In recent years, Smart watches They have made the leap from counting steps to closely monitoring the heartto the point of becoming another piece of the medical conversation about cardiovascular prevention. Atrial fibrillation, one of the most common arrhythmias and linked to serious strokes, has become central to this debate.
New Clinical trial conducted in the real world by Amsterdam UMC and published in the JACC journal This suggests that the Apple Watch could play a relevant role in the early detection of this arrhythmia, especially in older people and those with high vascular risk, a very common profile in the health systems of Spain and Europe.
A European clinical trial with 437 people over 65 years old
The work was designed as a randomized clinical trial under real-life conditionsFar from a laboratory and closer to what happens in primary care or cardiology consultations, the Dutch researchers recruited 437 people aged 65 and over, all of whom were at high risk of stroke.
The participants were divided into two groups: 219 people received an Apple Watch and were asked to wear it for about 12 hours a daywhile the other 218 continued with standard healthcare, based on scheduled visits, on-demand consultations and occasional cardiac tests.
The follow-up lasted for six full monthsDuring that period, the group with watches had virtually continuous monitoring of their pulse and heart rate from the wrist, as explained How to measure your heart rate with Apple Watchwhile the control group relied on electrocardiograms and scans that are performed conventionally when symptoms occur or check-ups are scheduled.
The authors note that the study has a moderate sample size and a median age close to 75 yearsTherefore, their conclusions are particularly relevant to older people and those at high vascular risk. In a different cohort, the figures could vary, although the general trends are expected to remain the same.
Four times more atrial fibrillation detected with Apple Watch
After six months of follow-up, the results caught the attention of the cardiology community: in the group that used the Apple Watch, atrial fibrillation or other conditions were diagnosed relevant arrhythmias in 21 patientswhile in the group with usual care only five cases were identified.
Translated into percentages, the group equipped with Apple Watch reached a detection rate close to 9,6%compared to approximately 2,3% in the control group. This difference was statistically significant and supports the idea that Prolonged wrist-based monitoring uncovers many more cases than the regular checkups.
There is one piece of data that is especially relevant for clinical practice: of the 21 diagnoses in the group with a clock, around 57% corresponded to people without symptomsThese were patients who were feeling well, without noticeable palpitations or clear discomfort, and who would hardly have sought medical help on their own initiative.
In the standard care group the situation was very different: the five people diagnosed Yes, they presented obvious symptomsThis highlights that, without continuous monitoring, it is common for only the most obvious cases to be detected, while the silent ones go unnoticed.
Why atrial fibrillation escapes classic controls
The arrhythmia that is the focus of this type of study is the atrial fibrillationThe most common heart rhythm disorder in older adults. In this condition, the atria stop contracting in an orderly fashion and begin to move rapidly and uncoordinatedly, producing an irregular and often accelerated heartbeat.
Cardiologists explain that the inside of the atrium has folds, ridges, and small pockets where blood can stagnateWhen the atrial wall only quivers and doesn't pump blood effectively, the risk of blood clots forming increases. If one of these clots travels to the brain and blocks an artery, it can trigger a stroke.
European and American scientific societies remind us that atrial fibrillation can multiply the risk of stroke by fiveThe problem is that it often occurs intermittently and, in a significant percentage of patients, without clear symptoms, or with such vague discomfort that it is attributed to age, stress, or lack of physical fitness.
When a person has a conventional electrocardiogram performed in a consultation, the professional only has access to a “snapshot” of a few seconds of the heart rhythm. If the heart is beating normally at that moment, the recording will be correct even if the patient suffers sporadic episodes of atrial fibrillation at other times of the day or night; therefore, it is advisable to supplement recordings with guidelines on How to take an electrocardiogram with the Apple Watch where applicable.
This intermittent nature explains why, despite undergoing regular checkups, Many patients remain undiagnosed until a complication arises. It would be like a stroke. This is precisely where devices capable of continuously recording the pulse for hours and days at a time can make a difference, although it's worth remembering that low-power mode can affect that capability, as analyses on [unclear] point out. functions affected by low power mode.
Apple Watch: PPG, ECG, and continuous wrist-based monitoring
Apple's commitment to heart health took a significant leap in 2018 with the arrival of the Apple Watch Series 4The first model to integrate an electrocardiogram (ECG) app and irregular heart rhythm notifications. Since then, numerous cases have accumulated of people who were alerted by the watch to a problem that was later confirmed in a doctor's office.
The device primarily combines two technologies: the Photoplethysmography (PPG) and a single-lead ECGPPG uses an optical sensor on the back of the watch to continuously measure heart rate and detect pulse patterns that don't fit a regular rhythm; how ECG works in Spain is explained in articles such as ECG Apple Watch in Spain.
When the algorithm identifies repeated irregularities, the clock can generate a notification of possible irregular rhythmFor its part, the ECG function allows the user to obtain a simple recording by placing a finger on the digital crown for a few seconds; this tracing, although less complete than a 12-lead clinical electrocardiogram, is useful for identifying atrial fibrillation in many cases.
