ECG 1 Flashcards
Heart- two functions essential for function
Electricity (conduction)
Pump (contraction)
The spread of the electrical stimulus through the heart muscle
Movement of electricity
depolarization
The return of the stimulated muscle to the resting state
Repolarization
Cells are in a resting, ready state
Two major electrolytes involved in polarization
K+ 3.5-4.5
Na+ 135-145
If potassium levels drop, or get high, it effects ______
electrical impulses
Patients in dialysis experience cardiac issues due to this shift in electrolyte levels
All electrical impulses should start in the _____
SA node (pacemaker)
SA node inherent pace rate: ____
Impulse starts in SA node, moves down and both atrias should contract (pump)
Impulse moves to _____- holds impulse for just a second, before moving on.
Holds for a second to allow atria to finish contracting before the ventricles contract.
60-100
AV node
While ventricles depolarize, atria are ____
repolarizing
ECG- snapshot of what heart is doing
______ - shows what heart is doing in real time.
continuous ECG
Atria depolarization =
P wave
Does P wave tell about atrial contraction?
No - does not tell that pump is working.
It does tell that the electrical impulse is working.
Ventricular depolarization
QRS complex
Takes more energy, thus larger complex
Test to see if ventricles are contracting
take a pulse
While monitoring ECG, feel for pulse to coordinate- proves that contraction is happening
Ventricular repolarization
T wave
Electrode placement:
3 leads, and 5 leads
Electrodes can move around as long as they are in the general area
RA- right, midclavicular line, 2nd intercoastal space
LA- left, midclavicular line, 2nd intercoastal space
Over heart 8th intercoastal, midclavicular
picture of impluse- _____
lead
primary monitoring lead-
lead 2 from RA (negative) to LL (positive)
sticker on chest to take picture
electrode
monitors electricity- does not generate electricity
looking at top of heart
lead:
RA to LA
lead 1
LA to LL
lead 3
RA- ___ polarity
LA- ____ polarity
LL- ____ polarity
RA - negative
LA- negative/positive
LL- positive
If electrodes are in the right place, the P wave should be ____
upright
QRS complex can look like anything as long as it stays within certain parameters
waveforms
positive deflection- waveform goes up
negative deflection- waveform goes down
biphasic deflection- waveform goes up and down
as impulse moves horizontally, it tells about ___
vertically ____
time
amplitude
one dark line to one dark line is
0.2 seconds
one small box is
0.04 sec
tag marks on paper indicate
3 sec.
You want at least ___ of time when looking at en ECG
6 sec.
Isoelectric line = ____ state
polarized
everything should return here
short return to isoelectric line following the p wave indicates:
AV junction holding impulse
the beginning of the P wave to the beginning of the QRS complex is called the:
PR interval
PR interval measurement
.12 sec. - .20 sec.
QRS complex measurement
less than .12 sec
Regular heart rate, distance between P waves should be equal
Distance between R and R should be equal
When do you stop measuring QRS complex?
When it stops moving vertically / when it changes from vertical to horizontal
period of time from when QRST complex ends and T wave begins
ST segment
depressed ST segment indicates:
elevated ST segment:
old heart injury
code STEMI ST elevation MI
Analyzing a rhythm strip step-by-step
- Determine the regularity of R waves
- Calculate the heart rate
- Identify and examine P waves
- Measure the PR Interval
- Measure the QRS complex
Calculate the heart rate
3 ways
Count pulse
Rapid rate calculation
Precise rate calculation
Rapid rate calculation
- Count the number of R waves in a 6 sec. strip
- Multiply by 10
- Do not include premature beats in calculating the heart rate
Precise rate calculation
- Count the number of small squares between two consecutive R waves
- Divide the number of small squares into 1500 or use a conversion chart
- Only accurate for regular rhythms
Identify and Examine P waves
One P wave preceding each QRS
All P waves identical in shape, size, and position
P to P interval should be regular
Measure the PR Interval (PRI)
PR interval should be .12 - .20 seconds
Abnormal if too short, too long, or absent
Measure the QRS complex
QRS should be less than .12 seconds
Examine the ST Segment
Normal ST segment is:
Elevation or depression measuring __________ is abnormal
flat and at the isoelectric line
1mm above or below
Examine the ST Segment
Elevation =
Depression =
acute myocardial injury
myocardial ischemia, hypokalemia, digitalis
ASSESS the patient
Is there a PULSE with that Rhythm???!!!
False high alarms
False low alarms
Artifact -Artefact is the name given to disturbances in rhythm monitoring caused by movement of the electrodes.
represents atrial depolarization, the spread of the electrical impulse throughout the right and left atria
P wave
represents the time from the onset of atrial depolarization to the onset of ventricular depolarization
PR interval
The _____, a part of the PR interval, is the short isoelectric line between the end of the P wave and the beginning of the QRS complex.
PR segment
The _____ represents ventricular depolarization, the spread of the electrical impulse throughout the left and right ventricle.
QRS complex
The ___ represents early ventricular repolarization
ST segment
The ____ represents ventricular repolarization
T wave
Which HR calculation method is only good for regular rhythms?
Precise rate calculation
Only ___ is used to calculate HR in irregular rhythms
rapid rate
