# Feasibility and reliability of a smartwatch to detect atrial fibrillation after cardiac surgery: a prospective study

## TL;DR

This study tested a smartwatch's ability to detect heart rhythm issues after surgery and found it has high accuracy but cannot fully replace traditional monitoring.

## Contribution

The first clinical evaluation of the Withings Scanwatch's photoplethysmography sensor for postoperative atrial fibrillation detection.

## Key findings

- The smartwatch detected atrial fibrillation with 69.0% sensitivity and 98.7% specificity.
- It showed a positive predictive value of 87.0% and a negative predictive value of 96.2%.
- The device may support conventional screening but cannot replace it due to moderate sensitivity.

## Abstract

Atrial fibrillation, the world's predominant cardiac arrhythmia, frequently emerges as a complication post-cardiac surgery, leading to serious outcomes like strokes, heart failures, and even death. Due to its often-silent nature, detecting it can be challenging. Smartwatches present a potential solution, offering screening that is more rigorous.

This prospective observational study sought to assess the Withings Scanwatch's efficacy in identifying postoperative atrial fibrillation.

After cardiac surgery, patients received a Withings Scanwatch. Over a span of 24 h, both the smartwatch's photoplethysmography sensor and standard telemetry kept track of any atrial fibrillation incidents.

At the end of the study, data from 260 patients was available for assessment. Atrial fibrillation was identified in 32 of these patients, either via telemetry or the smartwatch. Our data revealed a sensitivity of 69.0%, specificity of 98.7%, a positive predictive value of 87.0%, and a negative predictive value of 96.2%.

This clinical study is the first to evaluate the photoplethysmography sensor of the Withings Scanwatch, and it shows that the Scanwatch has high a specificity and moderate sensitivity in detecting postoperative atrial fibrillation. Thus, Scanwatch may support the conventional screening for atrial fibrillation, and potentially reducing complications and costs of atrial fibrillation. Because of lower than expected sensitivity this technology cannot replace conventional monitoring in postoperative patients.