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information on
Heart Rate
Variability (HRV),
Heartbeats, and
Autonomic Nervous
System (ANS)
You are at the official
site of
ANSWatch - a
multi-functional wrist
ANSWatch Pro
- Combining functions of ECG, Blood Pressure, and Pulse
Analyzers into one Integrated Portable Device
** ANSWatch employs patent protected biosensors to obtain true waveforms so that mean blood pressure can
be accurately calculated
*** Removal of irregular heartbeats from HRV analysis is required by
1996 International HRV Standard
(Circulation. 1996;93:1043-1065.); Lack of this feature could result in over-estimated total HRV and incorrect
LF, HF, and LF/HF parameters
Device Main Functions - ANSWatch Pro Wrist Monitor

  • Sensor technology: ANSWatch Pro wrist monitor employs a proprietary sensor
    array embedded in the wrist cuff to measure precise radial arterial waveforms (up to
    accuracy of 1 ms or 0.001 sec for x-axis and 1 mmHg for y-axis).  From arterial
    waveforms, the peak-to peak intervals are obtained.  Heart rate variability (HRV)
    analysis is then conducted on both time-domain and frequency-domain bases.  
    Irregular heartbeats (including cardiac arrhythmias) are auto detected, reported, and
    excluded from HRV analyses.  In addition, a high-precision pressure gauge is used for
    measurement of blood pressures (systolic and diastolic) based upon the standard
    oscillometric algorithms.  Mean blood pressure is also obtained by integration and
    averaging of arterial waveforms.

  • Testing posture and condition: ANSWatch Pro wrist monitor is to be worn on the
    left wrist.  Patients are lying down or sitting during testing.  A rest period of at least 10
    minutes is needed before test.  During test, patients should not talk or move.

  • Connection to PC: ANSWatch Pro is connected to a Windows operated PC during
    test and post-analysis via a USB port (recommended).  It can also conduct tests by
    itself and then "sync" to a PC for data download and post-analysis. Test data (including
    irregular pulse waveforms and up to 50 sets) are stored in ANSWatch Pro's on-board
    memory which can be viewed on the device's LCD screen

  • Standard Test (BP, HRV, and irregular heartbeats):  the standard test
    measures blood pressures, heart rate variability HRV, and irregular heartbeats.  The
    test lasts for 7 minutes.  Patient parameters measured include systolic pressure,
    diastolic pressure, mean blood pressure, heart rate, HRV (total ANS activity index), LF
    and LF% (sympathetic activity index), HF and HF% (parasympathetic activity index),
    LF/HF (sympathetic / parasympathetic ratio), and number of irregular heartbeats (in 5-

  • BP Test (skipping HRV and irregular heartbeat tests): the BP test  is a
    shortened test that only measures systolic pressure, diastolic pressure, and heart rate  

  • Real-time Test (user defined test period): the real-time test allows users to
    specify the test period (maximum 20 minutes each test). During test, arterial waveform,
    heart rate, and HRV are reported every 10 sec for their current (real-time) values.  The
    test is particularly suitable for recording transitory effects.

  • Arterial Waveform Analysis (detection of arterial hardening and mitral
    valve prolapse MVP): During a standard test, precise arterial waveforms are
    recorded at three selected air pressures (deep, medium, and shallow; simulation of
    finger strengths used by a traditional Chinese herbal doctor).  Detailed waveform
    analysis is then conducted to obtain important cardiovascular parameters, including
    pulse pressure and vascular stiffness which is related to arterial hardening.  Mitral valve
    prolapse is indicated by the existence of multiple small peaks preceding the next pulse
    (as a result of regurgitation, or back flow of blood from left ventricle to left atrium)

  • Electronic Patient Record (EPR) System: ANSWatch Pro comes with
    ANSWatch Manager, a fully functional electronic patient record system.  Users (as
    physicians, examiners, or patients) can set up their own accounts, store test data,
    analyze and plot test data, and print out test reports (autonomic nervous system,
    cardiovascular system, and pulse waveform analysis).  Raw data (500 data points/sec)
    are stored in PC after Sync.  See some demo figures / plots below

  • EXPORT / IMPORT / SAVE / EXCEL: Test data stored in PC can be saved into
    txt or dat files; Complete test data set can be exported and sent to another ANSWatch
    user (physicians, health professionals, etc.) via e-mail attachments.  Test data table can
    be transferred to Excel by clicking the button "EXCEL".  All plots in ANSWatch manager
    can be copied to Clipboard and pasted onto other standard document editors (such as
    Word, PowerPoint, etc.)

