Electrocardiogram (ECG) Hsiao-Lung Chan Dept Electrical Engineering Chang Gung University chanhl@mail.cgu.edu.tw
ECG measurements Patient Monitors First Electrocardiograph (ECG) by William Einthoven in 1903 Portable ECG system ECG Holter Embedded ECG ECG chip ECG 2
Heart anatomy and electrical conduction ECG 3
Pacing rate of cardiac cells John G. Webster, Bioinstrumentation, John Wiley & Sons, 2003. ECG 4
Formation of ECG ECG 5
Deporalization of atrial muscles Atrial reporalization Ventrical depolarization Ventrical repolarization R. Rangayyan, Biomedical Signal Analysis, John Wiely & Sons, 2002.
12-lead ECG Precordial leads: V 1 -V 6 Einthoven leads: I, II & III Goldberger augmented leads: V R, V L & V F ECG 7
ECG 8
Limb leads and augmented leads ECG 9
Bipolar limb leads in frontal plane Precordial leads in transversal plane ECG 10
Precordial leads (chest leads) Referenced to Wilson central terminal ECG 11
Vectorcardiogram (VCG) ECG 12
ECG features P wave : Atrial depolarization QRS complex : Ventricular depolarization T wave : Ventricular repolarization R-R : Heart period P-Q : Conduction delay in the atria Q-T : Ventricular repolarization time ECG 13
Power spectrum of P, QRS complex, and T wave ECG 14
Noise and artifacts in the ECG Baseline wander Electrode motion artifacts Electromyographic noise ECG 15
Pan-Tompkins QRS detection ECG Band-pass Filter 32 d 1 dt 2 32 n 1 Adaptive threshold ECG 16
Heart rate variability (HRV, 心率變異度 ) Parasympathetic modulation Sympathetic modulation 心率變異度 ECG 18
Sinus rhythm Normal sinus rhythm Respiratory sinus arrhythmia ECG 19
Respiratory sinus arrhythmia ECG 20
Premature beat A supraventricular premature beat with a small, negative P wave A premature ventricular beat followed by a compensatory pause ECG 21
Ectopic beats with different origins Bigeminy Trigeminy Interpolated ventricular premature beat ECG 22
Atrial and ventricular tachyarrhythmias Atrial flutter Atrial fibrillation Ventricular flutter Ventricular fibrillation
Atrial flutter ( 心房撲動 ) Atrial fibrillation ( 心房顫動 ) J. Malmivuo, Bioelectromagnetism, Oxfold University Press, 1995. ECG 24
Atria fibrillation Atrial fibrillation Sinus rhythm Blood that remains in the atria becomes "sluggish Allows blood clots to form, Risk of stroke Atria activity analysis ECG 25
Detecting VT and VF by TCI Thaker et al, IEEE Trans. Biomed. Eng. 1990 ECG 26
Threshold crossing interval (TCI) TCI ( N 1) 1000 T 2 T1 T 2 T3 T3 T 4 ECG 27
Detecting VT and VF by TCI ECG 28
Lempel-Ziv complexity (複雜度) ECG 29
Detecting Ventricular Tachycardia and Fibrillation by Complexity Measure (Xu-Sheng Zhang, et al, 1999) window length 3 s 5 s 7 s ECG 30
Sudden cardiac death Major risks for coronary artery disease Myocardial infarction Induced lethal cardiac arrhythmia by myocardial ischemia Major causes of sudden deaths in congestive heat failure Life threatening cardiac arrhythmia Ventricular tachycardia Ventricular fibrillation ECG 31
Myocardial Infarction Normal QRS complex QRS complex after myocardial infarction Infarcted area Lead avf ST-segment elevation upon arrival at emergency room after 10 days after 6 months ECG 32
Stress test: Diagnosis and prognosis of coronary artery disease (CAD) ST-segment depression due to myocardia ischemia 33
ST-Segment Elevation for Heart Attack Detection Robert Fischell on medical inventing, www.ted.com
ST segment elevation, a sign of a heart attack
ST segment elevations related to blockages
Implantable medical device
Acute myocardial infarction from implanted copper stents
AngelMed Guardian System
Reference Leif Sörnmo, Pablo Laguna, Bioelectrical Signal Processing in Cardiac and Neurological Applications, Academic Press, 2005. John Enderle, Susan Blanchard, Joseph Bronzino, Introduction to Biomedical Engineering, Academic Press, 2000. John G. Webster, Medical Instrumentation, application and design, 3 rd Ed., Houghton Mifflin, 2000. Joseph J. Carr, John M. Brown, Introduction to Biomedical Equipment Technology, Pearson Education, 2000.