Magnetic field interactions of smartwatches and portable electronic devices with cardiovascular implantable electronic devices

Funding Acknowledgements

Type of funding sources: None.

Introduction

Magnetic interference of portable electronic devices (PEDs), such as state-of-the-art mobile phones, with cardiovascular implantable electronic devices (CIEDs) has been reported.

Purpose

The aim of the study was to quantify the magnetic fields of latest generation Smartwatches and other PEDs and to evaluate and predict their risk of CIED interactions.

Method

High resolution magnetic field characterization of five smartwatches able to record an ECG Apple Watch, Series 6 and 7, Fitbit Sense, Samsung Galaxy Watch 3, and Withings Move ECG Watch was performed using a magnetic field camera consisting of 1024 calibrated three axis Hall sensors. Maximal distance of 1 mT (10 Gauss) field strength and 1 mT volume was calculated. Ex vivo measurements of the minimal safety distance (MSD) at which no mode switch can be observed between six representative CIEDs and the PEDs was performed. Results were compared to other PEDs, such as digital pens, headsets and their cases, and a Smartphone.

Result

Maximal 1 mT distances ranged between 10 mm and 19 mm, and 1 mT volumes between 6 cm3 and 19 cm3. The smartwatches and PEDs with measured 1 mT distance 15 mm (B: Microsoft surface pen, C: Airpods Pro case) showed device interaction up to > 15 mm (Figure). Linear regression analysis showed an inverse linear relationship of the MSD with 1 mT distance (B coefficient: 0.459; 95% CI: 0.246-0.672; p<0.001) but not with the volume (p=0.842)

Conclusions

Standardized measurements of the 1 mT field distance and volume is feasible and has the potential to assess the risk of CIED interaction. Smartwatches seem to be safe in contrast to other PEDs such as the Microsoft surface pen or Airpods Pro case with high 1mT volumes and maximal distances with regards to CIED interaction.

Versatile Trans-Replication Systems for Chikungunya Virus Allow Functional Analysis and Tagging of Every Replicase Protein

Chikungunya virus (CHIKV; genus Alphavirus, family Togaviridae) has recently caused several major outbreaks affecting millions of people. There are no licensed vaccines or antivirals, and the knowledge of the molecular biology of CHIKV, crucial for development of efficient antiviral strategies, remains fragmentary. CHIKV has a 12 kb positive-strand RNA genome, which is translated to yield a nonstructural (ns) or replicase polyprotein. CHIKV structural proteins are expressed from a subgenomic RNA synthesized in infected cells. Here we have developed CHIKV trans-replication systems, where replicase expression and RNA replication are uncoupled. Bacteriophage T7 RNA polymerase or cellular RNA polymerase II were used for production of mRNAs for CHIKV ns polyprotein and template RNAs, which are recognized by CHIKV replicase and encode for reporter proteins. CHIKV replicase efficiently amplified such RNA templates and synthesized large amounts of subgenomic RNA in several cell lines. This system was used to create tagged versions of ns proteins including nsP1 fused with enhanced green fluorescent protein and nsP4 with an immunological tag. Analysis of these constructs and a matching set of replicon vectors revealed that the replicases containing tagged ns proteins were functional and maintained their subcellular localizations. When cells were co-transfected with constructs expressing template RNA and wild type or tagged versions of CHIKV replicases, formation of characteristic replicase complexes (spherules) was observed. Analysis of mutations associated with noncytotoxic phenotype in CHIKV replicons showed that a low level of RNA replication is not a pre-requisite for reduced cytotoxicity. The CHIKV trans-replicase does not suffer from genetic instability and represents an efficient, sensitive and reliable tool for studies of different aspects of CHIKV RNA replication process.