The smartphone revolution is transforming healthcare, and a new study published in JAMA Cardiology highlights an exciting development in stroke prevention. Researchers at Karolinska Institutet and Danderyd Hospital have developed a smartphone-based tool that can screen populations for hidden stroke risks, particularly in patients with atrial fibrillation.
Atrial fibrillation is a common cardiac arrhythmia that affects adults, causing the heart to beat irregularly and too fast. When medication fails to control symptoms, electrical cardioversion is used to restore the heart's normal rhythm. However, this procedure requires skilled staff and careful patient preparation, and a significant challenge is that many patients spontaneously return to normal heart rhythm without realizing it.
This is where the new smartphone tool comes in. Called CORAI, it uses photoplethysmography (PPG) to measure small changes in blood flow in the fingertip, allowing for accurate heart rhythm assessment. Patients in the active monitoring group recorded their heart rhythm twice daily using a smartphone for one to two weeks before their planned cardioversion. If the recordings showed a return to normal heart rhythm, the patient was contacted, and the rhythm was confirmed with a standard ECG, allowing for the cancellation of the procedure in advance.
The results were impressive. In the monitored group, only 4.8% of cardioversions were cancelled on the same day, compared to 23.2% in the control group. When specifically looking at late cancellations caused by spontaneous return to normal heart rhythm, the difference was even more striking: 1.0% in the intervention group versus 18.2% in the control group, corresponding to a relative risk reduction of 94.7%.
This early detection method is crucial because untreated atrial fibrillation increases the risk of stroke and heart failure. The study also highlights the accessibility of smartphone-based heart rhythm diagnostics, as 99% of the patients who participated in the study owned a smartphone, even with a median age of 70 years.
As the study's author, Jonatan Fernstad, notes, this technology has the potential to improve access to heart rhythm assessment more generally. The research was funded by Vinnova and the Swedish Heart-Lung Foundation, and while Fernstad is the founder of Corai Medicinteknik AB, the study's authors have disclosed all potential conflicts of interest.
This study is a significant step forward in stroke prevention, and the potential for smartphone-based tools to revolutionize healthcare is immense. As we move forward, further research will explore the effectiveness of this method in detecting previously unknown atrial fibrillation compared to current healthcare methods.
