EKG Review
Function of Heart
• With any functioning unit you need:
Electricity and Plumbing
• ELECTRICITY: electrical current that stimulates the heart and
tells it to beat or contract
• PLUMBING: When the heart contracts it provides blood and
oxygenation to vessels, tissue and organs
• ***Keep in mind how electricity and plumbing affect each
other!!!
Electricity
• SA
AV
Bundle of HIS
BB
PF
• SA: 60-80bpm
• AV: 40-60bpm
• BH-BB: 20-40bpm
“ACCIDENTS ON A HIGHWAY”- will be detoured around the
blockage.
increased distance to travel = increased time to get to location
**Electrical current needs healthy tissue to conductdead tissue will not allow signal to pass through
Plumbing
Beats = contractions
• Each beat requires atrial and ventricular
contraction
• Heart is like a sponge. It absorbs and squeezes out
blood with each contraction. If it is not “rung out fully”
with each squeeze- it cannot absorb it’s full potential.
(preload, afterload)
• Ventricular contraction- pushes blood into arteries to be
sent to body, tissues, organs and lungs
• Tissue needs oxygen and blood to survive.
Without this, it cannot function
Basic principals of EKG
• Rate? FAST, SLOW, NORMAL
• Complex? “P” in front of every “QRS”
P- atrial contraction
QRS- ventricular contraction
qrs
p
T
What is my rate:
•Each Full complex is one beat
•Most strips are 6 seconds long
1
2
3
4
(# of complexes in 6 sec strip) X (10) = Heart Rate
(5 complexes) X (10) = 50 beats per minute
5
ARRYTHMIAS
• Normal: 60-100 bpm
• Slow: < 60 bpm
• Sinus Bradycardia, Junctional
• Fast: >100 bpm
• Sinus Tachycardia, Supraventricular Tachycardia, VTach.
-CARDIA : heart beat including contraction & relaxation
Sinus Rhythm
• Sinus rhythm is normal electricity and
normal plumbing.
• Electrical signal fires from ‘Sinus’ node.
Rate is either slow, fast or normal.
“P wave” is present in front of every “QRS”
SLOW ARRYHMIAS
• Sinus Bradycardia
• SLOW sinus rhythm
• Junctional Rhythm
• “P” wave is inverted or absent
FAST ARRYTHMIAS
• Sinus Tachycardia
• Fast sinus rhythm
• Supraventricular Tachycardia
• Supra-superior : “above” the ventricular
• Rate is greater than 160 bpm, “QRS” is narrow.
Ventricular rhythms
• Ventricular Tachycardia
• Tachycardia- firing from the ventricle
• WIDE “QRS”, no “P”
• Ventricular Fibrillation
• Fibrillation or “quivering” of the ventricles- no contraction/relaxation.
No organized rhythm
Atrial Arrhythmias
• Atrial Fibrillation
• Underlying rhythm is sinus, with fibrillation between complexes/beats
• Atrial Flutter
• Look at sawtooth pattern between waves
Asystole
• No movement of heart muscle
Just remember : “Dead meat don’t beat”
EKG GRIDS
Time (secs)
V
O
L
T
A
G
E
5 Large blocks = 1 sec. on strip
SMALL blocks: 0.04 sec
LARGE blocks: 0.20 sec
BLOCKS
• Underlying rhythm is sinus, (must have P-QRS)
• Normal P-R interval is .12-.20 sec (one big block)
•
•
•
•
1st degree: prolonged P-R interval (>.20)
2nd degree I: (WB) P-R gets longer, then drops beat
2nd degree II: more “P’s” than “QRS” (kids w/o parents)
3rd degree: total disassociation, no communication
Premature Complexes
• PAC- premature Atrial complex
• P wave upright in front of QRS
• PJC- premature Junctional complex
• P wave is inverted or absent
• PVC- premature Ventricular complex
• Wide and bizarre, No “P” wave
Other things to look at….
• S-T segment
***Classified as significant if
> 1 mm
• Depression- Ischemia or injury
• Elevation- infarct or death of tissue
**STEMI- is key point in ACS algorithm
Pacemaker spikes
• If Pacemaker is pacing the heart you will see a
spike. To determine what is being paced, Look at
location of spike
Before P: pacing ATRIA
Both- pacing both
Before QRS: Pacing VENTRICLE