1. Cardiac Arrhythmias A Guide For Medical Students
William Beaumont Hospital
Department of Emergency Medicine

2. In evaluating arrhythmias -
Rate - Is it fast or is it slow
If slow – is there group to group beating
Rhythm - Is it regular, irregular or irregularly irregular?
P waves - Are they present?
QRS - Is it narrow or wide?

3. Sinus Bradycardia What is it? What causes it? When do you treat it?
How do you treat it?
Answers in next slide

4. Sinus Bradycardia
A sinus rhythm with normal intervals and a rate less than 60 bpm
Normal variant, beta blocker overdose, dig, hypothermia, hypothyroidism, brady-tachy syndrome, and SA node ischemia
Requires treatment only if there is evidence of hypoperfusion
Two treatment options
Pacing: transvenous or transcutaneous
Atropine 0.5 mg IVP

5. Sinus Tachycardia A sinus rhythm faster than 100 bpm
Etiology - usually a physiologic response
to a stressor
Volume depletion / low stroke volume
Hypoxia
Systemic pathology: fever, anemia, hyperthyroidism
Drugs
Treatment - treat the underlying cause

6. PACs MAT Atrial Fibrillation, atrial flutter SVT
Atrial Arrhythmias
PACs
MAT
Atrial Fibrillation, atrial flutter
SVT

7. Multifocal Atrial Tachycardia
Diagnosis requires the presence of three distinct p waves in a narrow complex tachycardia
Almost always associated with pulmonary disease
Less often due to hypokalemia or hypomagnesemia
Treat the underlying disorder – usually hypoxia
Unlike the other atrial tachyarrhythmias, cardioversion is of no value in MAT

8. MAT Rule of Threes
3 different p waves, 3 different pr intervals and 3 different r to r intervals

9. Causes of A-fib
Cardiovascular - CAD, HTN, CHF, myopathy, myo-, endo- and pericarditis, infiltrative disease, valvular, congenital
Metabolic - thyroid, electrolytes
Pulmonary - pulmonary HTN, PE
Toxic - cocaine, ETOH (holiday heart), beta
agonists
Sepsis
Idiopathic

10. ECG Rules for A-fib Regularity - irregularly irregular
Rate - atrial rate usually > 350
Controlled - ventricular rate < 100
RVR - ventricular rate > 100
P wave - none discernable, may be f waves
QRS - less that 0.12 seconds (easy dx). If > 0.12 sec must rule out VT (which is usually more regular)

11. A-fib with RVR A fib with ventricular rate > than 100-120 bpm
Patients usually symptomatic requiring rapid tx
Unstable – cardioversion
Stable - control rate with calcium channel blockers, beta blockers or digitalis

12. A-fib treatment Recognize the underlying cause
A rate under 120 in an asymptomatic patient generally requires no emergent treatment
Unstable patients with acute rapid a-fib should receive synchronized cardioversion with J
Treatment otherwise depends on the duration

13. Treatment of A-fib Less than 48 hours duration
Cardioversion is indicated in any unstable patient, synchronized if possible, with J
May also be used electively in symptomatic but stable patients
Pharmacologic cardioversion may be attempted with procainamide, amiodarone or ibutilide

14. Treatment of A-fib > 48 hours
Longer duration predisposes the patient to atrial clot formation and failure of conversion
Rate control with diltiazem, beta blockers or digitalis
Do not attempt cardioversion unless emergently indicated
Anticoagulation and arrangement for echo

15. Atrial Flutter Patients usually with cardiac or pulmonary dz
Conduction through the AV node may be at a 2:1, 3:1, 4:1 or 5:1 rate
Whenever you see a ventricular rate close to 150 you should consider a flutter
Frequently is a transient rhythm which may degenerate into a-fib or convert to sinus

16. Treatment of A-flutter
Hemodynamically unstable - immediate synchronized cardioversion
Hemodynamically stable
Vagal manuevers – if no carotid bruits
Adenosine - will not terminate the atrial tachycardia, but may allow flutter waves to become more apparent
Dig, beta blockers or calcium channel blockers for AV nodal blockade to slow the ventricular rate

17. SVT AV nodal reentrant tachycardia
Usually you see a regular, narrow complex tachycardia without p waves
Treatment – adenosine, beta blockers, calcium channel blockers, digoxin

