Cardiology/EKG Flashcards
atrioventricular valves
- tricuspid valve- RA -> LV
- mitral (bicuspid) valve- LA -> LV
semilunar valves
- aortic valve- leaving LV -> atria
- pulmonic valve- RV -> pulmonary artery
chordae tendonae
- prevents backflow
- stops valve from over extending back into the atria
- papillary muscles
anatomy of the peripheral circulation
- blood leaving heart is leaving via artery
- blood coming back to heart is via veins
artery layers
- tunica intima- smooth inner layer
- tunica media- middle
- tunica adventitia- outer layer
capillaries
-one wall to allow for easy passage of gas
diastole
- whats happening when the heart is filling up
- at rest
- not contracting
- blood pressure thats left over the arteries after the heart contracted
- pressure the heart has to overcome to get blood back into circulation
systole
- when the heart is contracting
- left ventricle
ejection fraction
- how much the left ventricle is pumping out
- high ejection fraction is good
stroke volume
-the volume of blood being ejected
preload
- need to have good preload for good stroke volume
- amount of blood going back to the heart
- you need a lot to fill the heart back up
- whats coming back to the heart
- locking preload will minimize stroke volume
afterload
- pressure left in the system that the left ventricle has to overcome
- high number -> bad
- makes it harder for blood to get back into circulation
arterial system
- arteries
- arterioles
- capillaries
venous system
- capillaries
- venules
- veins
cardiac output
-stroke volume x heart rate
sympathetic
- things are going to increase
- increase circulation
- heart rate, contraction, and dromotropy increases with sympathetic stimulation to the heart
- chronotropy- heart rate
- inotropy- force of contraction
- dromotropy- makes impulse easier to be conducted through the heart -> initiates heart beats
cardiac depolarization
-1. resting potential- sodium outside, potassium inside
-2. action potential
-3. replorization
-potassium leaves and sodium is going in during depolarization
-potassium enters and sodium is leaving during repolarization -> back to polarized ready state
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cardiac conductive system: automaticity
-can create its own impulse
electrocardiogram
- sees with direction impulses are traveling
- positive (upward) and negative (downward) impulses
- summary of electrical impulses
isoelectric line
- flat line
- no electric activity
artifact
- things that get in the way of a ECG reading
- muscle tremors
- shivering
- patient movement
- loose electrodes
- 60-hertz interference
- machine malfunction
ECG leads: bipolar (limb)
- einthovens triangle
- Leads 1, 2, 3
- moves towards the positive lead -> positive deflection (line goes up)
- primary lead we look at is lead 2 -> goes diagonally down (important bc heart contracts top to bottom)
- negative sticky (lead 1) on the top right and negative on the bottom left leg -> this is lead 2
- lead 1- top right (neg) to top left (positive)
- lead 3- top left (pos) to bottom left leg (neg) - not a good reading
augmented (unipolar)
-aVR, aVL, aVF
precordial
-V1-V6
routine monitoring with a single lead
- looks at one lead
- commonly lead 2
- allows a good view
- information shown:
- rate and regularity
- time to conduct an impulse
what you cannot see:
- identify/locate an infarct
- identify axis deviation or chamber enlargement
- identify right to left differences in conduction
- show the quality or presence of pumping action
ECG paper
- speed
- amplitude and deflection
- calibration
- 1 small box- .04 seconds
- 1 big box- 5 little boxes wide = .2 sec
- 5 big boxes- 1 second
- 10 little boxes (2 big boxes) make up 1 millivolt
relationship of the ECG electrical events in the heart
- p wave
- QRS complex
- T wave
- U wave
p wave
- atrial depolarization
- normal, upright, only before each QRS complex
QRS complex
- ventricular depolarization
- ventricular contracting from bottom up
- spike
- atria is repolarizing
- normal, duration of .08-.12 seconds
U wave
- ventricles repolarizing
- extra wave sometimes
T wave
-ventricular repolarization
P-R interval
- impulse delay at AV junction
- .12-.2 seconds
AV junction
- initiates impulse if SA doesnt fire
- back up plan
PR interval (PRI) or PQ interval (PQI)
- .12-.2 seconds
- beginning of p wave till beginning of QRS complex
- 3-5 little boxes
QRS interval
- .08-.12
- width of the QRS complex
absolute refractory periods
- one of the ventricles gets to fire again
- after QRS, not until the peak of T wave are they ready to contract again
- no fire time
- absolute refractory period
relative refractory period
- ventricular filbrilation
- we dont like for things to land in this period
- in this peroid they are kind of ready to fire but it takes a lot
interpretation of rhythm strips
- consistent and analytical
- memorize the rules for each dysrhythmia
- analyze a given rhythm strip according to a specific format
- compare your analysis to the rules for each dysrhythmia
- identify the dysrhythmia by its similarity to establish rules
5 step procdure
- analyze the rate
- analyze rhythm
- analyze p waves
- analyze PR interval
- analyze QRS complex
analyzing rate
- 6 second method- count the complexes in 6 seconds and multiple by 10
- good tp use for irregular rhythms
analyzing regular rhythm ECG
- count the number of big boxes between complexes
- 300 divided by number of boxes between complexes
- only works for regular ECGs because the complexes are equally apart from each other
regularly irregular
- pattern in the irregularity
- two together one apart - repeating
irregularly irregular
- no pattern
- random
occasionally irregular
- blips in the ECG
- arrhythmias
analyzing p waves
- are the p waves present
- are the p waves regular
- 1:1 relationship with p waves and QRS complex
- are the p waves upright (normal) or inverted
- do all the p waves look alike
analyzing the QRS complex
- do all the QRS complexes look alike
- what is the QRS duration
regular sinus rhythm
-6-100 beat/min
leads
- lead I- positive electrode on LA and the negative electrode on the RA
- RL serves as a reference electrode for recording purposes
- lead II- positive electrode is on the LL and the negative electrode RA
- Lead III has the positive electrode on LL and the negative electrode LA
