of recording both the pulse and electrical activity of the heart have existed for some time, but Its effectiveness had not been properly evaluated This trial aims to fill that gap by screening patients at higher risk of atrial fibrillation in a real-world setting, outside of an experimental context.
Results in numbers: more detection, but also false positives
If the data is translated into percentages, the group with Apple Watch reached a atrial fibrillation detection rate close to 9,6% During the six-month follow-up period, the mortality rate was higher in the group receiving standard care, while the mortality rate remained around 2,3%. The difference, according to the researchers, is clinically relevant.
However, the photo isn't perfect. The data shows that the watch He's not always rightAlmost half of the alerts generated were false positives, that is, warnings of irregular rhythm that were later not confirmed as atrial fibrillation or another relevant arrhythmia after medical tests.
From a clinical point of view, these false positives represent, above all, a additional burden of visits and tests to confirm or rule out the diagnosis, in addition to the potential anxiety that receiving a notification from their watch may cause the user. However, specialists point out that, beyond this inconvenience, no direct negative consequences have been observed.
In other words, technology increases sensitivity—detecting many more potential cases—but at the cost of some specificity. In a healthcare system like Europe's, with its high demand for services, this raises the question of how to integrate these alerts efficiently, avoiding unnecessary overload of clinics while still ensuring that truly relevant cases are not overlooked.
Potential impact on stroke prevention and healthcare costs
the cardiologist Michiel Winter, Amsterdam UMCThis aptly summarizes the scope of these findings. In his statements, he emphasizes that the use of smartwatches with PPG and ECG functions helps diagnose arrhythmias in people who were unaware they had them, thus enabling speed up the diagnostic process and act before serious complications occur.
Once atrial fibrillation is confirmed, one of the main stroke prevention strategies is the prescription of anticoagulantswhich reduce the risk of dangerous blood clots forming. Even so, various studies indicate that up to half of the people who should be on anticoagulants are not, either due to lack of diagnosis or for other reasons.
If arrhythmia can be detected earlier and in more patients—including asymptomatic ones—it opens the door to start preventive treatments before This would reduce the incidence of strokes associated with atrial fibrillation. This would not only have a direct impact on patients' quality of life, but also on the costs to European public healthcare systems.
Winter himself points out that a reduction in the number of strokes and related hospitalizations could to offset the initial cost of the deviceespecially if it is intended for highly selected high-risk groups, such as those included in the study (people over 65 with high vascular risk).
What does all this mean for Europe and for Apple Watch users?
For countries like Spain, with an increasingly aging population and a high burden of cardiovascular diseaseThe possibility of integrating wearables like the Apple Watch into targeted screening programs is appealing, but it also raises questions. It's not about everyone having to wear a smartwatch, but rather about assessing which specific profiles can benefit more than conventional methods.
For now, scientific societies are cautious: they remind us that These devices are not a substitute for a medical diagnosis. They also acknowledge that any alert should be interpreted by a professional. However, they recognize that these alerts can serve as an additional tool for monitoring high-risk individuals, always within a structured strategy and with clear protocols.
From the user's perspective, the key message is that the watch can be a A useful tool for monitoring heart healthHowever, it is not a substitute for checkups or tests prescribed by a doctor. If the device repeatedly displays irregular rhythm warnings or if the values are striking, it is reasonable to seek a consultation for a complete evaluation and not just rely on the reading of the gadget.
At the same time, experts remind us that a normal result on the clock It does not guarantee 100% absence of problemsEspecially if you experience symptoms such as palpitations, dizziness, shortness of breath, or chest pain. In those cases, the appropriate course of action remains contacting the healthcare system, regardless of what the wrist indicates.
Taken together, the evidence gathered in this trial and other peer-reviewed studies reinforces the idea that the Apple Watch and similar devices can become another part of the cardiovascular prevention arsenal, especially for older adults and those with risk factors. The key will be in to integrate them sensibly into European clinical practice, taking advantage of its continuous monitoring capacity without neglecting medical criteria and the resources available in each health system.