Remote Monitoring of AF Recurrence using mHealth Technology (REMOTE-AF)
Authors: Adasuriya G , Barsky A , Kralj-Hans I , Mohan S , Gill S , Chen Z , Jarman J , Jones D , Valli H , Gkoutos G , Markides V , Hussain W , Wong T , Kotecha D , Haldar S 
Published: May 2023

Background

Atrial Fibrillation (AF) detection tools have rapidly developed over the last decade alongside the evolution of mobile health (mHealth) monitoring. mHealth wearable technologies have been hypothesised to be a potential non-invasive and near continuous modality for long term detection and monitoring of atrial arrhythmias. We conducted a proof-of-concept study to evaluate changes in heart rate obtained from a consumer wearable device and compare against implanted loop recorder (ILR)-detected recurrence of AF and atrial tachycardia (AT) after AF ablation.

Methods

REMOTE-AF (Remote Monitoring of AF Recurrence Using mHealth Technology;NCT05037136) was a prospectively designed sub study of the CASA-AF randomised controlled trial (NCT04280042). Participants without a permanent pacemaker had an ILR implanted at their index ablation procedure (catheter vs thoracoscopic) for longstanding persistent AF. Heart rate (HR) and step count were continuously monitored using a wrist-worn wearable device connected to a smartphone. Photoplethysmography (PPG) recorded HR data was pre-processed with noise filtration and episodes at 1 -minute intervals over 30 minutes of HR elevations (Z-score = 2) were compared to corresponding ILR data.

Arrhythmias detected by ILR were validated by an independent cardiac physiologist. The AF Effect on Quality of Life (AFEQT) questionnaire was completed by participants at baseline and at the conclusion of the study.

Results

Thirty-five patients were enrolled, with mean age 70.3 +/- 6.8 yrs, 12 (34%) women, and median follow-up 10 months (IQR 8-12 months). ILR analysis revealed 17 out of 35 patients (49%) had recurrence of AF/AT. Compared with ILR recurrence, wearable-derived elevations in HR ≥ 110 beats per minute had a sensitivity of 95.3%, specificity 54.1%, positive predictive value (PPV) 15.8%, negative predictive value (NPV) 99.2% and overall accuracy 57.4%. With PPG recorded HR elevation spikes (non-exercise related), the sensitivity was 87.5%, specificity 62.2%, PPV 39.2%, NPV 92.3% and overall accuracy 64.0% in the entire patient cohort. In the AF/AT recurrence only group, sensitivity was 87.6%, specificity 68.3%, PPV 53.6%, NPV 93.0% and overall accuracy 75.0%.

Conclusion

Consumer wearable devices have the potential to contribute to arrhythmia detection after AF ablation, but further work is needed to improve and validate new composite detection algorithms.

Clinical Perspectives

What is New?

We have utilised a new composite of data obtained from wearable devices in a predominantly older cohort of patients > 65 years old to detect AF/AT recurrence in a long-standing persistent AF (LSPAF) patient population who have undergone AF ablation.

We introduce a novel concept of the ‘spike score’, defined as the rate of change in HR over a consecutive two-minute period to detect AF/AT recurrence.

This is the first study to have achieved this in a post AF ablation cohort of LSPAF compared to the gold standard ILR.

Clinical Implications

The use of wearable devices to look for recurrence of atrial arrythmias in post ablation cohorts may enable a more rapid time to detection for more timely interventions.

Data composites recorded from wearables may be used alongside the PPG waveform to further improve accuracy in detecting atrial arrythmias.

AF/AT recurrence detected via wearable devices and associated smart mobile applications can encourage risk factor modification through lifestyle interventions and improve health literacy.