Discussion

This case highlights that non-medical devices, such as connected watches, can be helpful to diagnose arrhythmias. Nowadays, HRM watches or other connected watches are more and more worn by sportsmen. Physicians in emergency departments should be aware of the interest to interrogate these devices, as is the case in this case report. There are two types of heart rate monitoring devices: those using electrodes on the skin surface towards the cardiac apex, and wristbands using a transcutaneous technique on the wrist thanks to the photo plethysmograph principle. The precision of these devices remains open to debate due to the fact that they have never been independently tested, and also because there exists a reference technique such as an electrocardiographic record during rest, and during a physical strain. To the best of the authors’ knowledge, only Vasconcellos et alReference Vasconcellos, Seabra, Cunha, Montenegro, Bouskela and Farinatti ¹ tested the precision of a HRM device and a photo plethysmograph technique compared to a medical grade electrocardiographic record, and the test was conducted on 14 obese teenagers. The results did not show any substantial differences between all these techniques. A larger-scale study seems necessary before being able to validate these devices.

This patient presented two AF risks:Reference Miller, Aronis and Chrispin ² excessive weight and inadequate physical training. However, the link between physical activity and lowered AF risk is not linear. Hence, even though the conclusions of the Qureshi et al’s FIT projectReference Qureshi, Alirhayim and Blaha ³ seem to be without appeal, they assert that regular physical training reduces the risk of AF, even more so in the case of obese patients; other studies nuance that statement. For instance, whereas Tromso’s prospective study conducted by Morseth et alReference Morseth, Graff-Iversen and Jacobsen ⁴ on nearly 20,000 patients showed a lowered risk of AF with patients practicing a moderate physical activity compared to those practicing none, this risk increased significantly with patients practicing a high-intensity physical activity. Those results are correlated with Kim et al’s results:Reference Kim, Kim and Park ⁵ they observed that sportsmen having an AF during a physical strain have a maximal maximum volume of oxygen higher than the group with no arrhythmia. Independently, an AF happening during a physical activity, and stopping spontaneously when resting, is a well-known pathologyReference Coelho, Palileo, Ashley, Swiryn, Petropoulos and Welch ^{6 ,} Reference Furlanello, Bertoldi, Dallago, Galassi, Fernando and Biffi ⁷ whose physiopathological roots have yet to be fully explained. O’Keefe et alReference O’Keefe, Patil, Lavie, Magalski, Vogel and McCullough ⁸ suggest that extreme practices such as marathons, ultra-trails, and long biking races cause higher heart pressures and result in micro-lesions. Those micro-lesions can reverse themselves after a week or so, but their multiplication can cause a myocardial fibrosis responsible for disorders such as AF. Those paroxysmal AF episodes can evolve into constant AF in some people.Reference Hoogsteen, Schep, Van Hemel and Van Der Wall ⁹