One in every six people will have a stroke in their lifetime. With the aging of the population, this frequency is expected to increase in the coming years, and it is necessary to develop new strategies to improve the prevention of new cases. A study led by Vall d'Hebron has analyzed the use of smartwatches for early detection of atrial fibrillation, the most common type of arrhythmia, which increases the risk of stroke by up to five times. The results, published in Sensors, show that they could be a useful complementary tool to medical care in the follow-up of hospitalized patients after a stroke to prevent recurrence. The work has been led by Dr. Jorge Pagola, researcher of the Stroke Research Group of Vall d'Hebron Research Institute (VHIR) and adjunct of the Stroke Unit of the Vall d'Hebron University Hospital together with the Arrhythmia Unit and in collaboration with the Joan XXIII University Hospital and the University Hospital of Girona Dr. Josep Trueta.

The study was carried out with 70 patients from the Vall d'Hebron Hospital aged 80 years on average and hospitalized for having recently suffered a stroke. All of them wore a Fitbit smartwatch to measure heart rate and, in addition, a continuous electrocardiogram was performed for a few hours. The aim was to compare the results obtained with both strategies when detecting atrial fibrillation, which are associated with a higher probability of suffering a stroke and, moreover, of it being more severe and disabling. "The watches represent a simple-to-use, low-cost, non-invasive and well-accepted strategy that could be useful for monitoring patients, also in elderly people", explains Dr. Claudia Meza, member of the Stroke Unit of Vall d'Hebron Hospital and researcher of the Stroke Research Group at VHIR.

On the one hand, heart rate was measured in hospitalized patients, and it was observed that the watch tended to underestimate the real values, especially when they were higher than 100 beats per minute or when there was an episode of arrhythmia. It is thought that the changes in the skin and blood circulation present in advanced age may alter the measurement and, therefore, the watches would not be recommended for monitoring heart rate in these patients.

On the other hand, the researchers analyzed the watch alerts that appear when it detects that there is an irregular heart rhythm, suggestive of atrial fibrillation. It was found that the watch was capable of detecting 34.5% of real cases of this arrhythmia, with a specificity of 100%. In other words, it detected one third of the cases, but all of them actually had atrial fibrillation according to the electrocardiogram.

Based on the results, smartwatches can help track some stroke patients over the long term, especially those with intermittent episodes of arrhythmias and no clear associated symptoms, which can be difficult to detect without continuous monitoring. "It is important to emphasize that they should be a tool to help the usual diagnostic methods for detecting arrhythmias. In no case should they replace regular medical care, as we must then confirm the results obtained and adjust treatment accordingly if necessary to prevent subsequent strokes", emphasizes Dr. Jorge Pagola.

In the future, more research is needed to evaluate the effectiveness of these methods in clinical practice, both in younger people and in patients who are not hospitalized while going about their daily lives. In addition, it is expected that continued technological development will also increase the sensitivity to detect a higher percentage of cases.

The study has received funding from the Instituto de Salud Carlos III and co-financed by the European Union (ERDF/ESF) - A way to build Europe ((PI2001210), as well as the eHealth Center of the Universitat Oberta de Catalunya (UOC).