AMALFI - Active Monitoring for Atrial Fibrillation

This study looked at the possible benefits of screening people using a new Zio Patch monitor to detect atrial fibrillation. The results were presented at the European Society of Cardiology (ESC) Congress 2025 and published in JAMA on 29 August 2025. 

Atrial fibrillation is an irregular heart rhythm which may also be faster than normal. While some people with atrial fibrillation have symptoms such as palpitations, light-headedness or shortness of breath, others have no symptoms. The irregular heart beat may also be intermittent.

Small clots can form in the heart due to the irregular heart beat, these clots may travel to the brain where they can cause a stroke. People with atrial fibrillation are thought to be around five times more likely to have a stroke. 

Atrial fibrillation is normally diagnosed using an electrocardiogram (ECG) which records the heart rate at a single point in time. However, as atrial fibrillation may only happen intermittently an ECG might not always detect atrial fibrillation. Also, people without symptoms of atrial fibrillation are unlikely to see their doctor to have their pulse checked and have an ECG done.

The Zio Patch monitor gives a continuous heart trace reading for two weeks and the AMALFI study investigated whether wearing a Zio Patch would increase the number of people detected with atrial fibrillation.

Half of the study participants received the patch and half did not, so that we could compare the Zio Patch to the usual NHS medical care. The Zio Patch results were sent to GPs so that they could discuss any changes in treatment that might be needed. The study team will continue to monitor each participant's medical record for five years.

We hope that this will allow more people to be given the right treatment at an earlier stage and so bring down their risk of having a stroke.