Transcript Specific Aim I

Portable ECG Collection System
James Cook
Joe Konwinski
Carmen Hayes
Mentor: Dr. Mingui Sun
March 15st 2005
Outline
• Introduction
• My Focus
• Specific Aims
• What is left to do?
Introduction
• Develop a small device that can:
• Cleanly amplify the electric activity of the heart
• Save the amplified signal onto flash memory
• Produce a program that can:
• Analyze the ECG data and give heart-risk
feedback to the user
• Be sold over-the-counter
• Be user-friendly and safe
• Purpose: Assess heart risk of seemingly
healthy middle to upper aged individuals
My Focus
• Research methods of diagnosing heart
disease via ECG
• Research ECG analysis algorithms
• Develop analysis software
Specific Aim I
ECG System:
• Normally has 12
leads, each one
takes a “picture” of
the heart from a
different aspect.
Specific Aim I
• We will be using
only 1 electrode, so
a location must be
chosen that collects
all key parts of the
waveform
adequately
Specific Aim I
ECG and Heart Disease
• Heart Block
• Electrical pathway from Atria to
Ventricles is impaired or severed
entirely
• Non-consequential or very serious
depending on its extent
Specific Aim I
ECG and Heart Disease
• Heart Block
•1st Degree: P-R interval > 0.2 sec
•2nd Degree: Occasional lacking of
QRS wave
•3rd Degree: P and QRS waves are not
coupled at all
•Also Bundle Branch Block, but it’s less
consequential and more difficult to diagnose
Specific Aim I
ECG and Heart Disease
• Arrhythmia
• Heart Rate less than 60 or more than
100 BPM
• Periodic beat-to-beat change in P-R
interval
Specific Aim II
Analyzing the ECG Waveform
• Normally done via human
interpretation
• Few programmatic methods in
existence
Specific Aim II
Analyzing the ECG Waveform
• Triangle transformation
uses statistics to pick out
important parts of the
waveform.
• Somewhat complicated
and probably unnecessary
Specific Aim III
Analysis Software Development
• Preliminary data collected at 240 Hz
with the amplifier.
Specific Aim III
Analysis Software Development
• Data was imported
using LabVIEW.
• Baseline was
calculated using a
moving average filter
in intervals of 1 sec.
Specific Aim III
Analysis Software Development
• Baseline was subtracted and data
was filtered to remove
high-frequency noise
Specific Aim III
Analysis Software Development
• Peak detector algorithm run to find
locations of peaks (and valleys) as well
as their amplitudes, 1st, 2nd, and 3rd
derivatives
S Q
T
??P + noise
R
Specific Aim III
Analysis Software Development
• Groups of data were found using an edge
detection algorithm, which will be used to
isolate important parts of the waveform
Specific Aim III
Analysis Software Development
• Once peaks are identified, analyzing
timing is simple!
• For instance, Joe’s resting heart-rate is 78
BPM (no stethoscope required)
• This will be useful in diagnosing the
aforementioned diseases and many
others
What’s Left?
• More preliminary testing
• Perfect the software
• Flash memory
• Complete business plan
Questions??
Data Collection at
240 Hz:
uncompressed
compressed
140 KB
20 KB
1 hour:
8,400 KB
1,200 KB
1 day:
201,600 KB
28,800 KB
1 minute:
8+ days with
256 MB chip!