The document discusses key concepts related to cardiac electrophysiology including: 1. The properties that allow the heart to contract automatically (automaticity), become excited (excitability), conduct electrical signals (conductivity), contract (contractility), and refractory periods. 2. Normal cardiac rhythms originating from the sinoatrial node and other pacemaker sites, along with their typical rates. 3. Key intervals of the ECG including the PR, QRS, and QT intervals as well as normal values. 4. Common arrhythmias including their typical ECG patterns, symptoms, causes, and potential treatments.

2.  Automaticity
 Excitability
 Conductivity
 Contractility
 Refractoriness

5.  SA node
› 80–100 bpm
 Atrial foci
› 60–80 bpm
 Junctional foci
› 40–60 bpm
 Ventricular foci
› 20–40 bpm

8.  PR interval
 0.12 to 0.20 s (3 -
5 small squares)
 QRS complex
 < 0.12 s duration
(3 small squares)
 QT interval
 varies based on
rate
 QTc=Normal =
0.42 s.
 ST segment
 no elevation or
depression

9.  Count R waves in 6 sec strip
 Multiply by 6!
 What is this heart rate?

11.  Palpitations
 Dizziness
 Syncope
 Chest pain
 Nausea/vomiting
 Poor perfusion
› delayed cap refill,
cool/clammy
extremities, pallor
 Hypotension
 AMS- altered mental
status
 Cardiac arrest
 Weakness
 Fatigue

12.  Is patient symptomatic?
 Stable versus unstable
 Level of consciousness?
 Support ABCs
 Oxygen
 Monitor ECG, SpO2, blood pressure
 Identify and treat
 Determine cause, if possible
Code
versus
Rapid Response

15.  Sinus Rhythm is normal!
 Sinus Bradycardia
› Symptoms: loss of consciousness, pallor,
dizziness, chest pain, confusion, AMS,
hypotension, SOB, orthostatic blood pressure
changes
› Atropine
› Pacing
 external, transvenous, permanent
 Sinus Tachycardia
› Symptoms: loss of consciousness, pallor, dizziness,
chest pain, confusion, AMS, hypotension, SOB
› Normal in some circumstances
› Treat the cause
› Beta blockers, adenosine (SVT), Ca channel
blockers

16.  Premature Ventricular contractions (PVC)
 Treatment:
 Symptomatic versus asymptomatic
 Bigeminy, trigeminy
 Determine cause (stimulants, dehydration, etc)
 Beta blockers, ablation

18.  RIGHT BBB  LEFT BBB

19. •Rhythm - Irregularly irregular
•Rate - usually 100-160 beats per minute
but slower if on medication
•QRS Duration - Usually normal
•P Wave - Not distinguishable as the atria
are firing off all over
•P-R Interval - Not measurable
•The atria fire irregular electrical impulses
causing irregular heart rhythm

20. •Rhythm – Regular (usually)
•Rate - Around 110 beats per minute
•QRS Duration - Usually normal
•P Wave - Replaced with multiple F (flutter)
waves, usually at a ratio of 2:1 (2F -
1QRS) but sometimes 3:1
•P Wave rate - 300 beats per minute
•P-R Interval - Not measurable
Abnormal tissue generating the rapid heart
rate is in the atria

21.  Symptoms:
 AMS, chest pain, syncope, SOB,
hypotension
 Long term risk of stroke
 Treatment:
 Rate versus rhythm control
(Atrial Kick!)
 Beta blockers, Ca channel
blockers, synchronized
cardioversion , ablation, AV node
ablation+pacemaker

22.  PR interval > 0.20 seconds
 Rarely any symptoms or treatment
 Can be caused by medications (beta blockers)
or be a contradiction to medications
 Delayed conduction through the AV node

23. •Rhythm - Regularly irregular (P waves, QRS may be irregular)
•Rate - Normal or Slow
•QRS Duration - Normal
•P Wave - Ratio 1:1 for 2,3 or 4 cycles then 1:0.
•P Wave rate - Normal but faster than QRS rate
•P-R Interval - Progressive lengthening of P-R interval until a QRS
complex is dropped
•Increasing delayed conduction through the AV node, eventually
resulting in non conducted beat

25. •Rhythm – Regular (P
Waves, QRS will be
irregular)
•Rate - Normal or Slow
•QRS Duration – may be
prolonged
•P Wave - occur regularly
(“march out”)
•P-R Interval - Normal or
prolonged but constant
•Random lack of
conduction through the
AV node

28. •Rhythm - Regular
•Rate - Slow
•QRS Duration – Prolonged
•P Wave – Unrelated (but “march out”)
•P Wave rate - Normal but faster than QRS rate
•P-R Interval - Variable
• No atrial impulses pass through the atrioventricular node and
the ventricles generate their own rhythm
•A/V dissociation

30.  Symptoms:
› similar to bradycardia- SOB, dizziness, LOC, chest pain,
pallor, confusion, AMS, hypotension, orthostatic blood pressure
changes
 Causes:
› Damage to the AV node – MI, scar tissue
 Second Degree type 2 may lead to complete heart block
 Complete heart block is rarely stable
 Treatment:
 Atropine is not effective (stimulates the SA node which is
usually working, it’s the AV node that’s slowing
conduction or not conducting at all)
 Pacing- external in emergent situations, transcutaneous or
external with sedation if patient is conscious, permanent
implanted pacer for long term management

31. •Rhythm - Regular
•Rate - 180-190 Beats per minute
•QRS Duration - Prolonged
•P Wave - Not seen
•Poor cardiac output causes the pt to go into
cardiac arrest.
•Shock this rhythm if the patient is
unconscious and without a pulse

33. •Rhythm - Irregular
•Rate - 300+, disorganized
•QRS Duration - Not recognizable
•P Wave - Not seen
•NO PULSE
•Life Threatening Arrhythmia
•CPR, DEFIBRILLATE

34.  Causes:
 Ischemia, infarction, drugs, hypoxia, electrolytes
(Hypo/Hyper)
 Treatment:
› If unstable, defibrillate
› For VT, may synchronize cardiovert
› Drugs (ACLS)
› Torsades: Magnesium
 Determine cause and correct
 Long term treatment:
AICD

41.  Is the rhythm regular? Irregular? Fast? Slow? Is
there a P, QRS, T? Easily identifiable?
 Is there a P wave for every QRS? What is the
PR interval? Does it vary or is it the same? Is
the P wave rhythm regular?(do they “march
out”?)What is the atrial rate?
 What does the ventricular rhythm look like?
What is the rate? Fast? Slow?

42.  PR=.20 QRS= .08 Rate: 50’s
 PR=.16 QRS= .06 Rate: 70’s

43.  PR= ? QRS= .06 Rate: 100’s
 PR= .18 QRS= .08 Rate: 80’s

44.  PR= .18 QRS= .06 Rate: 120’s
 PR= ? QRS= .40 Rate: 180’s

45.  PR= .18 QRS= .12 Rate: 80’s Rhythm- multifocal
PVC’s
 PR= .18 -? QRS= .08 Rate: 180’s Rhythm- SR-PSVT

46.  PR= Varies QRS= .12 Rate: 60’s
 PR= ? QRS= .? Rate: ? Rhythm- V- Fib

47.  PR= ? QRS= .10 Rate: 80’s
 PR= -? QRS= .20 Rate: 40’s

48.  PR= varies -? QRS= .40 Rate: 40’s
 PR= ? QRS= .28 Rate: 40’s

49.  PR= .38 QRS= .08 Rate: 60’s