18. Is it SVT, afib, aflutter, sinus tach?
SVT – HR around 150s
Is it SVT, afib, aflutter, sinus tach?

19. Preexcitation syndrome
Wolf-Parkinson-White syndrome
AV re-entrant tachycardia (accessory pathway)
Short PR interval, delta waves
Treat like PSVT if the QRS is narrow
If the QRS is wide or if afib is present, use amiodarone or procainamide (slow the atrial rate and increase conduction through the AV node)
Avoid ABCD – adenosine, beta blockers, calcium channel blockers, dig – if WIDE QRS

20. Narrow complex WPW

21. Wide complex WPW

22. Atrioventricular Blocks
First Degree
Second Degree - Type I
Second Degree - Type II
Third Degree

23. Second Degree AV Blocks
Group to group beating
Second degree blocks are partial blocks
Two types
Type I, Mobitz I or Wenckebach - transient
Type II, Mobitz II or Classic - often degenerates into 3rd degree heart block

24. Second Degree Type I
Decremental Conduction: Grouped beats with progressively longer PR intervals until an impulse is not conducted (a p without a QRS)
Usually narrow QRS
Generally requires no treatment – atropine, temporary pacing if symptomatic
May be associated with inferior MI

25. Second Degree Type II
Conduction fails suddenly, without a change in the PR interval
This is not a benign rhythm, is chronic and often progresses to a complete heart block
Is associated with anteroseptal MI
May have wide QRS

26. Second Degree Type II
No pharmacologic treatment – atropine has no effect on the His-Purkinje system so not helpful and may worsen the conduction ratio
Emergency treatment - transcutaneous or transvenous pacing

27. Third Degree Block Complete block - there is total AV Dissociation
None of the atrial impulses are conducted through to the ventricles (P and QRS are independent, P-P and R-R intervals constant
An escape rhythm from a focus below the block will drive the ventricles
If the escape rhythm originates in the AV junction, the ventricular rate will be in the range of and the QRS less than 0.12
If the escape is generated from the ventricles, the rate will be in the range of with a wide QRS

28. Third Degree Block
Although patients may be asymptomatic, transcutaneous or transvenous pacing is warranted
Autonomic drugs such as atropine will have no effect on ventricular rate
Type I antiarrhythmics should be avoided (they may suppress the escape rhythm)

29. Ventricular Arrhythmias
PVCs
V tach
V fib

30. Premature Ventricular Contractions
Generally benign, but may be a consequence of a pathology, esp if multifocal
More concerning causes include hypoxia, ischemia, MI, toxins/drugs, acidosis or alkalosis, hypokalemia

31. Ventricular Tachycardia
Results from a dysrhythmia originating at or below the bundle of His
Has a wide QRS complex (>0.12 second)
May be monomorphic or polymorphic

32. Monomorphic V-tach Morphologically consistent QRS complexes
Most common form of v-tach
Seen primarily with cardiac ischemia
Also seen in cardiomyopathy, valvular disease, electrolyte imbalance, myocarditis

33. Polymorphic V-tach QRS complexes vary in structure and amplitude
Predominantly caused by CAD
Associated with more severe disease

34. Torsades de pointes A specific form of polymorphic v-tach
Associated with prolonged QT
May be due to drugs (tricyclics), electrolyte imbalance (hypo K, Mg or Ca), or subarachnoid hemorrhage

35. Treatment of Ventricular Tachycardias
Unstable - immediate cardioversion
100 – 200 – 300 – 360
Stable - amiodorone 150 mg IVP or lidocaine 1 mg/kg and prepare for elective cardioversion
If torsades de pointes – magnesium 1-2g IV

36. Ventricular Fibrillation
An irregularly irregular rhythm with no p waves or definite QRS complexes

37. Treatment of V Fib Defibrillate Adult 360/360/360 joules
Children 2 joules/kg
Epinephrine 1 mg IVP q 3-5 min (0.01 mg/kg)
Amiodarone, Lidocaine, Magnesium

38. Osborne Waves
Not a true arrhythmia, but an EKG abnormality suggestive of underlying pathology
Seen primarily in hypothermia, < 35.6 degrees
May also be seen in other conditions, such as hypercalcemia or brain injury
Also called J-waves, Camel backs, hathooks

