Jena, 15th March 2018. Using smartwatches in measuring important health data has been intensively discussed lately. Not only because of personal health data, but also discussing functional limitations and false positives results. The aim is clear – a smartwatch should not only stay a lifetime tool but contain medical grade applications, certified by a notified body. In relation, scientists from the German Center for Cardiovascular Research (DZHK) at the University Medical Center Greifswald and scientists from the University Hospital Basel published the WATCH AF results, which conclude that smartwatches could be used to comfortably and regularly survey the heart rhythm of patients at increased risk, when using specific algorithms. Atrial fibrillation could be discovered earlier, subsequently leading to prompter diagnosis and therapy initiation for stroke prevention.
Atrial fibrillation (AF) is the most common cardiac arrhythmia with increasing incidence. Unfortunately, AF often is undetected and thus left untreated, as it often occurs as a seizure and does not necessarily cause any discomfort. Undetected and untreated AF increases the stroke risk five times. Approximately a third of ischemic strokes come along with atrial fibrillation. Hence, systematic screening for AF in risk populations, also utilizing smartphone camera or smartwatch PPG, is recommended by the European Heart Rhythm Association.
The prospective controlled WATCH AF trial investigated 672 participants with and without atrial fibrillation to proof, how accurate AF can be detected with a smartwatch utilizing the Preventicus application. For this purpose, the PPG sensor based heart rhythm recordings of the smartwatches were analyzed by the automatic algorithm of Preventicus for the presence of atrial fibrillation. The results were compared with cardiologists final diagnosis based on a mobile electrocardiogram (ECG) device in a blinded way. It showed that the smartwatch can detect atrial fibrillation at least as well and accurately as the mobile ECG. “It was particularly important that not too many false-positive findings were raised by the app. “says Prof. Marcus Dörr, one of the Investigators. “Because this would result in unnecessary investigations and high costs.”
The study also showed that repeated one-minute recordings are sufficient to reliably detect cardiac arrhythmias. In conclusion the results of the WATCH AF trial suggest that detection of AF using a commercially available smartwatch is in principle feasible, with very high diagnostic accuracy, when using the Preventicus application.
Currently, patients with an increased risk of atrial fibrillation receive a long-term ECG (Holte- ECG) that records the heart rhythm mostly for 24h, in dedicated situations up to 72h. If nothing is discovered during this period, one can theoretically stop following the guidelines to monitor the heart rhythm. If the risk is very high and Holter-ECG remains negative, small implantable event recorders behind the sternum can be used in selected cases. A smartwatch is comparatively cheap and theoretically can be purchased by anyone. It may therefore close the gap between the long-term ECG and an implanted device in the future.