emergency and critical care notes on arrhytmia

1. Arrhythmias
Kibatu Gebre(BA,BSC)

2. Objectives
At the end of the lesson, students will be able to
 Describe arrhythmia and its’ causes
 Classify arrhythmias
 Define brady - tachy arrhythmias
 Recognize different types of brady - tachy
arrhythmias and their management
 Explain brady - tachy arrhythmias’ algorithms

3. Arrhythmia
• Refers to any disturbance in the rate, regularity,
site of origin, or conduction of the cardiac
electrical impulse
• Is any rhythm that is not normal sinus rhythm
with normal AV conduction

4. Causes
• Could be a symptom of Coronary Artery Disease
(CAD) or other medical problems such as:
- Irritable heart cells
- Blocked signals
- Abnormal pathway
- Drugs and stimulants (caffeine, nicotine…)

5. Classification
1. Bradyarrhyhmia / Bradycardia
2. Tachyarrhythmia / Tachycardia

6. 1. Bradycardia
• Is defined as a ventricular rate < 60 beats/min
• Occurs because of depression of the sinus node
or a conduction system block

7. Classification
A. Sinus bradycardia
B. Conduction blocks
-1st degree AV block
-2nd degree AV block
.Mobitz I (Wenckebach )
.Mobitz II
.3rd degree AV block - complete heart block

8. Simplified Approach to Bradycardia:
4 Steps
• Is my patient stable or unstable?
• Look at the PR interval
• Treat the patient, not the rhythm!
• Consider “DIE”
- Drugs
- Ischemia
- Electrolytes

9. Stable vs. Unstable
• Stable patients are ~ asymptomatic
• Unstable patients exhibit signs and symptoms of
hypo perfusion/circulatory compromise
- Altered mental status
- Ongoing chest pain
- Dyspnea/Tachypnea
- Hypotension

10. Drugs that cause bradycardia
• Beta-blockers
• Calcium-channel blockers
• Digoxine
• Opiates

11. Electrolytes causing bradycardia
• Hypocalcemia
• Hyperkalemia
Ischemic causes of bradycardia
• Acute MI

12. A. Sinus Bradycardia
• Heart rate < 60/min
• Normal PP and RR interval
• Could be physiological
• Identify underlying cause
Causes
• Hypothermia
• Hypothyroidism
• Severe hypoxia
• Myocarditis
• High vagal tone
• Drugs( beta blockers, ca channel blockers…)

13. Sinus bradycardia
*For sinus bradycardia, the heart rate is less than
60 and all other measurements are within normal
limits

14. Treatment
• Asymptomatic
- No specific treatment
• Symptomatic
- Atropine o.5mg IV, repeat as needed q 3-5
minutes to a total of 3mg
- Occasionally 2nd line drugs- dopamine/adrenaline
infusion

15. B. Conduction Block
First Degree AV Block
• Is from prolonged conduction at the level of the
atria, AV node (most common), or His-Purkinje S.
Similar to being in a “traffic jam”
• PR > 0.2 sec
• No specific treatment needed other than avoiding
prolonged nodal blocking agents

16. First Degree AVB
*With first degree atrioventricular block, the PR
interval is constant and measures greater than 0.20
second

17. Second Degree AV Block
• Is when one or more (but not all) atrial impulses
fail to reach the ventricles
• The conduction ratio is the number of P waves to
the number of QRS complexes over a period
of time ( e.g. 2:1 )

18. I. Type I Second-Degree AV Block
• Also called Wenckebach or Mobitz I AV block
• Is associated with progressive impairment of
conduction within the AV node
• Surface ECG shows a lengthening of the PR
interval from beat to beat until a P wave is entirely
blocked
• The PR interval before dropped QRS is longer than
after it

19. -
2nd degree AVB- Type 1
* A Mobitz I rhythm has a cyclical extending PR interval until the
QRS is dropped. Then the cycle begins again (irregular
ventricular response)

20. II. Type II Second-Degree AV Block
(Mobitz Type 2)
• Constant PR interval
• Pattern of conducted and skipped beats,
commonly 2:1 or 3:1
• Delay commonly below AV node (wide QRS)
• Often permanent
• Could be changed to third degree AVB

21. • Arises as a result of advanced aging degeneration,
drug toxicity, ischemia, or other pathologic
conditions
• The PR interval before the dropped QRS complex
is equal to after it

22. Second degree AVB –type 2
*A Mobitz II rhythm has a constant PR interval with
blocked QRS complexes (irregular ventricular response)

23. Management of Second Degree AVB
• Look for reversible causes:
- Electrolytes, Ca, Mg levels
- Digoxin level
- Myocarditis serology
- Cardiac enzymes
• Symptomatic Mobitz I or any Mobitz II – requires
monitoring +/- pacing
• Consult Medicine/Cardiology to determine if
pacemaker recommended

24. Third degree AV block
• Also called complete heart block
• No correlation bln atrial & ventricular
depolarization (complete AV dissociation)
• Patient may exhibit signs and symptoms of low CO

25. Third degree AVB
*In third degree atrioventricular block, the P-P and R-
R intervals are regular (constant) but firing at
different rates

26. Management of Third Degree AVB
• Transcutanuous pacing
• Think about “DIE” and correct reversible causes
- Drugs
- Ischemia
- Electrolytes
• Pressors as needed
• Call ICU/Cardiology/Medicine early!
• Definitive pacemaker

27. Bradycardia Algorithm

29. 2. Tachyarrhythmia
• Are defined as cardiac rhythms whose ventricular
rate exceeds 100 beat/min
• Rate-related symptoms are uncommon if it is
 150 beat/min

30. Classification of tachyarrhythmia

31. Rhythm assessment
Four questions to be raised
1. Is it sinus or not?
2. Is it a fast, slow or a normal rhythm?
3. Is it regular or irregular?
4. Is it narrow or wide?

