1. EKGs…The Basics for FP Residents
Jess Fogler, MD
University of California, San Francisco

2. Part III
Arrhythmias

3. An Approach… Attempt to diagnose NSR: Start with the rhythm strip Rate
Regularity
Measure RR interval carefully if rate fast
Check for P wave before every QRS

4. An Approach… Check leads I, II, aVF
If P waves upright and consistent morphology: originating from sinus node

5. An Approach… If not NSR…evaluate: Rate Regularity Width of QRS complex
Concentrate on finding P waves
V1 most sensitive for P waves
Ps are little “noses” that can deform other waves

7. Atrial Fibrillation The most common sustained arrhythmia
Afib: rapid, small amplitude waves that have inconsistent morphology
Best seen in V1-2, or inferior leads

8. Atrial Fibrillation Not all irregular rhythms are afib
Irregularly irregular
Aflutter with variable conduction
Multifocal atrial tachycardia
Multiple PAC’s or PVC’s
Regularly irregular
2° A-V block (type I or II)
Repetitive PVC’s, PJC’s, PAC’s (bigeminy, trigeminy)

9. Atrial Fibrillation
Organized Afib: fibrillatory waves with peak-to-peak amplitude > 2 mm
Waves can look similar
Examine over several seconds to reveal variations in morphology
Differentiate from aflutter (treatment different)

11. Atrial Flutter Continuous regular atrial activity
Re-entrant atrial circuit
Atrial rate /min
Flutter waves must have identical morphology
subtract for confounding effects of QRS, ST segment, T wave

12. Atrial Flutter Classical aflutter (seen in 2/3) Atypical flutter
Cover R waves and look for negative waves in II, III, F with rate
Atypical flutter
Continuous regular atrial activity at

13. Atrial Flutter Conduction of QRS complexes Rhythmicity 1:1 (rare)
2:1 (QRS rate ~ ) most common
3:1
Rhythmicity
Regular rhythm most common
Variable conduction possible
irregular rhythm
Can be irregularly irregular
Compare to afib, organized afib

14. Premature Atrial Complexes
PAC’s are the most common rhythm disturbance
Incidence increases with age
13% healthy boys
75% adult males
More common in patients with cardiac disease
Can trigger other arrhythmias
Afib, aflutter
PSVT

15. Premature Atrial Complexes
PAC’s come in three flavors
1. Premature P wave with normal QRS:
Ectopic atrial focus fires before the sinus node
Different morphology from sinus P wave
Normal QRS when AV node, conduction system repolarized and ready to go.

16. Premature Atrial Complexes
2. Premature P wave with no QRS:
P wave occurs very early
between onset of QRS and peak of T wave
Check T’s carefully for deformations
A-V node and bundles in refractory period (ie asleep)

17. Premature Atrial Complexes
3. Premature P wave with aberrant ventricular conduction
P wave falls after peak of T wave
A-V node “awake”
Other parts of the conduction system still “asleep”
Commonly has RBBB morphology
RB asleep, LB awake

18. Premature Atrial Complexes
All PAC’s are followed by a compensatory pause while the sinus node resets
With multiple PAC’s rhythm can become irregularly irregular

19. Multifocal Atrial Tachycardia
MAT: an irregularly irregular rhythm
P waves with ≥ 3 morphologies per lead
Mean atrial rate >100/min
Variable PR intervals
Non-conducted atrial activity common
Associated with pulmonary disease in 60%

20. Ekg 111
Sinus brady with wenckebach periodicity
?old ant infarct (prob nl)

21. First Degree A-V Block Prolonged A-V conduction
Atrio-ventricular ratio 1:1
P-R interval ≥ 210 msec

22. Second Degree A-V Block
Type I (Wenckebach):
PR prolongation
Regularly irregular rhythm (group beating)
Constant P-P interval
Increase in PR interval (but not necessarily progressive)
leading to a…
Non-conducted P wave
Pause < 2 x RR
Next PR interval usually shortest

23. Second Degree A-V Block
Type II (Mobitz): sudden failure
Constant P-R interval
Constant P-P interval
Dropped beats
Rare
Can progress to asystole, 3˚ A-V block, death
Permanent pacemaker required

