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Transcript of ECG1
Portable ECG Signal acquisition device with Bluetooth capabilities.
Designed for patients that had suffer a heart failure but are stable in their homes.
Able to send alert messages to emergency contacts and/or doctors when an
anomaly is detected in the heart activity of the patient.
The system is divided in four main parts:
Acquisition of ECG signals .
Transmission of data via Bluetooth to an Android mobile device.
Android Mobile application for display and processing of ECG waveforms.
Emergency Alert: Text Message (SMS) and/or Email. System Overview Wireless ECG Monitoring System Data is captured directly from the body using electrodes.
Signal is filtered in the ECG device by the bio-potential amplifier.
The analog signal is converter to digital using the Arduino® module. ECG Data Acquisition and A/D Conversion Transmission of ECG digital data via Bluetooth®.
Android® application receives the data for data processing and display. Wireless Transmission via Bluetooth® Data Stored in SD Card can be sent by email.
Text Messages (SMS) will be send automatically to emergency contacts in case of emergency. Emergency Alert System Bipolar leads: record voltage between electrodes placed on wrists & legs (right leg is ground)
Lead I : records between right arm & left arm
Lead II: right arm & left leg
Lead III: left arm & left leg Data Acquisition Condition the ECG signal for analog-to-digital (A/D) conversion Bio-potential Amplifier Specifications: Bio-potential Amplifier Bluegiga WT11 module
Bluetooth Class 1
Bluetooth v.2.1 + EDR
Baud rate: 115200 bps
Simple ASCII based host protocol
Transmit Power: + 17dBm
Receiver Sensitivity: -86 dBm
HCI over UART Bluetooth® Arduino BT Operation Voltage: 1.2 to 5.5V
A/D resolution: 10 bits
6 analog inputs
Memory : ATmega328P Microprocessor: Arduino BT-V06 Leonardo Rodríguez-Negrón
Mayrim Y. Verdejo-Wichy
Jaime J. Camacho-Rosa
November 27, 2012
INEL 5195: ECE Capstone
Prof. Lizdabel Morales / Prof. Raúl Torres Wireless ECG Monitoring System Motivation
Electrocardiogram (ECG) Theory
Data Acquisition & Biopotential Amplifier
ECG Processing Algorithms
Heart Rate Calculation
Agencies and Regulations
Questions Outline Heart related diseases are the main reasons for causing deaths in United States.
United States statistics:
Every 1 out of 3 deaths due to heart diseases.
5 million Americans suffer from heart failure
550,000 new cases every year
287,000 deaths each year
11 million physician visits each year
$44 billion cost of Heart diseases Motivation An electrocardiogram (ECG) is a test that records the electrical activity of the heart.
An ECG test shows:
How fast your heart is beating.
Whether the rhythm of your heartbeat is steady or irregular.
The strength and timing of electrical signals as they pass through each part of your heart. Electrocardiogram (ECG) With each heartbeat, an electrical signal spreads from the top of the heart to the bottom.
As it travels, the signal causes the heart to contract and pump blood.
The process repeats with each new heartbeat.
Three distinct waves are produced during cardiac cycle:
P wave: caused by atrial depolarization
QRS complex: caused by ventricular depolarization
T wave: results from ventricular repolarization ECG Signal Arrhythmias: abnormal heart rhythms
Heart Rate < 60/min is Bradycardia
Heart Rate >100/min is Tachycardia
Heart Rate = 0 is Ventricular Fibrillation Arrhythmias ATmega328’s ADC Arduino® SDK Serial Monitor Arduino® Software Development Kit Arduino Software Arduino BT Code Flowchart QRS Detection
Heart Rate Detection
Anomalies Detection ECG Algorithms Pan-Tompkins algorithm
Real-time QRS detection algorithm
Based on amplitude, slope and width of the QRS QRS Detection http://www.pponline.co.uk/encyc/heart-rate-variability-analysis-how-to-improve-your-training-performance-40837 The heart rate (HR) is the number of heartbeats per unit of time.
Heart rate calculation algorithm steps:
Identify the R peaks in consecutive beats.
Measure the distance between the R peaks.
Divide the distance by the sampling rate to obtain the RR interval in sec/beat.
Invert the RR interval (beat/sec).
Convert beats/sec to beats/min multiplying by 60
HR = (60*Fs)/(diff(R_location))
Heart Rate Algorithm PseudoCode:
if HR < 20
display(' Attention: Ventricular Fibrillation Detected.')
elseif HR < 60
display(' Attention: Bradycardia Detected.')
elseif HR > 100
display(' Attention: Tachycardia Detected.')
display(' Normal Heart Rate: No Bradycardia or Tachycardia Detected.')
end Anomalies Detection Algorithms The purpose of the band-pass filter is to emphasize the QRS-complex and attenuate other parts of the ECG wave and the noise. Input ECG Signal QRS Detection After differentiation, the signal is squared point-by-point to create a positive-valued signal.
Emphasizes high frequencies mainly due to QRS complexes. P and T waves are suppressed. Squaring Operation The differentiator is used for highlighting the high slopes that distinguish QRS complexes from low-frequency ECG components such as the P and T waves. Differentiator The moving window integrator is used to ensure that a measure of QRS complex width is included in the processed signal. The maximum value of the signal inside the peak interval is the R Wave.
The minimum value between the inside the peak interval left of the R wave is the Q wave.
The minimum value between the inside the peak interval right of the R wave is the S wave. QRS Peak Detection Moving Integrator Window Mobile Application ConnectMD®
Graphical User Interface for Doctors FDA Medical Devices
FDA 21 CFR 820 – Quality Systems
FDA 21 CFR 870 – Cardiac Devices
ISO Medical Devices
ISO 13485 - Quality Management Systems
HIPAA Agencies and Regulations QUESTIONS ? Future Work Implement the Biopotential Amplifier on a Printed Circuit Board with surface-mounted components to reduce space.
Upgrade the micro controller unit to one with a larger input dynamic range
Implement a notch filter in the Biopotential Amplifier to further eliminate 60 Hz noise
Improve the Android Application to reduce errors and crashing
Implement a database to keep record of the patient's recordings Features and Functions: Mobile Application Communicate with Arduino via Bluetooth
Acquire ECG Signals for Real-Time Display and Heart-Rate Calculation
Alert an emergency contact if abnormal cardiac activity is detected
Saves and send ECG data to physician via email DEMO QUESTIONS? Band-Pass Filter Real Time Data Display