32. Question
What is normal sinus Rhythm?

33. Normal Sinus Rhythm
• Rhythm - Regular
• Rate - 60 to 100 beat/minute
• QRS Duration – Normal
• P Wave - Visible before each QRS complex
• P-R Interval - Normal
*Indicates that the electrical signal is generated by
the sinus node

34. Normal sinus rhythm

35. Narrow QRS Complex Tachycardia
• HR > 100/min
• Narrow QRS < 0.12 sec

36. I. Narrow Complex Regular Tachycardia
A. Sinus Tachycardia
• Results from accelerated SA node discharge rate
• Normal sinus p waves
• Normal PR interval
• Rate 100-150 beat/min
* Identify and treat the underlying cause!

37. Sinus Tachycardia…
Causes
• Physiologic
- Anxiety, exertion
• Pharmacologic
- Caffeine, nicotine , atropine, sympathomimetcs
• Pathologic
- Fever, pain, pulmonary embolism, hemorrhage,
anemia, hypovolemia, shock, hyperthyroidism

38. Sinus Tachycardia

39. B. Paroxysmal Supraventricular Tachycardia
(PSVT)
• Regular rhythm
• P wave buried in preceding T wave
• Rate > 150/min
• Normal QRS interval
• Patients are symptomatic (palpitations,
lightheadedness…)
* Treatment required!

40. Paroxysmal Supraventricular Tachycardia (PSVT)

41. PSVT…
Treatment
• Vagal maneuvers
- Carotid sinus massage
- Valsalva manuever
- Cold water immersion
• Adenosine
• AV nodal blocking agents
- Digoxin / Diltiazem / Metoprolol
• Synchronized cardioversion (unstable)

42. C. Atrial Flutter
• Regular rhythm
• P waves replaced with multiple flutter waves
“Saw tooth Pattern”
• Best seen in inferior leads II, III, aVF
• Often 2:1 block with HR ~ 150 bpm (ventricular
rate)

43. Atrial Flutter…

44. Atrial Flutter…
Treatment
 Unstable
- Cardioversion with low energy
 Stable: Rate Control
.Slow AV conduction
- Metoprolol /Diltiazem / Verapamil/Digoxin

45. II. Narrow Complex Irregular Tachycardia
A. Atrial Fibrillation
• Multiple areas of atrial myocardium discharging
chaotically
• Loss of ‘atrial kick’
• Ventricular rate irregularly irregular
• Fibrillatory waves best seen V1, V2, V3, aVF
(no p wave)
Symptoms
 Syncope, palpitations, SOB, weakness

46. Atrial Fibrillation…
• Commonly associated with four disorders
- Rheumatic heart disease
- Hypertension
- Ischemic heart disease
- Thyrotoxicosis
• Other disorders
- Pulmonary embolism
- Pneumonia
- Pericarditis
- ASD

47. Atrial Fibrillation…

48. Atrial Fibrillation…
Treatment
Unstable
 Cardioversion with low energy
Stable
 Rate control
- Diltiazem/Verapamil/Metoprolol/
Digoxin/Amiodarone

49. II. Wide Complex Tachycardia
• Ventricular Rate > 100/min
• QRS duration > 0.12 sec

50. Wide complex…
A. Ventricular Tachycardia
• Rhythm - Regular
• Rate - > 100 bpm (usually 150-200)
• QRS Wide
• No P Waves

51. Monomorphic VT
Polymorphic VT

52. Ventricular tachycardia…
Treatment
Unstable
• Immediate synchronized cardioversion (with
pulse)
• Immediate defibrillation (without pulse)
• Correct electrolyte abnormality (e.g Mg+2)
Stable
• IV Lidocaine / IV Amiodarone

53. B. Ventricular fibrillation
• Rhythm – Irregular (disorganized)
• Rate - > 300bpm
• QRS Duration - Not recognizable
• No P Wave
• Fibrillating, chaotic, and ineffective ventricular
contractions
• Pulseless

54. Ventricular fibrillation…
Treatment
• Immediate defibrillation!

55. Adult Tachycardia(with pulse)

56. Summary
• Early diagnosis of arrhythmia is important
• Assess for signs and symptoms of hemodynamic
instability and maintain ABC
• Correct causes and treat the abnormal rythms as
soon as possible

57. References
• Tintinalli EM,8th edition
• Rosen EM,2018
• Internet
• Uptodate 19.3
• Cardiac Arrhythmias in the ED, Cheryl Hunchak
MD, CCFP(EM), MPH, Updated by: Anna
MacDonald, June 2013
• ECG interpretation significance

58. THANK YOU!