24. Third Degree A-V Block
Complete failure of atrial impulse propagation with independent junctional or ventricular escape rhythm
P waves and QRS complexes have no relation to each other
Usually will see more P waves than QRS complexes

26. Paroxysmal Supraventricular Tachycardia (PSVT)
Atrial rhythm: narrow QRS (usually)
Paroxysmal
Rate
AVRT
AVNRT
Atrial tachycardia

27. Paroxysmal Supraventricular Tachycardia (PSVT)
Differentiation between types usually not necessary as treatment for all similar
Unstable patients: DC cardioversion
Stable patients: vagal maneuvers, adenosine, verapamil etc.
Adenosine may reveal flutter waves
ST-T changes are frequent and a poor predictor of underlying CAD (even with chest pain)

28. Wide QRS Complex Tachycardia
First: is the rhythm regular?
Irregularity easily missed at fast rates
Use calipers or measure with paper
Treatment of irregular WCT different than regular WCT

29. Ekg 95
Afib with rapid ventricular response with anterior conduction over accessory pathway

30. Wide QRS Complex Tachycardia
Irregular rhythm:
Afib with BBB or IVCD (pre-existent or rate related)
Afib with anterograde conduction over accessory pathway in WPW
Other causes of an irregular rhythm (aflutter with variable conduction, MAT etc) with BBB, WPW, IVCD

31. ekg97 VT
(actually it’s avrt with anterograde conduction over accessory pathway)

32. Wide QRS Complex Tachycardia
Regular rhythm:
Ventricular driven rhythm:
Vtach - worst case scenario
Supraventricular rhythm with aberrant conduction:
Sinus tach with BBB (pre-existent or rate related) - most common
SVT (atrial tach, PSVT) with BBB
Antidromic reciprocating tachycardia in WPW

33. Wide QRS Complex Tachycardia
Basic diagnostic algorithm for WCT with regular rhythm:
If QRS complex doesn’t fit the typical pattern of either RBBB or LBBB, the diagnosis defaults to Vtach
Remember that sinus tach with BBB is most common so scrutinize for P waves
When in doubt treat for Vtach

34. Ekg 105
Sinus tach (p’s after T waves)
LAE
LBBB
Probable LVH

35. Ekg 104
VT by quick and brugada

36. Train your eyes Train your eyes for Rate: Train your eyes for Rhythm:
Check the computer
Train your eyes for Rhythm:
Check the rhythm strip
Check I, II, avF
Train your eyes for Axis:
Check I, II
Train your eyes for Intervals:
PR: check II
QT: check the computer
QRS: check I, V1

37. Train your eyes Train your eyes for LVH: Train your eyes for MI:
Look at…in order
avL V3 V1
V5,V6
Check your cheat sheet
Read the computer
Train your eyes for MI:
Look at all T waves
Look at all ST segments
Check for Q waves
Check for R waves in V1-2

38. Practice
Makes perfect

39. Rate: 250
QTC: 410
Ekg 80
AVRT short RP tachycardia

40. Rate: 42 QTC: 375 Ekg 111 Sinus brady with wenckebach periodicity
?old ant infarct (prob nl)

41. Rate: 74 QTC: 410 EKG #4: RBBB Lead V1: large R’
Lead I: broad terminal S

42. Rate: 150
QTC: 410
Ekg 71
A flutter with 2:1 conduction

43. Rate: 41 QTC: 360 Ekg 114 Sinus brady with 3AVB Lae
LVH with repol abnl

44. Rate: 62 QTC: 390 EKG #70 Organized afib Inverted T’s inferiorly
?dig effect

45. Rate: 114
QTC: 445
ekg97 VT
(actually it’s avrt with anterograde conduction over accessory pathway)

46. Ekg 113
2AVB mobitz II = dropped beats

47. Rate: 43 QTC: 440 EKG #5: Sinus brady AVB RBBB LAD LAFB
LVH with biphasic T’s

48. Rate: 73 QTC: 390 EKG #6 LBBB Lead V1: deep wide S wave
Lead I: broad, notched R wave (no Q or S)

49. Rate: 42
QTC: 420 I II
EKG #66
Junctional escape rhythm with retrograde Ps
III

50. Rate: 71
QTC: 380
EKG #1
Normal EKG