Features And Specifications; Rhythm Express Tm Model Rx-1 Features; Arrhythmia Detection - VivaQuant Rhythm Express RX-1 User Manual

Chapter 6: Features and Specifications
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Features and Specifications

TM
Rhythm Express Model RX-1 Features
• Combination device—operates as a Wireless Event Recorder, Wireless Holter or Mobile Cardiac Telemetry Device.
• Operating mode and settings can be changed wirelessly
• Long‐life rechargeable Lithium Ion battery.
• Designed for maximum patient compliance. Reliable and simple operation in a one‐piece device.
• Protected against water spray and brief water immersion.
• Significantly less expensive to operate than other devices.
TM
• Employs VivaQuant MDSP technology to reduce cellular data volume by > 95%, improve connectivity, and improve
arrhythmia detection accuracy under typical ambulatory conditions.
• High‐reliability design and simple operation reduce customer support calls.
• Automatic detection of brady, tachy, pause, and AF in Event Recorder and MCT Mode.
Arrhythmia Detection
The RX‐1 incorporates a real‐time embedded arrhythmia detection algorithm. The processing steps employ VivaQuant's
proprietary MDSP technology to remove noise, described in US Patent 8,632,465 (other patents issued and pending).
MDSP noise reduction technology has been shown to reduce noise by up to 26 dB (about 95%). Following noise reduction,
QRS complexes are detected using a proprietary technique described in US Patent 9,408,549 and beat‐to‐beat (btb) RR
intervals and btb heart rate (HR) are subsequently computed. Pause events are identified by the absence of a detected
QRS for longer than the pause threshold defined by the Device Notification Criteria settings. Tachycardia (tachy) is
detected based upon N consecutive beats exceeding the rate threshold setting. Bradycardia (brady) is detected if X
consecutive beats are below the brady threshold. Tachy and brady rate thresholds as well as N and X are defined in the
Device Notification Criteria settings.
Atrial fibrillation (AF) is detected using a proprietary technique described in US Patent 9,314,181. The technique involves
fitting a function to a sequence of btb HR values. The variability and entropy are conditionally evaluated to assess the
degree to which the RR values are irregularly irregular. Segments that are identified as potentially containing AF are then
evaluated for the presence of P‐waves to mitigate false positive events.
VivaQuant conducted performance testing according to the 60601‐2‐47 standard. A summary of performance is shown in
the tables below:
Database QRS Sens.
MIT‐BIH 99.9
AHA 99.7
NST 96.7
QRS PPV
99.8
99.8
89.5
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