1. EE 5340/7340, SMU Electrical Engineering Department, © 20051 Electrocardiogram (ECG) n Generated in the heart n amplitude range: 0.5 - 4 mV n frequency range: 0.01-250 Hz n measurement: surface electrodes

2. 2EE 5340/7340, SMU Electrical Engineering Department, © 20052 Structure of Heart n heart chambers n r. atrium, l. atrium n r. ventricle, l. ventricle n heart valves n tricuspid (RA:RV) n Mitral (LA:LV) n semilunar (RV:pulm. art.) n aortic (LV:aorta)

3. EE 5340/7340, SMU Electrical Engineering Department, © 20053 Structure of Heart (cont.) RA RV sup. vena cava pulmonary art. LA LV lungs pulmonary v. aorta coronary arteries coronary sinus

4. EE 5340/7340, SMU Electrical Engineering Department, © 20054 Conductive Tissues in Heart n sino-atrial (SA) node n internodal tracts n AV node n Bundle of His n Purkinje fibers } atria } ventricles

5. EE 5340/7340, SMU Electrical Engineering Department, © 20055 Cardiac Cycle n venous blood enters LA, passes through TC valve to RV n RV contracts, TC valve closes. n pulm. valve opens, blood goes to lungs via pulm. art. n blood enters LA through pulm. vein, passes through open mitral valve to LV n LA contracts, mitral valve closes, aortic valve opens, blood goes to aorta. n 2 atria contract nearly simultaneously (RA contracts a bit earlier) n 2 ventricles contract simultaneously.

6. EE 5340/7340, SMU Electrical Engineering Department, © 20056 Cardiac Output and Chamber Pressures n typically 5 l/min n 70-80% total blood volume in veins n 20% in arteries n remainder in capillaries n systolic (max) pressure: 95-140 mm Hg (120 average) n diastolic (min) pressure: 60-90 mm Hg (80 average) n LV: 130/5 mm Hg (sys/dias) n LA: 9/5 mm Hg n RV 20/5 mm Hg n RA: 3/0 mm Hg

7. EE 5340/7340, SMU Electrical Engineering Department, © 20057 Electrocardiogram Features P Q R S T 0.6s P: atrial depolarization QRS: ventricular depolarization T: ventricular repolarization typical heart rate: 72 BPM

8. EE 5340/7340, SMU Electrical Engineering Department, © 20058 Lead Configurations for ECG Measurement n Bipolar Leads n Augmented Leads n Chest (V) Leads

9. EE 5340/7340, SMU Electrical Engineering Department, © 20059 Bipolar Leads: lead I +_+_ + _

10. EE 5340/7340, SMU Electrical Engineering Department, © 200510 Bipolar Leads: lead II +_+_ + _

11. EE 5340/7340, SMU Electrical Engineering Department, © 200511 Bipolar Leads: lead III +_+_ + _

12. EE 5340/7340, SMU Electrical Engineering Department, © 200512 Augmented Leads: aVR +_+_ + _

13. EE 5340/7340, SMU Electrical Engineering Department, © 200513 Augmented Leads: aVL +_+_ + _

14. EE 5340/7340, SMU Electrical Engineering Department, © 200514 Augmented Leads: aVF +_+_ + _

15. EE 5340/7340, SMU Electrical Engineering Department, © 200415 Unipolar Chest Leads v 1 : fourth intercostal space, at right sternal margin. v 2 : fourth intercostal space, at left sternal margin. v 3 : midway between v 3 and v 4. v 4 : fifth intercostal space, at mid clavicular line. v 5 : same level as v 4, on anterior axillary line. v 6 : same level as v 4, on mid axillary line.

16. EE 5340/7340, SMU Electrical Engineering Department, © 200416 Unipolar Chest Leads (cont.) +_+_ + _

17. EE 5340/7340, SMU Electrical Engineering Department, © 200417 ECG Lead Color Codes C (brown) LA (black) LL (red) RL (green) RA (white)

18. EE 5340/7340, SMU Electrical Engineering Department, © 200418 Surface Cardiac Potentials taken at t = t o suggests an equivalent dipole located within the heart

19. EE 5340/7340, SMU Electrical Engineering Department, © 200419 Eindhoven’s Triangle -very crude solution to inverse problem using bipolar limb leads: RA LA LL _ _ + _ ++ lead II lead I lead III

20. EE 5340/7340, SMU Electrical Engineering Department, © 200420 Abnormal ECG Rhythms Complete Heart Block (AV Block): -atria and ventricles contract independently P P P P + = R T T T R R P R T P R T P

21. EE 5340/7340, SMU Electrical Engineering Department, © 200421 Abnormal ECG Rhythms (cont.) First Degree AV Block: increased AV node delay, get increased P-R intervals. Second Degree Block: get one QRS complext for every two P waves. heart block can be treated with drugs, artificial pacemakers. P P P R T

22. EE 5340/7340, SMU Electrical Engineering Department, © 200422 Ectopic Focus PVC’s Ectopic Focus: region of ischemic cardiac tissue that becomes injured, depolarizes spontaneously, may cause an entire ventricular contraction: PVC also called extrasystole

23. EE 5340/7340, SMU Electrical Engineering Department, © 200423 Tachycardia (Rapid Heart Rate) ectopic focus can also discharge repeatedly producing ventricular (paroxysmal) tachycardia: all QRS complexes if etopic focus is located in atrium, can get atrial flutter: P P P P P R R P P P P

24. EE 5340/7340, SMU Electrical Engineering Department, © 200424 Tachycardia (Rapid Heart Rate) ectopic focus can also discharge repeatedly producing ventricular (paroxysmal) tachycardia: all QRS complexes if etopic focus is located in atrium, can get atrial flutter: P P P P P R R P P P P