This document is from a 2007 MIT course on biomedical signal and image processing. It provides an introduction to clinical electrocardiography (ECG) through several sections: an overview of ECG and what it measures; a discussion of the electrophysiology of individual heart cells; how electrical currents propagate through heart tissue; specific structures of the heart that the currents pass through; and how this results in a measurable signal on the body surface. The document includes diagrams of heart anatomy and electrical activity, as well as illustrations of cellular electrophysiology.

1. MIT OpenCourseWare
http://ocw.mit.edu
HST.582J / 6.555J / 16.456J Biomedical Signal and Image Processing
Spring 2007
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2. Harvard-MIT Division of Health Sciences and Technology
HST.582J: Biomedical Signal and Image Processing, Spring 2007
Course Director: Dr. Julie Greenberg
Introduction to Clinical
Electrocardiography
Andrew Reisner, MD
MGH Dept. of Emergency Medicine
Visiting Scientist, HST
Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].

3. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Electrocardiography
{ The heart is an electrical organ, and
its activity can be measured non-
invasively
{ Wealth of information related to:
z The electrical patterns proper
z The geometry of the heart tissue
z The metabolic state of the heart
{ Standard tool used in a wide-range
of medical evaluations

4. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology . Downloaded on [DD Month YYYY].
A heart
• Blood circulates, passing near
every cell in the body, driven by this
pump
• …actually, two pumps…
• Atria = turbochargers
• Myocardium = muscle
• Mechanical systole
• Electrical systole
Courtesy of Dr. Roger Mark. HST.542J Quantitative Physiology: Organ
Transport Systems, Spring 2004. (Massachusetts Institute of Technology:
MIT OpenCourseWare). http://ocw.mit.edu (accessed June 17, 2008).
Figure adapted from Phillips RE, Feeney MK, 1980 The Cardiac Rhythms.
Saunders, Philadelphia and from Hoffman BF, Cranefield PF 1960 Electrophysiology
of the Heart. McGraw Hill, New York.

5. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
To understand the ECG:
{ Electrophysiology of a single cell
{ How a wave of electrical current
propagates through myocardium
{ Specific structures of the heart
through which the electrical wave
travels
{ How that leads to a measurable
signal on the surface of the body

6. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Part I: A little electrophysiology

7. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Once upon a time, there was a cell:
ATPase
ATPase

8. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
-
-90
90
Resting comfortably
a myocyte

9. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
Depolarizing trigger

10. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
Na
channels
open,
briefly

11. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
In: Na+
Mystery
current

12. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
In: Na+
Ca++ is in balance
with K+ out

13. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
In: Na+
Excitation/Contraction Coupling:
Ca++ causes the Troponin Complex
(C, I & T) to release inhibition
of Actin & Myosin

14. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
In: Na+
Ca++ in; K+ out
More K+ out;
Ca++ flow halts

15. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
In: Na+
In: Ca++; Out: K+
Out: K+
Sodium channels reset

16. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
In: Na+
Higher resting potential
Few sodium channels reset
Slower upstroke

17. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
a pacemaker cell
Slow current of Na+ in;
note the resting potential
is less negative in a
pacemaker cell
-
-55
55

18. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
a pacemaker cell
Threshold voltage
-
-40
40

19. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
Ca++ flows in

20. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
. . . and K+ flows out

21. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
. . . and when it is negative
again, a few Na+
channels open

22. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
How a wave of electrical current
propagates through myocardium
{ Typically, an impulse originating
anywhere in the myocardium will
propagate throughout the heart
{ Cells communicate electrically via
“gap junctions”
{ Behaves as a “syncytium”
{ Think of the “wave” at a football
game!

23. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
The dipole field due to current flow in a myocardial cell at the
advancing front of depolarization.
Vm is the transmembrane potential.
Courtesy of Dr. Roger Mark.HST.542J Quantitative Physiology: Organ Transport Systems, Spring 2004. (Massachusetts
Institute of Technology: MIT OpenCourseWare). http://ocw.mit.edu (accessed June 17, 2008).

24. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Cardiac Electrical Activity
Figure by MIT OpenCourseWare.
Q S
T
R
P
SA node
(Pacemaker)
AV node
(delay)
AV bundle
& branches
(Insulated)
Purkinje fibers (Activation)
Fibro-fatty atrioventricular
groove (Separates atrial and
ventricular tissue)
Contractile
Conductive
Nonconductive

25. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Important specific structures
{ Sino-atrial node = pacemaker
(usually)
{ Atria
{ After electrical excitation:
contraction
{ Atrioventricular node (a tactical
pause)
{ Ventricular conducting fibers
(freeways)
{ Ventricular myocardium (surface
roads)
After electrical excitation: contraction
{

26. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
The Idealized Spherical Torso with the
Centrally Located Cardiac Source (Simple
dipole model)
Courtesy of Dr. Roger Mark. HST.542J Quantitative Physiology: Organ Transport Systems, Spring 2004. (Massachusetts
Institute of Technology: MIT OpenCourseWare). http://ocw.mit.edu (accessed June 17, 2008).

27. Figure by MIT OpenCourseWare. After F. Netter.
Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Excitation of the Heart

28. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Excitation of the Heart
Figure by MIT OpenCourseWare. After F. Netter.

29. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Figure by MIT OpenCourseWare.

30. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
-1200
-1500
aVR
aVF
aVL
I
II
III
-900
-800
-300
+300
+600
+900
+1200
+1500
1800
00
Figure by MIT OpenCourseWare.

31. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
The temporal pattern of the heart vector
combined with the geometry of the standard
frontal plane limb leads.
Figure by MIT OpenCourseWare.
I
II
III

32. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Cardiac Electrical Activity
Figure by MIT OpenCourseWare.
Courtesy of Dr. Roger Mark. HST.542J Quantitative
Physiology: Organ Transport Systems, Spring 2004.
(Massachusetts Institute of Technology: MIT OpenCourseWare).
http://ocw.mit.edu (accessed June 17, 2008). Figure adapted
from Phillips RE, Feeney MK, 1980 The Cardiac Rhythms.
Saunders, Philadelphia and from Hoffman BF, Cranefiel
PF 1960 Electrophysiology of the Heart. McGraw Hill, New York.
Q S
T
R
P
SA node
(Pacemaker)
AV node
(delay)
AV bundle
& branches
(Insulated)
Purkinje fibers (Activation)
Fibro-fatty atrioventricular
groove (Separates atrial and
ventricular tissue)
Contractile
Conductive
Nonconductive

33. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Normal features of the electrocardiogram.
Figure by MIT OpenCourseWare. After p. 50 in Netter, Frank H. A Compilation of Paintings on the Normal and Pathologic
Anatomy and Physiology, Embryology, and Diseases of the Heart, edited by Fredrick F. Yonkman. Vol. 5 of The Ciba
Collection of Medical Illustrations. Summit, N.J.: Ciba Pharmaceutical Company, 1969.

34. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Normal sinus rhythm
Figure 15 - Normal Sinus Rhythm—Rate 85
Figure by MIT OpenCourseWare.

35. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
What has changed?
Figure 16 - Sinus Tachycardia—Rate 122
Figure by MIT OpenCourseWare.

36. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Sinus bradycardia
Figure 17 - Sinus Bradycardia—Rate 48
V1
Figure by MIT OpenCourseWare.

37. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
Neurohumeral factors
Vagal stimulation makes
the resting potential
MORE NEGATIVE. . .

38. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
Neurohumeral factors
. . . and the pacemaker
current SLOWER. . .

39. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
. . . and raise the
THRESHOLD

40. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
Catecholamines make
the resting potential
MORE EXCITED. . .

41. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
. . . and speed the
PACEMAKER
CURRENT. . .

42. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
. . . and lower the
THRESHOLD FOR
DISCHARGE. . .

43. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
Vagal Stimulation:

44. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
Ricardo Montelban Effect
Vagal Stimulation:
Image removed due to
copyright restrictions.
Photo of actor Ricardo
Montelban.

45. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
Adrenergic Stim. =

46. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
time
time
Intracellu
lar
Intracellu
lar
millivoltag
e
millivoltag
e
Adrenergic Stim. =
Potsy Effect
Image removed due to
copyright restrictions.
Photo of characters from TV
show “Happy Days,” including
Potsy.

47. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Sinus arrhythmia
Figure 18 - Sinus Arrhythmia
Figure by MIT OpenCourseWare.

48. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
(
Atrial premature contractions
(see arrowheads)
Figure by MIT OpenCourseWare.
Figure 25 - Atrial Premature Contractions

49. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].

50. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
{ Usually just a spark; rarely sufficient
for an explosion
{ “Leakiness” leads to pacemaker-like
current
{ Early after-depolarization
{ Late after-depolarization

51. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
What’s going on here?
Figure by MIT OpenCourseWare.
Figure 36 - Ventricular Premature Contractions

52. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Wave-front Trajectory in a Ventricular
Premature Contraction.

53. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Is this the same thing?
Figure by MIT OpenCourseWare.
Figure 24 - Ventricular Escape Beat

54. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
What’s going on here?
Figure 50 - Complete A-V Block with Junctional Escape Rhythm
Figure by MIT OpenCourseWare.

55. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
What’s going on here?
Figure 35 - Atrial Fibrillation (2 examples)
Figure by MIT OpenCourseWare.

56. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Non-sustained ventricular tachycardia
(3 episodes)
Figure by MIT OpenCourseWare.
Figure 43 - Short Bursts of Ventricular Tachycardia

57. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Slow Refractory
Quick Refractory
KeyWords:
Heterogeneous, Circus, Self-Perpetuating
Side “A” Side “B”

58. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
No Longer
Refractory
KeyWords:
Heterogeneous, Circus, Self-Perpetuating
Side “A” Side “B”

59. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
KeyWords:
Heterogeneous, Circus, Self-Perpetuating
Side “A” Side “B”

60. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
KeyWords:
Heterogeneous, Circus, Self-Perpetuating
Side “A” Side “B”

61. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
KeyWords:
Heterogeneous, Circus, Self-Perpetuating
Side “A” Side “B”

62. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
KeyWords:
Heterogeneous, Circus, Self-Perpetuating
Side “A” Side “B”

63. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
INCREASED
Refractory
Side “A” Side “B”

64. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
INCREASED
Refractory
Side “A” Side “B”

65. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
INCREASED
Refractory
Side “A” Side “B”

66. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
INCREASED
Refractory
Side “A” Side “B”

67. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
INCREASED
Refractory
Side “A” Side “B”

68. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
INCREASED
Refractory
Side “A” Side “B”

69. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Ventricular Fibrillation
Figure 45 - Three Examples of Ventricular Fibrillation
Figure by MIT OpenCourseWare.

70. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].

71. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].

72. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].

73. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].

74. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Heart attack

75. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Figure by MIT OpenCourseWare.
-1200
-1500
aVR
aVF
aVL
I
II
III
-900
-800
-300
+300
+600
+900
+1200
+1500
1800
00

76. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Figure by MIT OpenCourseWare.

77. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Heart attack

78. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Hyperkalemia
See ECG Wave-Maven (http://ecg.bidmc.harvard.edu/maven/mavenmain.asp) for
many other examples of how metabolic conditions can affect the ECG.
Courtesy of Ary Goldberger, M.D. Used with permission.
Source: Nathanson L A, McClennen S, Safran C, Goldberger AL. ECG Wave-Maven: Self-Assessment Program for Students and
Clinicians. http://ecg.bidmc.harvard.edu. Case #164.

79. Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].
Understanding the ECG:
A Cautionary Note
{ Basic cell electrophysiology, wavefront
propagation model, dipole model:
Powerful, but incomplete
{ There will always be electrophysiologic
phenomena which will not conform with
these explanatory models
{ Examples:
z metabolic disturbances
z anti-arrhythmic medications
z need for 12-lead ECG to record a 3-D
phenomenon

80. Questions?
Cite as: Andrew Reisner. Course materials for HST.582J / 6.555J / 16.456J, Biomedical Signal and Image Processing, Spring 2007. MIT OpenCourseWare
(http://ocw.mit.edu), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY].