The Apple Watch’s abnormal pulse detection feature risks overwhelming health services with false positive results, researchers have warned. 

In a paper for the Journal of the American Medical Informatics Association, researchers from the US-based Mayo Clinic expressed concern that the alerts or messages people receive from their watch could prompt them to visit their doctor unnecessarily. 

“False positive screening results have the potential to lead to excessive healthcare resource utilisation and anxiety among the ‘worried well’,” the researchers wrote.

They based their concern on a study of 264 people, whose doctors’ notes at Mayo Clinics in Minnesota, Arizona, Florida, Wisconsin and Iowa included reference to the Apple Watch and its abnormal pulse detection feature. Only 11pc of those patients were later diagnosed with a cardiovascular issue. 

Researchers suggest these false positives may be linked to users reading their watch data incorrectly. Only 41 of the 264 records explicitly mentioned receiving an Apple Watch “alert” that tells users to seek medical advice. In the other cases, reference to an alert could be missing because the doctor did not write it down, or because patients manually accessed their heart rate data in the monitoring app. 

But data accessed manually can include erratic pulses which are in fact harmless, Dr. Stephen Kopecky, a Mayo Clinic cardiologist and one of the paper’s authors, told the Telegraph. “Most of us have some irregular beats throughout the day,” he said. 

The study also suggested the feature was being used against guidance issued by The US Food and Drug Administration, which warned in 2018, that it had “not been tested for and is not intended for use in people under 22 years of age”.

“It is also not intended for use in individuals previously diagnosed with [atrial fibrillation].”

Yet 8.7pc of patients who featured in the Mayo Clinic study were under 22, and 22pc already suffered from the condition.

The Apple Watch has been capable of monitoring its users’ pulses since late 2018. But the launch for the new Apple Watch Series 6 this month focused specifically on the product’s ability to save lives via its health monitoring features. 

The latest Watch features an abnormal pulse detection tool which is designed to help its users understand if they are suffering from a condition called “silent” atrial fibrillation. This is one of the most common forms of Cardiac arrhythmia, where a heart beats irregularly. 

An optical heart sensor on the Watch is used to detect any variations in beat‑to‑beat intervals when the user is at rest. If the algorithm detects an irregular rhythm suggestive of atrial fibrillation, the user will receive an alert.

Six of the 41 study participants whose notes mention an abnormal pulse alert received a diagnosis. Even in a small study, it is unclear why this number is low – at 15pc. 

This could be because atrial fibrillation is difficult to diagnose as symptoms appear intermittently and it is thought that as many as one-third of cases may experience no symptoms at all. 

The Mayo Clinic’s Dr Kopecky also suggested these “false positives could be due to artifact” or errors, such as the watch misreading muscle movements as a person’s pulse. 

However there have been cases where Apple’s Watch has been linked to life-saving treatment. Last year, Paul Hutton, who was 48 at the time, received multiple alerts from his watch that his heart rate was too low. Those alerts eventually led him to be diagnosed with ventricular bigeminy, a condition where an irregular heart beat makes it difficult to effectively pump blood. 

The British Heart Foundation said the medical community is only beginning to understand the benefits and drawbacks of this technology.

“Although smart watches have potential for spotting an irregular heartbeat before the wearer displays any noticeable symptoms, more research is needed to determine how this data can be generated to be put to the best possible use,” a spokesperson said.

“If utilised correctly, innovative technology, such as wearable devices, could provide helpful resources for healthcare professionals in identifying patients at risk.”

Concerns about false positives highlight the challenges ahead as the emerging “medtech” sector pushes healthcare into a new era, making it possible for more people to monitor their health indetail. 

Apple has yet to reply to a request for comment. 

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