1. Basic Dysrhythmias Chemeketa Paramedic Program
-Basic Anatomy of the Heart
-Electrical Conduction of the Heart
-A System of Defining 3-Lead EKG’s

2. What is an:
EKG?
ECG?
EEG?
EGG?
Isn’t School Great?

3. Heart A & P Location Pieces, Parts Important Vessels Electrolyte Role
Pulling apart waveforms

4. Valves & Vessels

5. Review of Important Vessels

6. A System of Checks & Balances
Respond by:
Stimulating sympathetic
Adrenergic response
Alpha, Beta & Dopaminergic
Norepi & Epi release
Inhibiting Parasympathetic
Acetylcholine
Cholinergic Response
Medulla
Regulatory organ
Baroreceptors (Pressoreceptors)
Found:
Internal carotid arteries
Aortic Arch
Chemoreceptors
Found in same places
Monitors pH, O2 & CO2

7. Electrical Conduction System
Sympathetic-Thoracic/Lumbar Nerve
Norepinephrine
HR, Contractility
Parasympathetic-Vagus Nerve
Acetylcholine
HR (Valsalva)
Chronotropic-HR
Inotropic-Contraction

8. Electrolytes & Conduction
“Excitable” cells of the Heart
Self-depolarizing cells (Automaticity)
Electrolytes of the Heart (Na+ / K+/ Ca++)

9. Electrolytes & Conduction
Membrane Potential (MP)
Slight difference between charge inside & out
Threshold
MP becomes high enough to depolarize
Action Potential
Ability of cells at a given time
Difference (mV) between inside & out

10. The Cardiac Cycle

11. Membrane Potential

12. Sodium-Potassium Calcium “The Wave” MP Rises Slow Channels
Na+ Channels Open
Rapid Influx (Fast Channels)
Cell Attains + Charge
K+ Channels Open
Outflow
The Pump
ATP Transports:
3 Na+ out & 2 K+ in
Restores Resting cellular conditions
Calcium
Slow Channels
Selective Permeability
“The Wave”
One cell contraction
Spreads

13. Electrical Conduction System
Na+ - Depolarization
K+ - Repolarization
> = < Automaticity & Conduction
< = > Irritability
Ca++ - Depolarization and Contraction
> = > Contractility
< = < Contractility, > Irritability

14. Electrical Conduction System
Na+ in & K+ out = Depolarization
K+ in & Na+ out = Repolarization
Imbalances in K+ or Na+
Effects Automaticity & Conduction
Hypo & hyperkalemia affects irritability
Ca++ - Depolarization and Contraction
Affects Contractility
Hypo & Hypercalcemia effects contractile force

15. I know what you’re thinking… Who gives a @#$% !!!
You are caring for a patient with a rapid heart rate. You follow protocols and administer 20mg of Diltiazem.
You’re patient responds by becoming:
Less responsive
Bradycardic
B/P drops to 72/40
Weak Pulse at wrist
Not responding to fluid, time or positioning.
What now???
Calcium Gluconate 10%
500 – 1000 mg slow IV Push
@#$% = Dang

16. Phases Phase 0 – Rapid Depolarization
Reached max potential -90mV
Fast Na+ Channels Open
Cell now positive +25mV
Phase 1 – Early Rapid Repolarization
Fast Na+ Channels Close
K+ still being lost
MP approaching 0mV
Phase 2 – Prolonged Slow Repolarization
Plateau Phase
Muscle finishing contraction
Beginning to relax
MP staying close to 0mV

17. Phases Phase 3 – End of Rapid Repolarization Phase 4
K+ returns to inside
Cell returns to -90mV
Almost ready
Phase 4
Na+ - K+ Pump turns on
Sends Na+ out
Brings K+ in
Ready to do it all over again now 

18. Refractory Periods Excuse me!!! I hate to interrupt again, but, who cares???
Absolute Refractory Period
Polarity of cell prohibits depolarization
Relative Refractory Period
Cell is returning to ready state for depolarization
Impulse now is BAD!!!
R on T Phenomenon
Causes VT & VF
Treated with defibrillation
Can be caused by:
Frequent FLB’s
EMT-P not pushing the “sync” button

19. The Electrocardiograph (ECG, EKG)
Electrical Activity
Not Heart Action
Records + and – impulses
Paper runs at 25mm/s
Counting Rates
6 second strip x 10
10 Second Strip x 6
The little number on the monitor 

20. Lead Considerations $25,000 mVoltmeter Lead Views: 1 – Lateral
2 – Inferior
3 – Inferior

21. The Components SA Node Internodal Pathways AV Junction AV Node
Bundle of His
L & R Bundle Branch
Purkinje Network
Purkinje Fibers