  • Google Health* (Test data upload to cloud): ANSWatch Manager has a built-in
    button for uploading test data to Google Health.  By clicking the button, the user is
    taken to Google Health account log-in page.  Once logged in, the data transfer is
    automatic (detail here). *: Google Health is a trademark of Google Inc.
System Requirements (Computer)

  • Operating System: Windows XP, Vista, or Win 7
  • Display Monitor Resolution: 1024 x 768 (minimum) and up
  • Interface / Port: USB port
  • CPU / RAM: compatible with CPU / RAM of most desktop and notebook computers
    (netbooks or tablets may be too slow or exhibit a delay in display of pulse waveforms)
  • Hard Drive Memory: no particular requirement.  Each test data set takes up less
    than 1 Mb memory.
  • CD-ROM Drive: required for installation of ANSWatch CD (or using a USB flash
  • Peripherals: a printer is required for printout of ANSWatch reports
Play a demo-video to get a feel of
ANSWatch Manager - a complete
electronic patient record system
(hospital model)
(portable model)
ANSWatch Pro
Mobility / Portability
Yes (minimum 3
electrodes or leads)
Yes (minimum 2
electrodes or leads, gel
cream or alcohol)
Low to medium
Ease of operation
Special training needed
Some training needed
No training needed
Effect of Patient Body
Sensitive to test quality
Sensitive to test quality
Highly sensitive to test
Measurement of Heart
rate variability (HRV)
Measurement of heart rate
Measurement of blood
Yes (Systolic, diastolic,
and mean**)
Detection of irregular
Yes (auto and manual
No (some offer manual
removal from HRV
Yes (auto detection with
irregular heartbeats
removed from HRV
Calculation of biological
Yes (based upon the
clinical database
condensed from the public
and private test data)
Patient comfort
Patients are asked to
remove clothing from the
waist up
Patients need to remove
clothing in upper chest or
No removal of clothing
Analysis of arterial
Yes (ANSWatch Manager
System Test
and Pulse
Detection of arterial
Detection of mitral valve
Free customer service for
interpretation of test
Yes (up to 10 tests per
customer per device by

  • Physical dimension: Length 10 cm x width 7 cm x thickness 10 cm
  • Weight: 215 g
  • Power: rechargeable lithium battery
  • Charge time: 4 hours
  • Battery capacity: 700 mA*Hr (more than 10 tests per full charge)
  • Display: LCD (4 cm x 7 cm)
  • Data I/O port: Mini-USB (Virtual COM Port & USB)
  • Blood pressure range and accuracy: 50-180 mmHg (+- 8 mmHg)
  • Heart rate range and accuracy: 40-250 beat/min (+- 1 beat/min)
  • HRV range and accuracy: 0-999 ms (+- 5%)
  • HF% range and accuracy: 0-100% (+- 5%)
  • LF% range and accuracy: 0-100% (+- 5%)
  • LF/HF range and accuracy: 0-999 ((+- 5%)
  • Number of irregular heartbeats: 0-999
  • Data analyzer: ANSWatch Manager (Language: English, Traditional Chinese, and
    Simplified Chinese; Operating system: Windows XP, Vista, and 7)
  • Patient parameters measured: Systolic Pressure, Diastolic Pressure, Mean Blood
    Pressure, Heart Rate, Heart Rate Variability (HRV), High Frequency Component (HF),
    Low Frequency Component (LF), LF/HF, Number of Irregular Heartbeat (other patient
    parameters (such as Total Power, Variance, VLF, RMSSD, PNN50, and Vascular
    Stiffness Index,etc.) are obtained and recorded on PC post-analysis)
  • Operating environment: temperature (15 to 40 degree C); humidity (20% to 99%);
    indoor use.
Targeted Customers

