ECG Interpretation Part 1 (Josh) Flashcards
What is Ejection Fraction (EF)?
ratio of the SV ejected from the left ventricle with each beat to the volume of blood at the end of diastole (LVEDV)
What is a normal Ejection Fraction?
greater than 50%
What does an Ejection Fraction less than 35% indicate?
Poor Ventricular Function
Poor Ventricular Filling
Obstruction to Outflow
Which heart node fires off first?
SA node fires before AV node
What is LVEDV?
Left Ventricular End Diastolic Volume
What SV is compared with to get the Ejection Fraction
Ejection Fraction is a good indicator of — —
heart function
Which node is the Pacemaker?
SA node
**starts the spontaneous conduction of the heart
Cardiac Conduction:
What is the P-wave indicative of?
Atrial Contraction
- Depolarization of Atrium
Cardiac Conduction:
What does the PR Interval show us?
If there is any difficulty between conduction between the SA Node and the AV Node
If there is a problem with the AV node, where would we see it on ECG?
PR Interval
What does the QRS Complex represent?
Ventricular Depolarization
What QRS Complex is considered normal?
Abnormal?
Normal = Narrow
Abnormal = Wide
What does the ST Segment represent?
Beginning of repolarization
What does the T Wave represent?
Repolarization of Ventricle
What is a normal SA Node rate?
60 -100 bpm
What is a normal AV Node rate?
40- 60 bpm
What is contraction of AV Node called?
Atrial Kick
AV Node contraction is signified by — —
PR Segment
SA Node contraction is signified by — —
P Wave
What is normal rate of Bundle of His contraction?
20 - 40 bpm
What is the normal rate of contraction in the Perkunjie Fibers?
less than 15 bpm
Reading an ECG:
How much time does each 1 mm square count?
0.04 seconds
***5 mm square is 0.2 seconds
Reading an ECG:
How is amplitude measured?
milimeters
Reading an ECG:
How is duration measured?
seconds
Reading an ECG:
What is baseline?
isoelectric line
Reading an ECG:
What is the length of a typical measurement strip?
6 seconds
How do you estimate HR with ECG Waveform strip?
count number of QRS complexes in each 6 six second interval and multiply by 10
ex: if there are 9 QRS in 6 secs, then the HR is 90 bpm
Reading an ECG:
What is PR Segment?
the time required for impulse to travel through AV node, where it is delayed, and through the bundle of His, perkunjie fibers, just before Ventricular depolarization
end of P wave to beginning of QRS
Reading an ECG:
What is PR Interval?
Beginning of P-Wave to beginning of QRS (end of PR segment)
***represents time required for Atrial depolarization as well as impulse travel through BoH and Perkunjie.
Reading an ECG:
What does QRS Complex represent?
ventricular depolarization
Reading an ECG:
What is the J Point?
the junction where the QRS ends and the ST segment begins
Reading an ECG:
What is the ST Segment?
early part of ventricular repolarization
Reading an ECG:
What is the T Wave?
ventricular repolarization
Reading an ECG:
What is the U Wave?
late part of ventricular repolarization
Reading an ECG:
What is the QT Interval?
represents total time required for ventricular depolarization and repolarization
Reading an ECG:
How is QT Interval measured?
beginning of QRS to the end of T-Wave
P-Wave:
What is normal duration?
0.12-0.2 secs
**3-5 blocks (each block is 0.04 secs)
What should shape of P-Wave look like?
upright
rounded
***should all look the same because there is only one SA Node
Abnormal P Waves:
What is a tall, peaked P Wave?
P Pulmonale
***indicates right atrial hypertrophy
Abnormal P Waves:
What is an M-shaped P Wave?
P Mitrale
- **indicates left atrial hypertrophy
- **Mitral valve goes with left side of heart
QRS:
What is normal QRS duration?
0.06 - 0.1 seconds or less than 0.12
Which part of ECG shows ventricular excitation, contraction, and recovery?
QT Interval
What does length of QT Interval depend on?
HR
- **faster HR = short QT
- **slower HR - long QT
What are normal upper limits on QT Interval?
0.39 - 0.43 secs
***dependent upon HR
How long should QT Interval be in relation to the R to R Interval?
QT should be half of R-R Interval
***if more than that it is PROLONGED
A normal QT Interval should be — of the RR Interval.
half
What is a Corrected QT Interval (QTc)?
adjusts QT Interval to account for HR
***Normal QTc = less than 0.44 secs
What is a normal QTc?
less than 0.44 secs
Why are we worried about QT Interval?
prolonged can lead to V-tach (lethal)
Reading an ECG:
Which part of ECG is the time of no electrical activity?
ST Segment
***don’t measure LENGTH
***MEASURE HEIGHT ONLY
How is an ST Segment described?
by height
- isoelectric (flat)
- elevated
- depressed
Reading an ECG:
Which part indicates Ventricular Repolarization?
T-wave
**do NOT measure duration
How is a T-wave described?
upright, round and smooth, inverted, peaked or depressed
Reading an ECG:
What is the U Wave?
repolarization of His-Perkunjie
- **normal in kids
- **not normal in adults
What does U Wave signify in adults?
Hyperthyroidism or Hypokalemia
When doing ECG Rhythm analysis, what are we assessing?
Regularity
Rate
P-wave
PR Interval
QRS duration
Interpret Rhythm
ECG Rate Determination:
How do we determine rate if it is regular?
How do we determine rate if it is irregular?
Regular: count number of small boxes between 2 R waves and divide into 1500
Irregular: count number of R waves in a 6 second strip
What is Normal Sinus Rhythm?
