Dysrhythmia Interpretation And Management PART 1 Flashcards
Flow of electrical system of the heart
1st: SA node (pacemaker): 60-100bpm
2nd: AV node: 40-60
-if SA doesnt work
3rd: ventricular 20-40
-if AV doesnt work
Sympathetic nervous system
(Neurotransmitters)
(What they do)
Parasympathetic nervous system
(Neurotransmitters)
(What they do)
SNS: (fight/flight)
-epinephrine and norepinephrine
-increase HR/contractility, vasoconstriction
PSNS: (rest/digest)
-acetylcholine
-decrease HR/contractility, vasodilation
Depolarization vs repolarization (what are theses)
Contraction and relaxation are what
Depolarization and repolarization are electrical stimuli
Depolarization: contraction and heart muscles
Repolarization: relaxation of heart
Contraction and relaxation: mechanical response to stimuli
1.There is no heart beat without first having had what?
2.Electrical stimulus does not guarantee what?
1.Depolarization
2.Mechanical response
(There could be mechanical problem making incabable of pumping-PEA)
How often to change electrodes
24hrs
What is the placement of electrodes?
3lead
5lead
3lead
-RA (white) =upper
-LA (black) =upper
-LL (red) =lower
5lead:
-RA (white) (snow)
-RL (green) (grass)
-LA (black) (smoke)
-LL (red) (fire)
-V (center)
If you have bad rhythm what to check 1st
Artifact (leads)
12 lead EKG shows us what
Picture of electrical conduction of the heart (depolarization and repolarization)
Horizontal plane vs vertical plane of EKG
Horizontal: time (seconds)
Vertical: voltage (mm)
Time and voltage readings
Big box
Little box
Big box: (15 is 3 seconds/30 is 6 seconds)
-5mm
-0.2sec
Little box:
-1mm
-0.04sec
Isoelectric line
Flat line on the EKG paper that represents:
-the resting membrane potential of cardiac cells
(The line we always want to return to)
How to determine pulse with a EKG
What two ways 3 ways for a regular rhythm
Count # of small squares between 2 R waves
-divide by 1500
Count # of big squares between 2 R waves
-divide by 300
Count # of R waves in 6 second strip
-multiply by 10
How to determine pulse with a EKG
Irregular rhythms
Count # of R waves in a 6 second strip strip
-multiply by 10
(Can also be used for regular rhythm)
P wave
What is happening
How long do we want it
Atrial depolarization
Longer than 0.20 seconds-conduction delayed
P wave
4 types and what they mean
Peaked P wave:
-right atrial hypertrophy
Inverted P waves:
-SA node not the pacemaker
Varying P wave:
-impulse origin varies
Missing P wave:
-junctional or AV block rhythm
PRI (PR interval)
What is it
What is measured
Duration
Beginning of atrial depolarization (contraction)
To beginning of ventricular depolarization
Measures (start of P waves to QRS)
Duration: 0.12-0.20
PRI (PR interval)
Variations
Short PRI:
-SA node not the pacemaker
Prolonged PRI:
-impulse delay thru AV node (heart block)
QRS complex
What is it
Duration
What needs to be present
What does S do
Ventricular depolarization (contraction)
Duration: 0.06-0.10 (as long as its less than 0.12)
R must be present
(Q may be absent)
S goes below isoelectric line
QRS complex
Prolonged QRS >0.12
Causes
BBB
VT
PVC (premature ventricular contraction)
ST segment
Represents what
Should be on what
End of ventricular depolarization (contraction)
Beginning of ventricular repolarization (relax)
(Extends from end of S waves to beginning of T wave)
Whole thing should be on isoelectric line
ST segment variations
What to do if there is variation
ST elevation: 1mm or above line
myocardial injury
ST depression
myocardial ischemia
IF ST SEGMENT VARIATION IS NOTED AND IS NEW
-order a 12-lead and contact HCP
STEMI vs NSTEMI
Do we need one lead or more
STEMI (ST elevated MI)
NSTEMI (non-ST elevated MI)
We need to evaluate more than one lead
Tx: contact provider for 12-lead ekg
T wave
Represents
Amplitude needed
Ventricular reploarization
Amplitude (0.5-1 or less)
-first one to measure amplitude-
T wave variations
Peaked T wave (EXAM)
-hyperkalemia
Notched t wave (pericarditis)
Inverted T wave (ischemia)
-give O2
