The Electrocardiogram ECG - person.hst.aau.dk · Measurement of ECG Einthoven I, II og III +-Lead I...
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Transcript of The Electrocardiogram ECG - person.hst.aau.dk · Measurement of ECG Einthoven I, II og III +-Lead I...
SMI - ISTAalborg University KDN/2004
The ElectrocardiogramECG
SMI - ISTAalborg University KDN/2004
Content
• Heart and Electrocardiography• Recording exersize• Selfstudy using multimedia
SMI - ISTAalborg University KDN/2004
Vital Signs
1. Cardiovascular system2. Respiratory system3. Renal functions4. Central nerveous system5. Fluid, electrolytes and
bloodgas levels
SMI - ISTAalborg University KDN/2004
Vital Signs Monitoring
Observation
Decision
Plan
Patient
Info
diagnosistherapy
data
Diagnostic Therapeutic Cycle
SMI - ISTAalborg University KDN/2004
The Heart and ECG
SMI - ISTAalborg University KDN/2004
The Heart
•Muscle tissue
•Self-pacing
•1/200 * body mass
•4 chamber pump
•Transport O2, CO2• and metabolites
SMI - ISTAalborg University KDN/2004
Circulatory system
•The heart is a four chamber pump divided in twosides.
•Each side has one chamber (atrium) receiving the blood and one (ventricule) pumping the blood away
•The right side receive blood loaded with CO2 from the body to the lungs, and the left side moves blood loaded with O2 from the lungs to the body
SMI - ISTAalborg University KDN/2004
The Heart
Superior cava venaSinuatrial node
Right atriumInferior cava vena
Opening of coronary sinusAtrioventricular node
Interventricular septum
Right bundle branchPapillary muscles with
Purkinje fibers
Left atrium
Atrioventricular bundle (bundle of His)Bifurcation of atrioventricular bundle
Left bundle branchPapillary muscles
SMI - ISTAalborg University KDN/2004
Circulatory system
•The circulatory systems delivers oxygen, nutrients and hormones throughout the body,
•Provides mechanisms for body temperature regulation and removing the heat generated by the metabolic activities
•Diffusion of oxygen, carbon dioxide and others small solutes from cells to capillary and vice-versa
SMI - ISTAalborg University KDN/2004
Circulatory system
•Pulmonary circulation: vessels that lead from and to the lungs
•Systemic circulation: vessels that lead from and to the rest of the body tissues
•Arteries: blood vessels that carry blood way from the heart
•Veins: blood vessels that carry blood towards the heart
SMI - ISTAalborg University KDN/2004
Heart and circulation
1-way valves keep the blood moving in the correct direction during the systole.
SMI - ISTAalborg University KDN/2004
1. Cardiac cells are linked and tightly coupled so that action potentials spread (1 m/s)
2. Cells depolarisation results in contraction in the atria (atrialsystole - move blood in the from right/left atrium to right/left ventricule)
3. The activation wave moves to the atrioventricular node (0.05 m/s) - ventricules are completely filled with blood
4. Then, the activation wave moves to the Purkinje system (specialised conduction tissue) which spreads the wave very rapidly (3 m/s) to many cells in both ventricules resulting in simultaneous contraction of both ventricules (ventricular systole)
PQ
R
S
T
Electrocardiogram (ECG)
SMI - ISTAalborg University KDN/2004
Electrocardiogram (ECG)
The ECG is the electrical measure of the sum of ionic changes in the heart during pumping – it forms a vectorfield.
P
Q
R
S
T
•P: Depolarisation of the atria
•QRS: Depolarisation of the ventricules
•T: Repolarisation of the ventricules
P
Q
R
S
T
T
SMI - ISTAalborg University KDN/2004
ECG
Phases of contraction
SMI - ISTAalborg University KDN/2004
ECG andcirculation
Average Pulse Rates
Adult Males about 72
Adult Females 76 to 80
Newborns up to 140
Children about 90
Elderly 50 to 65
Average Blood Pressure Rates
Systolic 110 to 150 mm Hg
over
Diastolic 60 to 80 mm Hg
Normal Heart Sound S1 and S3Lupp Dupp
Aortic StenosisS1 and S3Lupp Dupp
SMI - ISTAalborg University KDN/2004
Multimedia Tutorial
Blaufuss multimedia www.blaufuss.org
SMI - ISTAalborg University KDN/2004
Measurement of ECG
Einthoven I, II og III
+
- Lead I - measures the potential difference between the right arm electrode and the left arm electrode. The third electrode (left leg) acts as neutral.
Lead II - measures the potential difference between the right arm and left leg electrode.
Lead III - measures the potential difference between the left arm and left leg electrode.
SMI - ISTAalborg University KDN/2004
Normal ECG
20 msec per div
0.1 mV per div
Derivation I ECG
SMI - ISTAalborg University KDN/2004
Normal ECG – Pre Cordial Derivations
Einthoven I isekvivalent withV5 derivation
+
-
Wilson reference scheme
SMI - ISTAalborg University KDN/2004
Non-Normal ECG
SMI - ISTAalborg University KDN/2004
Non-Normal ECG
SMI - ISTAalborg University KDN/2004
Non-Normal ECG
SMI - ISTAalborg University KDN/2004
ECG electrodes
SMI - ISTAalborg University KDN/2004
ECG Instrumentation biomedical applications
Feature
extraction.TransducingPhysiological
dataUser /
Decision
support
Conditioning Sampling
A/D
Classifikation
EEG
EKG
EMG
ENG
EOG
BP
Temp
.
Thresholding
Boolean inference
Fuzzy logic
Neural network
Bayesian net
.
Averaging
Amplitude
Bin integ.
FFT
AR(MA)
Kalman filters
TFA
Single Val. Dec.
Prime Comp. Ana.
.
Resolution
Sampling frequency
Amplification
Filtering
Noise reduction
Safety
Signalprocessing
.
SMI - ISTAalborg University KDN/2004
Bandwidths, Amplitude Ranges, and Quantization of Some Frequently Used Biosignals
Signal Bandwidth Amplitude Quantization(Hz) (range) (bits)
Electroencephalogram 0.2-50 600 µV 4-6
Electrooculogram 0.2-15 10 mV 4-6
Electrocardiogram 0.15-150 10 mV 10-12
Electromyogram 20-8000 10 mV 4-8
Blood pressure 0-60 400 mm Hg 8-10
Spirogram 0-40 10 L 8-10
Phonocardiogram 5-2000 80 dB 8-10
SMI - ISTAalborg University KDN/2004
ECG instrumentation
Gain: 10000.1 – 150Hz
SMI - ISTAalborg University KDN/2004
Normal ECGand
Artefacts
Mains-noise +movements
Loose electrodes +movements
Respiration +EMG
Amplifier saturation
SMI - ISTAalborg University KDN/2004
Normal ECGand bad
instrumentation HF-limitation
LF-limitation
SMI - ISTAalborg University KDN/2004
Noise removal and detection
SMI - ISTAalborg University KDN/2004
0 10 20 30 40 50 60-2000
-1000
0
1000
2000
3000
seconds
Am
plitu
deInputsignal
0 10 20 30 40 50 60-1.5
-1
-0.5
0
0.5
1x 10
5
seconds
Slo
pe
Differentialquotient
MATLAB
» EcgCounting
Number_of_QRS_Complexes =
68
Elapsed_time =
2.4700
Matlab
SMI - ISTAalborg University KDN/2004
Demonstration of ECG recording and vital signs monitoring
ECGSaO2NI-BPTemp
Propaq ICU-monitor