22. Flip and See ECG, Cohn/Gilroy-Doohan
Ode to a Node
Have a heart, and have no fear, The SA node is over here. Beating at a constant rate, 60 – 100 is really great. The AV node can make a show, If SA node has gone too slow. 40 – 60 is not too bad If it’s all you’ve got, you will be glad. Should the whole thing drop it’s speed, His and bundle branches will take the lead. And that, my friend is the whole and part, Of the conduction system of your heart.
Flip and See ECG, Cohn/Gilroy-Doohan

23. Sino Atrial Node The Natural “Pacemaker” Fires 60-100 times per minute
Connects directly to atrial fibers
Fires times per minute
Wavelike Atrial Depolarization
The P-Wave
P-Wave
P-R Interval
Q-Wave
.04 Sec
0.20 Seconds per 5 Boxes

24. AV Junction Receives impulses from SA Node via the Atrial Cells
An electrical funnel
Impulses hit at various times
Causes delay
PR-I
Susceptible to blockage
Path from A to V
Delivers impulse to the AV Node

25. Atrio-Ventricular Node
Lies between the Atria and Ventricles
Collects impulses from above
Stimulates Ventricles
If unstimulated
Intrinsic rate 40-60

26. Bundle of His / Left and Right Bundle Branches
Distributes Impulses from the Node
“The Ventricular Messengers”

27. Purkinje Network/Fibers
Direct connection with ventricular tissue
Intrinsic rate if unstimulated
P-Wave
P-R Interval
QRS Complex
T-Wave

28. P-Wave
P-R Interval
QRS Complex
T-Wave R
PRI
Baseline Q S

29. The Six Step Approach What is the Rate? Is the Rhythm Regular?
Are there P-Waves?
Is the P-R Interval Normal?
Is the QRS Complex Normal?
Is There a P-Wave for Every QRS?

30. Step 1 = Rate Is the rate between 60-100 (Sinus)
Between (Junctional/Bradycardic)
Above 100 (Tachycardic)
Between (Ventricular)

31. Step 2 = Regularity At-a-glance: Does it look regular?
Are the P-Waves evenly spaced?
Are the QRS Complexes evenly spaced?

32. Step 3 = P-Waves Are P-Waves present? Are they upright and rounded?
Are they irregular in any way: Notched / Peaked / Depressed…?
Are they all the same?

33. Step 4 = P-R Interval Is the P-R Interval between 0.12-0.20?
Is it too long / too short? (Block)
Is it the same on every conduction?
Is it absent?

34. Step 5 = QRS Complex Is it there? Is it between 0.04 - 0.12?
Does it have any abnormalities? (Notched / Rabbit Eared / Wide / Bizarre)

35. Step 6 = P-QRS Married? Is there a P-wave for every QRS?
Are there more P-Waves than QRS?
Are the P-Waves after or within the QRS?

36. Describe What You’ve Found!!!
IN GENERAL (underlying rhythms)!!!
What are the abnormalities?
Does it originate in the Sinus Node?
Does it follow through from the Atria to the ventricles? Are there abnormal delays?
What are the exceptions to the underlying rhythm? (Describe those also)

38. Normal Sinus Rhythm Rate: 60 - 100 Regularity: Very
P-Waves: Present and Normal
P-R I: sec
QRS: sec and Normal
Married: 1 P: 1 QRS, no extras or shortages

39. Sinus Arrhythmia Rate: 60 - 100 Regularity: Irregular
P-Waves: Present and Normal
P-R I: sec
QRS: sec and Normal
Married: 1 P: 1 QRS, no extras or shortages

40. Sinus Tachycardia Rate: Over 100 Regularity: Regular
P-Waves: Present and Normal
P-R I: sec
QRS: sec and Normal
Married: 1 P: 1 QRS, no extras or shortages

41. Sinus Bradycardia Rate: Less than 60 Regularity: Regular
P-Waves: Present and Normal
P-R I: sec
QRS: sec and Normal
Married: 1 P: 1 QRS, no extras or shortages

42. Atrial Fibrillation Rate: Usually tachy
Regularity: Irregular (Irregularly irregular)
P-Waves: Not Discernible
P-R I: Undeterminable
QRS: sec
Married: Undeterminable

43. Atrial Flutter Rate: Usually tachy Regularity: Atria Regular
Ventricles May be Irregular
P-Waves: Sawtooth Pattern 2:1, 3:1, 4:1...
P-R I: sec on conducting beat
QRS: sec
Married: P-waves outnumber QRS
(Picket fence)

44. (Paroxysmal) Supra Ventricular Tach
Rate:
Regularity: Regular
P-Waves: Usually falls within the QRS-T complex ( sometimes not visible)
P-R I: Shorter than 0.12, or absent
QRS: sec and Normal
Married: Undeterminable

