Heart Monitor Application for Android Craig Santangelo Advisor: Professor Hedrick

Background Information According to the American Heart Association, each year: 785,000 Americans will have a new coronary attack 470,000 will have a recurrent attack 195,000 silent myocardial infarctions Every 25 seconds someone will have a coronary event Every 60 seconds someone will die of one

Background Information Quick response time is crucial to surviving a heart attack because: Cardiac arrest normally occurs within the first 2 hours of the heart attack If victim is not treated within the first 2 hours, permanent heart damage can occur Also, many infarctions can occur without the victim knowing

General System Block Diagram Heart sensors (electrodes) Signal Conditioning A/D Converter Signal Processing Android Application

Specifications Comfortable enough for around-the-house use Quality signal and heart attack detection Minimize error Low noise Sample rate high enough Efficient algorithm Signal processing time frame

Heart sensors Kendall Q-Trace 5400 Resting ECG Electrode Silver/Silver Chloride (Ag/AgCl) sensing system Pre-equipped with conductive adhesive hydrogel Low impedance for a clearer signal

Project Break Down: 2 parts 1. Analog Circuit Developing, constructing, and testing the following: Instrumentation Amplifier Input Driver Optocoupler Output Driver High Pass Filter Low Pass Filter Output gain stage 2. Algorithm Research how a heart attack affects an ECG waveform Develop an algorithm to detect the occurrence of a heart attack Translate the algorithm into MATLAB code for testing

Analog Circuit: Block Diagram Electrodes Instrumentation Amplifier Input Driver Opto- coupler Output Driver Filters Output Gain Stage 9 V BatteryPower Supply (9 V)

Analog Circuit: Main Components Instrumentation Amp AD620 chip Gain = 11 V/V Output Gain Stage LM248 quad op-amp chip Non-inverting amp Gain = 100 V/V High Pass Filter LM248 quad op-amp chip Cutoff frequency: 0.05 Hz Low Pass Filter LM248 quad op-amp chip Cutoff frequency: 160 Hz

A/D Converter Vernier Sensor DAQ USB data acquisition Can sample up to 48 kHz 13 bits single-ended

Common Heart Signal Typical time spans: PR interval: ms PR segment: ms QRS complex: ms ST segment: ms QT interval: ms

Sample rate: 1000 Hz

Heart Attack Algorithm: ST Elevation Most common and most damaging form of a heart attack Requires immediate treatment

Heart Attack Algorithm Necessities 1.Establish a baseline (average of all samples in the PQRST waveform) 2.Detect QRS peak 3.Make sure the signal returns to the baseline directly after the peak within approximately 100 ms (width of ST segment) 4.If signal does not return to the baseline within 100 ms of QRS complex, alert the victim and dial 911

Testing MCI Patient Simulator Physionet.org MATLAB

Possible Problems Muscle activity Extra common mode noise Solution: Better amplifiers with higher CMRR Use of Right Leg Driver Power-line noise Solution: notch filter at 60 Hz

Special Thanks Professor Takashi Buma Professor Hedrick EE Department

Sources Kuangwei Hwang, Diane Limsui, Lianhan Zhao, “Wireless Heart Detector with GPS”, Fall 2004, University of Illinois at Urbana-Champaign. T. Buma, class notes for ECE 386, Department of Electrical Engineering, Union College, Winter 2012 ABC News, “What does an EKG show during a heart attack?” CNWq3w CNWq3w MedicineNet.com, “Electrocardiogram (ECG or EKG)” R. Spengler, “How does my doctor interpret my EKG,” 2002, us/support/topic.asp?hwid=tu6258abc.html us/support/topic.asp?hwid=tu6258abc.html Vernier.com, “SensorDAQ”, Helen Kim, Choon Yik Lee, “Walking Stick with Heart Attack Detection”, Spring 2005, University of Illinois at Urbana-Champaign.

Questions?