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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!