Compared to more traditional monitoring systems, such as Holter monitors with adhesive electrodes and a bulky external device Unlike implantable heart rate monitors, smartwatches have the advantage of integrating into daily life with less inconvenience. Most users wear them for many hours a day without giving it much thought, which significantly increases the probability of "catching" a sporadic episode.
The researchers at Amsterdam UMC emphasize that devices capable of recording pulse and cardiac electrical activity already existed, but There was a lack of robust studies in real-world settings that assessed its usefulness as a screening tool. in high-risk populations. This trial aims to fill part of that gap with measurable data.
More diagnoses… and a significant number of false positives
Besides the clear difference in the number of confirmed cases, detailed analysis of the work shows that the Apple Watch It's not a perfect instrumentAlmost half of the alerts generated by the watch during monitoring turned out to be false positives, that is, irregular rhythm warnings that were later not confirmed as atrial fibrillation or another clinically significant arrhythmia.
From a healthcare perspective, this implies a increased workload of consultations and additional tests to clarify whether or not there is a real problem. It can also cause concern in some users, who, upon receiving a heart alert from their watch, naturally tend to worry and consult their doctor; for these cases, it is helpful to remember guidelines and Apple Watch tips that help interpret alerts.
However, specialists point out that beyond this possible anxiety and the time spent ruling out pathology, No direct adverse effects associated with the alerts have been observed.In technical terms, the technology gains in sensitivity —detecting more potential cases—, but loses some specificity.
In healthcare systems with high demand, as is the case in much of Europe and in the Spanish public healthcare system, this situation opens up a debate about how Integrate notifications from smartwatches in an orderly manner in the bypass and diagnostic circuits, avoiding both unnecessary saturation and underestimation of important warnings.
The authors of the study insist that, although the watch can accurately identify patterns consistent with atrial fibrillation, Diagnostic confirmation should always be performed in a medical setting.with higher quality records and professional evaluation. The Apple Watch is therefore intended as an early warning system, not as a substitute for a formal diagnosis.
Potential impact on stroke and healthcare costs in Europe
the cardiologist Michiel Winter, Amsterdam UMC, summarizes the scope of these results by highlighting that the use of smartwatches with PPG and ECG helps doctors diagnose arrhythmias in people who were completely unaware of their problem, accelerating the diagnostic process and allowing for earlier intervention.
When atrial fibrillation is confirmed, one of the main stroke prevention measures is the prescription of anticoagulant treatment In high-risk patients, anticoagulation is used to reduce clot formation. However, various international studies indicate that up to half of those who should be on anticoagulants are not, often due to a lack of diagnosis.
If more people—including asymptomatic patients—can be identified in the early stages, professionals can start preventive therapies earlier and reduce the likelihood of strokes related to atrial fibrillation. The benefit would be twofold: improved quality of life for patients and reduction of costs associated with hospitalizations, sequelae and rehabilitationStudies and analyses on how the Apple Watch can influence the prevention of cardiac events have also explored this economic and clinical impact, as discussed in articles on heart attack prevention.
Winter himself points out that, in highly selected, high-risk groups such as those included in the trial, The reduction in complications could offset the initial cost of the watch.This point is especially relevant in public health systems like the Spanish one, where any investment in technology must be justified by its impact on health and economic sustainability.
What does this mean for users in Spain and the rest of Europe?
For the general population, and particularly for those who already use an Apple Watch or another smartwatch with heart rate monitoring, the underlying message is that the device can be a an interesting ally for monitoring heart rateHowever, it should not be seen as a substitute for medical check-ups or tests prescribed by a professional.
If the watch gives repeated warnings of irregular rhythm or records unusual ECG tracings, the reasonable thing to do is Contact the healthcare system and request a full evaluation., instead of just relying on the interpretation offered by the app itself, however advanced the algorithm may be.
At the same time, it's best to avoid the opposite extreme: an Apple Watch without alerts. It does not guarantee 100% that there is no heart problem.Especially if you experience intense palpitations, dizziness, shortness of breath, chest pain, or fainting spells. In these cases, the recommendation remains to consult a healthcare professional, regardless of what the screen indicates.
European scientific societies remind us that these clocks should be understood as complementary tools within a cardiovascular prevention strategyTheir real usefulness will depend on how they are integrated into care pathways, the training of professionals and patients, and the ability to filter and prioritize the information they generate.
With the evidence provided by the Amsterdam UMC trial and other peer-reviewed studies, the idea that the Apple Watch and similar devices can play a relevant role in the early detection of atrial fibrillation and in reducing the risk of strokeThis is especially true for older people and those with risk factors. It remains to be seen how this will translate into clinical guidelines and the organization of care in Spain and the rest of Europe, but all indications are that the wrist is becoming a new strategic point for monitoring heart health.
