portable ecg collection system james cook joe konwinski carmen hayes mentor: dr. mingui sun march 15...

Portable ECG Collection SystemJames CookJoe KonwinskiCarmen Hayes

Mentor: Dr. Mingui SunMarch 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 transformationuses statistics to pick outimportant 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

ST

R??

Q

P + noise

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

1 minute: 140 KB 20 KB

1 hour: 8,400 KB 1,200 KB

1 day: 201,600 KB 28,800 KB 8+ days with 256 MB chip!