ANSWatch Pro Wrist Monitor is most suitable for the following customers:
  • Teaching hospitals, universities, HRV research groups
  • Major clinics, practitioners (family physicians, psychiatrists, cardiologists, physiologists,
    physical therapists)
  • Chinese herbal doctors
  • Alternative medicine (chiropractics, massage, health spas, acupuncture,etc.)
  • Patients under supervision of physicians with frequent monitoring needs for
    dysautonomia, cardiac arrhythmias, hypertension or hypotension, sleep disorder,
    anxiety/depression/panic disorder, arterial hardening, or mitral valve prolapse (MVP)
  • Graduate students for conducting M.S. or Ph.D. thesis work

  • ANSWatch products are sold with a two-year (24-month) limited warranty (except for
    the bio-sensor module and the lithium battery, both carrying one-year (12-month)
    warranty). Within the warranty period, if your product does not work properly because
    of a defect in materials or workmanship, we will repair your product with new or
    refurbished parts or replace it with a new or a refurbished product. Customers should
    contact Sun Scientific Corporation by e-mail at or their sales
    representative first to arrange for carry-in or mail-in service. There will be no charge for
    labor or parts. The limited warranty does not cover normal wear, mechanical damage,
    or water damage. Warranty is invalidated if the product cover fixed by screws has been
    opened. Product repair with a charge is available for work not covered in the warranty.
    Contact us or your sales representative for details.
Clincal Trials / Studies

  • Large Animal Study Team
University of Utah, SLC, Utah
J. Clark, Ph.D., Professor
E. Jones, M.D., Anesthetist
G. Billings, Ph.D., Research Associate
M. Criddle, Ph.D., Research Associate
G. Burns, V.M.D., Professor

  • Human Clinical Trial Team (1)
Lynn Health Science Institute
Oklahoma University Health Sciences Center
William C. Orr PhD,President and CEO, Clinical
Professor of Medicine

  • Human Clinical Trial Team (2)
Performance and Longevity Center
Salt Laky City, Utah
Carl Kent Hebdon, M.D. ,M.S. President and CEO

  • Human Clinical Trial Team (3)
Tzu-Chi Hospital, HuaLen, Taiwan
T. Kuo, M.D., Ph.D., Professor
J.L. Chen, M.D., Interist
J.H. Yang, Ph.D., Professor
Y. S. Liu, Research Assistant

  • Human Clinical Test Team (4)
Tri-Service General Hospital, Taipei, Taiwan
W.M. Chi, M.D., Ph.D., Director, Professor
Y.F. Lin, M.D., Internist, Ph.d., Director, Professor
T. C. Yen, M.D., Internist
L. Pai, Ph.D., Professor
L. Liang, Director
G.B. Chang, Director
S.H. Tong, Research Assistant

  • Small Animal Study Team
Academia Sinica, Taipei, Taiwan
W.K. Wang, Ph.D., Research Fellow, Professor
T.L. Hsu, Ph.D., Research Associate
I. Chiang, Research Assistant
ANSWatch Journal and
Conference Papers

*Wen Chieh Liang,  John Yuan, Deh Chuan
Sun, Ming Han Lin, Changes in
Physiological Parameters Induced by
Indoor Simulated Driving: Effect of Lower
Body Exercise at Mid-Term Break,
Sensors 2009, 9, 6913-6933

*Liang, W.C., Yuan, J.,Sun, D.C., Lin,
M.H., Changes In Physiological Parameters
Induced By Simulated Driving Tasks:
Morning Vs. Afternoon Session,  J. Chin.
Inst. of Industrial Eng., 25(6), 457-471,