39. Osborne Waves - Hypothermia

40. Osborne Waves - Hypercalcemia

41. Brugada Syndrome Genetic disease - autosomal dominant
Mutation in the gene that controls the Na channel
Characteristic ECG – ST segment elevation V1-V3
no signs of ischemia
short QT interval
Most common cause of sudden death in young
males with no underlying cardiac disease
Prevalence for Asians
Cause of death – polymorphic V tach or V fib
Treatment – no medicine will prevent
AICD to abort lethal arhythmias

42. Diagnostic Criteria
Type I is the only ECG criterion that is diagnostic of Brugada syndrome. (see figure).
Definitive diagnosis - type 1 ST-segment is observed in >1 right precordial lead (V1 to V3) and one of the following:
documented ventricular fibrillation (VF)
polymorphic ventricular tachycardia (VT)
a family history of sudden cardiac death at <45 years old
coved-type ECGs in family members
inducibility of VT with programmed
electrical stimulation
syncope
nocturnal agonal respiration.

43. Brugada Syndrome

44. Now for some cases…

45. 82 yo male with hx HTN c/o weakness dizziness SOB BP 100/50 HR 155 What does the EKG show? What is the treatment?
EKG = a fib with RVR A-adenosine B-beta blockers C-ca channel blocker D-dig

46. 35 yo female c/o palpitations, near syncope, occasional episodes of rapid HR What does the EKG show What medicines should be avoided in this patient?
EKG= WPW avoid adenosine, beta blockers, ca channel blockers, dig

47. 65 yo male with COPD c/o SOB, wheezing and pedal edema What does the EKG show? What is the treatment?
EKG=MAT Treat the COPD

48. 91 yo female c/o weakness and syncope. What does the EKG show
91 yo female c/o weakness and syncope. What does the EKG show? What is the treatment?
EKG= 3rd degree block

49. What does the monitor show? What is the treatment?
26 yo medical student presents with N,V altered mental status. She has not been eating well. She is on Erythromycin for a URI. Her K=2.1 Mg=1.0 (nl= ) She collapses in the ER and is placed on a monitor.
What does the monitor show?
What is the treatment?
Monitor = torsades treatment = IV magnesium

50. 48 y/o F presents lightheaded after walking
48 y/o F presents lightheaded after walking. She just started metoprolol. What does the ecg show? What is the treatment?
Ecg = SB no rx if stable, pacing or atropine if unstable

51. 42 y/o F presents with palpitations and DIB. What does the ecg show
42 y/o F presents with palpitations and DIB? What does the ecg show? How could you differentiate the rhythm?
Ecg = SVT, could give adenosine to differentiate SVT, afib, aflutter

52. You are working in the EC. The nurses come get you for this rhythm
You are working in the EC. The nurses come get you for this rhythm. It appeared 45 min after giving thrombolytics for AMI. Previously it was NSR. What is this? What should you do?
Ecg= idioventricular rhythm, do nothing for AMI thrombolytics as it is transient, other circumstances treat if unstable

53. 86 y/o M c/o weakness and DIB.
What rhythm is this on the monitor?
What should you worry about?
Are you going to treat this?
Wenckebach, inferior mi, treat with pacing/atropine if unstable

54. 61 y/o M with CP, palpitations, and dizziness. What is the ecg show
61 y/o M with CP, palpitations, and dizziness. What is the ecg show? What do you want to do?
Ecg = VT, cardiovert if there is a pulse and unstable or symptomatic

55. What should you do (besides soil yourself)?
So you cardioverted the previous rhythm and now this is on the monitor…
What is this?
What should you check?
What should you do (besides soil yourself)?
Vfib, pulse, defibrillate

56. 24 y/o pregnant F presents with 3 days of vomiting…
What does the ecg show?
What is the treatment of choice?
Ecg = ST, fluids, the p waves are clearly seen in lead III

57. 52 y/o M who is homeless and found sleeping in an alley
52 y/o M who is homeless and found sleeping in an alley. What does the ecg show? What is the treatment?
Osborne waves, re-warming, check electrolytes

58. 45 y/o M with CKD on HD presents with palpitations and DIB after missing dialysis.
What does this ecg show?
What should you do to treat this?
Hyperkalemia, calcium, bicarb, D50/insulin, kayexalate plus fluids and potentially lasix or albuterol

59. Had enough yet?
The End