MetriSense, Inc., Innovative products for ambulatory monitoring of physiological signals and waveforms.
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Actiheart®


Overview

The Actiheart MonitorActiheart is a compact, chest-worn device that records heart rate, inter-beat-interval (IBI), and physical activity. Actiheart digitizes the ECG signal and determines the IBI from the R-to-R interval. Through the use of a software program, the user configures the device for data recording. At the time of configuration, the user may determine which combinations of IBI, Heart Rate, and Activity to record on board the monitor for later download. Following the recording session, the data are transferred to the computer for storage, viewing, and analysis. From the IBI recordings, the heart rate and heart rate variability parameters are calculated. Caloric expenditure can be obtained through the use of a software algorithm that combines concurrent heart rate and activity data. Actiheart is the new gold standard for measuring energy expenditure and has been validated against doubly labeled water (publication in press).

Applications

  • Sports Medicine and Exercise Science: measurement of heart rate, activity, and energy expenditure 
  • Obesity Research: measurement of activity and energy expenditure
  • Stress Monitoring: recording of heart rate and variability during sedentary periods
  • Epidemiology: long-term recording of heart rate and energy expenditure in free-living environments

Actiheart and Energy Expenditure

Actiheart easily measures activity and heart rate as well as calculates energy expenditure for ambulatory activities such as bike riding, skate boarding, weight lifting, etc. Using a validated system of branched modeling**, the Actiheart uses both activity and heart rate data to calculate energy expenditure. This increases the accuracy of energy expenditure measurements over systems that use accelerometry data alone. The user has the option of selecting from daily energy expenditure or advanced energy expenditure modes.

Daily energy expenditure mode displays the amount of energy expended during each day of the recording as shown:

Activity Energy Expenditure using Heart rate and activity


** See bibliography page for details

Advanced energy expenditure mode permits viewing the heart rate and energy expenditure in more detail. An example recording is shown:

Activity Energy Expenditure Software

Actiheart and IBI

The Actiheart can be used in short-term recording mode to record heart rate variability data (HRV). The time stamp of every beat is logged and can be displayed together with the inter-beat interval (IBI) for up to 440,000 beats.

Actiheart Recording Times

The Actiheart is ideal for use in both short- and long-term monitoring situations. The following table shows the maximum recording times available in different modes:

Epoch 15 Seconds 30 Seconds 1 Minute
Recording time HR+Act21 days21 days21 days
Recording time HR+Act +IBI Max-Min 10 days20 days21 days
IBI recording capacity (Beats)440,000N/AN/A

Wearing the Actiheart

MetriSense Actiheart monitor in useThe unit is worn on two standard ECG pads on the chest, and can be worn in one of the two positions as shown at right. The small size of the recorder and the use of standard biocompatible ECG electrodes ensure that the Actiheart monitor is securely but comfortably attached. Actiheart is designed for multiple day use. It is water resistant and is compatible with daily activities. Placement of the device to record accurate data is easily confirmed by a flashing heart rate signal LED.

Weighing less than 10 grams, the Actiheart is easy to wear, and can be worn by subjects of most ages. Actiheart is equipped with a rechargeable battery that is recharged using the USB reader interface or a multiple-device charging station. Data are recorded on board the monitor for future download to a computer using a standard USB connection.

Actiheart Reader/Multicharger

Actiheart monitors communicate with the PC through the use of a Reader/Charger. The Reader/Charger is used to configure the device via the USB port on the computer and to charge the device. Charging may be accomplished from the computer via the USB port or from an external wall converter (available separately). The Actiheart Reader/Charger is a three-port charging station capable of simultaneously charging up to three Actihearts. Multicolored LEDs indicate charging and fully charged states.

Actiheart Reader and Monitor

Actiheart® Features

Monitor

  • ECG signal processing for highly accurate and consistent heart rate data
  • Activity accelerometer samples at 32 Hz
  • 21-day recording time at 15-second epochs
  • Clips onto two ECG electrodes worn on the chest
  • Noninvasive technology
  • Compact and lightweight, weighs less than 10 grams
  • Splash-proof design
  • Nonvolatile memory
  • Ideal for use on various age groups

Software

Actiheart provides the easiest way ever to simultaneously record heart rate and activity data from ambulatory subjects. The device is controlled via the USB reader and the intuitive software, which can be used in the following ways:

  • Configure/setup of the Actiheart
  • Download data from the Actiheart
  • View simultaneous activity and heart rate waveform data
  • Print waveform data
  • Export ASCII data for external analysis
  • Unique, validated algorithm for calculating energy expenditure
  • Calculate daily energy expenditure

PC Requirements

  • Windows 2000 and XP compatible
  • Pentium II® Processor (266 MHz or higher)
  • 64 MB of RAM
  • CD-ROM Drive
  • USB communications port

Additional Information for Actiheart

Download
Brochure
Download
PC software guide to getting started
Download
Actiheart Bibliography
PricesPricing request


Product Images


1 Inter-Beat-Interval (IBI) is the elapsed time in milliseconds between individual QRS waveforms, normally measured relative to the QRS R-wave.