*Wen Chien Liang, John Yuan, D.C. Sun,
Parameters Before and After an Indoor
Simulated Driving Task: Effect of Exercise
Break, 2007 International Conference on
Gerontic Technology and Service
Management (ICGTSM), Nantou County,
Taiwan, March-26-2007

*Wen Chien Liang, John Yuan, D.C. Sun,
Ming Han Lin, Variation in Physiological
Parameters Before and After a Simulated
Driving Task (Part 2) The 14th Annual
Meeting, Ergonomics Society of Taiwan,
March 31, 2007 / Wufong, Taichung County

*Wen Chien Liang, John Yuan, D.C. Sun,
Ming Han Lin, Variation In Physiological
Parameters Before And After An Indoor
Simulated Driving Task In The Afternoon,
2006 Biomedical Engineering and
Technology Conference, Taichung, Taiwan

*D.C. sun, Y.I. Kuo, Y.H. Liang,  S. H.
Tang, Y.F. Lin, Y.H. Chang, J.K, Lin,  
Introduction to a New Wrist Patient Monitor
- ANSWatch and its Clinical Applications,  
9th Conference on Engineering Technology
and Applications of Chinese and Western
Medicine, Taichung, Taiwan, Conference
Proceeding, Page 33-38

More than 10  Ph.D. and M.S. theses
have been published
ECG or ANSWatch for HRV Analysis?

  • HRV analyzers using ECG (Electrocardiography) are widely available.  ANSWatch Pro
    wrist monitor offers several advantages over ECG as compared feature-to-feature
DEMO- ANSWatch Manager (a complete electronic patient
record system)
DEMO- ANSWatch Pro: Standard Test (measurement of
blood pressures, HRV, and irregular heartbeats)
Play a demo-video for a typical
standard test using ANSWatch Pro
connected to a PC
DEMO- ANSWatch Pro: Test Data Page
Download ANSWatch
Manager (free copy)
DEMO- ANSWatch Pro: Wave Page with Auto detected
Irregular Heartbeats (Cardiac Arrhythmias)
Premature contraction followed
by delayed contraction
by delayed contraction
DEMO- ANSWatch Pro: Wave Analysis Page
Normal pulse wave from a young patient (first peak: maximum blood flow;
second peak: closure of aortic valve; third peak: closure of mitral valve)
Pulse wave from a 79-years-old young patient (broadened first peak- an
indication of arterial hardening)
Pulse wave from a 39-years-old lady patient (multiple small peaks
preceding the next waveform - the patient was diagnosed with mitral valve prolapse
and regurgitation by  utrasound echocardiology)
DEMO- ANSWatch Pro: Autonomic Nervous System Test
DEMO- ANSWatch Pro: Pulse Analysis Report
DEMO- ANSWatch Pro: 脈象檢查報告(for Chinese Medicine
(professionals and
individuals) for
experience sharing and
in-depth discussions at  
(click to enter)
Do you have     
- are you monitoring   
- are you taking
prescription drugs?
- are you aware of drug
side effects on ANS?
- self-improvement tips
Read more......
Feeling dizzy      
- are you low in blood
pressure or heart rate?
- are you taking
prescription drugs?
- You may experience
Baroreflex failure
Read more......
Irregular heartbeats?
- often noticing abnormal
heartbeats (missing,
uneven, or super-fast)?
- Yo might have cardiac
- Most sudden death
events are preceded by
irregular heartbeats
Read more......
Mitral Valve Prolapse?
- Mitral valve is the
bicuspid valve between left
atrium and ventricle
- If mitral valve is not
closed properly (called
mitral valve prolapse
MVP), the blood may
backflow during pumping
- there is a strong
connection between panic
attackes and MVP
- How to detect it?
Read more......
Am I having   
- autonomic nervous
system works to fine tune
body conditions depending
on physiological needs
- ANS consists of two
branches: sympathetic and
- do you have balanced
- what are the symptoms of
Read more......
DEMO- ANSWatch Pro: CVS Test Report (for Cardiovascular
system, still in beta)