EKG (exam 3) Flashcards
positive towards a positive
upward deflection
positive towards a negative
downward deflection
when is the wave the biggest
when it’s traveling parallel to the lead
where is lead one?
L UE
which lead is always the ground lead
R leg
how do the signals travel?
lead 1: LA + and RA- (pos. deflection)
lead 2: LL + and RA- (big pos. deflection)
lead 3: LL + and LA- (pos. deflection)
what are the augmented leads?
AVR, AVF, AVL
what are the precordial leads?
V1-V6
where are the precordial leads placed?
v1= R side, 4th int. space v2=L side, 4th int. space v3=halfway tween 2 & 3 v4= 5th int. space at midclavicular line v5=5th int. space at ant. axillary line v6=5th int. space at midaxillary line
R gets bigger going from where to where?
V1 towards V6
S gets bigger going which direction?
V6–> V1
why is the T wave positive if it’s repolarizing?
bc the heart repolarizes backwards, neg. current towards a neg. electrode= T wave
what leads monitor the lateral heart?
limb lead 1
AVL
V5
V6
what leads monitor anterior heart?
V3,V4
what leads monitor the septal heart?
V1,V2
what leads monitor the inferior heart
Limb leads 1 and 2
AVf
each tiny box is how many volts?
0.1 mv, so 10 tinies= 1mV
each tiny box is how many seconds?
0.04 sec.
one large box= how many tiny boxes
5 tinies in one biggie, so each biggie= 0.2 sec
how do u quickly count a regular rate?
start, 300, 150, 100, 75, 60, 50
6 sec method of counting
count how many R-R cycles in a 6 sec. strip then mult. by 10
the hash marks on a strip are how far apart?
3 sec.
How to determine hear deviations?
1) find the most isoelectric lead
2) find that lead on the graph
3) what is perpendicular to it?
4) is the perpendicular lead u just found + or - on the EKG
5) Go to where its negative on the graph
+90 to -30
normal
-30 to -90
L axis dev.
-90 to 180
extreme/unclear
180 to +90
R axis dev.
Causes of Extreme axis deviation:
H- hyperkalemia E- emphysema L-lead transposition P- pace makers V- V tach
causes of L axis deviation
H- hyperkalemia E- emphysema L- left ant. hemiblock P- pacemaker Q- Q waves of inf. MI
causes of R axis deviation
R-right- R vent. hypertro. N-now-norm in kids/ tall thin adults C- cows- chronic lung disease A-are- ant. lat MI L-leaping- left pos. hemiblock P-playfully- PE A-above- atrial septal defect V-vehicles- vent. septal defect
how long should a p wave be?
no longer than .11 sec, so not more than 3 little boxes
how tall should a p wave be?
not taller than 3mm and not notched or peaked
where is p wave positive?
leads 1,2, aVF and V4-6
PR interval should be how long?
.12-.20 sec (3-5 little boxes, not bigger than one large box)
what condition causes a PR interval to be too long
first degree AV block
when is a PR segment elevated?
atrial infarct or pericarditis
what does the QRS complex reflect?
depolarization of ventricles
Q wave should be how long?
.04 sec
what is a Q wave represent? is it pos. or neg?
septal depolarization, its a small neg wave, first downward defelction preceding the R wave
Q waves are present where?
lead 1, aVL, V5, V6
what does it mean if a Q wave i sdeeper than 1/3 of the QRS complex?
MI!
QRS complex should be how long?
.07-.11 sec(bigger than one small box but not bigger than one big box)
best leads to look at for QRS complex
1 and V1
R wave represents what?
ventricular depolarization
when does an R wave get bigger?
bigger and bigger from V1-V6, biggest in V5,V6, if its not may mean MI or injury to ant. L vent.
ST segment represents what?
vent. cells are in absolute refractory
what if an ST segment is elevated?
BAD! MI!
what if an ST segment is depressed?
ischemia
T wave
repolarization of vents- should have same polarity as Ventricles!
quick and dirty axis assessment
is limb lead 1 upright? is aVF upright? then its normal
normal cardiac cycle lasts how long?
apprx. 0.9 sec. at 67 bpm
atrial kick?
final push to get all blood out, responsible for about 20% of filling volume
what happens to the atrial kick as ppl get older?
it gets weaker, blood vol. getting to vents= dec.
lub sound
closing of AV valves “s1” sound
dub sound
closing of semilunar valves (aortic and pulmonary), s2 sound
which is the pacemaker cell?
SA node
what calms down the heart?
parasympathetic NS, vagus nerve, through the SA node
what speeds the heart up?
sympathetic NS, catacholamines
what is the body’s ideal Q?
5-5.2 L/min @ rest, up to 20 L/min
5 main duties of the CV system?
deliver O2 remove CO2 transport nutrients and hormones maintenence, fluid balance and pH prevention- remove LDLs
what is a max RER according to ACSM
1.09- 1.15 (remember 1 or greater means ur in anaerobic mode)
what is a max effort RER according to AHA
1.10
what is pre-load?
amnt of pressure on heart during EDV
what is afterload?
amnt of resistance the heart feels as it pumps blood into the periphery–> CAD, HTN, pulm HTN = afterload will be greater
does Q at submax change with exercise training?
no, only at max efforts
norm sV
100-200 ml/beat
does SV change at submax with training?
YES!
does max and submax HR change with training?
submax= yes, decreases with same workload
max HR= no, thats pretty much fixed
how long do u give someone’s heart rate to come back down to baseline before you seek medical help
10 mins
what is VO2 max a measure of?
how well ur heart, mm and lungs are working together, do u get enough o2 in, then does ur heart pump well enough to profuse properly and do ur mm use it properly
VO2 formula
SVxHRx(aVO2 diff)
how does VO2 change with training?
at submax= decreased
at max= increased
how does training change blood volume?
increases it, however, plasma inc. more than RBCs do wo the hematocrit actually dec. with training