Regular
Rate = 60-100
P Wave = normal and upright with 1:1 with QRS
PR Interval = 0.12 - 0.2 secs and constant
QRS = 0.04 - 0.1 and constant
What rate is Sinus Tachycardia?
101-150
***treat by correcting underlying cause not to decrease the rate
What is Sinus Bradycardia?
less than 60 bpm
What are causes of Sinus Bradycardia?
Increased Parasympathetic Tone in Athletes (Lance Armstrong)
SA Nodal disease (Sick Sinus Syndrome)
Medications
VAGAL STIMULATION
What is the hemodynamic effect of Sinus Bradycardia?
Decreased CO
Hypotension
- orthostatic
- syncope
What is the management for Symptomatic Bradycardia?
Atropine (DOC)
Pacemaker
***only treat sinus bradycardia if it is symptomatic
Sinus Bradycardia:
What is PR Interval?
QRS?
PRI = 0.12 to 0.20
QRS = less than 0.12
Which is a Sinus Arrhythmia?
normal rate with irregular rhythm
***not normal for adults
What is cause of Sinus Arrhythmia?
HR varies with respiration due to fluctuations in parasympathetic outflow
What is a PAC?
Premature Atrial Contraction: single beat originates in atria and comes early in cardiac cycle
***Cyclic
***Bigeminy (every other beat)
***Trigeminy (every other beat)
What is difference between Atrial Tachycardia and Sinus Tachycardia?
the rate is more in Atrial Tach (150-250) than in Sinus Tach (101-150)
What would the rate of an Atrial Flutter be and what would P Wave look like?
250-350 bpm
P-Wave has a ‘sawtooth’ appearance
What is the hemodynamic effect of Atrial Fibrillation?
lose Atrial Kick
decreased SV
***CO can decrease by 20-30%
What is the most common dysrhythmia?
A-fib
***Can be compensated for if Ventricular Response is high enough (80 bpm or something like that)
What is the main problem with A.Fib?
atria is quivering and not pumping blood good so….
STASIS of BLOOD in atria that can lead to PE, VTE, etc
Management for A.Fib?
Get them out of the rhythm
Control Ventricular Response
Prevent complications from stasis of blood
What is a Junctional Rhythm?
AV node takes over when a higher pacemaker fails to initiate AV node
How do you tell difference between Junctional Rhythm and Sinus Bradycardia?
inverted P Wave in Junctional Rhythm
***both have slow rate of 40-60
If they have a Symptomatic Junctional Rhythm, what med do we give?
Atropine
Why does the Junctional Rhythm have an inverted P Wave?
electrical rhythm is going back up the heart
What can Dig Toxicity cause?
Premature Junctional Contractions
What is Supraventricular Tachycardia?
a broad term for a group of rhythms originating ABOVE the ventricle
***any fast rhythm not coming form ventricle
What does the QRS look like in a Premature Ventricular Contraction (PVC)?
wide and bizarre
***can be positive (going up) or negative (going down)
What is an R on T?
a Preventricular Contraction that happens on top of T wave
***QRS will be on top of T Wave
What is danger with an R on T?
Can cause V-tach
If V-tach is with a pulse, treat with —-
If V-tach is without a pulse, treat with —-
meds
defibrillation
***always check for a pulse with V-tach
V-tach caused by prolonged QT Interval?
Torsades do Pointe
**correct cause and give IV Mag
What is an Idioventricular Rhythm?
QRS is wide and bizarre (greater than 0.12) with a slow rate (20-40 bpm)
What meds with Idioventricular Rhythm?
Atropine
PPM
***not Amiodarone or Lidocaine because it’s the only rhythm we have
Nursing mgmt for Vfiv or Pulseless Vtach?
Check for pulse (if none, then)
Shock
CPR for 5 cycles (about 2 mins)
Check for Pulse
What are shockable rhythms?
Pulseless Vtach
Vfib
What is Ventricular Asystole?
no electrical activity and a flat line on ECG monitor
Mgmt for Ventricular Asystole?
Check diff. lead
CPR (NOT SHOCKABLE)
Epi every 3-5 mins
Can you shock
Ventricular Systole?
NO
give CPR and Epi q 3-5 mins
What is PEA?
Pulseless Electical Activity
***electical activity with no corresponding contraction, which means no PULSE
What are the 5 H’s of PEA?
Hypovolemia
Hypoxia
Hydrogen ions (acidosis)
Hyper or Hypokalemia
Hypothermia
What are teh 5 T’s of PEA?
Tables (drug overdose)
Tamponade
Tension Pneumothorax
Thrombosis (coronary or pulmonary)
What is the Compression/Ventilation ratio for CPR?
30:2
Which AV Block?
All sinus impulses eventually reach ventricles.
First Degree
Which AV Block?
Some sinus impulses reach ventricles but some do not
Second Degree
Which AV Block?
No sinus impulses reach ventricles.
Third Degree
What does P Wave look like with Wenckebach (Type 1) Second Degree AV Block?
progressively lengthens until one P Wave is blocked
***blocked means you have a P Wave with no corresponding QRS
What are the two types of Second Degree AV Blocks?
Type 1 (Weckebach)
Type 2 (Mobitz) *** no warning with this one
Which type of Second Degree block is worse?
Type 1 is usually benign
Type 2 is MORE OMINOUS
What do P Waves and QRS look like in Complete (Third Degree) AV Block?
not connected
P Waves regular to themselves
QRS regular to themselves