45. SVT WPW Usually based on Hx. Delta wave on Q Shortened PR-I
No Verapamil – Accessory Path use increase

46. 1st Degree Heart Block Rate: 60 - 100 Regularity: Very
P-Waves: Present and Normal
P-R I: Longer than 0.20 sec
QRS: sec and Normal
Married: 1 P: 1 QRS, no extras or shortages

47. 2nd Degree Heart Block (Type 1) Wenkebach
Rate: Can be Normal, or usually brady
Regularity: Irregular
P-Waves: Present and Normal
P-R I: Lengthens until beat is dropped
QRS: sec and Normal
Married: P-wave present on conducting beats, increased delay causes missed QRS

48. 2nd Degree Heart Block (Type 2) Mobitz II
Rate: Less than 60
Regularity: Irregular
P-Waves: Present, 2:1, 3:1, 4:1
P-R I: sec on conducting beat
QRS: sec, may begin to widen
Married: P-wave for every QRS and extras depending on conduction ratio

49. 3rd Degree Heart Block (CHB) Complete Heart Block
Rate: Ventricular Rate 40-60
Regularity: Atria-Regular
Vent-Regular
P-Waves: Present and Normal
P-R I: Atria independent of Ventricles
QRS: Usually greater than 0.12 sec
Married: P-waves completely unrelated to QRS Complexes.

50. Complete Heart Block

51. Junctional Rhythm Rate: 40-60 Regularity: Regular
P-Waves: Inverted, Retrograde or Absent
P-R I: Shortened or absent
QRS: sec
Married: P-wave for every QRS, sometimes not visible

52. Junctional

53. Junctional Accelerated Rhythm
Regularity: Regular
P-Waves: Inverted, Retrograde or Absent
P-R I: Shortened or absent
QRS: sec
Married: P-wave for every QRS, sometimes not visible

54. Accelerated Junctional

55. Junctional Tachycardia
Rate:
Regularity: Regular
P-Waves: Inverted, Retrograde or Absent
P-R I: Shortened or absent
QRS: sec
Married: P-wave for every QRS, sometimes not visible

56. Junctional Tachycardia

57. Ventricular Tachycardia
Rate:
Regularity: Regular
P-Waves: None
P-R I: None
QRS: Greater than 0.12 sec
Married: NO
We’ll look at Torsades de Pointes in Lab

58. Ventricular Tachycardia

59. Ventricular Fibrillation
Rate: No ventricular rate
Regularity: Irregular
P-Waves: No
P-R I: No
QRS: No, unorganized ventricular baseline
Married: No

60. Ventricular Fibrillation

61. Asystole Rate: 0 Regularity: N/A P-Waves: None P-R I: N/A QRS: None
Married: No (verify a second lead)

62. Asystole

63. Agonal / Idioventricular
Rate: 20-40
Regularity: Irregular
P-Waves: None
P-R I: N/A
QRS: Wider than 0.12 sec
Married: NO (a dying heart)

64. Idioventricular
Less regular than this!

65. Exceptions / Disruptions
Premature Ventricular Contractions
Premature Atrial Contractions
Bundle Branch Blocks
Pacer Considerations (Atrial, Ventricular or Both)

66. Premature Ventricular Contractions
Wide, Bizarre QRS Complex
Always identify the underlying rhythm first
Can appear in couplets, triplets, short runs of V-Tach, bigeminy and trigeminy
Can be uni-focal or multi-focal
Caused by random firing within the ventricles
Not accompanied by a P-wave

67. PVC’s

68. PAC’s P-QRS Complex appearing in an unexpected location
Caused by a stimulus from within the Atria, but not from the SA Node

69. PJC

70. Bundle Branch Block
Any rhythm having a BBB will have a widened twin peaked R-Wave

71. Paced Rhythms Patients may have various types of pacemakers Atrial
Ventricular
Both
Vertical spike on monitor is an indicator

72. Paced Rhythms Various

73. Loose Leads/Moving Ambulance
Artifact
60 Cycle Interference
Loose Leads/Moving Ambulance

74. In Summary Really Cool Physiology!!! GENERAL RULES to Interpretation
Applicable to 3 – lead monitoring
Practice, Practice, Practice…
Remember the rules, NOT how it looks coming from one patient or one rhythm generator!!!

75. Sources – In order of preference
Many of the pictures and info from:
Flip and See ECG, 2nd Edition
Cohn/Gilroy-Doohan
A great resource
Paramedic Paramedic Textbook, Revised 2nd Edition
Mick J. Sanders, Mosby
ECG’s Made Easy, 2nd Edition
Barbara Aehlert, RN, Mosby
Basic Dysrhythmias, Interpretation and Management, 3rd Edition
Robert J. Huszar, Mosby